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Fisheries impacts on marine ecosystems and biological diversity : the role for marine protected areas… Wallace, S. Scott 1999

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F i s h e r i e s I m p a c t s o n M a r i n e E c o s y s t e m s a n d B i o l o g i c a l D i v e r s i t y : T h e R o l e f o r M a r i n e P r o t e c t e d A r e a s i n B r i t i s h C o l u m b i a . by S. Scott Wallace B.Sc. (Hons.) Queen's University, Kingston, 1991 M . M . M . Dalhousie University, Halifax, 1993 A THESIS S U B M I T T E D IN P A R T I A L F U L F I L M E N T OF T H E R E Q U I R E M E N T S FOR T H E D E G R E E OF D O C T O R OF P H I L O S O P H Y in T H E F A C U L T Y OF G R A D U A T E STUDIES (Resource Management and Environmental Studies) We accept this thesis as conforming to the required standard The University of British Columbia 1999 © S. Scott Wallace In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of n£>c«sc£ /^^oj-O^^/-t £>, upturn *iL/ S-^ecAj The University of British Columbia Vancouver, Canada DE-6 (2/88) Abstract This research examines the impacts of fishing on marine ecosystems and marine biodiversity in British Columbia, Canada and examines the role of marine protected areas (MPAs) in mitigating these impacts. A variety of ecological approaches are taken to understand fisheries impacts. First, a catch database of historical landings in British Columbia was assembled covering the years between 1875 and 1996 for all species in all fisheries. It was shown that combined landings of all species have been very high for nearly 80 years, but the composition has changed dramatically primarily due to overfishing. Using the catch database, an assessment of large-scale ecosystem changes from overfishing was determined by a mean trophic level analysis and an estimation of marine primary productivity requirements to sustain the fishery. The mean trophic level of the catches in British Columbia's fisheries has steadily declined since the 1950's indicating an erosion of ecosystem structure from the systematic removal of long-lived, non-migratory, high trophic level species. Primary productivity requirements of the fishery as a whole has remained very high, although the relative contributions of each species group has changed significantly demonstrating fishing impacts on biodiversity and ecosystem structure. Two ecosystem models of the Strait of Georgia, one of present day and the other of 100 years ago, were developed using Ecopath software to demonstrate fishing induced changes at an ecosystem level. Results show that many species have been depleted to a point where they no longer have a functional ecosystem role in the Strait. Overall, the ecosystem is considered to be quite mature due to a substitution of higher valued commercial fish, to low value under-exploited fish occupying the same trophic niche. This was demonstrated by a trophic level analysis which indicated that virtually no high trophic level, resident species are found in present day fisheries landings. Marine protected areas were examined as tools to rebuild ecosystem structure by performing field-based studies on two severely depleted species found in the Strait, northern abalone (Haliotis kamtschatkana) and lingcod (Ophiodon elongatus). It was shown that populations of both species respond positively to the absence of human harvest in a defined area. These findings suggest that other species, and entire ecosystems may benefit from the creation of M P As. It was concluded that fisheries have had enormous impacts on marine ecosystem structure in British Columbia waters and that M P As offer one tool to restore, protect, and conserve marine resources. iii T a b l e o f Contents Abstract i i Table of Contents i i i List of Tables vi i i List of Figures x i Acknowledgments xiv" Chapter 1 Introduction Introduction 1 Impacts on Marine Ecosystems and Biodiversity from Exploitation of Living Marine Resources 2 Marine Ecosystem Modelling 4 Marine Protected Areas 4 Comparison of Terrestrial and Marine Reserves 6 Status of Marine Protected Areas in British Columbia 8 Research Objectives 8 Outline of Chapters in Thesis 9 Chapter 2 Catch Database of British Columbia's Fisheries between 1875 and 1997 INTRODUCTION 11 Background 11 Purpose of Database 13 S T R U C T U R E A N D SOURCES OF I N F O R M A T I O N FOR D A T A B A S E 13 Categories of Fisheries in Database 13 Species Groups Included in Database 14 Sources of Landing Information 14 Wet Weight Conversions 17 Missing Values 17 S U M M A R Y OF FISHERIES 18 Commercial 18 1875-1899 18 1900-1925 21 1926-1950 21 1951-1975 22 1976-Present 22 Aboriginal 23 Recreational 25 Marine Mammals 25 Bycatch 26 Discard Ratio of Targeted Species 27 iv Bycatch Ratio for Non-targeted Species 28 International and Joint Venture Fisheries 29 Designation of Species into Larger Groups 30 Sources of Error 31 Chapter 3 Patterns of Human Appropriat ion of Mar ine Pr imary Production and Biodiversity Loss in Bri t ish Columbia I N T R O D U C T I O N 32 PREMISES 33 M E T H O D S 35 Calculation of Primary Production Requirements 3 5 Calculation of Mean Trophic Levels 36 Correction for Resident Salmon 37 Calculation of Marine Footprint 3 7 A N A L Y S E S A N D R E S U L T S 38 Mean Trophic Level of Fishery 38 Mean Trophic Level of Non-migratory Species Groups 41 Primary Production Requirements and Ecological Footprint 41 DISCUSSION 43 Chapter 4 Ecosystem Models of the Strait of Georgia INTRODUCTION 47 Physical Description of the Strait of Georgia 47 Human Impact to the Marine Ecosystem 47 E C O P A T H A P P R O A C H TO E C O S Y S T E M - B A S E D M A N A G E M E N T 49 How Ecopath works 49 Existing Strait of Georgia Ecopath Models 50 Assumptions, Inputs, and Outputs of the Models 50 P R E S E N T D A Y M O D E L 50 Primary producers 50 Zooplankton 51 Benthic invertebrates 51 Birds 52 Herring 52 Small pelagics 53 Eulachon 53 Miscellaneous demersal fish 53 Salmon 53 Hake 54 Dogfish 54 Halibut 54 Lampreys 55 Lingcod 55 Mammals 55 Diet Compositions 55 P A S T M O D E L OF T H E STRAIT OF G E O R G I A 5 8 V Sources of Information for Past Model 58 Input and Output Parameters of Functional Groups for the Past Model 60 Primary producers 60 Benthic invertebrates 60 Birds 60 Herring 60 Eulachon • 61 Small pelagics 62 Miscellaneous demersal fishes 62 Salmon 63 Hake 63 Dogfish 64 Halibut 64 Lampreys 64 Lingcod 64 Sturgeon 65 Mammals 65 Aboriginal Catches 65 B A L A N C I N G T H E M O D E L S 67 Present Day Model 67 Past Model 67 Changes in Diet Compositions 67 Summary Statistics of the Two Ecosystems 68 R E S U L T S A N D DISCUSSION 72 Comparison of the Past and Present Day Ecosystems 72 The Whole 72 Ecosystem Maturity of the Strait of Georgia Ecosystem 72 Changes to the Parts 74 Dynamic Simulations using Ecosim 74 Changes in the Commercial Fishery as a Result of a Shifting Ecosystem 78 Mean Trophic Level of the Strait's Commercial Fishery 79 Restoration of the Strait of Georgia Ecosystem 81 Incorporating Economic and Social Values into the Models 83 Economic Analysis 83 Social Indices 84 C O N C L U S I O N 85 Chapter 5 Non-intentional Marine Reserves I N T R O D U C T I O N 86 Non-Intentional Reserves: Anecdotal Information 86 Vancouver Harbour: A de facto reserve? 91 Chapter 6 Evaluating the Effects of Three Forms of Marine Reserve on Northern Abalone Populations I N T R O D U C T I O N 93 Fisheries History 93 Life History Characteristics 94 VI Description of Abalone Reserves 95 M E T H O D S 96 R E S U L T S 99 DISCUSSION 101 What is a natural abalone population? 103 C O N C L U S I O N 104 Chapter 7 The Role of Marine Reserves in the Conservation of Rocky Reef Fishes in British Columbia: The Use of Lingcod (Ophiodon elongatus) as an Indicator. INTRODUCTION 105 Fisheries History 106 Life History Information 107 Role of Lingcod in the Ecosystem 109 Rationale, Goals, and Components of the Study 109 Introduction to Howe Sound 109 Description of Study Sites 110 Reserve Sites 111 Exploited Sites 112 M E T H O D S 112 Demographic Study 112 Age Structure Data 113 Abundance Data 113 Egg mass surveys 114 Tagging Study 114 Equipment 115 A N A L Y S I S A N D R E S U L T S 117 Comparison of Encounter Rates Between Years and Geographic Location 117 Comparison of Size between Years and Location 117 Fishing Pressure Impacts 120 Demographic Study by Habitat Type 122 Egg Mass Survey 122 Tagging Study 123 DISCUSSION 125 Abundance 126 Spawning Potential 129 Humans, Seals, or Climate? 129 Limitations of the Study 130 Poaching 131 Improving the Current System of No-Take Marine Reserves 132 Incidental Observations 132 Fisheries or B iodiversity 13 4 C O N C L U S I O N 134 Chapter 8 Summary Summary of Ecosystem Models 136 Summary of Marine Reserve Case Studies 138 Marine Reserves as an Ecological Approach to Management 140 Future of Marine Reserves in British Columbia Literature Cited Appendices Chapter 2 Commercial fishery catches Aboriginal fishery catches Recreational fishery catches Marine mammal landings Bycatch International and joint venture catches Chapter 3 Trophic levels of bycatch Chapter 4 Ecopath inputs for marine mammals in the Strait of Georgia Value of commercial species between 1995-1997 Chapter 5 Length frequency distributions of dungeness crab populations Chapter 6 Summary of underwater visual censuses Summary of 1998 tagging dives A N O V A summary for lingcod encounter rates Summary of tagging recapture events Chapter 7 Benefits of marine reserves viii L i s t of Tab les Table 2.1 Breakdown of species groups found in each category of fishery represented in the catch database of British Columbia between 1875-1997. 14 Table 2.2 Sources of landing data for species groups in the commercial (C), recreational (R), aboriginal (A), marine mammal (M), international (I), joint (J), and incidental (B) fisheries in British Columbia from 1875-1997. 15 Table 2.3 Values used to convert reported quantities of species into metric fresh weight equivalents and source of information. 17 Table 2.4 Ranking of the ten most important species in British Columbia's commercial fisheries (including marine mammals) by weight during 25 year intervals between 1875-1997. 19 Table 2.5 Catch of discarded fish by species group in the ' A ' licensed commercial trawl fishery between 1996-1998. 27 Table 2.6 Summary information on by-catch of non-targeted species in British Columbia's commercial trawl fishery between 1996-1998 based on observer data. 28 Table 2.7 Summary of observer reports of catches in the joint fishery for the years of 1996 and 1997. 29 Table 2.8 Species composition of the six fisheries classifications 30 Table 4.1 Parameter estimates of functional groups in the Present day model of the Strait of Georgia arranged in order of ascending trophic level. 51 Table 4.2 Average commercial catch in the Strait of Georgia of various species groups represented in the present model. 52 Table 4.3 Diet matrix for species groups in the Present day model of the Strait. 56 Table 4.4 Summary of input and output parameters of the balanced Past model of the Strait of Georgia. 61 Table 4.5 Diet matrix for species groups in the Past model of the Strait 69 Table 4.6 Summary of changes in biomass of species groups expressed as a percentage change from the Present to the Past. 71 Table 4.7 Summary of ecosystem attributes used to compare the Past and Present models of the Strait of Georgia. Table 6.1 Comparison of abalone abundance and size in three forms of reserve and 72 ix historical government data. 99 Table 6.2 Relative fecundity of abalone in study sites based on abalone per minute diving and mean fecundity. 100 Table 7.1 Summary of information obtained in each component of the research between 1996-1998. 112 Table 7.2 Survey effort (hours), number of lingcod encountered (n), and size of lingcod by year and general location. 118 Table 7.3 Summary of spawning surveys by year, location, underwater visual census effort, and size frequencies. 123 Table 7.4 Summary of tagging, resighting, and ranking of lingcod resident behaviour by site. 124 Table 7.5 Summary of the number and mean size (L) of lingcod at time of tagging, during resighting events, and total by survey location recorded during 1998 under-water visual census surveys. 124 Appendix 2.1 Commercial landings (t) of all species from 1875-1997. 165 Appendix 2.2 Aboriginal landings (t) between 1875 and 1996. 174 Appendix 2.3 Recreational landings (t) between 1911 and 1996. 176 Appendix 2.4 Marine mammal landings reported as numbers of kills in British Columbia from 1877-1968. 178 Appendix 2.5 Summary of bycatch in the commercial ' A ' licensed trawl fisheries between 1996 and 1998 sorted from highest to lowest. 180 Appendix 2.6 International and Joint Venture fisheries landings (t) from 1965 to 1996. 182 Appendix 3.1 Mean trophic level of incidentally caught species. 183 Appendix 4.1 Ecopath inputs for marine mammals in the Strait of Georgia. 184 Appendix 4.2 Average wholesale value and landed value for landings of British Columbia's commercial fisheries for the years 1995-1997. 185 Appendix 7.1a Summary of all underwater visual census surveys in 1996. 187 Appendix 7.1b Summary of all underwater visual census surveys in 1997. 188 Appendix 7. l c Summary of all underwater visual census surveys in 1998. 190 X Appendix 7.2 Summary of 1998 tagging dives by date, location, bottom time, total number of lingcod tagged during diver, tag numbers, tag colour and diver. 193 Appendix 7.4 Summary of tagging recapture events in 1998. 195 xi L i s t o f F igu res Figure 2.1 Graph of catch contributions by fishery type represented as a decadal average from 1875-1997. 18 Figure 2.2 Catch histories of major species in British Columbia from 1875-1996. 21 Figure 2.3 Commercial catch of all species (including marine mammals and incidental catch) from 1875-1997. 22 Figure 2.4 Catch contributions of major groups represented as a decadal means from 1875-1997. 30 Figure 3.1 A conceptual representation of the relationship between biodiversity (S) and energy (E n p p ) . 34 Figure 3.2 (A) Fisheries catch and, (B) mean trophic level trend in British Columbia's fisheries from 1875-1997. 40 Figure 3.3 Mean trophic level of non-migratory species (including by-catch) in British Columbia's fisheries from 1875-1997 with and without herring. 41 Figure 3.4 Primary productivity requirement (PPRj of British Columbia's fisheries by major group averaged out by decade. 42 Figure 3.5 Primary productivity requirements of the British Columbia's catches (PPR) and percentage (APPy) of the continental shelf area required to support these catches from 1875 to 1997. 42 Figure 3.6 Percentage of total primary production requirements derived from species resident to Canadian waters at all stages of their life cycle. 44 Figure 3.7 Plot of primary productivity required and mean trophic level of British Columbia's fisheries from 1960-1997. 45 Figure 4.1 Map of the Strait of Georgia ecosystem with place names mentioned in the text. 48 Figure 4.2 Box model of the present day Strait showing the pathways of energy flow between the 25 functional groups. 57 Figure 4.3 Box model of the Past ecosystem of the Strait of Georgia. 70 Figure 4.4 Simulations of ecosystem effects of fisheries exploitation on A) baleen whales, B) yelloweye rockfish, C) dogfish, and D) herring. 76 xii Figure 4.5 Simulation of ecosystem impacts of a multi-species fishery in the Strait of Georgia over a 100 year period. 78 Figure 4.6 Mean trophic levels (left) of the Strait of Georgia commercial fishery between 1951 and 1996 and landings (right). 80 Figure 4.7 Percentage of commercial catch in the Strait of Georgia comprised of resident species between 1951 and 1996. 81 Figure 4.8 Landed value of catches of resident species from 1951 -1996 scaled to average prices of resident fish between 1995-1997. 84 Figure 5.1 Mean carapace lengths (mm) of dungeness crab in Vancouver Harbour (closed to fishing) and Indian Arm before and after each fishing season. 91 Figure 6.1 Commercial landings (t) of northern abalone in British Columbia, 1951-1990. 93 Figure 6.2 Northern abalone survey sites along the southern coast of Vancouver Island. 98 Figure 6.3 Frequency distributions of abalone in survey sites and government data representing percentage of abalone in each size class. 100 Figure 7.1 Lingcod landings in the Strait of Georgia and all of British Columbia between 1951 and 1997. 107 Figure 7.2. Estimated recreational lingcod landings in the Strait of Georgia (1980-1993). 107 Figure 7.3 Map of Howe Sound showing study sites. 110 Figure 7.4 Lingcod tagging procedure (not to scale). 116 Figure 7.5 Lingcod encounter rates (A) between years and all locations and (B) between locations and year. 117 Figure 7.6 Comparison of lingcod size between locations: (A) 1996 and 1997 size as percentage of lingcod greater than 3 years old; (B) 1998 comparisons using mean lengths. 118 Figure 7.7 Length frequency distributions of lingcod. 120 Figure 7.8 Comparison of (A) lingcod encounters and (B) mean size in areas exposed to low, medium, and high fishing pressures (excluding two reserves). 121 Figure 7.9 Mean length of lingcod in sites with shallow (0-15 m), moderate (15-35 m), and deep (>35 m) bedrock. 122 Figure 7.10 Landings of lingcod in the Strait of Georgia broken down into DFO statistical regions. XIII 126 Figures in Appendices Appendix 2.3 Estimated recreational landings of salmon (chinook and coho) prior to 1950 based on human population growth in British Columbia and recorded landings. 177 Appendix 5.1 Length frequency distributions of dungeness crab populations in Vancouver Harbour (Reserve) and Indian Arm (Non-reserve) before (June) and after (October) the crab season between 1994 and 1997. 186 XIV A c k n o w l e d g m e n t s I am thankful to many people who have provided assistance and support over the duration of this research. I would like to first thank my supervisory committee. Special thanks to Dr. Jeff Marliave who provided me with numerous opportunities throughout this research and was very helpful in providing feedback. Furthermore, I would like to thank Jeff for arranging funding, through the Howe Sound Research and Conservation Group, which provided the means for me to eat food other than rice and cabbage. I would like to thank Dr. Daniel Pauly for his creative insights and enthusiasm with the research, but also for recognizing my "tarantoola legs". Thanks to Dr. Michael Hawkes for his continuous interest and feedback on my work. I would like to thank Richard Paisley for being interested in marine protected areas long before the rest of the academic and government community. Richard's work was instrumental in getting marine conservation on the provincial political agenda and hence provided me with the opportunity to conduct research during an exciting period. Many thanks to Dr. Les Lavkulich who provided continuous academic and personal support throughout the dissertation. I would like to thank the agencies and individuals who provided financial and logistical support to conduct my research; Vancouver Aquarium Marine Science Centre, Department of Fisheries and Oceans, Parks Canada, Ministry of Environment, Lands and Parks, Mountain Equipment Co-op, and Pearson College. Field based studies would not have been possible without the generous financial and logistical support of Rudy North and Don Garnett. I would like to thank numerous staff and volunteers at the Vancouver Aquarium Marine Science Centre; Danny Kent, Jeremy Heywood, Aydan Peterson, and Steve Martell for being a reliable dive partner and co-researcher. Thanks to the many volunteers that helped with data collection. Donna Gibbs deserves special recognition for volunteering over 20 days during this research; also Jennifer Norton, Jean-Paul Danko, Nathan Taylor, and Steve Church. Thank-you to Dr. Jane Watson who provided assistance during the early stages of my dissertation by providing ideas and guidance. On a personal note I would like to thank Debbie Lacroix who provided valuable personal support and numerous hours of volunteer diving. I would like to thank L i l l y Wilkinson, who showed interest in my research above and beyond the call of grandmotherly duty. Many thanks to my parents Hugh and Evie Wallace for relentless interest and support. Thanks to Glenda Wallace and Mike Maslechko for caloric support. Thanks to fellow students Peter Tyedmers and Gary Kofinas for acting as sounding boards for ideas. Chapter 1 Introduction to Fisheries Impacts on Marine Biodiversity and Marine Protected Areas Introduction Humans now dominate most of the world's ecosystems, marine and terrestrial (Vitousek 1997). From the onset of this dissertation, September 1995, world population has increased by approximately 500 million people, half of whom have settled within 100 km of a marine coastline.1 Along with the growth comes an inevitable increase of pressure on already heavily impacted coastal ecosystems. Humans are undoubtedly a powerful ecological force threatening marine biological diversity from a variety of activities. In this thesis I examine the impacts from human exploitation of living marine resources on ecosystems and biological diversity, and assess the role of marine protected areas in mitigating these impacts in British Columbia (B.C.). 2 I explore these impacts using a variety of methods and analyses, including ecosystem models, historical information, empirical field studies, and qualitative evidence. Globally it has been shown that human activities can directly or indirectly affect biodiversity in marine ecosystems (Aronson 1990, Upton 1992, Hammer et al. 1993, Norse 1993, Norse 1995, National Research Council 1995, 1999, Boehlert 1996). Direct threats to marine biodiversity include exploitation of fishes, invertebrates, and seaweeds; and alteration of habitat (by trampling, trawling, dredging, drilling, aquaculture, building and dumping) (Watling and Norse 1998). Indirect threats include pollution, noise, heat, and chemical (both toxins and nutrients); biological invasions (Carlton and Geller 1993, McCarthy and Khambaty 1994, Carlton and Hodder 1995); and global threats such as climate change and increases in ultraviolet-B radiation (Smith et al. 1992, Roemmich and McGowan 1995). Globally, human exploitation of living marine resources is considered to be the single greatest threat to marine biodiversity (National Research Council 1995). 1 www.popexpo.net, web site visited March 9, 1999. 2 Biological diversity or biodiversity is here broken down into three hierarchical levels of biological organization: genetic, species, and ecosystem diversity. Genetic diversity is the collection of genes within and among populations of a species; species diversity is the number of species in a higher taxon or a particular place; ecosystem diversity is the functional relationships between biological communities and their physical settings, characterized by differences in species composition, physical structure, and function (Norse 1993). 1 Impacts on Marine Ecosystems and Biodiversity from Exploitation of Living Marine Resources In 1376, concern over destruction of sea bed vegetation due to trawling was brought to England's House of Commons (Graham 1955). Even in the scientific literature, concern about fishing impacts on marine ecosystems is not new (Petersen 1903, Garstang 1903, Russell 1942). Empirical quantitative studies showing the effects of fishing on fish populations have been conducted for nearly 100 years (Atkinson 1908). Concern in recent years is driven by statistics that indicate that of the world's 15 major fishing regions, the catch in all but two has fallen; in four, the catch has shrunk by more than 30 percent as a result of over-exploitation (Weber 1994). There are no new fishing areas to exploit, and to maintain global catches at current level requires fishing species at increasingly lower trophic levels, resulting in a major shift in structure of the world's marine ecosystems (Pauly et al. 1998a). World fisheries remove approximately 120 million tons of biomass from the ocean per year, including 27 million tons of bycatch (Alverson et al. 1994, F A O 1997). Eighty five percent of this is comprised of marine fish mass, the other 15% is comprised of freshwater fish, invertebrates, and sea weed (Weber 1994) . When global landings are re-expressed in terms of their primary productivity requirement, it is estimated that world fisheries remove approximately 8% of total aquatic primary production. On continental shelves, where approximately 90% of global catches originate, from 25 to 35 percent of primary production in the ocean is appropriated by humans (Pauly and Christensen 1995). Despite the fact that overfishing of many commercially valuable species has resulted in the demise of numerous fisheries around the world, there is very little specific information about the overall consequences to genetic, species, or ecosystem diversity in most of the affected systems (Hilborn 1990). Nonetheless, there is increasing evidence that biodiversity can be affected by fishing. In a natural (unexploited) ecosystem, life history strategies evolve through natural selection to reflect dominant pressures of the environment, including fluctuations on varied spatial and temporal scales (Adams 1980, Parrish et al. 1981). Fishing increases the rate of mortality on the target population, acting as an agent of directional selection (Wohlfarth 1986). For example, dominant age modes of lightly and heavily exploited populations of ocean perch (Sebastes alutus) off Vancouver Island were 30 and 12 years of age (Leaman 1991). Whether alterations to the age structure reflect changes in genetic diversity in fishes is unknown, but genetic regulation of longevity has been demonstrated in other species (Larsen et al. 1995) . Impacts of fisheries exploitation on mean size and growth rate has also been shown. In pink salmon, for example, a 35 year decline in mean size was associated with removals of larger fish by the commercial fishery (McAllister et al. 1992). Furthermore, selective fishing technologies remove 2 intrinsically faster growing fish (Parma and Deriso 1990), which consequently may alter genetic mechanisms controlling growth rates (Wohlfarfh 1986). Fishing has also been shown to have effects on species level diversity. In unexploited populations, fish assemblages are structured through predation, competition, and morphological adaptations (Britz and Moyle 1993). Fishing (including bycatch) changes the relative abundance of species, thereby altering community structure (Gulland 1987, Botsford et al. 1997). Many examples exist which demonstrate this point: Gulf of Mexico shrimp trawl fishery (Kaiser and Spencer 1995), Barents Sea cod fishery (Hamre 1994), and Georges Bank groundfish fishery (Anthony 1990). Changes in species diversity under fisheries selection will favour species with certain life history characteristics, thereby altering diversity. Impacts on ecosystem diversity, although complex and difficult to isolate, have also been demonstrated. The changes in biomass associated with fisheries exploitation may alter trophic or energy flow pathways with consequences for ecosystem diversity and productivity (Parsons 1992, Dayton et al. 1995, Boehlert 1996) . For example, Walsh (1981) and Jarre et al. (1991) described striking changes in the carbon budget of the Peruvian upwelling coastal ecosystem before and after decreases in the anchoveta population. Pauly (1988) documents indirect effects of fishing on demersal communities in the Gulf of Thailand. Hofman (1990) estimates that 700,000 t of whales are thought to have been removed from the Gulf of Maine during commercial whaling operations. The present day food web in the Gulf of Maine is markedly different than the past ecosystem due to impacts from whaling and other fisheries. The realization that fisheries can have impacts on the flows of energy within an ecosystem indicates the need to take an ecological approach to managing marine resources (Daan and Sissenwine 1991). Although there is not yet a consensus as to what exactly an ecological approach is (Walters et al. 1997) , there is recognition that it involves understanding fisheries impacts on other components of the ecosystem which must be considered for responsible management. It is uncertain as to how the concept wi l l be fully adopted, but for certain a major shift in the way we study and manage marine resources wil l be necessary. An ecosystem approach requires research to investigate the linkages between fisheries and ecosystem impacts and also requires developing a method of management which incorporates as many of these linkages as possible. This thesis uses ecosystem modelling as a research method to better understand the marine ecosystem in question and human impacts on it, and explores the use of marine protected areas as a management tool to base an ecosystem approach. 3 Marine Ecosystem Modelling Evidence of the complexity of food webs in aquatic environments has been demonstrated for a long time (Hardy 1924, Steele 1974). A common approach to understanding and simplifying complex marine ecosystems has been the construction of whole-system budgets of material and energy transactions in an ecosystem (Polovina 1984, Christensen and Pauly 1992). The results of studies using this approach are usually represented as a network of exchanges among the functional components of the community or ecosystem being examined. Because these flows are described in material or energetic units common to any system, ecosystem intercomparison is greatly facilitated in a manner similar to comparative anatomy (Ulanowicz 1986). There are many who consider any ecosystem model to be a simplistic misrepresentation of the true intricacies of nature. However, Ulanowicz (1986) points out that, Leonardo da Vinci sketched the structure of the human body long before the functions of many of the body parts were fully appreciated and certainly before most physiological mechanisms were discovered. Understanding ecosystems even in a simplified form is an advance towards adopting an ecosystem approach to managing the marine environment. Even in simple models, the networks that result are so complex that one wonders i f the information they contain can be meaningfully utilized. Nevertheless, research has shown that network analysis of ecosystems is able to identify major functional components and relationships within and between communities. Models provide useful theoretical testing grounds for ecosystem based management. Because of the inherent complexities of ecosystems, it is unrealistic at this point to have a single ecosystem management technique. In this thesis I wil l attempt to demonstrate that marine protected areas are the most practical tool presently available for studying and understanding ecosystem based management. Marine Protected Areas Human exploitation of living marine resources undoubtedly exerts a profound effect on marine species, communities, and ecosystems. Spatially managing human activities in the marine environment in the form of marine protected areas has been gaining credibility as an ecosystem management tool to control human threats (Agardy 1997, Allison et al. 1998). Since there are many different names given to marine areas with spatial restrictions, this thesis uses the term 'reserve' defined as: 4 • A form of marine protected area which prohibits extractive and disruptive use of biological and physical features in order to maintain fundamental ecological processes consistent with the conservation objective of the protected area. Reserves have been designated in a wide variety of habitats, with a number of designs, and conservation goals (Roberts and Polunin 1991, Rowley 1994, Guenette 1998). Reserves have been broadly distinguished as areas designated for biodiversity conservation (biodiversity reserves) and those for fisheries management and enhancement (fisheries refugia) (Allison et al. 1998). Biodiversity reserves are primarily concerned with threatened species, ecosystems, and habitats, and providing baseline areas with minimal human influence. Fisheries refugia, on the other hand, are primarily concerned with improving yields or more effectively managing commercially important species. The two types of reserves are not mutually exclusive as fisheries are products of functional ecosystems. In both types of reserves the ecological rationale is the same. Both are established to decrease the chances of organisms interfacing with human-created threats. The marine protected area component of this research is concerned with the threat of fisheries to marine biodiversity and to the integrity of marine ecosystems, and therefore is centered on trying to understand ecological changes resulting from spatially removing the influence of human exploitation. Experimental manipulation of species is the cornerstone of empirical ecology. In this thesis, I use reserves as predator exclusion experiments, where the predator is Homo sapiens. Removing humans from marine areas has been shown to have significant ecological effects at the level of the individual and community in terms of species abundance, size, age structure, and diversity (Moreno 1984, Castilla and Duran 1985, Castilla and Bustamante 1989), with reviews in Roberts and Polunin (1991) and Rowley (1994). Most published studies are results of monitoring single species in protected areas over small temporal and spatial scales, usually in areas protected for less than 10 years and in areas less than 10 km 2 . These studies indicate that the ecology of reserve areas often varies significantly from the adjacent exploited area, indicating the potential of reserves to conserve components of marine biodiversity at larger scales. These observed ecological changes suggest that reserves are useful testing grounds for ecosystem-based management. Many ecosystem processes occur at large temporal and spatial scales which is problematic for understanding and adopting an ecosystem approach. The first barrier is that there are no large scale reserves, and it is presently unrealistic to believe that human activities around centres of human settlements will ever be completely excluded from areas at larger scales. Despite this, there are examples where humans have been excluded from large areas. A large closure was non-intentionally put in place 5 in the North Sea as a result of deploying extensive mine fields during World War I. Hardy (1965) explains that, after four and half years' respite the stock of fish had increased enormously and, instead of there being a vast number of small unprofitable fish as in 1914, there were plenty of the very large fish which used to mark the fishery in the early days of the century. World War II allowed for a repeat of this experiment with similar results. Other examples exist from documenting early expansions of fisheries into new geographic areas, where serial depletion indicates that ecosystems or at least components of marine ecosystems are delimited spatially. Marine reserves are the most practical management tool currently available to evaluate the potential of ecosystem-based management. Comparison of Terrestrial and Marine Reserves Reserves have been studied for a long time in the field of terrestrial conservation biology. Marine conservation biology is in its infancy compared to its terrestrial counterpart and therefore it is tempting to draw on developed terrestrial theories. Although a number of concepts are equally applicable to land or water, there are major differences between the two systems in terms of scale and processes which are relevant to marine reserves (Steele 1985). The first difference to consider is the difference between water and air as the primary medium for ecological processes. Oceanographic events influence dispersal and survival of organisms, primary productivity, and human created threats such as pollution and introduced species over spatial scales larger than typically found in terrestrial systems. The basis of marine food webs are typically short-lived, mobile phytoplankton, where on land most primary productivity is in the form of old-lived, sessile trees. Trees also provide the habitat basis for most terrestrial animals and therefore terrestrial reserves, which often focus on forested areas, protect not only the primary energy source for the food web, but also the physical structure providing habitat (i.e., trees). In marine environments, the primary production sources do not typically provide habitat, kelp beds being the one exception. Human impact on terrestrial communities is primarily the consumption or destruction of the primary productivity unit by forestry, agriculture, and development. In the marine realm, human exploitation is directed at higher trophic levels in marine food webs. Species life histories are generally more complex in marine environments, requiring larger areas and more habitat types. Furthermore, patterns of trophic ontogeny in marine systems are much more 6 pronounced (Werner and Gilliam 1984). Top level predators, which structure the ecosystem, are in early life stages prey to species which they later consume as adults. As a result, trophic linkages are much more intricate. The measurement of conservation success in the two systems is different. Terrestrial parks for the most part are concerned with protecting existing key components of a natural ecosystem in an area, whereas in the marine environment, the measure is restoring lost components of a natural ecosystem in an area. This difference is indicated by the marine reserve literature which until recently (Wallace in press) had no examples of reserves that were established prior to a period of intense exploitation. To date there are no 'protected' areas in the marine environment, only rehabilitation areas. As most of the world's marine ecosystems are over-exploited or at best fully exploited, there as of yet are no marine protected areas similar to terrestrial protected areas where large tracts of undisturbed land are protected. The differences described indicate that certain principles of terrestrial conservation biology are unusable. For example, marine reserves do not draw upon, to the same extent, principles of island biogeography (Diamond and May 1981), patch dynamics (Pickett and Thompson 1978), or corridors (Simberloff et al. 1992). Spatial protection in the marine environment does not really exist as it is really volumetric protection which is being achieved. This has important conservation implications as humans tend to think in terms of area, and place areas on maps to define percentages of protection. Despite the differences, there are also many similarities. No protected area is a complete ecosystem. A l l reserves are subject to larger scale processes which influence the dynamics within the boundaries. The boundaries themselves in protected areas, terrestrial and marine, are seldom designated on scientific criteria. Both systems share the political, economic, and social realities of reserve designation. Protected areas, by definition, are designed to limit human access for the well being of biological diversity, which is a disputed value, and hence leads to disputed boundaries. Terrestrial protected areas generally manage for extractive resource activities such as forestry, hunting, mining, and urban development. Marine protected areas aim also to exclude extraction in the form of fishing and habitat destruction but with one important difference. Excluding activities in marine reserves theoretically can provide benefits to the resource users themselves by processes of larval export and emigration (Plan Development Team 1990), management insurance (Lauck et al. 1998), and the protection of biodiversity in which fisheries are embedded (National Research 7 Council 1995). Despite potential benefits from the creation of reserves, jurisdictions have been slow to implement them. Status of Marine Protected Areas in British Columbia The number of marine protected areas in B . C . varies depending on the definition used. By the International Union for the Conservation of Nature's (1988) definition, we have 106 marine protected areas in the province.3 These are categorized as provincial marine parks (69), provincial ecological reserves (25), national parks (3), and others (9), comprised of wildlife management areas, migratory bird sanctuaries, and fisheries closures. O f these, 72 have no restrictions in place to protect any species, 20 protect between 1-5 species, 8 protect 6-10 species, 4 have restrictions to protect 10-15 species, and 2 are completely closed to all fisheries. In total less than 0.1% of B.C. ' s marine waters have complete protection from all fisheries. Clearly the current system is inadequate to protect the biological diversity of B.C. ' s marine waters. Research Objectives The overall aim of this thesis is to determine the role marine reserves may have as tools for ecologically based management of B . C . 's marine environment. This is achieved by using ecosystem models and empirical case studies. The models used in this study have been developed using a variety of historical sources of information in order to place present day conservation into a historical perspective. In other words, the models provide a baseline against which we can compare the present marine ecosystems of B . C . to what they might have been like in the recent past. Empirical case studies were done to illustrate the potential that reserves have in restoring and protecting components of marine ecosystems. A number of smaller objectives are embedded in the overall aim: What has been the historical pattern of human exploitation of marine resources in B.C.? What species have been affected by fisheries impacts? What are the impacts of fishing on ecosystem structure? What species can most benefit from spatial protection? What evidence is available to demonstrate the effects of reserves on ecosystems or species? 3 IUCN definition of marine protected area: "any area of intertidal or subtidal terrain, together with its overlying waters and associated flora and fauna, and historical and cultural features, which has been reserved by legislation to manage and protect part or all of the enclosed environment." 8 r Outline of Chapters in Thesis The first section of this thesis is designed to introduce the ecological role of humans as 'predators' in B.C.'s marine ecosystems and to detail their 'diet composition'. The chapter consists of a fisheries landings database I assembled based on qualitative and quantitative accounts of historical exploitation of all living marine resources in B.C. from pre-contact to present day including bycatch. Exploitation prior to 1873 is described using published historical information. Post 1873 exploitation is quantified using a variety of sources of historical landings. The resultant database is comprised of 122 years of landing data, 48 species groups, and seven categories of fisheries (e.g., commercial, aboriginal, and recreational). I used this data set to perform the ecosystem analyses in Chapter 3. Chapter 3 is an analysis of how B.C. ' s fisheries have impacted marine ecosystem structure and biodiversity, and the implications for sustainability. First, using B.C. ' s fisheries landings described in Chapter 2 and the trophic levels of major species caught as estimated by Ecopath models (see below), a historical trend of trophic impacts of fishing on the ecosystem is presented. Next, the primary productivity required to sustain the fisheries in B .C . over the last 122 years is calculated. The trend in primary productivity requirements is used as a measure to assess the impacts of fishing on marine biodiversity. In Chapter 4,1 present two mass-balance trophic models of one of B.C. 's marine ecosystems, the Strait of Georgia, in order to understand changes at an ecosystem level. One model represents the present day ecosystem and the other represents the ecosystem of the Strait of Georgia as it may have been 100 years ago. Historical information on species abundance, distributions, and commercial fish landings are combined to model the trophic interactions of the past ecosystem. The past ecosystem, represented as a mass-balance Ecopath model, is compared to a present day model. Differences in the two ecosystems due to changes in species composition, abundance, and fisheries are explained. Ecosystem attributes resulting from outputs of the model are compared and used to conduct further analyses (e.g., mean trophic level estimates). Chapters 5 and 6 use empirical case studies to examine the role marine reserves have in conserving biodiversity and rehabilitating components of marine systems. Chapters 5 and 6 use examples and case studies of non-intentional protected areas to give an alternative method to test the effectiveness of marine reserves at different temporal and spatial scales. A case study based on northern abalone (Haliotis kamtschatkana) in waters adjacent to a restricted area is used both to demonstrate the role 9 of non-intentional areas as study sites, and also to show the strengths and weakness of marine reserves. Chapter 7 is a case study to evaluate the role of reserves in protecting rocky reef fish in B . C . The results of a three year monitoring program of marine reserves using lingcod (Ophiodon elongatus) as an indicator species are discussed. Three studies were conducted to assess the effectiveness of marine reserves: (1) a lingcod demographic study; (2) egg mass surveys; and (3) a tagging study. The final chapter, Chapter 7, is a review of the findings of the research with recommendations for management and future research. 10 Chapter 2 Catch Database of British Columbia's Fisheries between 1875 and 1997 I N T R O D U C T I O N Steller's sea cow (Hydrodamalis gigas) was widespread in the North Pacific as recently as 20,000 years ago. By 1741, when Georg Wilhelm Steller first described this animal, it had already been extirpated from essentially all but a small area of marginal habitat in the Commander Islands near Kamtschatka. The decline of the Steller's sea cow cannot be explained by natural enemies or changes in climate. Due to the ease with which these animals could be approached and harpooned, it has been suggested that early humans on the West coast of North America hunted these animals to near extinction (Domning 1972). By 1768 the remainder of the population was hunted to extinction by European fur traders (Steineger 1886). The sea cow, being the only large animal known to eat macro-algae, undoubtedly played an important ecological role in structuring nearshore kelp forest communities on what is now British Columbia's coast (Pitcher 1998a). Over-exploitation and the ensuing scarcity of ecological knowledge resulting from the event does not apply only to historical extinction episodes. Even for modem-day fisheries there is a lack of evidence indicating how large-scale removal of marine life alters the ecological community structure in which they are embedded. In this chapter, a historical catch database of British Columbia's fisheries is presented. The database is a compilation of all landings in British Columbia of all fisheries since 1875. The information assembled is then used to perform subsequent ecosystem-based analyses (Chapter 3), providing insight into how long-term industrial fisheries may have impacted B.C. 's marine ecosystems. Background By the time Europeans arrived on the coast at the end of the 1700s, the marine ecosystem was already structured by human influence. Not only had the Steller's sea cow disappeared, but as well the aboriginal peoples of coastal B .C. were consuming considerable amounts of salmon, eulachon, clams, marine mammals, and in some regions, bluefin tuna (Crockford 1997). Midden remains indicate that native peoples along the entire Pacific rim exploited sea otters (Enhydra lutris), perhaps driving populations locally extinct (Simenstad et al. 1978). Furthermore, by the 1800s, Steller sea lion (Eumetopias jubatus) 11 populations were also depleted by the aboriginal hunt for meat, hides, and oil. Numbers increased in the late 1800s and early 1900s when aboriginal hunting was reduced (Newcombe and Newcombe 1914). The arrival of the Europeans on the west coast of Vancouver Island in 1774 initiated another phase of marine resource extraction from the coast. In 1778, Captain James Cook traded with the Mowachaht people for 300 sea otter pelts (Arima 1983). B y the end of the 18th century, the entire west coast of North America was bustling with ships engaged in trading and hunting for otter pelts (Pethick 1980). The bulk of the trade for otters lasted only 60 years, and by 1830, the otter had become commercially extinct (Robinson 1979). The total North Pacific sea otter population during this time had dropped from an estimated 300,000 to 2,000 animals (Reidman and Estes 1990). The trade had a dramatic influence on the culture and economics of British Columbia. Europeans introduced diseases which decimated aboriginal populations to one third of their pre-contact numbers (Duff 1964). While the historical consequences have been well examined, the ecological consequences of the sea otter's near extinction went largely unnoticed (Estes et al. 1989, Watson 1993). The sea otter is a keystone species in structuring nearshore communities (Estes 1974). The absence of this animal would have profoundly altered the ecological functioning of B.C. 's coast (Pitcher 1998a). The next onslaught by the Europeans was on northern fur seals (Callorhinus ursinus). In B.C. , this trade began much later than the Russian trade and was initially a seasonal pelagic hunt during the fur seal migration in early Spring. The most kills recorded by B.C. sealers was in 1894 when 94,474 seals were taken for their pelts.4 Although these animals were only part-time migrants in B .C . waters, the sheer biomass of these high trophic level predators would have had a profound impact in structuring the ecosystem on the outer coast. Removal of whales may also have had far reaching ecosystem effects (Butman et al. 1995). In 1842 whaling began in B .C . but very few whales were taken. The first real assault started in 1866 with the establishment of whaling within the Strait of Georgia. However, by 1875 most of the whales had been removed from the Strait (Merilees 1985). The second onslaught began in 1905. Four whaling stations were built along the outer coast which were in use until the end of whaling in 1967. During this time over 23,000 whales were taken from B.C. 's waters (Pike and MacAskie, 1969). However, prior to 1905, American vessels were whaling in what is now Canada's exclusive economic zone, and therefore, the actual take of whales providing an ecological role in what is now considered to be Canada's waters was 4 Canada, S j \ , 1895, no. 11A, p. 374. 12 much higher. Similar to the sea cow, sea otter, and northern fur seal, the ecological impact of large scale removal of whales has never been understood. In addition to marine mammal kills, over one hundred species of fish and invertebrates have been heavily exploited in B.C. marine ecosystems over the last two centuries. The remainder of this chapter describes and quantifies the fisheries catches of B.C. from 1875 to the present day. The resultant catch database is used for further analyses in Chapter 3 to gain insight into the impacts of the fisheries on marine ecosystems, biodiversity, and the long-term sustainability of B.C. 's marine ecosystems. Purpose of Database • The purpose of compiling B.C. catches for all species, all fisheries, and all years (since 1875) was to create a database that could be used to assess long-term ecosystem impacts from fisheries. STRUCTURE AND SOURCES OF INFORMATION FOR DATABASE Categories of Fisheries in Database Seven categories of fisheries are considered: aboriginal, commercial, recreational, international, marine mammal, joint-venture fisheries, and incidental catches. Commercial catches are those fisheries where catches are sold. Aboriginal fisheries are fisheries which were conducted by any aboriginal group in British Columbia for the purpose of trade, subsistence or ceremonial purposes but not recorded as commercial fisheries. Recreational fisheries are those conducted for the purpose of recreation or consumption where no economic transaction has taken place. Marine mammal fisheries include the commercial or bounty take of any cetacean or pinniped. International fisheries are those fisheries conducted by nations other than Canada within the Canadian exclusive economic zone of Canada's Pacific Ocean. Joint-venture fisheries are those in which an arrangement between Canada and another nation is in place where Canadian boats and fishers catch the fish, but landings are delivered to processing boats belonging to other nations. Incidental catch consists of all species caught non-intentionally (i.e., bycatch) as well as targeted species groups that are discarded. 13 Species Groups Included in Database Forty-eight groups of species are included in the database. Some groups are comprised of multiple species (e.g., Sebastes and related genera, here including 31 species),5 others consist of single species (e.g., halibut Hippoglossus stenolepis). Species groups were chosen based on how the landing data had been recorded historically. For example, between 1875 and 1920, there was one category in fisheries reports called "cod" which represented lingcod (Ophiodon elongatus), Pacific cod (Gadus macrocephalus), sablefish (Anoplopoma fimbria), and all rockfish species. Today each of these species comprise a separate category. Not all fisheries exploit all species groups (Table 2.1). Table 2.1 Breakdown of species groups found in each category of fishery represented in the catch database of British Columbia between 1875-1997. Category of Fishery (number of species groups) Years Species Groups Commercial (n=37) 1875-1997 salmon species [coho, chinook, sockeye, pink, chum], steelhead, halibut, hake, dogfish, sturgeon, rockfish , Pacific ocean perch, pollock, skate, flounder, sole, turbot, lingcod, Pacific cod, herring, pilchard, smelt, eulachon, mackerel, abalone, clams, crabs, geoducks, gooseneck, horseclams, octopus, oyster, prawns, shrimp, scallops, sea cucumber, sea urchin Recreational (n=10) 1911-1996 salmon species (n=5), steelhead, rockfish, halibut, lingcod, dogfish Aboriginal (n=8) 1875-1997 salmon species (n=5), clams, sturgeon, eulachon Joint-venture (n=4) 1978-1996 hake, rockfish [yellowtail], pollock, dogfish International (n=7) 1965-1991 rockfish, Pacific ocean perch, herring, dogfish, hake, pollock, sablefish Marine Mammal (n=4) 1883-1974 cetaceans (humpback, blue, sperm, fin, sei, minke, right, Baird's beaked, grey) Steller sea lion, harbour seal, northern fur seal Incidental (n=10) 1875-1997 dogfish, rockfish, Pacific ocean perch, pollock, skate, flounder, sole, turbot, lingcod, Pacific cod Sources of Landing Information The diversity of the species considered and the time scale covered required access to a wide variety of data sources. Table 2.2 summarizes the primary data sources for each species group, fishery type, and time period. 5 One Sebastes species, Sebastes alutus (Pacific Ocean perch) forms a separate species group. 14 Table 2.2 Sources of landing data for species groups in the commercial (C), recreational (R), aboriginal (A), marine mammal (M), international (I), joint-venture (J), and incidental (B) fisheries in British Columbia from 1875-1997. Species Group Scientific Name Fishery Years Source Coho Oncorhynchus spp. C 1875-82 Shepardet al. (1985) Chinook 1983-97 DFO1, Annual Summary Pink A 1875-1919 Hewes (1973) Sockeye 1920-51 Argue et al. (1990) Chum 1951-84 Bijsterveld and James (1986) 1985-97 DFO (1997) R 1953-94 DFO (1996) Steelhead Oncorhynchus mykiss C 1895-1917 DBS2 1930-47 B.C., Provincial Fisheries Department Herring Clupea pallasi C 1884-18 Canada, Sessional Papers 1918-37 DBS 1938-50 Hourston (1980) 1950-97 DFO Annual Summary Dogfish Squalus acanthias C 1877-82 Ketchen(1986) 1983-97 DFO Annual Summary Sole and Flounder Aggregated group3 C 1920-51 Waddell and Ware (1995) Cod spp. 1952-97 DFO Annual Summary 1889-1919 Canada, Sessional Papers Pacific Cod Gadus macrocephalus 1920-49 DBS 1950 Waddell and Ware (1995) 1951-97 DFO Annual Summary Hake Merluccius productus C 1985-97 DFO Annual Summary J,I 1966-91 Waddell and Ware (1995) Walleye pollock Theragra C 1920-50 Waddell and Ware (1995) chalcogramma 1982-97 DFO J,I 1965-91 Waddell and Ware (1995) Lingcod Ophiodon elongatus c 1927-46 Waddell and Ware (1995) 1947-50 Cass et al. (1990) 1951-97 DFO Annual Summary Sablefish Anoplopoma fimbria c 1913-50 Stocker(1994) 1951-97 DFO, Annual Summary Rockfish & Pacific Sebastes spp. c 1920-51 Waddell and Ware (1995) Ocean Perch 1952-97 DFO Annual Summary Halibut Hippoglossus stenolepis c 1884-37 Carrothers (1941) 1938-50 Department of Fisheries, Annual. Report 1951-97 DFO Annual Summary A 1875-00 Carrothers (1941, Average) R 1982-97 DFO Annual Summary 15 Table 2.2 (continued) Sources of landing data for species groups in the commercial (C), recreational (R), aboriginal (A), marine mammal (M), international (I), joint-venture (J), and incidental (B) fisheries in British Columbia from 1875-1997. Species Group Scientific Name Fishery Years Source Sturgeon Acipenser spp. C 1880-18 Canada, Sessional Papers 1919-37 DBS A 1879-00 Carrothers (1941) Pilchard Sardinops sagax C 1917-37 DBS 1938-48 Culley (1971) Smelt Spirinchus thaleichthys C 1890-38 Hart and McHugh (1944) Hypomesus pretiosus Eulachon Thaleichthys pacificus C 1880-35 Hart and McHugh (1944) Whales Aggregated group4 M 1905-67 Pike and MacAski (1969) Harbour Seals Phoca vitulina M 1880-13 Canada, Sessional Papers 1914-64 Bigg (1969) Steller Sea Lion Eumetopias jubatus M 1914-68 Bigg (1988) N. Fur Seal Callorhinus ursinus M 1877-39 Canada, Sessional Papers Oysters Ostrea spp. C 1884-1967 Quayle (1969) Crassostrea gigas 1968-97 DFO, Annual Summary Clams Aggregated group5 C 1923-32 Schink et al. (1983) 1933-48 DBS 1951-96 DFO, Annual Summary Shrimp & Prawns C 1932-39 DBS 1951-96 DFO, Annual Summary Crabs Cancer magister C 1928-39 DBS Other Invertebrates C 1951-97 DFO, Annual Summary Incidental see Appendix 2.5 B 1996-1998 DFO, trawl observer database 1 Department of Fisheries and Oceans, 2 Dominion Bureau of Statistics, 3 Isopsetta isolepis, Lepidopsetta bilineata, Limanda aspera, Lyopsetta exilis, Microstomus pacificus, Parophrys vetulus, Platichthys stellatus, Pleuronichthys coenosus, P. decurrens, Reinhardtius hippoglossoides. 4 Physeter catodon, Balaenoptera musculus, B. physalus, B. borealis, B. acutorostrata, Megaptera novaeangliae, Eschrichtius robustus, Eubalaena glacialis, Beardius bairdii. 5 Tresus nuttalli, T. capax, Siliqua patula, Protothaca staminea, Venerupis japonica, Saxidomus giganteus, Mya arenaria, Panope generosa 16 Wet Weight Conversions A l l landings presented in the database have been converted to a wet weight in tonnes (t). Sources prior to 1970 often reported landings in values other than metric. Moreover, for some species only the weights of the final product were available (i.e., cans offish), and therefore a number of conversions were applied (Table 2.3). Table 2.3 Values used to convert reported quantities of species into metric fresh weight equivalents and source of information. Species Group Units Metric Equivalent (Wet Weight) Source Chinook 1 fresh fish 9.05 kg Argue etal. (1990) Sockeye 2.71 kg it Chum and Coho it 4.52 kg ti Pink a 1.81 kg ii Steelhead Trout a 4.52 kg n Salmon & Steelhead 1 can 0.79 kg Shephard and Argue (1989) 1 case 48 cans Cod species 1 cwt 45.4 kg Eulachon 10 gallons 452 kg Stacey(1995) Oysters 490 dozen 1 t Heath (1997)' Oysters 1 Barrel 91kg Quayle(1988) Harbour Seal 1 cull 81 kg Fisher (1952) Northern Fur Seal 1 skin 160 kg Jefferson et al. (1993) Steller Sea Lion 1 cull 535 kg Schusterman (1981), Bigg (1988) (Average) Humpback whale 1 kill 40 t Jefferson et al. (1993) Blue whale a lOOt Sei whale it 301 Fin whale a 75 t Minke whale 14 t Right whale tt. 80 t Grey whale it 35 t Sperm whale ti 57 t Baird's Beaked whale ti 12 t 1 Bill Heath, B.C. Ministry of Agriculture, Fisheries, and Food. Fax to author, January 15, 1998. Missing Values In some years data were unavailable, but a fishery existed. Rather than assuming zero values, missing landings were interpolated. In cases where landings were never recorded, for example recreational fishing for lingcod, conservative values were entered based on assumptions described in the relevant sections below. 17 S U M M A R Y O F F I S H E R I E S Commercial The commercial fishery is by the far the most significant fishery in British Columbia in terms of landings (Appendix 2.1). Over the 122 years covered by this database, commercial fisheries accounted for 77% of all recorded landings (Figure 2.1). Of the seven fisheries in this database, the commercial fishery has the best historical records due to financial transactions requiring some form of written documentation. 350 300 250 ° 200 | 150 ra O 100 50 0 1875 1895 1915 1935 1955 1975 1995 Year Figure 2.1 Graph of catch contributions by fishery type represented as a decadal average from 1875-1997. The category 'Others' includes aboriginal, recreational fisheries, and bycatch, see Appendix 2 for records. 1875-1899 With the advent of new technologies and accessible markets towards the end of the 1870s, the commercial fishery started growing rapidly. It was also at this time that records were first systematically kept by the Canadian Government and published as annual Sessional Papers. During this era, the most important export fisheries, by descending monetary value, were salmon (canned and pickled), northern fur seal skins, and fish oil (dogfish, seal, eulachon, and porpoise).6 A decade later the order was still the same, but new fisheries for other species such as halibut, sturgeon, and sablefish were starting to expand.7 By 1897, salmon catches had reached a new high of 38,000 t.8 A distant second in both 6 Canada, S i 1877, no. 1, p. 308. 7 Canada, S i , 1889, no. 8, p. 254. 8 Compared to 1997 landings of 48,0001. 18 monetary value and weight was fur seal, followed by halibut, sturgeon, fish oils, and herring.9 Table 2.4A summarizes the top ten species by weight between 1875 and 1899. Table 2.4 Ranking of the ten most important species in British Columbia's commercial fisheries (including marine mammals) by weight during 25 year intervals between 1875-1997 including maximum, minimum, and average catch of each species. Years Species Group Landings (HO3) % Max. (t-io3) Min. (t-io3) Average (fl(f) A. 1875-1899 Sockeye 252 48 36 0.3 10 Dogfish 110 21 12 0.0 4 Fur Seal 72 14 11 0.0 3 Coho 35 7 3 0.0 1 Chinook 19 4 2 0.0 1 Halibut 9 2 1 0.0 0 Harbour Seal 9 2 2 0.0 0 Chum 8 2 2 0.0 0 Sturgeon 3 1 1 0.0 0 Herring 2 0 0 0.0 0 All others 6 1 - - -TOTAL 525 100 - - -B. 1900-1924 Herring 546 20 52 0.5 22 Whales 543 19 60 0.0 22 Sockeye 429 15 40 5.9 17 Chum 316 11 33 3.9 13 Pink 226 8 26 0.5 9 Halibut 209 7 15 1.9 8 Coho 180 6 17 1.7 7 Chinook 112 4 9 1.1 4 Dogfish 64 2 5 0.0 3 Fur Seal 57 2 15 0.0 2 All others 105 4 - - -TOTAL 2,787 100 - - -C. 1925-1949 Herring 2,041 34 167 37.1 82 Pilchard 1,002 17 80 0.0 40 Chum 623 10 46 13.6 25 Pink 487 8 40 4.8 19 Sockeye 307 5 23 5.7 12 Whales 306 5 26 0.0 12 Coho 279 5 17 7.2 11 Dogfish 277 5 31 1.6 11 Halibut 230 4 14 5.0 9 Chinook 147 2 8 3.9 6 All others 244 5 - - -TOTAL 5,944 100 - - -9 Canada, S.P.. 1899, no.l 1A, p. 228. 1897 recorded the highest landings of sturgeon in the history of B.C. (515 t). 19 Table 2.4 continued: Ranking of the ten most important species in British Columbia's commercial fisheries (including marine mammals) by weight during 25 year intervals between 1875-1997 including maximum, minimum, and average catch of each species. Years F. All Years 1875-1997 Species Groups Landings (NO3) % Max. (HO3) Min. (NO3) Average (NO3) Herring 3,105 50 258 2.0 124 Whales 576 9 55 0.0 32 Pink 511 8 42 6.3 20 Chum 377 6 36 3.0 15 Sockeye 335 5 34 5.4 13 Coho 290 5 18 6.4 12 Halibut 277 4 15 3.4 11 Chinook 157 3 9 4.1 6 Oyster 93 1 6 2.3 4 Pacific Cod 92 1 9 0.7 4 All others 424 7 - - -TOTAL 6,238 100 - - -Herring 954 22 97 16.3 41 Pink 486 11 39 3.3 21 Sockeye 485 11 43 5.7 21 Chum 303 7 30 4.4 13 Rockfish spp. 296 7 22 3.2 13 Hake 266 6 58 0.0 12 Coho 186 4 13 0.8 8 Pacific Cod 144 3 14 0.7 6 Sole 131 3 15 2.7 6 Chinook 122 3 8 0.5 5 All others 913 21 - - -TOTAL 3,374 100 - - -Herring 6,649 34 258 0.0 53 Sockeye 1,809 9 43 0.3 15 Pink 1,711 9 42 0.0 14 Chum 1,627 8 46 0.0 13 Whales 1,425 7 60 0.0 21 Pilchard 1,017 5 80 0.0 13 Coho 970 5 18 0.0 8 Halibut 816 4 15 0.0 7 Dogfish 558 3 31 0.0 4 Chinook 557 3 9 0.0 5 All others 2,643 13 - - -TOTAL 19,781 100 - - -20 1900-1925 This era is characterized by the expansion of the herring fishery and the beginning of industrial whaling. For all commercial fisheries, the top ten species groups of this period are summarized in Table 2.4B. In 1900 the landings of herring were only 518 t, by 1924 they were 52,000 t (Figure 2.2B). This was a market driven expansion of dry salted herring to be exported to Asia which peaked during this era in 1927 with landings of 78,000 t (Hourston 1980). In 1908, the whaling industry was expanded by the creation of five new whaling stations, three on Vancouver Island and two on the Queen Charlotte Islands. Although whaling persisted until 1967, the two peak years in terms of both landed weight and numbers of whales were 1911 and 1912 (Figure 2.2C, Pike and MacAski 1969). A Salmon 150 7. 100 <3 50[ B Herring 1875 1900 1925 1950 1975 2000 1900 1925 1950 1975 2000 1900 1925 1950 1975 1950 1975 2000 1950 1975 2000 1900 1925 1950 1975 2000 Year Year Year Figure 2.2 Catch histories of major species in British Columbia from 1875-1997. N O T E : Each graph is represented with different time and weight scales. 1926-1950 The most significant development in this twenty five year period was the pilchard fishery (Figure 2.2E, Table 2.4 C). This reduction fishery began in 1917 with catches of 611 but was slow to expand. By 1924 21 the catch was 12,000 t, and five years later (1929) landings had reached 78,000 t. High levels continued for 20 years, fluctuating typically between 26,000 t and 80,000 t per year until 1948, the last recorded year of the pilchard fishery. Although the fishery only lasted 32 years, it still remains as the sixth most productive commercial fishery of all time in B.C. (Table 2.4F). Herring fisheries continued to expand during this period with a new record in 1949 of 167,0001. 1951-1975 The reduction herring fisheries continued to expand during the first half of this period with a historical maximum recorded in 1963 of 268,000 t. High landings of whales continued until 1967 due to technological advances which allowed for the pursuit of the fastest whale species, fin and sei. By 1970 the two dominant fisheries in terms of biomass, herring and whales, had completely collapsed. The herring fishery was reduced to 3,800 t, and whaling came to an end for both political and ecological reasons. This caused a dramatic decrease in the overall landings (Figure 2.3). The top ten species of this period are summarized in Table 2.4D. re o 1875 1900 1925 1950 Year 1975 2000 Figure 2.3 Commercial catch of all species (including marine mammals and incidental catch) from 1875-1997. 1976-Present The most noteworthy changes in the landings during the last time period were the expansion of the hake (Figure 2.2H) and invertebrate fisheries. Commercial hake fisheries, which exclude joint-venture venture fisheries, have expanded from zero in 1984 to 55,000 t in 1995, making hake the largest British 22 Columbia commercial fishery in terms of landings. Invertebrates have also made a significant contribution to the landings, although there is no single invertebrate species accounting for large quantities. In 1975 invertebrates comprised 5% of the total landings, whereas in 1995 they accounted for 15% of commercial landings in terms of weight. Aboriginal Aboriginal fisheries on the B.C. coast have taken place for at least 6,000 years (Barnett 1955). In 1875, the starting date of this database, the aboriginal population in B.C. was already reduced to one third (30,000) of their pre-contact population due to widespread mortality from introduced diseases (Duff 1964). Even with a much reduced population, aboriginal landings of salmon, halibut, sturgeon, and eulachons were considered to be substantial. However, the amount of marine resources consumed by aboriginal people during this period is unknown, and estimates are highly controversial (Hewes 1973). For the years between 1904 and 1950 there have been attempts by Argue et al. (1990) to quantify aboriginal landings of salmon but this data set is from reported counts and therefore "there is little question that the historical data are incomplete and that some may be inaccurate" (Argue et al. 1990). Indeed, modelled values of historic salmon catches by Hewes (1973), and early estimates by Alex Anderson, the inspector of fisheries in 1879, were found to be substantially higher than reported values found by Argue et al. (1990). Hewes (1973) calculated that on average, pre-contact coastal aboriginal groups required 486 lbs (220 kg) of salmon per person per year to sustain basic food requirements and interior groups required 438 lbs (198 kg). Similarly, in 1879, Alex Anderson, the inspector for fisheries in British Columbia, estimated that annual consumption of salmon per person was 500 lbs (226 kg), halibut 150 lbs (68 kg), and 10 gallons per person of eulachon o i l . " The discrepancy between early estimates of aboriginal salmon catch and early reported catch indicates vast uncertainty in the actual value (see Appendix 2.2). Since 1950, landing data for reported aboriginal salmon fisheries have been collected and published in data reports (Bijsterveld and James 1986, DFO 1997). These data, comprised of only reported catches, are undoubtedly conservative. However, present day aboriginal salmon landings, which are also reported catches and therefore also considered conservative, have surpassed historical pre-contact estimates. Due to better reporting 1 0 These data do NOT include hake landings in the joint-venture fishery. " Canada, S i 1880, no. 9, p. viii 23 methods, present day values are considered to be closer to the true value (Argue et al. 1990). For the purpose of this database and subsequent analyses, a value of 8,000 t per year has been entered for all years to account for all aboriginal salmon catch. This was based on Hewe's estimate of 7,914 tonnes and DFO statistics which reported a peak in 1993 of 8,704 t. Although this is not a precise estimate, it is a closer approximation to the true values than those reported. Reported catches underestimate the true catch. For example, in 1923, only 3 t of sockeye were reported to have been caught (see Appendix 2.2). Estimating aboriginal consumption of other important marine species such as halibut, clams, eulachon, sturgeon, and marine mammals presents even greater difficulties than for salmon. It has been acknowledged that these species were important in the diets of aboriginal peoples on the coast (Suttles 1951, Barnett 1955). Present day data are not recorded and past quantitative data only exist from Alex Anderson's account from 1879 mentioned above. These values for halibut and sturgeon are used in the database for the years 1875-1910. After 1910 no values are entered, and although this underestimates the true value, it is not possible to estimate a reliable value. This is in part due to the fact that an increasing number of aboriginal people were fishing in the commercial fishery (Stacey 1995). Alex Anderson's estimated consumption of 10 gallons of eulachon oil per person (and assuming an aboriginal population of 30,000) results in landings of 13,500 t. However this appears to be a gross over-estimate as the highest recorded commercial catch is less than 500 t (Hart and McHugh 1944). Anderson's account is likely correct for those actively engaged in the production. However, when his estimates are applied to the entire population of aboriginal people in B .C . during that time period, it over-estimates the catch. The true value is probably an order of magnitude less than Anderson's estimate. In the absence of better knowledge no value was entered for eulachons. Various species of shellfish are known to have been essential components of the diets of aboriginal people on B.C. 's coast (Barnett 1955, Mitchell 1988a), but estimating consumption is difficult. Modern day commercial landings average 7,000 t annually (bivalves only). In this analysis, for lack of better data, it was assumed that aboriginal catch was half of the salmon value (i.e., 4,0001) until 1910. One problem worth noting is that the values entered assume that aboriginal consumption of marine resources remained the same between 1875 and 1920. Historical evidence indicates that European influence, by way of aboriginal involvement in a cash economy, diminished the consumption of traditional food items starting from the 1870s (Stacey 1995). As well, native fishers became increasingly more involved in selling catches to commercial buyers (Stacey 1995). Therefore, aboriginal catch, from 24 the perspective of assembling this database, became less important to overall landings as commercial fisheries for salmon, halibut, whales, and herring increased. Recreational Fishing Since 1987, a minimum of 400,000 recreational fishing licenses have been sold annually, indicating a large fishery.12 Recreational catch statistics were not kept for any landings prior to 1953. In that year, statistics for salmon were first recorded (Canada 1953). Starting in 1981, estimates of other species such as lingcod and rockfish were also included in the annual creel surveys (DFO 1997). Landings of other recreational fisheries for clams, prawns, crabs, and spear-fishing have never been recorded. For species that are recorded, the values are likely an underestimate. Rather than using a zero value for recreational fishing for lingcod and rockfish prior to 1981, an average of the landings between 1981-1994 was entered into the database (Appendix 2.3). Furthermore, values for salmon prior to 1953 were estimated by scaling the values based on human population growth of the province (Appendix 2.3). Overall, the recreational landings are minor in comparison to other fisheries, comprising approximately 1% of the total landings represented in the database (Figure 2.1), and therefore these numbers will not unduly influence the overall results. Marine Mammals Marine mammals, although not killed in any large quantity for over 30 years, were at one time the object of a commercial fishery, and management 'culls' (Appendix 2.4). The combined landed weight of all whaling operations in B.C. add up to 1.4 million tonnes (Table 2.4F) making whales the fifth most important species group of all time. Landed weight and culls of marine mammals were calculated by assuming a 1:1 sex ratio and then applying a constant average weight to each reported kill (Table 2.3, Appendix 2.1). In the case of harbour seal culls between 1914 and 1964, it has been conservatively estimated that only half of the actual number of animals killed were actually recorded as they sink immediately after being shot (Bigg 1969). Some estimates are that only one in five seals killed received a bounty.13 This ratio was soon found to be unprofitable for fishers as the ammunition cost exceeded the bounty reward. A number of other government sponsored programs were initiated to eliminate the "enemy of salmon". In particular there was one program worthy of mention. 1 2 Fax to author from DFO, B.C. Tidal Waters Sport Fishing Licence Sales division. 1 3 Canada, S i , 1918, no. 39, p. 235. 25 On April 24, 1918, J. McHugh, a fisheries engineer, reports that, the first steps were taken by the department in laying down a scheme for the destruction of the hair seals [harbour seal] which congregate in the Fraser River and which for the past few years have proved such a menace to the salmon fishing industry. It was decided on this day that a systematic search for the bars most favoured by the seals should be commenced, and after several days spent in careful examination on the sand heads at the mouth of the Fraser river, a bar was discovered which seemed to be the favoured spot of a herd consisting of, I would suggest, anywhere between two and three hundred seals. The report proceeds to describe the technique of planting mines on the haulout and then, at the proper moment the mines were fired, and the explosion was quite successfully accomplished. On arriving on the ground it was observed that the explosion had been more destructive than I had intended. Evidently many of the seals were lying immediately over some of the mines as their bodies were blown to atoms, not a piece larger than two inches being found. A l l this for the "expenditure of approximately $150." In this analysis the actual number of culls (Appendix 2.1) was multiplied by 2 which reflects a conservative estimate of the true kill of harbour seals. Steller sea lions were similarly managed. The magazine Western Fisheries reports in a 1941 article entitled, Machine-Gunners Raid Breeding Rookeries. Another machine-gunner sends a hail of lead into the ranks of the fish raiders of the Pacific [Steller sea lions]. The white water is stained a vivid red. A heavy toll of life is taken in this conservation effort to save the seafood wealth of the nation....Then rookery after rookery, usually situated in the heart of prolific fishing areas, is raided by the gunners.14 In total, 71,406 Steller sea lions were accounted for by culling or, approximately six times the current population.15 B y c a t c h Bycatch of fish, although poorly documented, occurs in all non-selective fisheries. O f all B.C. 's fisheries, the trawl fleet is the largest contributor of bycatch. Bycatch can be thought of as two types: undersized or damaged targeted species and catch of non-targeted species. Both types are discarded at sea. For the years 1996-98, observers have been placed on all option ' A ' trawl licensed vessels in British Western Fisheries, January 1941, p. 11. 1 5 Andrew Trites, University of British Columbia, personal communication with author. 26 Columbia (DFO 1998). Estimates of bycatch in the trawl fishery during this period have been derived using data collected from observers.16 Unfortunately, there is no quantitative information available prior to 1996, although incidental catches have always existed to various degrees in all fisheries. For example, anecdotal information pertaining to the early hand-line lingcod fishery indicates that the average boat caught three or four red snappers (yelloweye rockfish) as bycatch for every lingcod. These snappers were discarded because there was no market for them at that time (Spilsbury 1990). Assuming that no incidental catch existed prior to 1996 would drastically under-estimate the true value of bycatch in the fishery. However, determining i f bycatch was historically greater or less than at present is not possible. The assumption is therefore made for this data set and the analyses found in the following chapter, that the weighted bycatch ratio calculated for the years 1996-98 for all trawl caught species groups is applicable to prior years. Trawl caught species groups are those commercial groundfish fisheries listed in Table 2.5. Table 2.5 Catch of discarded fish by species group in the ' A ' licensed commercial trawl fishery between 1996-1998 (Source: Department of Fisheries and Oceans Groundfish Management Unit). Trawl Caught Total Retained Discarded Discard/ % Species Groups Catch (t) (t) (t) Retained Discard Spiny dogfish 3761 187 3,574 19.09 95 Flounder 56 37 19 0.50 33 Walleye pollock 1,538 1,235 303 0.25 20 Skate 2,882 1,672 1,210 0.72 42 Sole 14,243 11,527 2,715 0.24 19 Turbot 16,093 9,285 6,808 0.73 42 Lingcod 3,620 3,334 287 0.09 8 Pacific ocean perch 15,651 15,175 476 0.03 3 Rockfish 35,366 33,548 1,819 0.05 5 Pacific cod 3,052 2,816 236 0.08 8 TOTAL 96,262 78,817 17,446 0.22 18.1 Discard Ratio of Targeted Species To compute a weighted discard ratio, the annual discarded trawl landings of each relevant species group is summed and divided by the total annual retained trawl landings (Table 2.5). The resulting weighted ratio of 0.22 is then used to calculate the estimated discards (D) for each year (/') by the equation, 1 6 Bycatch data from the observer program are not published. Raw data were sent to author from Kate Rutherford of the Groundfish Management Unit at the Pacific Biological Station, Nanaimo, B.C. 27 Equation 2.1 £>,=IZ r(0.22) where Lr is the retained landings of trawl caught species groups for each year (j) found in Table 2.5. Using a discard ratio of 0.22 is an overestimate for some species but an underestimate for others. Using the discard ratios determined for each species (Table 2.5) cannot be applied over time as some species such as dogfish, at one time were a targeted fishery. Applying the present day ratio would grossly overestimate the actual discard rate. Bycatch Ratio for Non-targeted Species The next portion of the bycatch is from non-targeted species. Bycatch of non-targeted species is separated from targeted species and represents 45 species groups that are inadvertently caught by the trawl fishery (Table 2.6, Appendix 2.5). Although a total of 248 different species were recorded by on-board observers as bycatch, only species with a combined catch of over one tonne for the period of 1996-1998 were used here. Typically these are species of little or no commercial value. In some cases, such as non-targeted bycatch of halibut and hake, there is an established market. However, for management and economic reasons fishers do not retain these species. Table 2.6 Summary information on bycatch of non-targeted species in British Columbia's commercial trawl fishery between 1996-1998 based on observer data. Common Name Total Retained Discarded Discarded/ % (t) (t) (t) Retained Discard Spotted Ratfish 1,716.4 18.2 1,698.3 93.5 98.9 Halibut 1,286.6 0.4 1,286.2 3,458.1 100.0 Hake 1,414.7 221.7 1,193.0 5.4 84.3 Other fish 710.0 25.3 684.6 27.0 96.4 Invertebrates 540.6 2.3 538.3 235.0 99.6 Sharks 22.1 0.5 21.6 42.4 97.7 Mammals 5.1 0.0 5.1 - 100.0 Total 5,695.5 268.4 5,427.1 20.2 95.3 The bycatch ratio for non-targeted species was derived by dividing the total weight of discarded bycatch (5427.1 t, Table 2.6) by the total retained catch (78,817 t, Table 2.5). The ratio of non-targeted discards to retained fish is 0.069 or 6.9% of the retained catch. Overall incidental catch (7) is calculated by, Equation 2.2 I=ZZr(Rati0 targeted + Ratio non-targeted) I=ZLr(0-22 + 0.07) where Lr is the landings of the retained catch. In other words, landings of retained trawl caught fish only represent 71% of the biomass actually caught. Based on these assumptions the landings of trawl caught 28 targeted species (Table 2.5) were multiplied by 0.29 over all years in the database. In total, incidental catches comprised only 2.7% of the total weight of all species groups over all years. This is primarily because most of the catch in B.C. 's fishery is comprised of species which incur low levels of incidental catch (i.e., herring, salmon). This estimate is consistent with global estimates of incidental trawl catch (Alverson et al. 1994), and is conservative overall as it does not include incidental catches in shrimp trawls, halibut longlines, or live rockfish fisheries which also generate bycatch. International and Joint-venture Fisheries Over the last century, international fisheries for a variety of species have existed in what are now Canadian waters, in particular the early halibut fishery and whaling. The more recent fisheries from which data are available, began in 1965 and consist primarily of Russian, Japanese, and Polish trawl vessels fishing for hake, rockfish species, and Pacific ocean perch (Appendix 2.6). The peak year was in 1969 when 115,000 t of fish were landed. However, the catches fell dramatically over the next decade for ecological and political reasons, and by 1979 the landings were only 9,000 t (Wadell and Ware 1995). The joint-venture fishery began in 1979 and increased dramatically to a peak in 1991 of 101,000 t, mostly consisting of hake (Figure 2.1). On board observers in the joint-venture fishery have reported 76 species in the incidental catch. However these occurred only in very small quantities (Table 2.7) Table 2.7 Summary of observer reports of catches in the joint-venture fishery for the years of 1996 and 1997. (Source: Department of Fisheries and Oceans groundfish management unit database). Species Catch %of (t) Total catch Pacific hake 109,354 94.8 Walleye pollock 2,466 2.2 Spiny dogfish 2,016 1.7 Yellowtail rockfish 1,186 1.0 Others (73 species) 394 0.3 Total catch 115,417 100 29 Designation of Species into Larger Groups For the subsequent ecological analysis in Chapter 3, the 46 species groups found in the database have been further designated into six groups; salmon, groundfish, small pelagics, marine mammals, hake, and invertebrates (Table 2.8, Figure 2.4). These designations are based on categories found in the Annual Summary of British Columbia Commercial Catch Statistics. Catch statistics for individual species groups are found in Appendices 2.1-2.6. Table 2.8 Species composition of the six fisheries classifications Species Categories Species Included Salmon Pink, coho, chinook, sockeye, chum, and steelhead. Groundfish Halibut, sole, flounder, dogfish, lingcod, rockfish spp., sturgeon, sablefish, Pacific cod, pollock, Pacific ocean perch, turbot, rays. Small Pelagics Pilchard, herring, eulachon, smelt Marine Mammals Whales (humpback, blue, fin, sei, minke, right, Baird's beaked, grey) Steller sea lion, harbour seal, northern fur seal. Hake Hake Invertebrates Abalone, crabs, shrimp, prawns, urchins, sea cucumbers, all bivalves, oysters, octopus, barnacles 400 r 300 i . 200 ro O 100 Bycatch Marine mammals Invertebrates 0 1865 1875 1885 1895 1905 1915 1925 1935 1945 1955 1965 1975 1985 1995 Year Figure 2.4 Catch contributions of major groups represented as decadal means from 1875 to 1997. Sources of Error The subsequent analyses in Chapter 3 are all based on the values contained in the database presented in this chapter and therefore it is important to be aware of the potential sources of error. There are inherent problems with using catch data for any species, any fishery, or any year. The resultant data set presented in this chapter is comprised of 3,844 entries representing catch weights by species, fishery, and year. Each point sometimes represents thousands of boat-loads of fish. Each point has some level of uncertainty resulting from misreporting, weighing error, data entry, and unaccounted bycatches and discards. However most of the data points (3,048) are from the commercial fishery, and since fishers are paid by the weight, the landings likely represent a conservative value. It is expected that catch data collection techniques have improved over time. This is most likely true for aboriginal and recreational fisheries. Combined, these fisheries have accounted for only 6.2% of all landings in the database, which is likely a conservative estimate, especially for the recreational fishery (0.8%). A shortcoming of this data set for the subsequent ecosystem analyses is that the early landing data only represent British Columbia-caught fish, when in fact it is well known that international fishing, especially from fishers based in the United States, has always existed in what is now Canada's exclusive economic zone. Catches therefore underestimate the actual biomass removal from Canadian waters. The data set, although imperfect, is the first attempt so far to assemble landings of all species, for all years, by all marine fisheries in B.C. This data set, combined with recently developed conceptual and analytical methods, thus allows for ecosystem-based evaluation of long-term fisheries impacts on marine ecosystems. 31 Chapter 3 Patterns of Human Appropriation of Marine Primary Production and Biodiversity Loss in British Columbia INTRODUCTION The exclusive economic zone of Canada's west coast covers an area of 457,663 km 2 (Zacharias and Howes 1998) and extends into two major oceanographic domains, the Alaska current to the north, and the California current to the south (Thomson 1981), providing conditions for rich fisheries resources (Ware and McFarlane 1989). It was shown in the previous chapter that since the beginning of the commercial fishery in British Columbia (1870s), the species composition and the size of the catch has changed dramatically. This phenomenon is not unique to British Columbia. World-wide catches have undergone fluctuations in terms of species and quantity. There is enough historical evidence of marked changes in abundance of fish populations independently of fishing, to allow the postulation that natural factors can cause switches in ecological communities (Cushing 1982). On the other hand, there is increasing evidence strongly implicating fisheries as primary factors for ecological change (Dayton et al. 1995). Both the environment and fisheries undoubtedly play a role. Underlying the difficulty in clarifying this debate is the difficulty of detecting changes in marine ecosystems. The ocean is a difficult place to work. Research is expensive, animals often live in deep, hard to access places, and the out-of-sight, out-of-mind principle often prevails. Because of these limitations, in practice, only species that are heavily exploited or are caught incidentally in commercial fisheries have been well documented. This limits us to considering only a small part of the world's marine species and primarily only for a period of about 100 years. The catch data-set presented in the previous chapter demonstrated the magnitude of B.C. 's fisheries over the last 122 years. Ecosystem impacts from years of large scale removal of a variety of species, each functioning in a food web, are unknown, but obviously occur. Humans have developed fishing practices which allow for the removal of species at all trophic levels, from low-level, filter-feeding herbivores and detritivores, to high-level piscivores. In the North-east Pacific, fisheries have targeted small clams weighing 20 g to large cetaceans weighing as much as 160 tonnes. We have developed technologies to exploit marine organisms that live 2 meters deep into the mud, graze on rocks, swim mid-water, or haul out on land. We target species that roam thousands of kilometres foraging, as well as those that are 32 completely sessile. Each removal of a marine organism probably generates an ecosystem impact, but we are rarely able to detect these changes given our limited capacity. Moreover, when changes are observed, natural fluctuations often confound the results. The goal of this chapter is to evaluate some of the ecosystem impacts of British Columbia's fisheries by examining the ecosystem support required to sustain them. It wil l be shown that the ecosystem support required to sustain the fishery is higher at present day than at any other period in history, and raises serious concerns regarding the long-term sustainability of the fishery and threats to marine biodiversity. PREMISES The analyses in this chapter are based on the following premises: Premise 1: Each marine animal taken by humans subtly alters the existing ecosystem structure. To sustain basic needs of food, water, and shelter, humans utilize services and energy produced from functioning ecosystems. With each additional unit of consumption, an additional amount of photosynthetically derived energy is reallocated from the existing system into the human enterprise, and then redistributed back to the ecosphere in degraded form. We live in a closed system, and we depend exclusively on this energy to maintain ourselves. Given that humans are only one component of a marine food web, an assumption can be made that each additional unit of energy appropriated by the human system is inevitably a loss to the natural system. It follows that with increased re-direction of energy comes an erosion of the natural ecosystem structure. A number of examples are available which demonstrate how the full or partial removal of a certain group of organisms from an ecosystem results in dramatic changes to community structure (Paine 1966, Estes 1972, Dayton et al. 1995). Premise 2: Each marine animal taken is embedded in a trophic structure and therefore requires support from the ecosystem in the form of photosynthetic energy. Lindeman (1942) was the first to acknowledge that all living species are embedded in an ecosystem structure governed by thermodynamic principles. The energy reaching each trophic level is determined by the net primary production and the efficiencies in which food energy is converted to biomass at each trophic step. With this conceptual framework in place, ecologists began to measure energy flow and the cycling of nutrients in ecosystems (Odum 1953). 33 In this analysis, energy flow required to sustain present and past fisheries is calculated. The results represent the amount of ecosystem energy appropriated by British Columbia's fisheries. Premise 3: There is a positive relationship between the amount of ecosystem energy appropriated by the human system and the erosion of ecosystem structure. The realisation that humans are dependent on ecological services of the earth has provided the impetus for analyses undertaken to understand large-scale human impact to terrestrial ecosystems (Vitousek et al. 1986). Net primary production (NPP) appropriation by humans is a good indicator of the magnitude of the human enterprise. At some level NPP appropriation is related to the loss of biodiversity, ecological integrity, or whatever concept is chosen to describe the earth's system of living species dependent on primary production. The two end points are known. At zero percent appropriation there is no biodiversity loss, at 100% appropriation of energy there is no biodiversity left (Figure 3.1). CO co CD > TD O co C l - D E " Energy (E) E° Figure 3.1 A conceptual representation of the relationship between biodiversity (S) and energy (E). The curve passes through the point (E, S) which represents pre-appropriation energy and biodiversity of the system. As humans appropriate more energy from the system (1-r) there is a corresponding decrease in biological diversity (Source: Wright 1990). In terrestrial systems, primary production forms the energy basis of food chains and also habitat in terms of grasses, shrubs, and trees. Numerous studies indicate that areas of higher primary production support a greater number of species (Wright 1983, Wright 1990, Currie 1991, Wylie and Currie 1992, Currie and Fritz 1993). By back-extrapolating along curves similar to Figure 3.1, the reduction in natural energy flow due to human activities can be used as a surrogate to estimate impact upon ecological integrity or 34 biodiversity. Although all aforementioned studies are based in terrestrial ecosystems, a similar concept can be applied to marine ones. Analyses using marine primary productivity have been conducted in marine ecosystems to estimate exploitation limits (Graham and Edwards, 1962, Ryther 1969, Moiseev 1994). In these studies, estimates are derived from global estimates of primary production and energy transfers in food webs. Similarly, using global estimates of marine primary productivity, the amount of primary production required to sustain world fish catches compared to the productivity available has been estimated at 8% (Pauly and Christensen 1995). In some marine systems such as upwelling and shelf systems, primary productivity requirement may be as high as 35%. The appropriated marine ecosystem area, also called an 'ecological footprint', is a spatial expression of the ecosystem area necessary to sustain resource consumption and waste discharge by a given human population (Wackernagel and Rees 1996). It has been used to assess and compare sustainability of marine resource extraction between nations (Folke et al. 1997,1998). A n ecological footprint-type analysis is used in this study to determine the percentage of marine energy appropriated by British Columbia's fisheries and the area required to sustain current and historic fish landings. No estimates of waste assimilation are included. Calculations are based on the continental shelf (100,627 km 2) and continental slope (33,000 km 2) within Canada's west coast exclusive economic zone, a total combined area of 133,627 km 2 (Zacharias and Howes 1998) and a primary production value of 388 g C-m2-year"'(Longhurst et al. 1995). METHODS Calculation of Primary Production Requirements Fisheries catches consist of species occupying a variety of trophic levels in marine food webs. The primary production required to produce the fish caught is calculated using three pieces of information: catch, trophic level, and the transfer efficiency between trophic levels (Christensen and Pauly 1993). The following equation from Pauly and Christensen (1995) is used to calculate primary production (PPR,) required to produce the catch ( Q of each for each species group (j) in year (i): Equation 3.1: PPRrlVlCij-TE^fV where TE is the mean transfer efficiency between trophic levels, and TLj is the trophic level of species group j. The data set described in the previous chapter is the source of all fisheries catch (Q in wet 35 weight.1 7 Primary production requirements (PPR,) are expressed in units of grams of carbon and therefore the right side of the equation is divided by 9 to reflect a conservative 9:1 ratio for the conversion of wet weight to carbon (Strathmann 1967). Each of the 47 species groups (j) (including bycatch) in the data set is assigned a trophic level (TL) (Table 3.1). The TL is a fractional number given to each species group resulting from a routine in Ecopath software (Christensen and Pauly 1992) that uses the weighted average of the prey's trophic level to estimate the trophic level of the predator. In this analysis, the trophic level for most species groups (j) was calculated from an Ecopath model representing all of British Columbia (Pauly et al. 1999). Trophic levels for salmon species were independently calculated by Peter Tyedmers (thesis in progress). Table 3.1 Fractional trophic level of species groups in British Columbia's fisheries. Species Group Trophic Level" Fur seal, harbour seal, sea lions 4.3 Lingcod, tuna 4.2b Pacific cod, misc. cod, chinook salmon, steelhead 3.9C Coho, halibut 3.8 Sablefish 3.7 Turbot 3.6 Sockeye, pink, chum, dogfish, flounder, sole, skate, bycatch 3.5d Hake, pollock, mackerel, Pacific ocean perch 3.3 Rockfish species, miscellaneous ground fish, whales 3.2 Herring, pilchard, smelt, eulachon 3.1 Octopus, miscellaneous pelagic fish 3.0 Sturgeon 2.7 Prawns, shrimp 2.6 Crabs 2.5 Gooseneck barnacles 2.3 Geoducks, horseclams, oyster 2.2 Abalone, clams, scallops, sea cucumbers, sea urchin 2.1 a All trophic levels from Pauly et al. (1999) unless otherwise mentioned. b Tuna trophic level from Pauly and Christensen (1995). c All salmon trophic levels from Peter Tyedmers (thesis in progress). d Bycatch trophic level calculated using a weighted average (see Appendix 3.1). A value of 10% for the mean energy transfer between trophic levels was used throughout the analysis (Pauly and Christensen 1995), derived by averaging the transfer efficiencies resulting from 48 published trophic models of aquatic ecosystems. Calculation of Mean Trophic Levels It was shown by Pauly et al. (1998a) that the mean trophic level of species groups reported in Food and Agricultural Organization (FAO) global fisheries statistics has declined over the last four decades. This 1 7 See Chapter 2 (p. 31) for potential sources of error and limitations of the database. 36 process, called "fishing down marine food webs" is an unsustainable trend reflecting the transition of fisheries from old-lived, high trophic level species toward short-lived, low trophic level species. A mean trophic level analysis is carried out in this chapter for each year covered in the data set using the following equation, Equation 3.2: Mean TL=L{Cf TLJ) / E Q where Q is the landed weight of each species group (/) in year (i), and TLj is the trophic level of each group found in Table 3.1. Much of B.C. 's catch is comprised of migratory species such as sockeye, pink, and chum salmon, herring, and hake. With the exception of herring and the Strait of Georgia hake population, all of these species live outside of Canadian waters during some stage of their life cycle. The trophic impact of their removal from the ecosystem is not as localized as the removal of non-migratory species. For this reason a trophic level analysis is also conducted using only non-migratory species.18 Correction for Resident Salmon Chinook and coho salmon, although considered resident in this analysis, have large portions of their populations extending outside of B.C.'s continental shelf area. No published data exist on the relative percentage of resident coho and chinook populations compared to the migratory ones. For lack of better information a 50% ratio was assumed (i.e., only 50% of the total chinook and coho landings are considered to be resident). Calculation of Marine Footprint Two pieces of information were required to calculate the percentage of annual primary production (APP(o/o)) from the continental shelf required to sustain British Columbia's fisheries: the annual primary production available (Pa) and the primary production requirements of the catches (PPRi, see equation 3.1). The Pa is the annual total primary production in the geographical area being considered (i.e., the continental shelf area). P a is calculated using a rate of phytoplankton production (Rp) measured in grams of carbon per meter square multiplied by the total area (At) in square meters (Equation 3.3). 18 Non-migratory species: are species which spend the adult stage of their lifecycle in Canadian waters and include resident coho, resident chinook, halibut, dogfish, flounder, pollock, sablefish, skate, sole, turbot, sturgeon, smelt, eulachon, lingcod, Pacific cod, Pacific ocean perch, rockfish spp., abalone, clam spp., crabs, geoducks, gooseneck barnacles, horse clams, octopus, oyster, prawns, shrimp, scallops, sea cucumber, sea urchin. 37 Equation 3.3: Pa = A,Rp The value of At used in this analysis, as previously mentioned, is the area of the continental shelf. The percentage of annual production required to sustain the fishery for each year (/) is calculated by equation 3.4. Equation 3.4: APP%=[PPRi/PJ 100 It should be noted that catches in B.C. consist of migratory species that utilize primary production in areas outside Canadian political boundaries (i.e., EEZ) and ecological boundaries (i.e., continental shelf). This is discussed in further detail in subsequent sections. The goal of this chapter is to use analyses of mean trophic level, primary productivity requirements, and marine footprints as surrogate measures to understand the trend of fisheries impacts on British Columbia's marine ecosystems. Understanding the exact cause and effect of removing each unit of marine productivity is not necessary for examining the larger trend of human impact on marine ecosystems. As Ehrlich (1994) stated: It is not necessary to have counted, named and established measures of similarity among the grains of sand, pebbles, shells, and rocks on a beach to determine for practical purposes how rapidly the beach is eroding. A N A L Y S E S A N D R E S U L T S Mean Trophic Level of Fishery The data set presented in Chapter 2 provided the catch weights ( Q for the mean trophic level analysis (Figure 3.2A). For all species in all fisheries the trend has been an overall decline in the mean trophic level from 1875-1997 (Figure 3.2B). A rapid increase in the mean T L between 1870-1900 occurred due to the transition of the fishery from primarily subsistence aboriginal catches of salmon, eulachon, and clams, to a commercial fishery targeting high trophic level species such as salmon, dogfish, and northern fur seals. A historic maximum mean was reached in 1900 of 3.65 and then decreased quickly. This was primarily due to a decrease in northern fur seal kills combined with a steady increase in herring and 38 whales into the 1920s (Figure 3.2B). The increase in herring and pilchard catches, both low trophic level species, resulted in a gradual decrease of the mean T L until the mid-1960s. During the 1960s numerous ecological, technological, economic, and political factors simultaneously contributed to an increase in the average TL. The herring fishery, which had contributed over 50% of all landings during the previous decade, collapsed in 1963, likely from overfishing. As a result, the catch became comprised of a greater proportion of high T L species. Furthermore, commercial whaling had exhausted the supply of whales, also a low T L animal. During this same period, markets and technology made deep sea trawling for previously unexploited, high trophic level groundfish profitable. Meanwhile, international fishing in what is now Canada's E E Z began, targeting rockfish species resulting in an expansion which saw landings increase from essentially a non-existent fishery to a historical maximum in only two years. Catches in 1971 contributed to a mean T L of 3.5 but since this time there has been a downwards trend of the mean T L (Figure 3.2B). There are a number of factors contributing to the decline in mean trophic level over the last 25 years. The predominant force is the increase landings in hake (TL=3.3) combined with increased landings of invertebrates (TL<2.5). 39 40 Mean Trophic Level of Non-migratory Species Groups Represented in the Catch A downward trend in the mean T L of non-migratory species in the catch is obvious since 1932 (Figure 3.3). Herring are also included in the analysis as their populations, although migratory, do not leave Canadian waters. A comparison of the two trends (Figure 3.3) demonstrates the importance of herring catches in altering the mean trophic level. The trend illustrates the transition of B.C.'s fisheries from high trophic level relatively sedentary species such as lingcod and rockfish species, to lower trophic level sedentary invertebrate species. 2.7 P — 1 — 1 — 1 — t — • — 1 — 1 — 1 — I — ' — 1 — 1 — ' — I — ' — 1 — 1 — 1 — l — 1 — 1 — ' — 1 — i 1875 1900 1925 1950 1975 2000 Year Figure 3.3 Mean trophic level of non-migratory species (including bycatch) in British Columbia's fisheries from 1875-1997 with and without herring. Primary Production Requirements and Ecological Footprint The primary production required (PPR) to sustain the fishery increased rapidly from the late 1800s until 1925 (Figure 3.4). The PPR increased gradually from 1925 to 1970 when the overall decrease in catch, primarily herring, resulted in a decrease in PPR. Invertebrates, although contributing increasing amounts to the catch in terms of weight, contribute little to the PPR, due to their low trophic level. Although the PPR has remained relatively stable, the species composition contributing to the PPR has changed dramatically (Figure 3.4). 41 Figure 3.4 Primary productivity requirement (PPRj of British Columbia's fisheries by major group by decade. See Table 3.3 for list of species in each group. The ecological footprint {APP%) is directly related to the PPR and therefore the historic trend follows an identical curve (Figure 3.5). The peak year, using an average primary production value of 388 g C m 2 year"1, was in 1991 when an estimated 23.2% of the primary production was required to sustain the fishery (Fieure 3.5V The averaee APPo/„ between 1925-1997 was 16.3%. 25 1875 1900 1925 1950 1975 Year 2000 Figure 3.5 Primary productivity requirements of the British Columbia's catches (PPR) and percentage (APPo^) of the continental shelf area required to support these catches from 1875 to 1997 using a primary production rate of 388 g C-m"2. 42 Discussion The primary production required to sustain British Columbia's fisheries in the 1990s was higher than in any other decade in history (Figure 3.4), meaning that more energy has been reallocated from marine systems to the human system during the last decade than during any other period. This appears contradictory to scientific, public, and resource users' perceptions of the state of the fishery. Furthermore, this is contrary to scientific evidence that suggests that the 1990s have been the least productive period since the 1950s in terms of zooplankton production in the N E Pacific (McGowan et al. 1998, Francis et al. 1998). The findings of my analysis is consistent with the idea proposed by Ludwig et al. (1993) that the only consistent trend in fisheries science is that humans tend to over-exploit available resources. Although populations of some fish populations demonstrate a strong relationship to climatic variation, the models presented in this chapter suggest that these trends have yet to influence our exploitation patterns. Substitution of species, coupled with technological advances, has maintained a high level of appropriation. If the premises outlined in the introduction are accepted, it follows that British Columbia's fishery is having an increasing impact on marine biodiversity. It is estimated from the models that i f our fishery were to be sustained solely from the photosynthetic energy produced on our continental shelves, we would appropriate on average 16% of the primary production annually. This is higher than Pauly and Christensen's (1995) analysis of 8% world-wide, but less than their estimates of non-tropical shelves of 35%. The numbers themselves are less important than the observed trend. On one hand the results are conservative in that the catch data set represents conservative estimates of catches and the primary production rate is high. However, all landings are considered to be a product of primary production from Canadian waters. These results, which are based on the assumption that fish are produced in the EEZ, over-estimate the actual appropriation of energy occurring in Canadian waters. In reality, much of the catch is comprised of species collecting their body mass or energy from either American waters or the global commons, and conveniently transporting themselves back to us. When migratory species were separated out, it was calculated that over 40% of the PPR in the 1990s came from outside our waters (Figure 3.6). 43 70 a. a. o. 10 0 1875 1900 1925 1950 1975 2000 Year Figure 3.6 Percentage of total primary production requirements derived from species resident to Canadian waters at all stages of their life cycle. This is not to be interpreted to justify increasing the take of marine life from our waters. Most i f not all resident species are fully or over-exploited, their catches being sustained over time by increasing technology, effort, and geographical expansion. Mitchell and Cleveland (1993) show that landings in the New Bedford fisheries, although consistently decreasing, have had to triple their fossil fuel consumption to maintain the catch. Fossil fuel consumption in B.C. , although not considered in the current analysis, would likely follow a similar trend as the New Bedford fisheries. In this analysis, only biological extraction was used to calculate the footprint, and a constant transfer efficiency between trophic levels was applied. Theoretically, the efficiency of mature ecosystems is higher than over-exploited systems (Odum 1969, Christensen and Pauly 1998). In their models, it was demonstrated that a mature system would be more efficient in recycling and retaining the portion of primary production going to detritus than an exploited system. Consequently, the transfer efficiencies between trophic levels is greater, suggesting a greater biomass supported by the same primary production base, and a more efficient overall use of energy. A higher transfer efficiency would lead to a smaller footprint. The tenet of their theory is that mature ecosystems are more productive; that is, they can maintain higher biomasses of high trophic level fish with the same primary production base. Fisheries management, by encouraging fishing down the food web, erodes the natural structure, resulting in a less mature system and consequently less fish. Using primary production as the only indicator of ecological impact can be misleading. In a severely depleted ecosystem where all top level predators have been removed, the fishery is comprised of lower trophic level species, which by definition, require less ecosystem support in the form of primary production requirements. A footprint analysis in this situation would show that less energy is being 44 appropriated, and therefore, i f following the premises presented earlier in this chapter, biodiversity is being conserved. Catches between 1992-97 illustrate this problem. According to the analysis, primary productivity requirements have dropped by nearly half over this period (Figure 3.5), which would imply benefits to biodiversity. A better indicator is the combination of both primary production requirements and mean trophic level trends (Figure 3.7). 3.55 j P P R ( g C . 1 0 1 2 ) Figure 3.7 Plot of primary productivity required and mean trophic level of British Columbia's fisheries from 1960-1997. When these two indicators were examined for B.C. 's fisheries, it was shown that between 1975 and 1997 the mean trophic level of the catch has decreased, but the PPR for most of that period until 1991 was steadily increasing. This suggests an increase in landings of low trophic level species, combined with continued exploitation of higher trophic level species. This is consistent with theory that predicts fishing down the food web leads at first to increasing catches, then a transition to stagnating or decreasing catches (Pauly et al. 1998a). Although the 1990s as a whole have been very productive, in recent years (1994-97) the landings, trophic level, and PPR have declined indicating a heavily exploited ecosystem from biomass and trophic perspectives (Figures 3.2A & B). This trend is even more pronounced when only non-migratory species are included in the analysis (Figure 3.3). The mean trophic level has steadily declined since the 1930s to present day from a mean T L of 3.8 to less than 3.2., accompanied by an increase in catch. Since 1992, the landings of resident species have also started to decline. The trophic level trend of resident species strongly suggests that the composition of species in the fishery is largely independent of climatic factors and that the removal of resident, high trophic level, valuable, old-lived species has been primarily a function of fisheries exploitation. 45 In conclusion, it was shown in my analysis that, 'fishing down the food web' is indeed occurring in B.C. while simultaneously an increase in primary productivity requirements was shown to be required to support the fishery. Based on the underlying premises of this chapter, both of these analyses indicate a loss of ecosystem structure and biodiversity. Although management decisions and economics play a role in the species composition of the fishery, it can be safely assumed that i f there were large biomasses of commercially valuable, high trophic level species present in the ecosystem then there would be fisheries targeting them. In fact, what is actually maintaining the high PPR are large catches of low value species such as hake ($0.15/kg) and pink salmon ($0.54/kg).19 The trends shown represent a conservative estimate of the impact to biodiversity, not only because the reported landings used are under-estimates, but also because of numerous other threats which have increased during the same period, but were not formally examined. These other threats include: bottom trawling for groundfish has been shown to destroy critical micro-habitats required as refuge space for important commercial species (Watling and Norse 1998); loss of critical coastal habitats such as eel grass beds for herring spawning; increases in bycatch with unknown ecosystem impacts; and loss of salmon spawning habitat in streams. Additionally, serial depletion of species with functional roles but not large primary production requirements are not accurately represented. For example, clam beds have been shown to be critical in structuring benthic communities and providing dominant pathways of primary production utilization (Dame 1996), but the PPR of clam landings are negligible in this analysis. The synergistic and cumulative effect of all these threats is unknown. Continued fishing down marine food webs, coupled with increased technologies for exploiting resources, precludes the opportunity to restore marine ecosystems and maintain biodiversity. Whereas this chapter presented a general picture of ecosystem impacts from fishing, the next chapter examines more closely the changes in trophic and food web interactions resulting from fishing. Conventionally, fishing impacts on fish populations are examined on a species by species basis. The next chapter examines cumulative ecosystem impacts of multiple depletions on food web structure, using mass-balanced ecosystem models. 1 9 Prices from 1997 British Columbia Seafood Industry in Review. B.C. Ministry of Fisheries. 46 Chapter 4 Ecosystem Models of the Strait of Georgia INTRODUCTION Humans have exploited resources of the Georgia Basin ecosystem for at least 7,000 years (Barnett 1955). In the last 100 years, increasing settlement of people into the Basin has brought with it growing pressures on renewable resources in both terrestrial and marine environments. Changes in terrestrial ecosystem structure and loss of biodiversity resulting from human influences have been better documented than for the marine counterpart (Harding and McCul lum 1994). In this chapter, the present ecosystem of the Strait of Georgia is compared to a hypothetical ecosystem of the Strait 100 years ago, using mass-balance ecosystem models. 2 0 It is my intention in this chapter to illustrate ecosystem changes to the Strait by synthesizing and inputting into models historical ecological information of changes in species abundance thought to have occurred. Furthermore, the models provide a much needed historical context for present day conservation initiatives described in the later chapters. Physical Description of the Strait of Georgia The ecosystem of the Strait defined for this model is the inland sea between Vancouver Island and the British Columbia mainland covering an area of 6,900 km^ including the six branching inlets (Thomson 1994) (Figure 4.1). The Strait is primarily a deep basin connected to the Pacific Ocean by complexes of shallow channels causing strong daily tidal mixing at both the northern and southern ends. Oceanographic conditions in the southern half of the Strait are strongly influenced by the freshwater discharge of the Fraser River (Harrison et al. 1983). This combination of geological and oceanographic features provides conditions for a unique biological community as freshwater influence and shallow passages present a barrier to some marine organisms. Human Impact to the Marine Ecosystem The semi-enclosed nature of the Strait makes it susceptible to influences from industrial pollution, sewage, ocean dumping, dredging, coastal development and over-exploitation (MacBride 1991). There is evidence that numerous species and habitats have been altered from these activities (Ketchen et al. 1983, Levings and Thorn 1994), but there has been no attempt to try to understand these cumulative changes from an ecosystem perspective. The decline in many economically important marine species suggests that the ecosystem structure of the Strait has been influenced by a combination of these activities (Ketchen et al. 1983, Levings and Thorn 1994, Levy et al. 1996). The Strait of Georgia from this point forward will be referred to as the Strait. 47 Howe Sound Figure 4.1 Map of the Strait of Georgia ecosystem with place names mentioned in the text. Dotted lines at the north and south ends represent the ecosystem boundaries used in the models. Depletions of various fish resources in the Strait during the last century have been attributed to many human activities. However, overfishing is considered the primary cause for the collapse of many fish populations. Each reduction alters the direction of energy pathways in the ecosystem but understanding this cumulative effect has not been possible until recently. 48 Using the Ecopath ecosystem modelling software (Christensen and Pauly 1992), I compare the present day ecosystem (1990's) of the Strait with the ecosystem of 100 years ago.21 The two models are from this point forward referred to as the 'Present' and the 'Past' model. The first section introduces the Ecopath modelling software, followed by the Present model, Past model, analysis, results, and discussion. E C O P A T H A P P R O A C H T O E C O S Y S T E M - B A S E D M A N A G E M E N T This chapter has two aims: one is to understand how human-caused changes in abundance of individual species may have altered the functioning of the Strait's ecosystem, and the second is to identify the significant ecological linkages and changes important for present day ecosystem-based management. The Ecopath software used for this is a mass balance accounting system used to describe trophic interactions within an ecosystem. It has been used in a variety of aquatic ecosystems to examine the energy flows (Christensen and Pauly 1993) and as a diagnostic tool to compare ecosystems (Christensen and Pauly 1998). In this analysis Ecopath is used to compare the Past ecosystem of the Strait with the Present day using the 'Back to the Future' approach (Pitcher 1998b). This approach first requires a balanced model of a present day ecosystem based on published estimates of ecosystem parameters. A past model is then created using the present day model as a starting point. Information required to construct past models is based on qualitative and quantitative sources of historical information as inputs. How Ecopath works The underlying premise of Ecopath is that the ecosystem being examined is mass balanced, that is, for the time period under consideration, total production is equivalent to total loss. Therefore for each group of species (/) in the model: [production by (/)] - [all predation on (/)] - [ non-predation losses of (/)] - [export of (/)]=0 or B jP /B i -S jBj*Q/Bj*DCj i -P /B i *Bi ( l -EE i ) -EX i =0 2 1 This study incorporates the work of many people, in particular Johanna Dalsgaard, Silvia Salas, and Dave Preikshot. See contributions in Pauly et al. 1998b. 49 where, Bj=biomass of (i), P/B=production biomass ratio of (i), Q/B=consumption biomass ratio of (i), DCjj=fraction of prey (i) in the average diet of predator (j), EEj=ecotrophic efficiency of (i) and EXpexport of (i) (Christensen and Pauly 1992). A total of six input parameters are required for each equation. Existing Strait of Georgia Ecopath Models The Present Ecopath model of the Strait is based on two previous models of the present-day ecosystem (Pauly and Christensen 1996, Dalsgaard et al. 1998). The first model was a summer model with a total of 15 functional/species groups. The second, revised model, changed the original model in two ways: (1) ten functional/species groups were added and; (2) the model was converted into a yearly model from a seasonal model. Dalsgaard et al. (1998) then used the revised Present day model (1990s) as a base to develop a model representing the Strait 100 years ago (1890s). Two additional groups were added during the construction of the Past model in order to represent historically important species. In this chapter I present a third revision with only minor changes to both the Present and Past models developed by Dalsgaard et al. (1998). For the Present day model no additional groups were added. However, I modified the diet compositions of some groups. For the Past model, I added one more group and modified the diet compositions of some groups as well. These changes wil l be described in detail under the relevant headings in later sections. Assumptions, Inputs, and Outputs of the Models This section contains a description of the Present and Past Ecopath models. For each model, a summary of the assumptions, inputs, and model outputs for each species group is presented, followed by a diagram representing energy flows in the ecosystem. Most of the inputs are the same as those found in Pauly and Christensen (1996) and Dalsgaard et al. (1998), and therefore only a review of the most important information is provided here. PRESENT DAY M O D E L Primary producers Two groups of primary producers were identified: phytoplankton and kelp/sea grass. Estimations of P/B and E E input values for both groups can be found in Pauly and Christensen (1996), while the biomass is calculated by Ecopath. Based on Levings' (1983) area of kelp habitat in the Strait (2%) and annual production of kelp from other geographical locations (Mackinson 1996), a value of 200 t km"2 was estimated by Dalsgaard et al. (1998) during the balancing of the model. This does not include sea grass and therefore is an underestimate of the biomass of the kelp/sea grass group. The input parameters and Ecopath-generated outputs for primary producers and all subsequent groups are summarized in Table 4.1. 50 Table 4.1 Parameter estimates of functional groups in the Present model of the Strait of Georgia arranged in order of ascending trophic level. Values in BOLD characters are outputs calculated by the Ecopath software. Group / parameter B (t-km2) P/B (year1) Q/B (year1) EE (-) EX (t-km2) Trophic level Omnivory Index Detritus 7.000 0.00 0.000 0.929 0.000 1.0 0.347 Phytoplankton 41.460 200.00 0.000 0.600 0.000 1.0 0.000 Kelp / sea grass 200.000 4.43 0.000 0.021 0.000 1.0 0.000 Herbivorous zooplankton 16.138 55.00 183.300 0.950 0.000 2.0 0.000 Shellfish 220.500 0.50 5.600 0.258 0.266 2.0 0.000 Grazing invertebrates 400.000 3.50 23.000 0.378 0.203 2.1 0.053 Carnivorous zooplankton 34.140 12.00 40.000 0.950 0.001 2.4 0.240 Predatory invertebrates 9.100 1.65 8.800 0.713 0.076 2.5 0.285 Shorebirds 0.001 0.10 92.000 0.000 0.000 3.0 0.000 Jellyfish 15.000 3.00 12.000 0.134 0.000 3.1 0.056 Herring 6.500 0.60 9.000 0.911 1.910 3.2 0.038 Eulachon 0.657 2.00 18.000 0.950 0.002 3.2 0.040 Small pelagics 15.295 2.00 18.000 0.950 0.020 3.2 0.038 Seabirds 0.020 0.10 91.700 0.044 0.000 3.3 0.690 Misc. demersal fishes 12.600 1.00 4.200 0.663 0.111 3.4 0.198 Transient salmon 6.370 0.42 2.500 0.500 0.082 3.4 0.190 Hake 35.500 0.72 5.000 0.900 0.986 3.5 0.130 Dogfish 8.700 0.20 5.000 0.040 0.064 3.7 0.281 Resident salmon 1.929 1.32 3.820 0.950 1.656 3.9 0.199 Toothed whales 0.040 0.02 7.300 0.740 0.000 4.1 0.284 Halibut 0.004 0.44 1.700 0.568 0.001 4.1 0.078 Lampreys 0.200 0.90 3.000 0.000 0.000 4.2 0.021 Lingcod 0.050 0.58 3.300 0.753 0.001 4.3 0.192 Pinnipeds 0.600 0.06 8.100 0.802 0.000 4.5 0.043 Transient orcas 0.004 0.02 7.400 0.000 0.000 5.5 0.009 Zooplankton Plankton is considered as three functional groups: herbivorous zooplankton, carnivorous zooplankton, and jellyfish. Input parameters for all three groups are the same as previous models (Pauly and Christensen 1996) and are summarized in Table 4.1. Benthic invertebrates The macro-benthic invertebrate group in Guenette (1996), was split by Dalsgaard et al. (1998) into grazing invertebrates22, predatory invertebrates23, and shellfish2 4. These groupings remain the same for this model. Biomass estimates for all three groups were obtained by synthesizing data from five comprehensive studies by Ellis (1967a, 1967b, 1968a, 1968b, and 1968c) described in Pauly and Christensen 1996. Commercial fisheries for all three groups are summarized in Table 4.2. 2 2 Grazing invertebrates includes annelids, polychaetes, sipunculoids, echiuroidea, porifera, most arthropods, amphipods, copepods, cumaceans, barnacles, isopods, ophiurids, holothurians, echinoids, amphineura, nemerteans, shrimps, cnidaria and others. 2 3 Predatory invertebrates include crabs, and octopus. 2 4 Shellfish include all gastropods and bivalves. 51 Table 4.2 Average commercial catch in the Strait of Georgia of various species groups represented in the present model. Landings are from statistical areas 13-19, 28 and 29 averaged for the years 1990 to 1996 (Source: Department of Fisheries and Oceans, Catch Statistic Unit, Vancouver). Species Group Average catch (t-yeaf1) Catch (t-km2 year'1) Grazing invertebrates" 1399.0 0.203 Predatory invertebrates'3 523.6 0.076 Shellfish0 1835.0 0.266 Herring 13178.0 1.910 Eulachon 14.7 0.002 Misc. demersal fishesd 663.0 0.096 Resident salmone 401.0 0.058 Transient salmonf 10197.0 1.480 Hake 6806.0 0.986 Dogfish 440.0 0.064 Halibut 8.4 0.001 Lingcod 2.8 O.001 a prawns, shrimps, sea urchins, sea cucumbers; crab and octopus;c misc. clams, geoducks, horseclams, and scallops;d flounder, sole, turbot, misc. rockfish, Pacific cod, Pacific ocean perch, sablefish, and skate;e coho and chinook,f pink, chum, sockeye. Birds Seabirds and shorebirds were included as two separate groups. A l l parameters for the seabirds came from a detailed analysis in a prior model (Wada 1996). His analysis averaged the population and Q/B of 12 categories of the most abundant sea bird species in the Strait to estimate representative Ecopath parameters.25 Shorebird biomass is estimated to be less than 0.001 t-km"2 and values for P/B and Q/B were set equal to those for seabirds (Dalsgaard et al. 1998). 2 6 Herring Pacific herring (Clupea pallasi) is the most important forage fish in the Strait as well as an important commercial species. Because of its importance, quantifying the amount of herring in the Strait has been the subject of considerable study and controversy (review in Stacker 1993). According to some estimates, spawning population biomass has fluctuated between 20,000 t and 120,000 t tonnes since 1970 (Schweigert and Fort 1994). Herring in the Strait is thought of generally as two types: resident and migratory. When considering biomass inputs for the Ecopath model, the proportions of each are important. Glavin (1997) explains two different accepted views of the present day herring population. One is that there is one large migratory population spawning in the Strait with other smaller resident populations comprising approximately five percent of the herring biomass. The other view claims 2 5 Seabirds include: glaucous-winged gull, cormorants (double-crested, pelagic, and Brandt's), grebes (all species), scoters (white winged and surf), other diving ducks (golden eyes), pigeon guillemot, other auks, and great blue heron. 2 6 sandpipers, dunlins, and plovers 52 that there are several migratory populations spawning in the Strait, and a dozen smaller resident populations comprising approximately a third of the herring. Due to the controversy, the assumption was made that 20% of the herring today are resident and that the migratory population is present in the Strait for 20 weeks (Hay and Fulton 1983). These assumptions combined with herring population biomass estimates (80,000 t) from DFO (Schweigert et al. 1996) give an average present day biomass of 6 t-km'2. Values for P/B (0.6 yea r 1 ) and Q/B (18 yea r 1 ) were from Venier (1996). The Q/B value was halved (9 yea r 1 ) taking into account that herring feed less in the winter (Stacker 1993). Small pelagics27 The biomass was estimated by Ecopath and P/B, Q/B, and E E were taken from Venier (1996). Present day catches of this group are too small to include in the model. Eulachon Eulachon (Thaleichthys pacificus) was added by Dalsgaard et al. (1998) to the original Present model because of its historical and cultural importance to many First Nations in the province. Aside from species-specific diet information and a small present day catch, no data were found, and therefore the group was given the same input parameters as the small pelagics. The biomass was left blank and calculated by Ecopath. Miscellaneous demersal fish A biomass estimate of 4.84 t-km"2 based on DFO records for the major commercial species was the only data available for demersal fish (Stocker and Fargo 1994). 2 8 Many important non-commercial demersal species are found in the ecosystem that are important as forage fish, and therefore Venier (1996) increased this value to 13 t km"2. Dalsgaard et al. (1998) later decreased this value to 12.6 t km"2 which is the value inputted into this model. Commercial catch consists of flounders, Pacific cod (Gadus macrocephalus), Pacific Ocean perch (Sebastes alutus), pollock (Theragra chalcogramma), rockfish {Sebastes spp.), sablefish (Anoplopoma fimbria), skate (Raja spp.), sole species, turbot (Atheresthes stomias), and perch species to total 0.111 t-km^-year 1 (Table 4.2). Salmon One of the features that was criticized in the original Strait of Georgia model, in Pauly and Christensen (1996), was that it considered all salmon as non-eating temporary visitors. Thus, Dalsgaard et al. (1998) divided salmon into two groups. The first group, chinook and coho salmon, are considered to have some portion of their population resident in the Strait throughout the year. Sockeye, chum and pink salmon are considered to be seasonal non-eating transients during spawning 2 7 This group consists of squid and fish such as smelt, sardines, anchovies, sandlance, and others. 2 8 This group includes all fish living in the benthic environment with exception of lingcod, halibut, and dogfish. The group is comprised mainly of rockfish species, Pacific cod, walleye pollock, soles, and flounders. 53 migrations to rivers. Biomass estimates were unavailable for either group and therefore were calculated by Ecopath. Ecotrophic efficiency was assumed to be 0.95 for resident salmon and as 0.5 for transient salmon assuming that 50% of the salmon escape to the spawning rivers. Dalsgaard (1998) used P/B values for both salmon groups derived from means in Ricker (1976). I kept these values for the transient salmon but changed them for resident salmon. For resident salmon P/B was decreased from 3.9 year"! to 1.32 year"! based on information from Bradford (1995). The Q/B is zero for transients under the assumption that they do not eat during the period in which they are in the Strait. A revised Q/B value (3.82 year"!) for resident salmon was estimated using the empirical equation of Palomares and Pauly (1998), with an aspect ratio of the caudal fin of 2.5 2 9, asymptotic weight of 7.5 kg (Browning 1980) and an average ocean temperature of 10°C. At present, commercial catches of salmon average 0.058 t-km^-year 1 for resident and 1.478 t-knf 2-year"l for transient (Table 4.2). Aboriginal catch today is 169 tonnes (0.024 t-km^-year 1) of resident and 1,228 tonnes (0.178 t-km^-year 1) of transient salmon 3 0. Hake Pacific hake is the most abundant resident fish in the Strait of Georgia, estimated at 245,000 t in 1993 (Stacker and Fargo 1994). The population was discovered in 1974 but not commercially exploited until 1978 (Levy et al. 1996). P/B (0.72 yea r 1 ) and Q/B (5.0 y e a r 1 ) values were taken from Venier and Kelson (1996). Dogfish Dogfish living in the Strait of Georgia and Puget Sound are considered to be one population (Ketchen et al. 1983) estimated at 60,000 t (Stacker and Fargo 1994). For the purpose of this model, the population was assumed to be evenly distributed with one half in Puget Sound and the other half in the Strait of Georgia equaling 4.3 t-krn 2 in the Strait. Present day commercial catches are estimated as 0.064 t-km"2-year1 (Table 4.2). Halibut Halibut is occasionally caught (0.001 t-km^-year 1) in the Strait today, indicating that the species does exist to a small degree (Table 4.2). Input parameters of B (0.004 t-km"2), Q/B (1.73 yea r 1 ) , and P/B (0.44 y e a r 1 ) came from values for halibut on the Southern B . C . Shelf (Venier 1996). 2 9 The aspect ratio used was derived for steelhead salmon. 3 0 Department of Fisheries and Oceans, Catch Statistics Unit (Fax), October 27, 1997. 54 Lampreys A l l data for this group were derived from Beamish and Youson (1987), including the biomass of 1.04 t-km"2 (Buckworth 1996). Lamprey are present in the Strait for about 10 weeks when they feed on herring (86%) and salmon (14%), and therefore P/B is estimated to be 0.9 year"! taking into account only the 10 weeks that lampreys occur in the Strait. While in the Strait, lampreys k i l l and/or consume an estimated 19,600 t of herring and 3,200 t of salmon (Dalsgaard et al. 1998). The sum divided by the total biomass results in a Q/B-3 yea r 1 . Lingcod Based on catch and effort data starting in 1951, present day lingcod biomass is estimated at 0.05 t-km"2 (Martell and Wallace 1998). Cass et al. (1990) estimate the survival rate for adult male and female lingcod combined (age 6 to 12) to range between 0.52-0.68 with an average of 0.6. This gives a total mortality rate of 0.4 and thus a P/B value of 0.4 yea r 1 . The Q/B value of 3.3 y e a r 1 came from Venier and Kelson (1996). Mammals Marine mammals were divided into three groups, toothed whales, transient orcas, and pinnipeds31: A detailed analysis of their input parameters and diet compositions are described in Winship (1998) and may be found in Appendix 4.1. Diet Compositions The diet compositions for each functional group were based on published estimates and then modified during the balancing of the model (Table 4.3). 3 1 toothed whales (resident orcas, Dall's porpoise, and harbour porpoise), transient orcas, and pinnipeds (harbour seal, Steller sea lion, and California sea lion) 55 co ™ • CD CO T3 a cd so r-*, -a 3 CD CJ CO H - l O I H CJ -a u-o e 00 o CH c CJ J3 CJ J3 CJ o s _ O N CJ w >. . 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References • CM CO to m CD CO 0 CM *r 0 CO •t m • Transient orcas • • • • • 0.001 I 0.003 | • • • 0.108 | 0.100 | • • 0.788 | • • Pinnipeds • 0.001 I 0.001 I • • 0.050 | 0.010 I 0.070 | 0.450 | 0.040 | 0.120 | • 0.100 I • • 0.030 | 0.128 | Lampreys 0.038 | • • • 0.100 I • 0.150 | • 0.138 | 0.338 | 0.038 | 0.100 | 0.038 | • • • 0.010 | 0.050 | • • Lingcod • • • • • 0.860 | • • • 0.031 | • • • • 0.109 | • • • • • Yeiloweye • • 0.100 I 0.250 | • 0.250 | • 0.400 | • • • • • • • • • Halibut • • • 0.120 O.2O0 j • 0.5O0 | 0.180 | • • • • • • • • Toothed whales • • • 0.146 • 0.146 | • • 0.050 | 0.002 | 0.189 | • 0.113 | 0.019 | 0.241 | • • 0.094 | • • • • • Resident salmon 0.065 | • • 0.265 | • 980 0 | 0.014 | 0.450 | • 0.120 | • • • • • • • • • • Sturgeon • • • 0.250 | • • 0.500 | 0.240 | • • • • • • 0.010 I • • • • • Baleen whales • • • 009 0 | • 0.100 | 0.200 | 0.100 | • • • • • • • • • • • Dogfish • 0.050 | • 0.680 | 0.010 I 0.005 | 0.005 | 0.005 | • 0.150 | 0.025 | 0.010 I • • • 0900 • • • • Hake • • 0.050 | • 0.784 | • • 0.001 | 0.005 | 0.110 | • • • 0.050 | • • • • • • • Transient salmon • 0.350 | 0.490 • 0.040 | • • • • 0.120 | • • • • • • • • • • • Misc.dem. fish • 0.050 j 0.150 | 0.299 | 0.271 j 0.080 j • • • 0.040 | • 0.100 | • 0.010 | • • • • • • • • • • Seabirds 0.010 I • 0.060 | 0.200 | 0.190 | • • • 0.060 I 0.007 | 0.153 | • 0.150 | • • • • • • • • 0.170 | Small pelagics 0.400| 0.100 0.500 Eulachon 0.500| 0.500| Herring 0.450| 0.100I 0.450| Jellyfish 0.770| 0.2001 0.030| Shorebirds 0.115| 0.885| Predatory invb. 0.2211 0.252| 0.0271 0.500| Cam. zooplankton 0.150| 0.4001 0.4501 Grazing invertebrates 0.240| 0.002] 0.050| 0.708| Shellfish 1.000| Herb, zooplankton 0.9001 8 O Prey\ Predator Phytoplankton Kelp/sea grass 1 Herb, zooplankton | Shellfish | Grazing invertebrates j Cam. zooplankton J Predatory invts. | Shorebirds | Jellyfish | Herring | Eulachon | Small pelagics | Seabirds | Misc.dem. fish | Transient salmon | Hake I Dogfish | Baleen whales | Sturgeon | Resident salmon ] Toothed whales | Halibut | Yeiloweye | Lingcod | Lampreys I Pinnipeds | Transient orcas I Detritus | 56 cd cd e o CO <u _ X - ° O (U PQ -c c* o O 03 C/3 o ts cd o E >--=! 'r; tjT) (U N aj > <» « l cn S 2 0 8 A c « S 1 3 2 M O (U O o, . <D « o cr JS ^ —-< cd O 8 -g • 2 £ 60 O s « r h C ^ <U O g cd p ca — . cn U y > PH —1 u o 2 ^ 0 S 1 ° c d . £ o I " 53 cd < N > i s PH cd P A S T M O D E L O F T H E S T R A I T O F G E O R G I A The Past model of the Strait was obtained by modifying the Present model. Three functional groups which are ecologically extinct at present, yelloweye rockfish (Sebastes ruberrimus), sturgeon and baleen whales, were added to reflect their past abundance. A l l P/B and Q/B input parameters for the other functional groups were kept the same, biomass was adjusted based on sources indicating a change in abundance, and E E was usually an output generated by Ecopath. Sources of Information for Past Model Catch Statistics The Annual Reports of the Department of Marine and Fisheries were the primary source of historical catch information for the period of 1890-1900. These reports were written by the British Columbia Inspector of Fisheries and published in the annual Canada Sessional Papers (as described in Chapter 2). These documents present the amount of fish caught in marketed form (e.g., barrels of salted salmon), district in which the fish were caught, and a written summary of that year's most noteworthy events. Historical Accounts Accounts of the early explorers of the coast provided interesting information on species distribution and abundance. For example, The Naturalist in British Columbia (Lord 1866), describes the eulachon fishery of the aboriginal people and estimates that, "seven hundred weight [of oil] wi l l be made by one small tribe." Although a lot of interpretation is required with this type of information, it does lead to tentative estimates of catches and biomass when no other data are available. Archaeology Literature Most of what is known about historical aboriginal diet comes from archaeological information derived from middens. This information was used to determine relative importance of species in the diets of the first peoples. From this literature it emerges that salmon and shellfish were the most important seafood consumed (Mitchell 1988b). Anthropology Literature Stories passed down from generation to generation provide information on historical abundance and distributions of species. For example, the Sechelt Nation describes porpoise as an important component of their diet (Peterson 1990). However, porpoise are a rare occurrence in that area today. 58 Newspapers and Magazines In the later part of the 1800s, newspapers were great sources of fisheries information. In particular, whaling exploits were regularly reported. Consequently, this information was compiled and used to derive an estimate of the Strait of Georgia whale population. Photographs Historical photographs confirm the presence of certain species in an area. As well, some photographs, i f accompanied by a written description can provide other information. For example, I found one photo of a pile of rockfish with the caption, "450 lbs of cod, two rods, two hours" (UB.C. Special Collections, Spilsbury Photo Collection, Box 25). This information expressed in fisheries terminology is equivalent to catch per unit effort which is used as an indicator of abundance. Maps and Charts Maps often have places with animal names which can provide interesting information. For example, in the Strait there is 'Ballenas Channel' named by the Spaniards after the whales that once existed there. Other examples include Halibut and Sturgeon Banks, named by fishers who fished for those species, whereas now, both species are considered commercially extinct in the Strait (Canadian Hydrographic Chart LC3001). Expert and Workshop Opinions Experts provided estimates of historical abundance when no quantitative data sources were available. This was done on an individual basis, and formally at a workshop held in November of 1997 (Wallace et al. 1998). Participants (mostly experts) at the workshop were asked to estimate changes in functional group biomasses. Interviews Interviews with First Nations peoples were conducted to gain insight into resources used historically by aboriginal people (Salas et al. 1998). Cross-validation of Sources Having numerous sources allowed for cross-validation of information. This was true for a number of the model inputs. For example, porpoise was found to be an important component of aboriginal peoples diet, the Sessional Papers indicate that porpoise was caught and combined with dogfish to produce "fish oils", and as well, the bay at the end of Sechelt Inlet was once called 'Porpoise Bay'. Based on this information it can be deduced that porpoise abundance in the Strait of Georgia was greater than present day. Although much of the historical data was qualitative, cross-validation is a useful method for basing quantitative assumptions. 59 Input and Output Parameters of Functional Groups for the Past Model Primary producers In the workshop, consensus was that the phytoplankton abundance in the Strait one hundred years ago, i f any different, would be lower than it is today, as land-based sources of nitrogen have likely increased production (Wallace et al. 1998). However, with no sources quantifying any difference, it was decided to keep the values consistent between models. Sea grass beds in the marsh areas around the Fraser and other rivers that flow into the Strait were much larger 100 years ago than today (Levings and Thorn 1994). A n increase of 25% was entered into the model based on workshop discussions. Benthic invertebrates This estimate was increased by 25% for all three groups in this category for the Past model based on the assumption that there was 25% more habitat as kelp/sea grass group serves as habitat. No commercial catch data were found for the Past model. Birds No changes were made with the seabird numbers for the Past model. In the Past model, the shorebird biomass was doubled considering a population of Brandt's geese that once frequented the Strait in greater numbers (Campbell et al. 1990, White and Spilsbury 1988). Herring In the workshop it was put forward by Doug Hay that the amount of herring living in the Strait today is close to carrying capacity (Wallace et al. 1998). This would imply there is no reason to believe that the biomass of herring one hundred years ago was much higher than it is now. However, the fraction of resident fish may have been higher so that, on a yearly basis, the biomass would have been slightly higher. Assuming that 30% of the herring was resident in the Strait one hundred years ago, compared to 20% today, the biomass would have been approximately 7 t-km"2 (Dalsgaard et al. 1998). Historical catch was estimated to be 0.024 t-km"2-year"' during the 1890s (Table 4.4). 60 Table 4.4 Summary of input and output parameters of the balanced Past model of the Strait of Georgia. Values in BOLD were calculated by Ecopath software. Group / parameter B P/B Q/B EE Catch Trophic Omnivory (t-km2) (year1) (year1) (t-km2) level Index Detritus 7.000 0.00 0.00 0.943 0.000 1.0 0.358 Phytoplankton 42.292 200.00 0.00 0.600 0.000 1.0 0.000 Kelp/sea grass 200.000 4.43 0.00 0.021 0.000 1.0 0.000 Herb, zooplankton 14.914 55.00 183.00 0.950 0.000 2.0 0.000 Shellfish 220.500 0.50 5.60 0.437 0.230 2.0 0.000 Grazing invertebrates 400.000 3.50 23.00 0.402 0.000 2.1 0.053 Cam. zooplankton 29.58 12.0 40.00 0.95 0.000 2.4 0.240 Predatory invertebrates 11.000 1.65 8.80 0.931 0.000 2.5 0.285 Shorebirds 0.002 0.10 92.00 0.000 0.000 3.0 0.000 Jellyfish 15.000 3.00 12.00 0.171 0.000 3.1 0.056 Herring 9.966 0.60 9.00 0.970 0.029 3.2 0.038 Eulachon 1.300 2.00 18.00 0.803 0.011 3.2 0.040 Small pelagics 11.603 2.00 18.00 0.950 0.013 3.2 0.038 Seabirds 0.020 0.10 91.70 0.044 0.000 3.3 0.688 Misc.demersal fish 38.000 1.00 4.20 0.981 0.020 3.4 0.200 Transient salmon 23.054 0.76 2.50 0.129 0.836 3.4 0.194 Hake 9.000 0.72 5.00 0.825 0.000 3.5 0.330 Dogfish 8.700 0.20 5.00 0.257 0.259 3.7 0.130 Baleen whales 1.900 0.02 3.40 0.110 0.001 3.7 0.153 Sturgeon 0.020 0.22 5.60 0.482 0.001 3.9 0.265 Resident salmon 5.072 1.32 3.82 0.531 0.423 3.9 0.056 Toothed whales 0.200 0.02 2.30 0.740 0.000 4.1 0.257 Halibut 0.140 0.44 1.70 0.552 0.034 4.1 0.188 Yelloweye 1.500 0.15 3.44 0.790 0.014 4.2 0.077 Lingcod 1.500 0.58 3.30 0.879 0.030 4.3 0.054 Lampreys 0.200 0.90 3.00 0.000 0.000 4.3 0.195 Pinnipeds 0.470 0.06 8.10 0.827 0.000 4.6 0.129 Transient orcas 0.004 0.02 7.40 0.000 0.000 5.4 0.083 Eulachon Historically, eulachon has played a very important role to aboriginal people. They caught the fish in the spring as it ascended the Fraser River to spawn, extracted its oil and used the product as a supplement to the diet (Drake and Wilson 1991). Macfie (1865) wrote: The Indians catch this species of fish by impaling them on rows of nails as the end of a stick about four feet long, and so thickly do they swarm, that every time this rude implement is waved in the water, two or three of them adhere to it. Oil produced from the eulachon was traded throughout the province along the so called 'grease trails' (Harrington 1967) indicating the importance of eulachon to First Nation's culture. To produce the oil required considerable amount of raw material. Lord (1886) describes that each small tribe would take 700 cwt (32 tonnes) of oil . According to Glavin (1995), 12 tons (5.4 tonnes) of fresh eulachon may be needed to produce 200 gallons (910 litres) of oil, and Stacey (1995) reports from historical evidence that 1 ton (0.45 tonnes) is required for 10 gallons (45.5 litres). Unfortunately determining 61 the volume of eulachon grease consumed that originated from the Strait is not possible, and therefore a biomass can not be determined using this approach. There is little known about eulachon abundance over time given its historical importance. In the 1889 Sessional Paper the Fisheries Inspector wrote: As the delicacy of these fish becomes better known, each year finds an increasing demand, and when the Fraser River fails to supply them they are brought from the Nass, these being the only two streams in this Province where they are found in quantities, especially in the latter, and where hundreds of tons are wasted each season by being caught (principally by American Indians) and allowed to decay on the bank. Past abundance of eulachon was undoubtedly much greater, but there is only qualitative evidence. Present day estimates are unknown. Considered a conservative guess, the biomass estimate from the Present model was doubled and entered in the Past model. Small pelagics With no evidence suggesting otherwise, the biomass in the Past model was assumed to have been equal to that of the Present. Miscellaneous demersal fishes For the Past model, yelloweye rockfish were added as a group. They are found in extremely low abundance in the Strait today (Kronlund et al. 1998), but historically there is evidence indicating otherwise. In an 1886 expedition exploring fisheries resources in the North Arm Burrard Inlet, the inspector of fisheries describes whiting [walleye-pollock] and the "large red rock cod" [yellow-eye rockfish] as being "plentiful."3 3 Between 1890-1895, landings of "rock cod" in the Strait averaged 94 tonnes34. Qualitative anecdotal information pertaining to the abundance of yellow-eye rockfish is from descriptions of the early hand-line lingcod fishery between 1914-1920 where, at that time there was no market for red snapper [yellow-eye rockfish], the average boat caught three or four red snappers for every lingcod. The fishermen simply threw them overboard as they caught them~I can recall seeing long strings of these bloated red fish floating away from the stern of every cod-fishing boat—miles of them. (Spilsbury 1990) Canada, S i , 1889, no. 17, p. 250. Canada, S i , 1886, no.ll, p. 276. Canada, S i , 1890-95 62 Clemens and Wilby (1961) state that: In February, 1942, several large catches of red snappers were seen at Vancouver fish docks, the fish having been caught near Pender Harbour....These were mostly of large size up to 3 feet in length. In the photo described earlier on page 59, there are six large yeiloweye rockfish weighing at least 12 kg each indicating the prior abundance of this species. This is consistent with information obtained from an interview with Tor Miller, an ex-lingcod fisher, who fished during the 1930s in the Strait who recounted that some days he would catch "400 pounds of snapper, but only 300 pounds of lingcod." Based on this cross-validation of historical information, it was assumed that biomass of yeiloweye rockfish would have been at least equal to that of lingcod. A biomass value of 1.5 t-km"2 was entered, and life history parameters derived for B . C . shelf rockfish species were used (Venier and Kelson 1996). For other demersals, the catch per unit of effort data (CPUE) of sole from Levy et al. (1996) showed a decrease to one third of its original value from the late 1970s to the early 1990s. Based on this, and consensus in the workshop, the biomass of the group was conservatively assumed to have been three times higher one hundred years ago. Catches published in the Sessional Papers from one hundred years ago listed an average catch of 0.0243 t-km"2-year"' consisting of cod (rockfish, sablefish, and Pacific cod), whiting (walleye-pollock), and flatfishes (soles) (Table 4.4). Salmon Carl Walters (in Wallace et al. 1998) suggested that one hundred years ago, resident salmon might have been 10 times more abundant than today, while transient salmon (mostly sockeye) may have been twice as abundant. These suggestions were used to obtain preliminary biomasses for the 100 year model (later changed in the balancing of the model). Catch statistics from a hundred years ago did not list catches by species. The biomass ratio between the two groups was therefore used to split the catch with roughly 1/3 or 1.11 t-km'^year"1 on resident salmon and 2/3 or 2.22 t-km"2-year"' on transient salmon. Hake Since hake populations in the Strait were only discovered in the 1970s, no prior historical information exists. Biomass estimates from the 1970s (Levy et al. 1996) were about 1.5 times lower than in 1993 and Dick Beamish (in Wallace et al. 1998) suggested that hake might have been 10 times less abundant one hundred years ago. A conservative guess of 25% of the present day hake biomass was used in the Past model. There are no known catches from 100 years ago. 63 Dogfish Dogfish has been caught historically for a number of reasons, and therefore has been subjected to periods of intensive exploitation. Dogfish was one of the most important marine resources at the beginning of British Columbia's commercial fishery between 1870-1890 (Ketchen 1986). A result was declining catches in the 1890s (the period considered in this model). The populations recovered and forty years later, in 1930, the landings peaked at 12,000 t. Based on consensus at the workshop, the present day biomass was used as representative value for the Past model. Commercial landings in the 1890s averaged 0.169 t-km"2-year"' (Ketchen 1986). Halibut Before commercial exploitation, halibut in the Strait certainly existed in higher abundance than at present day. However, the population could not withstand heavy fishing, and may have already disappeared by the 1890s (Thomson and Freeman 1930, Bel l 1981). The fish landed in Vancouver, and listed in the catch statistics from a century ago, were most likely taken from outside the Strait, on the rich banks of Juan de Fuca and the west coast of Vancouver Island. Fisheries inspector Thomas Mowat reports in 1887 that halibut "are met with only in average numbers along the Straits of Georgia." 3 5 With no data available to allow estimating the biomass or even the annual catch of halibut from within the Strait, it is conservatively assumed the biomass of halibut to be 20 times that of the present. Input parameters were assumed to be the same as the present model (Dalsgaard et al. 1998). Lampreys No changes were made with respect to the Present model. Lingcod The commercial fishery for lingcod in the Strait of Georgia dates back to the 1860s where the fish were caught from small vessels and kept alive until sold (Cass et al. 1990). According to Sessional Paper accounts, lingcod landings averaged 82 tonnes (0.012 t-km"2 year"1) between 1890-94 (Table 4.4). Based on a model by Martell and Wallace (1998), the past biomass was conservatively estimated to be 1.5 t-km"2. Canada, S i , 1887, no. 16, p. 261. 64 Sturgeon There is considerable evidence that sturgeon was far more abundant 100 years ago than present day (Glavin 1994). On August 14, 1897 the New Westminister Columbian reported a 1,390 pound [629 kg] white sturgeon being caught on the Fraser River and a unconfirmed report of one weighing 1,800 pounds [816 kg] also being caught. Wilkeson (1817-1889) wrote: Sturgeon of immense size are plenty off the mouths of the Fraser and other rivers. So abundant is this fish that isinglass made from it is a regular article of export by the Hudson's Bay Company. The parameters for the Past model and catches (0.027 t-km"2-year"') are described in Dalsgaard et al (1998). It is noteworthy to mention that only 4% of the population occurred within the Strait. Most of the catch was taken above Mission which is considered to be outside of the ecosystem boundaries considered in this model. Accordingly, only 4% of the catch (0.001 t-km^-year"1) was assumed to come from the Strait. Mammals A detailed description of 100 year ago biomasses for all marine mammal species can be found in Winship (1998; Appendix 4.1). The most conspicuous change is the presence of baleen whales. Humpback whales were once very abundant in the Strait (Merilees 1985). The British Colonist reported on September 28, 1869: The Howe Sound Whaling Company have caught two more whales. Several of these huge finny visitors have also made their appearance in Burrard Inlet and spouted their defiance at the millmen. The first whaling effort occurred in the Strait between 1866 and 1875 followed by a second episode between 1905 and 1908 (Merilees 1985). With advances in technology, the second episode took only two years to effectively wipe out the remaining population. Pre-exploitation population is estimated between 208-596, with 430 chosen as the number represented in the Past model (Winship 1998). Since this time there have only been sporadic sightings of humpbacks in the Strait. A symbolic catch of 0.001 t-km"2-year_1 was entered in the Past model and a biomass of 1.9 t km"2 year (-430 individuals). Aboriginal Catches The Coast Salish people living around the Strait obtained most of their food supply from the Strait (Barnett 1955). Salmon was probably the most important species, followed by shellfish, eulachon, herring, other pelagic fishes, dogfish, flatfishes, rockfishes, porpoise and others comprising smaller components of the diet. 65 Hewes (1973) estimated that aboriginal people on average consumed 583 pounds [264 kg] of salmon per capita per year. Assuming that 6,000 Coast Salish people lived around the Strait one hundred years ago (Duff 1964) gives a total consumption of 1,590 tonnes or 0.23 t-km"2-year"1. The biomass ratio of resident to transient salmon was used to split this consumption with 0.08 t-km 2-year_1 on resident salmon and 0.15 t-km"2-year"' on transient salmon. Estimated catch values of other fish species are speculative. Based on historical midden data, values were derived to account for exploitation of dogfish, demersal fish, and herring (Dalsgaard et al. 1998). Using the estimated annual consumption of salmon and assuming that salmon constituted 50% of the fish diet, 0.23 t-km"2-year"' of other fish must have been consumed. This consumption was proportionately distributed between dogfish, herring and demersal fish according to the amounts found in middens. Shellfish were also important in the diets of Coast Salish people. In this model, an assumption was made that 1/3 third of the seafood diet was from shellfish and the other 2/3 from fish. Other fish, such as halibut, were not as important to the Coast Salish as other fish as indicated by the following: Halibut are most abundant on the west coast of Vancouver Island, though occasional fish are taken on the eastern shore [Strait of Georgia]. They appear to vary greatly in quality and size, according to the locality, they are found in. Those brought to Victoria are very inferior. Halibut are to the westcoast Indian what the salmon are to those residing on the east coast or mainland. (Anon, 1891) Likewise, Thompson and Freeman (1930) wrote: The halibut was most important to the coast Indians, especially at Neah Bay [near Cape Flattery], Sitka, and the Queen Charlottes. Elsewhere the salmon exceeded it in amount, and on the whole, very greatly. Many other species were used also, such as the eulachon, or oolakan, and the herring. The oil of the eulachon and seal was preserved, and dried halibut was dipped in it before eating. A l l aboriginal catch data were added to the commercial catch data and entered into the Past model (Table 4.4). 66 B A L A N C I N G T H E M O D E L S Present Day Model Few changes were made to the balanced Present model (Dalsgaard et al. 1998). Salmon diets were changed based on a compilation of several studies on diets of all salmon species by P. Tyedmers (thesis in progress). The revisions were made to better represent the piscivorous habits of chinook and coho salmon. No other changes were made to the Present model. Figure 4.2 is a diagram representing the direction of energy flows in the Present model. Past Model A change to the diet composition coupled with a suggested ten fold increase of biomass of resident salmon resulted in an enormous predation pressure on herring in the Past model. However, increasing the present biomass of resident salmon by ten times is likely an overestimate. Present day biomass of resident salmon was estimated by Ecopath to be 1.9 t km"2 year"' (13,100 t), an increase of an order of magnitude would result in a biomass of 130,000 t, or a biomass twice that of herring. The largest recorded landing of coho in the Strait since 1950 occurred in 1951 with a landing of 1,600 t, and largest year for Chinook was in 1953 with landings of 1,900 t for a combined maximum of resident fish of only 3,500 t.36 In this model I assumed a conservative fishing mortality of 0.1 year"1 during the peak catch, which resulted in a biomass of 35,000 t. This is approximately two and a half times greater than today. A biomass of 5.07 t km"2 year"1 was therefore used for resident salmon in the Past model. Even with a revised value of resident salmon it was not possible to balance the model using the present day estimate of herring at 6.5 t km"2 year"1. Therefore it was decided to leave the biomass of herring as an unknown parameter while the E E , P/B, and Q/B were taken from the Present model. The estimated value by Ecopath was 9.49 t km"2 year"1 (65,000 t) for herring. Schweigert and Fort (1994) estimated a historical peak spawning biomass of herring occurred in 1954 with a value of 150,000 t. This is still within acceptable limits of herring production considering the herring fishery in the Strait alone removed 82,353 t in one year.37 Furthermore, the present day value of 6.5 t km"2 year"1 is based on spawning population biomass and not juveniles which are also present in the Strait. Changes in Diet Compositions To balance the Past model, changes in diet compositions of various species groups had to be modified in order to reflect the changes in abundance of various species groups. Since the biomass of hake was decreased to 25% of the present day value, predation from dogfish, lingcod, and pinnipeds 3 6 Department of Fisheries and Oceans, British Columbia Annual Catch Statistics, 1951 and 1953. 3 7 Department of Fisheries and Oceans, British Columbia Annual Catch Statistics, 1963. 67 was decreased and re-distributed to carnivorous zooplankton, miscellaneous demersals, and lingcod respectively. Changes were also made to the diet compositions of baleen whales and pinnipeds in the Past model of Dalsgaard et al. (1998). Merilees (1985) reports, presumably from a historical document, that In early December, good catches were made off the mouth of the Fraser River, where it was believed the whales [humpbacks] were lying in wait of small fish running up the river. As humpbacks are known to eat more small pelagic fish than other baleen whales (Jefferson et al. 1993), their diet was changed from Dalsgaard et al (1998) to include more herring, eulachon, and small pelagics (Table 4.5). Figure 4.3 is a graphic representation of energy flows in the Past ecosystem. Summary Statistics of the Two Ecosystems The two systems examined can be compared by examining the whole or their parts. Changes in abundance of individual species groups (the parts) are summarized in Table 4.6. The whole is expressed in terms of ecosystem maturity and is summarized on Table 4.7. 68 eo J3 C co 0> 3 CO 5 t o 0 0 CO CJ o cj M >. 6 0 ON C ON C cj o CO CO cj ^ CO •— 1 CJ CO rr] l . w " O CJ r- -G .S Q " H •* h 6 0 ^ 5 NO 2 o c ON CO — ( CO '& o cj o <+H o tU ON "S s — CJ cj a T3 *CJ O 3 E O . 3 -O C cj E CJ SO co g M E 3 « . PH 2 Q, ON g ON 2 43 E CJ O CO CO & _ 0 s CJ CO PJ E 1 :§ CL, CJ .S § « "7 g « ( N O fcl> c 6 0 NO -3 ° ^ 2 ON s — O w '+3 (H O CJ cH cj * > •2 S2 5 CJ a. *H C co « c ON ca vo . ON ON — VO ON • c CJ > ON ON CO O E CJ S ,w o <+H •S «3 . 1 3 CS II o 2 o a *H CJ co PH -a c w CO cj s crt CO P CO PH O PH .2 coQ % 2 « T 3 « J "cO S > cd o H 3 vo C ON co 2 g o w 5 ON •a £ 2 g Cn u vo references Transient orcas Pinnipeds Lingcod Lampreys Halibut Toothed whales Resident salmon Dogfish Hake Transient salmon Misc.dem. fish Seabirds Small pelagics Eulachon Herring Jellyfish Shorebirds Predatory invb. Cam. zooplankton Grazing invb Shellfish Herb, zooplankton 1 2\. 8 2 |3Aa~I O I L j d O J J . 70 Table 4.6 Summary of changes in biomass of species groups expressed as a percentage change the Present to the Past. Category Species Group Past (t km'2) Present (t km2) Change (%) Extirpated Groups Baleen whales 1.900 - OO Sturgeon 0.020 - OO Yelloweye 1.500 - oo Subtotal 3.420 -Decreased Groups Halibut 0.140 0.004 -3,400 Lingcod 1.500 0.050 -2,900 Toothed whales 0.200 0.040 -400 Misc. demersal fish 38.000 12.600 -202 Resident Salmon 5.072 1.929 -163 Shorebirds 0.002 0.001 -100 Trans, salmon 23.054 11.527 -100 Eulachon 1.300 0.664 -96 Herring 9.490 6.500 -46 Predatory invertebrates 11.000 9.100 -21 Subtotal 89.758 42.415 -112 Increased Groups Hake 9.000 35.500 75 Pinnipeds 0.470 0.600 22 Small pelagics 12.464 15.295 19 Cam. zooplankton 27.672 33.664 18 Herb, zooplankton 14.029 15.919 12 Phytoplankton 41.460 41.968 1 Subtotal 105.095 142.946 26 Groups with no changes Detritus 7.000 7.000 -Dogfish 8.700 8.700 -Grazing invertebrates 400.000 400.000 -Jellyfish 15.000 15.000 -Kelp/sea grass 200.000 200.000 -Lampreys 0.200 0.200 -Seabirds 0.020 0.020 -Shellfish 220.500 220.500 -Transient orcas 0.004 0.004 -Total 1,049.697 1,036.785 -1 RESULTS AND DISCUSSION Comparison of the Past and Present Day Ecosystem of the Strait of Georgia The Whole One of the most important results of the modelling exercise was demonstrating that the past system easily supported the biomass of species that are no longer present. This was supported not just by the model outputs, but also by qualitative and quantitative information collected from a variety of sources. However, whether or not the Strait of Georgia is less 'productive' today than in the past is a matter of perspective. The findings of these models discussed below indicate that both systems are in a state of high maturity (Odum 1969, Christensen 1995; Table 4.7) and the Strait at present supports an equal or greater biomass of top predators compared to the past. However there are substantial differences in the relative abundances of species and consequently the energetic pathways. Table 4.7 Summary of ecosystem attributes used to compare the Past and Present models of the Strait of Georgia. Ecosystem Attribute Present Past Production/Respiration 1.077 1.046 Production/Biomass 9.113 8.752 Biomass Throughput (%) 3.000 3.200 Finn's cycling index 17.80 16.800 Finn's mean path length 3.880 3.770 Ecosystem Maturity of the Strait of Georgia Ecosystem Odum suggested 24 attributes which could be used to assess the development of ecosystems (Odum 1969). Several of these have been integrated into ecosystem diagnostic routines in Ecopath (Christensen 1995), five of which have been selected to compare the state of maturity between the two systems. One indicator of system maturity is the ratio of primary production to total respiration (PP/R). In a mature aquatic system this ratio should approach one as production remains more or less constant, but respiration increases with the increase in the number of organisms in the system. No significant difference was observed between the Past model (1.046) and the Present (1.077). Both models demonstrate a high level of ecosystem maturity based on this indicator compared to a disturbed ecosystem such as San Miguel Bay in the Philippines, which was shown to have a value of 2.35 (Bundy 1997). The ratio of the total system productivity and total system biomass (P/B) was also similar between the two systems (Present: 9.113; Past: 8.752). There is a negligible difference 72 between the two systems, and compared to systems elsewhere, they are both high (Christensen and Pauly 1993). As a system continues to mature, the available energy should support an increasingly larger biomass. This can be measured as a ratio of Biomass/Throughput (%). Once again, the index of maturity between the two systems is similar (Table 4.7). The last indicator of system maturity is the Finn Cycling Index (FCI) which is the percentage of total throughput which is actually recycled. Total throughput is the sum of all flows, exports, respiration, consumption, and flows to detritus. Both systems show a low FCI. Christensen and Pauly (1998) tested 15 of Odum's 24 ecosystem attributes of mature systems by simulating the effect of a ten-fold increase in top predator biomass in two presently exploited ecosystems. The results of their study showed that exploited ecosystems can in theory support a much higher level of consumer biomass under the same level of primary production. In comparing the two Strait of Georgia ecosystems, the results did not demonstrate any differences in maturity. However, this is not surprising given the model inputs. Although there have been significant changes in relative abundance of species in the Strait during the last 100 years (Table 4.6), consumer biomass has been maintained at the same level, likely by a substitution effect (Daan 1980). Therefore as one species group is driven to low levels, another group at a similar trophic level occupies the same trophic niche. This is most clearly demonstrated in the models by examining the trophic similarities between hake and baleen whales. Both species groups have similar diet compositions and consequently occupy the same trophic level (3.5). As a result, the extirpation of humpback whales from the ecosystem had little effect on the overall energy flows in the model as large increases in the population of hake may have consumed the excess. Similarly, some species such as lingcod and yelloweye rockfish never occurred in sufficient biomass to have an impact on the indicators used to test the maturity of these models. The large biomass of hake also provides an ample food source for the pinniped group, which in turn provides the flow of energy to the apex predator, the transient killer whale. As a result, the Present ecosystem model contains a large biomass of high trophic level species resulting in a mature system in terms of its mean pathlength. Mean pathlength is the average number of species groups that a unit of energy passes through while in an ecosystem (Christensen 1995). Both ecosystems have high values of mean pathlength (Present: 3.88 Past:3.77) compared to heavily exploited ecosystems (Christensen and Pauly 1993). The similarity between the two systems in terms of ecosystem maturity may seem to suggest that there has been very little change to the Strait of Georgia ecosystem but that is known to be untrue. 73 The results, which simply reflect the input parameters for individual species groups used in the model, may not be different enough between models to be detected at an ecosystem level. Alternatively, the substitution effect of biomasses between similar trophic groups in the two models may have been sufficient enough to maintain aggregate system properties. If this is the case, aggregate ecosystem indices of maturity are not an appropriate diagnostic to assess ecosystem change in these two systems. Changes to the Parts I suggested in the previous section that the input parameters may not be different enough between models to detect a change in ecosystem maturity. From Table 4.6 of biomass changes, there are in fact large changes in high trophic level species groups. Most of the estimated changes have shown a decrease, with the exception of hake. Given that most of the lower trophic level species groups are the same between the models, the indices are not detecting the substitution effect. It is important for comparisons of maturity between two ecosystems that the biomass of primary production is similar between the systems as many of the indices involve a ratio using primary production. Both the Past and Present models were assumed to have the same primary production, and therefore this is not a relevant factor here. Working up the food-chain, the input parameters for zooplankton and grazing invertebrates were either left the same as the Present model or estimated by Ecopath. Higher trophic levels, particularly for fished species, is where most of the biomass changes are thought to have occurred. These changes are considered in the model. In the Past model, herring was increased by nearly 50%, miscellaneous demersal fish biomass was tripled, lingcod biomass was increased by 30 times, resident salmon by 2.5 times, transient salmon by twice as many, and baleen whales, sturgeon, and yeiloweye rockfish were added. The only decrease was in the biomass of hake, which was estimated to have been 25% of present day biomass, and a 25% decrease in the abundance of pinnipeds. Clearly, aggregated indices mask some of the ecosystem changes. Dynamic Simulations using Ecosim It was shown in the previous section that although the ecosystem models as a whole did not show dramatic differences in maturity, the relative abundance of species changed, indicating that dynamic processes are regulating population biomasses. There are several ecological hypotheses using mass-balance relationships which may explain the transition of the past system to the present day system. Using the mass balanced model of the past ecosystem, various fishing scenarios were tested using the Ecosim software which builds on Ecopath (Walters et al. 1997). The software converts the linear equations in mass-balance from Ecopath into differential equations, which can be integrated over time. The balanced state can then be artificially perturbed by 74 introducing various levels of fishing mortality to multiple or single species groups. Details of the workings and assumptions of Ecosim can be found in Walters et al. (1997). Ecosim has been used on a variety of mass-balanced Ecopath models to test 'what i f questions pertaining to present fisheries management scenarios (Bundy 1997, Trites et al. 1999). For this analysis, Ecosim was used primarily to examine how the Past ecosystem, when exposed to various fishing intensities on functional groups, could lead to an ecosystem structure similar to the Present model. The main simulation questions are: • Is there an ecological regime expressed in mass-balance relationships which accounts for the large increases in the biomass of hake while maintaining populations of over-exploited fish low? • What is the potential for recovery of exploited populations? Forces from both predation and competition could alter the biomass of hake. There are four important predator groups of carnivorous zooplankton represented in the Past model that have been exposed to intense fisheries (see diet composition matrix Table 4.5): baleen whales, dogfish, herring, and miscellaneous demersals. Furthermore, predators of hake in the Past model are primarily comprised of miscellaneous demersals and pinnipeds. Both groups have been exposed to periods of high exploitation over the last century which would lessen the predation pressure on hake. The combination of these ecological forces should theoretically create a trophic niche suitable for hake under the assumptions of the model. Ecosim allows the user to input the time period of the simulation. I used a period of one hundred years as this was the time period between the Past and the Present models. Simulations to test the effects of single species fisheries on ecosystem dynamics were made by adjusting fishing mortality on a species by species basis. Four species were examined by themselves, yeiloweye rockfish, herring, dogfish, and baleen whales. To test the effects of multi-species fisheries, the same fishing efforts were kept for the previous four species, but in addition, fishing efforts for seal culls, resident salmon, and miscellaneous demersals were also assigned. In all cases, periods of exploitation were simulated to represent the approximate duration and intensity of the fishery. For illustrative purposes, only species groups with a direct ecological interaction are displayed, but all groups were shown during the actual simulations. The first simulation was the removal of the baleen whales from the Past model (Figure 4.4A). This fishery was a brief but intense fishery which effectively extirpated the entire population of baleen 75 whales. Two clear results emerge from this simulation. The first is that, after their exploitation, baleen whales failed to recover despite nearly a century without whaling. From a tropho-dynamic perspective, the simulations suggest that once a population of an old-lived, slow growing species (i.e., humpback whales) is depleted, ecological processes, such as a competition and predation, may prevent a recovery of the population, even in the absence of a fishery. The second result is that the removal of baleen whales from the Strait did not have any noticeable effect on populations of other species groups. Although an ecosystem impact must have occurred, these results demonstrate that baleen whales were not a major ecological force from a trophic perspective within the assumptions and constraints of the model. 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 5 10 15 20 25 30 35 40 45 50 55 60 G5 70 75 00 65 90 95 Figure 4.4 Simulations of ecosystem effects of fisheries exploitation on A) baleen whales, B) yelloweye rockfish, C) dogfish, and D) herring. The fishing rate (Y/B) is the ratio of the yield (catch) to the biomass at each time step. 76 Similar to baleen whales, yeiloweye rockfish are also old-lived, slow-growing, and were found in low biomasses even in an unexploited system (Figure 4.4B). Although no information exists on their removal rates, this simulation assumed a fishing mortality rate of 0.05 for most of the century, with a period of higher rates during the peak period of the lingcod handline fishery. The simulation shows a steady decline in the biomass, but with little effect on other ecosystem components. Herring increased slightly in response to the depletion of yeiloweye, but otherwise no major ecosystem changes occurred. Figure 4.4C, simulates the dogfish fishery based on known exploitation rates (Ketchen 1983). Dogfish were heavily exploited from the 1940s to the late 1960s by reduction fisheries as well as government sponsored eradication programs in the early 1960s. Diet composition of dogfish in the model is composed of 68% carnivorous zooplankton (Table 4.5). The reduction of dogfish results both in the increase in carnivorous zooplankton, and a direct increase in hake populations which are competitors of dogfish in the model. Herring are considered to be the most important forage fish in the Strait. In this model, all of the higher trophic level species have herring in their diets. The results of simulating their depletion and subsequent recovery failed to show any major changes in ecosystem dynamics (Figure 4.4D). The most likely explanation is the model structure which over-aggregates some groups. As a result, there is no group completely dependent on herring, and therefore, as herring populations become depleted, predators of herring switch to an alternate species group. In the model, herring typically accounts for 25% or less of the diet requirements for each species group (Table 4.5) leaving considerable flexibility for alternate prey sources.38 The previous simulations examined the impacts of single species depletions on ecosystem dynamics. During the time period considered, nearly all species groups have undergone some form of exploitation. The combined effect of all of these removals is depicted in figure 4.5. Groups not individually examined in the single species simulations were included for simulations using multi-species, including resident salmon, miscellaneous demersals, and seal kills. The trends shown for the single species simulations continue using a multi-species simulation. Baleen whales, yeiloweye, and dogfish demonstrate severe population depletions under the multi-species simulations. Although hake biomass increases slightly in response to the depletions, it is small in comparison to the increase thought to have occurred. Nonetheless, the simulations do demonstrate that there is an ecological mechanism which accounts for the direction of observed change in many species. Lampreys are the only exception (diet consists of 86% herring). 77 It was also shown that even a low, steady, fishing pressure on certain species, such as yelloweye rockfish results in an inevitable depletion of the population. Recovery of these species may take decades, assuming that only trophic forces are at work. It was also demonstrated that some species, such as yelloweye rockfish, baleen whales, and others not shown, such as sturgeon, halibut, and lingcod, are not found in sufficient biomass to alter the tropho-dynamics of the system at the scale used in this model. Further improvements to Ecopath, such as Ecospace (Walters et al. 1998), wil l allow for the spatial segregation of ecological interactions which may indicate the importance of these species at smaller spatial scales. In summary, an ecological scenario that fully accounts for emergence of a large biomass of hake was not found. This is similar to Trites et al. 1999 who could not generate a scenario explaining the emergence of pollock in the Eastern Bering Sea. In my simulations, competition was found to more strongly influence the hake population than predation. That is, the removal of competitors by fishing dogfish and herring resulted in a population increase of hake. In contrast, large populations of seals/sealions and lingcod did not noticeably alter the hake population. The simulations show that the recovery of many species wil l likely take decades. Changes in the Commercial Fishery as a Result of a Shifting Ecosystem The previous section demonstrated how fisheries in the Strait of Georgia may have changed the ecosystem; this next section examines how the altered ecosystem has changed the fishery. In this section, commercial catch statistics from the Strait are combined with the trophic level outputs of the Present model (Table 4.1), to demonstrate how the changed ecosystem has resulted in a change in the mean trophic level of the fishery. 78 Mean Trophic Level of the Strait's Commercial Fishery Pauly et al. (1998a) conducted a trophic level analysis on species landed in global fisheries to demonstrate how humans have altered the trophic structure of ecosystem by 'fishing down the food web'. The conclusion of their analysis was that there has been a gradual loss of long-lived, high trophic level piscivorous bottom fish, therefore forcing fisheries into short-lived, low trophic level invertebrates and planktivorous pelagic fish. The results imply that food webs have undergone severe restructuring and that current fisheries exploitation is undesirable. Using trophic levels derived in the Present model (Table 4.1), the mean trophic level of the commercial fishery in the Strait can be calculated using: Mean TL=L(CfTLj) I EC# where Cj is the landed weight of each species group (j) in year (i), Q is the total catch of all species, and TL is the trophic level of each j (Table 4.9). A mean trophic level analysis was conducted using four combinations of data39. The first is a trophic level analysis of all commercial fish landings in the Strait.4 0 Because of the unique physical features of the Strait, a number of fish populations are considered to be resident only to the Strait of Georgia and Puget Sound. A second analysis is therefore conducted using only resident species, a third analysis uses resident species but excludes hake, and finally a fourth analysis uses only sedentary populations (i.e., populations with strong association with micro-scale habitats) (Figure 4.6). In Figure 4.6A, the steady mean trophic level is maintained despite a large decline in landings. During the 1950s and 1960s, high trophic levels were maintained by large catches of transient salmon, despite large quantities of herring bringing down the mean trophic level. The decrease in landings in 1967 from the collapse of the herring fishery had a slight increase effect on the mean trophic level, as would be expected. Present day trophic levels are maintained at a high level by large annual migration of salmon, and increasing catches of hake.. However, when migratory species are taken out of the landings, and only resident species are considered (Figure 4.6B), there is a distinct decline in the mean trophic level between the years of 1951-1989, at which time, large catches of hake (TL=3.5) account for an increase in the mean. The contribution from hake is solely responsible for maintaining the high T L as can be seen from Figure 4.6C. Removing hake from the data set results in a steady decline in the mean trophic level of resident species. Furthermore, when only sedentary species are included, the trend is even more dramatic, indicating the virtual ecological 3 9 All landings from Department of Fisheries and Oceans, British Columbia Annual Catch Statistics, 1951-1996. 4 0 Species groups caught in the Strait of Georgia commercial fishery: all salmonids, herring, halibut, sole, rockfish spp., lingcod, Pacific cod, sablefish, flounder, skate, dogfish, smelt, eulachon, sturgeon, hake, walleye-pollock, turbot, perch, abalone, clams, crabs, oysters, geoducks, horse clams, octopus, prawns, shrimp, scallops, sea cucumber, sea urchin, euphausiids, and squid 79 extinction of commercially important resident reef fish, and the switch to predominantly sessile invertebrates (Figure 4.6D). Landings of invertebrates, which are primarily old-lived species, increased at first, but have declined in the last 5 years as can be seen in the landings in Figure 4.6D. 4.0 3.5 3.0 2.5 2.0 A All species 100 80 60 40 20 1950 1960 1970 1980 1990 2000 1950 1960 1970 1980 1990 2000 0) > 0) Q . O c ro 4.0 3.5 3.0 2.5 2.0 B Resident populations 1950 1960 1970 1980 1990 2000 C c CO 20 15 10 5 0 1950 1960 1970 1980 1990 2000 4.0 3.5 3.0 2.5 2.0 C Resident species excluding hake 1950 1960 1970 1980 1990 2000 20 15 10 1950 1960 1970 1980 1990 2000 4.0 3.5 3.0 2.5 2.0 D Species with high site fidelity * " " * ^ W I » H . 1950 1960 1970 1980 1990 2000 Year 10 0 1950 1960 1970 1980 1990 2000 Year Figure 4.6 Mean trophic levels (left) of the Strait of Georgia commercial fishery between 1951 and 1996 and landings (right); for (A) all species, (B) resident populations, (C) resident populations excluding hake, and (D) species with high site fidelity. (Note: 1977 data were not available) 80 The trends shown in the trophic level analyses are consistent with the findings of Pauly et al. (1998a) and indicate that current fisheries exploitation in the Strait is ecologically unsustainable. Changes in the mean trophic level indicate a fundamental change in not only the resource base, but also in resource exploitation. This contradicts the common belief, that the resource base is fluctuating under natural forces and humans have little influence on the overall dynamics (Cushing 1982). It is unlikely that this trend can be reversed without significant changes in fisheries management. Restoration of the Strait of Georgia Ecosystem It was demonstrated throughout this analysis that the Strait of Georgia is different today than in the past as both an ecosystem and as a resource base. Large changes, primarily the depletion of resident high trophic level fish and whales, may have left a vacant trophic niche for hake which now has the single largest biomass of any species in the Strait. For the Strait to function in a capacity similar to the Past model would, for starters, require drastic changes to approaches of ocean management, and then a lot of luck beyond the realm of human control. A changed ecosystem can obviously never return to its precise former state. However, i f all the components still exist and are left alone, they may re-arrange themselves into a structure resembling that based on eons of natural selection. The previous mean trophic level analysis indicates that fisheries impacts have been most noticeable on resident fish and in particular those with small home ranges (Figure 4.6D). Fisheries management traditionally has not opted for spatially based management (Guenette et al. 1998), but the results of my analysis demonstrate that a larger percentage of present fisheries landings in the Strait are comprised of sessile or sedentary species (Figure 4.7). Restoring lost species which occupy small home ranges wil l require that some areas be completely closed to most or all forms of fishing. _ 60 Q . S" 40 c o T> '35 OJ £ 20 o u re O o 1950 1960 1970 1980 1990 2000 Year Figure 4.7 Percentage of commercial catch in the Strait of Georgia comprised of resident species between 1951 and 1996. Resident species are those which spend the adult stage of their life cycle in the Strait of Georgia. 81 The species most affected by fishing at small spatial scales in the Strait of Georgia are inhabitants of rocky reef habitats. This type of habitat in the past supported a much larger biomass of resident reef species such as lingcod, rockfish species, and abalone. Using estimates from Levings et al. (1983) and Luternauer et al. (1983) it is estimated that this type of habitat accounts for less than 5% of the Strait and is typically close to shore, making access to fishing very easy. For depleted species to rebuild to the same abundance, and consequently the same ecosystem structure, wi l l require that areas be closed to all fishing.4 1 Given the movement patterns of these species, it is at least within the realm of possibility to restore populations based on some form of spatial management. However, returns of some species, such as yeiloweye rockfish, may take decades to return even with the complete closure assumed in the simulations (see Figure 4.4). Although their populations are a small fraction of their historical abundance, commercial fisheries for yeiloweye still exist in the Strait despite C P U E being less than 1/kg per hour (Kronlund and Yamanaka 1997). Restoration of other impacted components of the ecosystem such as humpback whales and halibut, wil l depend on luck or perhaps a spill-over effect. Humpback whale populations have steadily increased globally since international protection in 1944 (Jefferson et al. 1993). In the North Pacific, humpback populations, once numbering approximately 12,500 are now estimated at 8,000 and are growing steadily.42 Although individuals are seen nearly every year passing through the Strait, humpbacks show strong site fidelity, indicating that re-colonization of the Strait may take a long time (Weinrich 1998). Furthermore, industrial commotion (i.e., vessel noise) may also act as a deterrent to recolonization. Halibut once occurring on 'Halibut Banks' were most likely strays as the habitat does not suit what we now believe is optimal (Ketchen 1983). However, it is known that as species' populations, and hence ranges, expand, sub-optimal habitats are utilized (MacCall 1990). If this process accounted for the Strait's halibut, the source population was likely from the Juan de Fuca Strait. Given that this population is also depleted, it is not likely that halibut wi l l soon return. For sturgeon to reoccupy 'Sturgeon Banks' wi l l require a change in management and patience. Despite a province-wide non-retention policy for white sturgeon, due to their listing as endangered by the Committee on the Status of Endangered Wildlife in Canada, there are still substantial levels of incidental catches in salmon fisheries as well as poaching (Echols 1995). Sturgeon can reach ages of over 100 years, are slow growing, and reach sexual maturity at between 11-22 years for males, and 4 1 More details on this in Chapters 5 and 6 where populations of two depleted resident species (abalone and lingcod) in marine protected areas are examined. 4 2 John Ford, Director of Marine Mammal Research, Vancouver Aquarium Marine Science Centre, conversation with the author, January 1999. 82 26-34 years for females (Scott and Crossman 1973). For sturgeon to have the opportunity to rebuild may require a change of Fraser River salmon fishing gears to more selective technologies. Incorporating Economic and Social Values into the Models As mentioned in an earlier section, both models are considered to be mature compared to other published ecosystem models. In terms of higher trophic level species, there is no indication from the models that there is less biomass of high trophic level species occupying the Strait today than in the past, contrary to both public and scientific opinion (Glavin 1996). However, the relative abundance of species groups in the Strait was shown to have changed dramatically to a system which may be less desirable from economic and social points of view. Economic Analysis The wholesale value of all resident species between 1951 and 1995, standardized to average coast-wide prices between 1995 and 1997, indicates that present value is higher than in the past, but has been steadily declining since 1985 (Figure 4.8). 4 3 High value has been maintained by a substitution effect of the fishing industry exploiting previously unmarketed species. The trend observed since 1985 wil l likely continue or at best stabilize in the future. This is consistent with the theory of fishing down the food web which suggests that initially there is an increase in catches followed by stagnating or decreasing catches (Pauly et al. 1998a). The commercially valuable, resident species comprising the new fisheries (i.e., since 1975) are slow growing and old-lived animals which throughout B.C. ' s history have been shown to be the most vulnerable species to overfishing. Furthermore, there is limited room for exploitation of 'new' species as most species are now fully utilized. Appendix 4.2 is a summary of the values used to calculate the prices. 83 10 -0 I . 1 1 * — 1950 1960 1970 1980 1990 Year Figure 4.8 Landed value of catches of resident species from 1951-1996 scaled to average prices of resident fish between 1995-1997. Prices for landed values from The 1997 British Columbia Seafood Industry in Review (B.C. Ministry of Fisheries (see Appendix 4.2)). Herring not included. 4 4 This analysis conservatively describes the trend in economic value. It only includes wholesale value of species, and therefore other economic benefits and opportunities such as recreational fishing, scuba diving, and whale watching are not included. The trend suggests that current and historical exploitation patterns are economically unsustainable and foreclose future opportunities. Social Indices Public concern regarding the changes in the Strait of Georgia ecosystem is evident by the amount of coverage of the issue in the regional media (Baron 1998, Hume 1998). Restoration of the Strait of Georgia ecosystem wil l be driven by social values, not trophic structure, and therefore a future analysis comparing the two modelled systems from a social value point of view would add an important dimension. Although no formal social survey was conducted, it is reasonable to suggest that the past ecosystem, as modelled, would be more socially valued than the present day modelled system. A n analysis using techniques such as paired comparisons (Chuenpagdee 1998) which combines both the scientific knowledge acquired and social values would likely gain credibility among managers facing the realities of public involvement in decision making. 4 4 Herring was not included because the present day fishery consists of a low-volume, high value roe fishery, whereas historically it was a high-volume, low value fishery used for reduction purposes. Including herring in the analysis would inaccurately demonstrate the changes in economic value. Al l other species included in the analysis are harvested for the same purpose (i.e., food). 84 C O N C L U S I O N Presumably, since ecosystem diversity is included in most definitions of biological diversity (Norse 1995), then ecosystems can be categorized as extinct, endangered, threatened or vulnerable similar to single species. A l l ecosystems embody dynamic processes, and therefore changes may be more akin to the Greek proverb, you can not cross the same river twice. The Strait of Georgia as presented in the Past model is extinct in that it wil l never return to that exact state, even i f left alone to do so. Some species in the system, due to human exploitation, are ecologically extinct or commercially extinct, their populations no longer structuring the ecological or economic system in which they are embedded. Regardless of the word chosen to describe the current status of the Strait of Georgia ecosystem, there has been a loss in structure and composition which wil l require a change in management, plus luck, to rebuild. It has been argued that fisheries management goals for severely depleted systems should be to rebuild and restore rather then sustain the present systems (Pauly et al. 1998c). Although this may be a worthy and achievable management goal in some systems, it should not be considered solely as a fishery objective in the Strait of Georgia. Rebuilding is more likely to happen as a biodiversity conservation objective similar to initiatives in terrestrial ecosystems driven by social values. Many of the lost species wi l l not 'rebuild' in time scales amenable to fisheries management; they do not and never did have large enough biomasses coupled with economic value to be an important management concern, and many depleted species do not have life histories compatible to sustain even low levels of fisheries exploitation. We can never go 'back' and the 'future' is by definition uncertain. Nonetheless the Back to the Future approach was shown to be valuable in synthesizing historical knowledge, developing new knowledge, and illustrating potential goals for present day marine conservation. Pauly et al. (1998c) state that this approach may "turn around what right now is a rather bleak situation in the Strait of Georgia." Past trends analyzed in this chapter suggest that serial depletion of resources is ecologically and economically unsustainable. 85 Chapter 5 Non-intentional Marine Reserves Introduction In the previous chapters it was shown how industrial fisheries on B.C. ' s coast have resulted in numerous ecological changes. Some fisheries have remained more or less constant, while others have been severely depleted. It has been argued that any successful long term fishery is a result of the target species having some form of spatial protection during vulnerable stages of their life cycle (Walters 1996). Typically, spatial protection from human exploitation is non-intentional, resulting o*from natural physical barriers such as depth, oceanographic conditions, and substrate which have made certain areas inaccessible to fishing. Marine reserves, which completely or partially remove human exploitation of living marine resources, have only recently been seriously considered as an intentional method of spatial protection to assist in managing habitats and species (Agardy 1997, Allison etal. 1998). Excluding the human predator from marine areas results in dramatic ecological changes. This has been shown in a number of reserves around the world (Roberts and Polunin 1991, Dugan and Davis 1993, Rowley 1994). However, enforced reserves that restrict some aspect of marine resource exploitation are not that common. This becomes problematic i f trying to understand their potential as a management technique. However, there are many areas that have non-intentionally restricted human access and as a result have had de facto protection. There are many different ways in which an area or even a species can receive de facto protection all of which provide valuable insight into the potential value of reserves. This chapter explores ecological changes occurring in non-intentional marine reserves to illustrate potential benefits of intentionally establishing reserves. The chapter describes anecdotal and published information on non-intentional reserves worldwide which were collected throughout my dissertation. Non-Intentional Reserves: Anecdotal Information In 1989, while visiting the Bay of Pigs in Cuba as a tourist, I had my first experience with non-intentional reserves. I was snorkeling on a reef in the Bay, and was amazed by the health of the reef, as most sites I had previously visited were depleted of fish, and the coral reef structures invariably had been destroyed. Ten minutes after entering the water I was ordered to leave by a machine-gun-86 slinging military officer speaking through a megaphone from a military jeep. At the time I was not interested in M P As per se, but as a lay person I observed an obvious difference in the ecology attributable to the military restrictions in the Bay. In 1741, when G. W. Steller discovered a population of sea cows in the Commander Islands, these easy prey had most likely been extirpated from most of their range by aboriginal people of North America (Domning 1973). This remnant population was geographically inaccessible to pre-historic hunting efforts and hence was protected. Once the refuge was found by Europeans, it took only 27 years to drive the last animals to extinction. In 1907, George Atkinson embarked on a journey to the Barents Sea : As this area was only exploited commercially by trawlers for the first time in 1905, an exceptional opportunity was afforded for the study of an accumulated stock of plaice unaffected by the influence of man. His study showed dramatic impacts between fished (North Sea) and unfished areas (Barents Sea). He then concluded that the "theoretical effects of overfishing were now being substantiated." It was noticed that with each passing year, the plaice landed became increasingly smaller. There were suggestions to close certain areas of the North Sea to allow for recovery, but the different nations could not agree on which areas. Then came the First World War, and a de facto closure took place due to extensive mine fields and naval craft. After four and a half years of respite, the fish were as large as the early days of the fishery, but by 1920 were once again depleted and small (Hardy 1965). World War II repeated the experiment, and post-war yields throughout all the northeast Atlantic increased up to 100% of the 1938 value. Military actions, while having obvious negative environmental impacts, have also provided numerous examples of de facto protection. Closed areas result from military bases, bombing ranges, and war zones. In California, the Vandenberg A i r Force Base has acted as a reserve for Lottia gigantia, an intertidal limpet which is primarily taken in recreational fisheries. In the base area, densities were on average three times higher than control areas (Ambrose et al. 1995). In Puerto Rico, Vieques Island has a bombing range on one end of the island. This area is permanently closed because of the unexploded warheads, as well as occasional testing. A population of endangered manatees uses this area quite regularly, perhaps because of less interactions with human activities.4 5 Other bombing ranges with apparent de facto protection include a bombing range in a region of 4 5 Callum Roberts, University of York, conversation with author, Annual meeting of the Society for Conservation Biology, June 6-9, 1997, Victoria, Canada. 87 Hawaii called Koo Lawe which since 1952 has had restricted access, resulting in high concentrations of reef fish that have been depleted in nearby waters46. Another area is the demilitarized zone between North and South Korea. This area, which is about 4 km wide and 256 km long, is home to a variety of marine and terrestrial species which receive de facto protection.4 7 In the marine portion there is an endangered sub-species of harbour seals (Phoca vitulina largha).4& Two I U C N red listed species of crane use an estuary in the zone (Pae et al. 1996) as well as five other species of vulnerable marine birds which use this habitat. Apparently there are also healthy abalone populations found on reefs in the marine portions which are otherwise non-existent throughout most of Korea 4 9 . The Spratly Islands are another example of a disputed area which affords biodiversity protection. The conflict over access between China, Taiwan, Vietnam, Philippines, and Malaysia, has consequently not only protected certain components of the marine ecosystem, but may also be supplying larvae to overfished areas in the South China Sea (McManus 1994). The Chafarinas Islands in the Mediterranean are Spanish military-controlled and support a population of the endangered Monk Seal, that is elsewhere on the verge of extinction 5 0. On St. Nicholas Island, California, there is a military base which supports densities of black abalone (Haliotis cracherodii) much greater than adjacent exploited sites.51 Restricted areas due to military activities are similar to government managed protected areas in that there are legal arrangements restricting human access and activities. A number of other types of protection result as consequence of cultural practices. The Mijikida people of Kenya once believed that rocky outcrops in the sea were possessed with spirits of ancestors which died there. These sites, called mizimu, resulted in de facto protection for reef areas. Prior to the breakdown of this cultural belief in the 1950s, it may have provided a role in sustaining fisheries (McClanahan et al. 1997). 4 Jim Bohnsack, National Marine Fisheries Service, Miami, Florida, conversation with author, Annual meeting of the Society for Conservation Biology, June 6-9, 1997, Victoria, Canada. 4 7 Westing, A. H. unpublished report received by author entitled, "A transfrontier reserve for peace and nature on the Korean Peninsula." 4 8 Jong-Geel Je, Korea Ocean Research and Development Institute, conversation with author, May 1997. 4 9 Ibid. 5 0 Enric Sala, University of California-San Diego, conversation with author, Annual meeting of the Society for Conservation Biology, June 6-9, 1997, Victoria, Canada. 5 1 Peter Haaker, California Department of Fish and Wildlife, conversation with author, Annual meeting of the Society for Conservation Biology, June 6-9, 1997, Victoria, Canada. 88 Similarly, colourful reef fish in a region of Flores, Indonesia, are protected by the local custom which allows only silver fish to be consumed. The cultural reason behind this is unknown. 5 2 The influence of Europeans on the east coast of Africa has resulted in at least one known de facto reserve. There is a small island in Tanzania owned by a wealthy German. According to Tim McClanahan, she chases people away from her beach "with a frying pan", thereby protecting 150 m of coral reef.53 As a result significant ecological changes have been observed including "edge effects". The lack of grazing fish outside the reserve due to fisheries exploitation has resulted in algal growth on corals, and consequently high observed rates of coral mortality. The edges of this 150 m reserve have algal growth, whereas the middle is completely grazed. Similarly, on the island of Sulawesi, Indonesia, the owner of Prince Johns's Dive Resort pays locals not to fish in certain areas, and hired an enforcer to ensure there is no fishing. According to Josh Nowlish, a marine reserve modeller from the University of the Virgin Islands, the fish populations are greater than those found in fished areas. Even space exploration has provided a de facto reserve. The Cape Kennedy Space Center has had restricted public access in the adjoining coastal area since 1967. These waters were important testing grounds for advancing marine reserves. Significantly more fish were documented in the closed areas. Furthermore, tagging studies show that fish migrated outside the area suggesting that the excess biomass may be accessible to sport fishing (Funicelli et al. 1988). Some species have received protection due to either perceived or real risks involved i f eaten. In the Amazon river fisheries, prior to the involvement of Brazil 's central government, the natives of Amazonas never ate catfish species, nor arapaima, because of a perceived skin disease resulting from their consumption. These fish were protected, but now a cash incentive exists to exploit them. Consequently the population has become depleted.54 In Maryland, the media was responsible for instilling fear into fish buyers with the threat that the single celled dinoflagellate PJiesteria piscidia could cause adverse health effects (Donald 1998). 5 2 Joshua Nowlis, University of the Virgin Islands, St. Thomas, conversation with author, Annual meeting of the Society for Conservation Biology, June 6-9, 1997, Victoria, Canada. 5 3 Tim McClannahan, Wildlife Conservation Society, Kenya, conversation with author, Annual meeting of the Society for Conservation Biology, June 6-9, 1997, Victoria, Canada. 5 4 Victoria Isaacs, "Fisheries assessment and management in the Amazonas, Brazil." Talk presented at the University of British Columbia Fisheries Centre, Vancouver, British Columbia, 16 October 1997. 89 Although no conclusive medical evidence exists, perceived threat of disease portrayed by the media effectively closed down all local fisheries for all species for a short period. Other health risks, such as ciguatera poisoning found in barracuda in the Caribbean and paralytic shellfish poisoning found in many areas result in some protection to these species. Contaminated animals, such as those found near sewage outfalls, bioaccumulate concentrations of undesirable pathogenic organisms or harmful chemicals. These contaminated animals are then protected from human consumption. Tourism in St. Lucia has pushed fishers out of some regions. Thousands of tourists arrive by catamaran every week and snorkel. This discourages fishers from leaving their pots in a heavily visited bay. According to studies, this area has good populations of parrotfish and grunts when compared to many areas in St. L u c i a . 5 5 In the case of the North Sea, with many areas estimated to be trawled in excess of ten times a year, the only refuge may be areas where oil rigs are found (Riemann and Hoffman 1991). The presence of rigs requires trawlers to take wide berths around them, resulting in areas that are not fished. This is the only form of spatial protection in the North Sea. Whether or not the rigs are helping the fisheries is uncertain, but many people assert that i f it were not for such de facto areas, the fish yields would not be as high as they are now. However, there is little published evidence supporting this. 5 6 In the initial phases of industrial fishing, technology limited fishing in most of the world's ocean. Boats were ill-equipped to handle deep waters or rough sea conditions. Consequently fishers chose not to fish some areas. These inaccessible areas acted as natural refuges from fisheries. Advances in our technology have allowed us to exploit nearly all productive areas. Global positioning systems (GPS) have made micro-habitat refuges vulnerable to fisheries. On Australia's Great Barrier Reef, there are areas of small coral outcroppings that five years ago were too risky to trawl. Now, due to GPS technology combined with detailed hydrographic charts, trawls can access areas directly adjacent to the outcroppings (Robins et al. 1998). In the study by Robins et al. (1998) it was estimated that in the next three years all trawl boats wi l l have this technology, resulting in a 12% increase in fishing power. It is interesting to note that a reserve covering 12% would result in only maintaining the current exploitation rate. 5 5 Julie Hawkins, University of York, UK, email letter to the author, 12 February 1998. 5 6 Nicholas Polunin, University of Newcastle, UK, email letter to the author, 17 June 1997. 90 V a n c o u v e r H a r b o u r : A de facto reserve? Coast Guard regulations restrict the placement of commercial dungeness crab (Cancer magister) traps in Vancouver Harbour between First and Second Narrows bridges. The Department of Fisheries and Oceans has permission to conduct annual surveys in the closed area. Each year, a demographic survey using carapace size as an indicator is undertaken in the closed area and the adjacent fished area. Surveys are conducted at the beginning of the crab season (June) and at the end (October). What can be seen in Figure 5.1 is that the closed area has had significantly larger crabs for all years. What is more interesting is the average size difference before and after each season in both locations, due either to juveniles being recruited to the area over the fishing season and therefore reducing the average size, or alternatively by the fishery removing all the legal size large crabs (>165 mm). The length frequency distribution in Appendix 5.1 supports the latter hypothesis. Annually, in the exploited area, the fishery removes virtually all legal size crabs in the population. Furthermore, it is possible that legal size crabs in the reserve area are emigrating to the exploited area, thereby resulting in a decrease in average size of the protected population. 175 170 165 160 H Ui c * 155 a> u ra 150 a ra ra 145 o « 140 135 130 •Vancouver Harbour Indian Arm co cn Q. CD C/3 i c 3 I O O in Gi c 3 co 05 r -O O D a t e Figure 5.1 Mean carapace lengths (mm) of dungeness crab in Vancouver Harbour (closed to fishing) and Indian Arm before each fishing season (June) and after (October) with 95% confidence intervals. Data source: D F O Shellfish Unit. Although these results are preliminary, the average size and length-frequency distributions indicate that Vancouver Harbour may in fact be acting at some level as a de facto reserve. 91 Examples of non-intentional protection clearly demonstrate that spatially defined reserves can come in a variety of forms aside from legal designation. In the next chapter I evaluate the effectiveness of a non-intentional reserve, a government managed ecological reserve, and a coast-wide closure on northern abalone populations. 92 Chapter 6 Evaluating the Effects of Three Forms of Marine Reserve on Northern Abalone Populations INTRODUCTION This research evaluates three forms of spatial closure on northern abalone (Haliotis kamtschatkana Jonas 1845) in British Columbia; a non-intentional reserve, a provincial Ecological Reserve, and a coast-wide closure. Many abalone populations throughout the world, including the population which is the subject of study in this research, have been exploited to the point of commercial extinction. In the case of the California white abalone (Haliotis sorenseni) biological extinction may have already occurred (Davis et al. 1996, Tegner et al. 1996). Previous work suggests marine reserves could assist in the recovery and management of abalone populations (Tegner et al. 1992, Tegner 1993). Fisheries History Abalone populations in B . C . are in such low abundance from overfishing that they are being considered as a 'threatened species' by the Committee on the Status of Endangered Wildlife in Canada. 5 7 In the past abalone were in much higher densities. In 1914, Thompson reported that there is best of reasons to regard the abalone as a very abundant and, in the future, important shellfish, and well worthy of attention. He later suggested that "its abundance seems to have been unappreciated" and in certain localities "a man armed with suitable implements may easily gather several sackfuls at each low tide". Intertidal take of abalone sustained a small fishery until the early 1970s. At this time the advent of sub-tidal techniques for abalone removal using scuba, combined with international markets, intensified the fishery. Shortly thereafter an unregulated, open access fishery began. Landings increased dramatically until 1979 when finally a quota was set (Figure 6.1) (Breen and Adkins 1986). From this point to 1990, when the fishery was closed, the quota was never reached despite an ever decreasing quota. 5 7 Unpublished report submitted to COSEWIC by Glen Jamieson, Shellfish Coordinator, Department of Fisheries and Oceans, February 1999. 93 450 400 3 5 0 ~ 300 o) 250 I 200 150 100 50 0 1950 1960 1970 1980 1990 2000 Year Figure 6.1 Commercial landings (t) of northern abalone in British Columbia, 1951-1990. Although a coast-wide commercial and recreational closure on abalone exists, abalone populations have not recovered. There are a number of possible explanations for the lack of recovery. The most obvious is the continuation of abalone exploitation in an illegal fishery, which is substantial and non-selective (Campbell et al. 1998). The black market value for abalone ranges anywhere from $20 to $100 per kilogram. Although it is not possible to accurately quantify the level of illegal kills, it could be in the order of two to four times the quotas that were set during the commercial fishery (Adkins 1996). A second explanation is found in the life history of this species. Life History Characteristics Referring to the life history of northern abalone for management considerations, Thompson (1914) stated: The general lack of knowledge concerning the breeding seasons, the rate of growth, and natural history facts in general are less pressing questions, but wi l l have to be solved in the end. Thompson was correct in that most of what is known about northern abalone has been acquired after the period of intense exploitation, or at the "end". Abalone are old-lived, sedentary, slow growing, and have reproductive strategies which favour large size and densities of individuals (Breen 1986). Although considered to be old-lived, maximum age of northern abalone is unknown as there is no method for age determination (Fournier and Breen 1983). Growth curves suggest that the largest abalone are at least 30 years of age, but Breen (1980) speculates using an analysis of shell characteristics that abalone may commonly reach 50 years. Abalone become sexually mature after three years (50 mm shell length) (Quayle 1971). There are no published data on the fecundity of northern abalone, but results from research on other abalone species is quite dramatic. It was found that H. iris between 68 mm and 155 94 mm long produced on average 1,300 and 11.3 million eggs respectively (Poore 1973). Other abalone species show similar fecundity increases with size. It is therefore reasonable to assume that northern abalone would also become exponentially more fecund with size. Northern abalone are synchronous broadcast spawners. During spawning events, northern abalone have shown to aggregate at the highest spot available and stack up one on top of another up to six high (Breen and Adkins 1980). Being broadcast spawners, aggregative behaviour has undoubtedly evolved to maximize fertilization success. Research has shown that increased densities result in increased spawning success (Clavier 1992). These characteristics make them a suitable species for reserves, but these same characteristics make them vulnerable to overfishing. The low abundance of abalone due to the commercial fishery and subsequent illegal fishery may have resulted in recruitment overfishing. This occurs when the adult population is too depleted to produce sufficient larvae required for recruitment to the fishery. The continued low abundance of abalone observed coast-wide, therefore, may in part be an artifact of recruitment overfishing. Since high densities of abalone are considered crucial for successful recruitment, it has been proposed by some to establish marine reserves to assist abalone recovery (Tegner 1993). For these reserves to work, abalone would be collected from large areas and placed in a reserve area in hopes of establishing densities high enough for successful gamete fertilization which would then drift outside the reserve and re-populate depleted areas. Although the theory is strong, there is no quantitative evidence that marine reserves can protect a spawning population of abalone. The problem with testing this theory is that there are few long standing, enforced marine reserves designed for species with this type of life history. Previous studies have indicated that the cessation of human predation results in dramatic changes in target species size and abundance and subsequent changes to the ecological community (Castilla and Duran 1985, Moreno etal. 1986). Description of Abalone Reserves This research was designed to evaluate three forms of abalone reserve. The first is a non-intentional fishery closure resulting from access restrictions enforced by a prison situated on 95 the coast. The second is a provincially managed marine ecological reserve closed to all fisheries for invertebrates since 1980 and enforced by a full time lighthouse keeper. The third form of reserve is the coast-wide closure of all abalone fisheries since 1990, which on paper makes all British Columbia waters an abalone reserve. Hereafter, these reserves wil l be labeled as the prison reserve, the ecological reserve, and the coast-wide reserve respectively. A unique and noteworthy characteristic of the prison reserve is that it has been in effect since 1958 when the prison was founded. There has to be a study of a marine reserve which has been in effect throughout the period in which over-exploitation of a fishery has occurred. A l l previous marine reserve studies have taken place in marine equivalents of 'forest clearcuts' and the 'succession' monitored. This form of long-term closure allows the sustainability of the reserve to be evaluated in the context of source-sink relationships. The objectives of the study were to compare abalone size, abundance, and potential reproductive outputs between the three forms of reserve. METHODS I conducted abalone surveys in March of 1996 and February of 1997 in the Juan de Fuca Strait off Southern Vancouver Island (Figure 6.2). The prison reserve and ecological reserve were compared to six sites in the coast-wide reserve for a total of eight areas. Sites used in previous government population assessment surveys were used for selecting the six sites in the coast-wide reserve. Government survey sites were in turn based on fishers' logbooks to ensure that survey sites were suitable abalone habitat (Adkins 1996). The coast-wide sites have been heavily exploited by both legal and illegal fisheries. A l l sites are of sloping bedrock to 3-7 m with algal coverage dominated by the kelps Nereocystis luetkeana and Laminaria spp. A l l observations and measurements were done in situ by scuba divers. Using calipers, divers measured and recorded shell lengths (L) of all exposed abalone to the nearest 0.2 cm. Data from both years were pooled and a test of homogeneity of variance followed by a one way analysis of variance ( A N O V A ) was applied to test for significant size differences between all sites. Subsequently, a Bonferroni multiple range test was used to test for significance between specific sites. Additionally, government surveys in the study region from 1982, 1985, and 1986, designed to determine average size of exposed abalone, were combined and included in the analysis to add to the database (Adkins 1996). Relative abundances were estimated using an index of abalone per minute diving ( A P M D ) based on a method developed by McShane (1994, 1995). Potential reproductive outputs of the sites were estimated by first converting length to whole weight (W, g) by: W=0.0001 • L 3 0 3 4 (Breen and Adkins 1982). Fecundity was then estimated by using Breen's (1986) egg per recruit model fitted for northern abalone:/= 0.0065-W" 0 0 9 8, where / = fecundity in millions of eggs. Relative reproductive output was calculated by multiplying the A P M D in each site by the mean fecundity of abalone in each study site. 48° 30' t t ••o < Ecological Reserve (Race Rocks) - *- Coast-wide reserve sites 3 . 5 km Figure 6.2 Northern abalone survey sites along the southern coast of Vancouver Island. 98 RESULTS The abundance of abalone in the study sites varied as indicated by the A P M D (Table 6.1). Five of the six coast-wide reserve sites surveyed had insufficient abalone to provide the necessary sample size (n=30) for statistical comparisons. This in itself is telling. However, one exploited site had sufficient abalone, and in fact it had a higher relative abundance than the two reserve areas (Table 6.1). For this reason it was separated out from the coast-wide closure sites. This site is located adjacent to military land and wil l be referred to as the military site in the subsequent text. Table 6.1 Comparison of abalone abundance and size in three forms of reserve and historical government data. Location Number of Effort APMD" Average Size Confidence % abalone (minutes) (n/min) size Range Interval (mmf >130 (n) (mm) (mm) mm Prison Reserve 211 275 0.77 115.6b 62-154 ±2.7 26.5 Ecological Reserve 241 345 0.70 99.7 40-148 ±2.9 8.8 Military Site 163 134 1.22 100.4 40-152 +3.1 6.1 Government Data 298 NA — 98.1 50-142 ±2.1 3.4 5 Coast-wide Sites 9 173 0.05 109.4C 72-127 ±10.8 0 "Abalone per minute diving, Significant, Bonferroni test, p<0.01%,c Not used in ANOVA as only sites with 30 or more abalone were considered,d 95% confidence. Because abundances were too low in most coast-wide reserve sites to conduct statistical comparisons, size comparisons were made only between the prison reserve, the ecological reserve, the military site, and government data. Size of abalone between the four sources were significantly different ( A N O V A , P<0.01), with the prison reserve showing a significant size difference when compared to the other three sites (Bonferroni test, p <0.01). The average size of abalone in the prison reserve was found to be 16 mm greater than the other locations (Table 6.1). Relative frequency distributions of shell length indicate differences in size structure of the sites (Figure 6.3). The abalone population at the prison site had a large proportion of abalone greater than 130 mm (Table 6.1). The proportion of abalone less than 100 mm in the prison reserve was found to be lower than the other three study sites (Figure 6.3). 99 Prison Reserve n = 211 30 25 20 15 10 5 Military Site n = 163 Ecological Reserve n = 240 Length (mm) 30 r Government Data 25 20 15 10 n = 298 Length (mm) Figure 6.3 Frequency distributions of abalone in survey sites and government data representing percentage of abalone in each size class. The prison reserve showed the highest reproductive output per abalone simply as a function of the average size (Table 6.2). However, when relative abundance (see A P M D Table 6.1) was factored into the fecundity equation, the military site was shown to be the most productive. Table 6.2 Relative fecundity of abalone in study sites based on abalone per minute diving and mean fecundity. Location Mean Fecundity (106 eggs/'abalone) Relative Fecundity (APMD • Mean Fecundity) Prison Reserve 1.19 0.91 Ecological Reserve 0.78 0.55 Military Site 0.77 0.94 5 Coast-wide Sites 0.90 0.05 100 D I S C U S S I O N In 1990, due to depleted populations, all abalone fisheries were closed in British Columbia, making the entire coast an abalone reserve. This research evaluated the effects of three types of reserves: a coast-wide closure, an unintentional long-term closure, and an intentional ecological reserve. High black market value of abalone (up to $100/kg) encourages considerable illegal catches in British Columbia. In the study region alone, more than 20 poaching convictions have been made since 1990, demonstrating that the coast-wide reserve is being violated (Adkins 1996). M y results indicate that only closed areas which completely restrict all take of abalone result in significant changes to local populations. The most obvious result in this study was the low abundance of abalone in five of the six coast-wide reserve sites. With the exception of the military site, abundance of abalone in the coast-wide reserve areas was too low for statistical comparisons. Prior to this study the military site was considered as a representative coast-wide closure site. However it now appears that this site may also receive unintentional protection from illegal fishing. This site is adjacent to land owned by the Department of National Defence. There is a light station on the adjacent land which is occasionally occupied, and during most days there is military presence on the land. As well, according to nautical charts, the waters around the military site are restricted access. As there are no obvious bio-physical differences between sites (i.e., sea otters, disease, substrate type), and given the current levels of indiscriminate illegal catches, it is highly unlikely that the larger abalone populations in the military site can be attributed to anything other than some form of unintentional protection. This provides a strong case for the role of reserves in re-establishing populations providing there is adequate enforcement. The original study intended to measure a minimum of 30 abalone at each study site in order to use size (age) as an indicator of fishing pressure. As mentioned previously, it was not possible to find coast-wide closure sites in the study area where 30 abalone could be found. Only the three areas receiving some form of additional protection had sufficient abalone. The prison reserve, perhaps as a function of a 39 year closure, had significantly larger abalone than the other two sites. 101 Northern abalone growth rates depend on water temperature and availability of food types (Paul et al. 1977). Temperature is considered to be the same throughout the study area (Thomson, 1981). Food availability is a function of dominant macro-algal type. A l l areas selected were covered by similar macro-algae, Nereocystis luetkeana and Laminaria spp., which eliminates dominant food type as a variable. Breen (1980b) showed that abalone inhabiting Pterygophora californica dominated substrates showed the slowest growth rates, whereas Macrocystis integrifolia had the fastest, and N. luetkeana was in between. Algal coverage was surveyed in previous government studies and was re-examined in this study, and it was found that the areas had not changed. Variables affecting abalone growth rates are unlikely to be a factor contributing to the significant differences observed between sites. Over one quarter (26.5%) of the abalone at the prison reserve were larger than 130 mm. Using a conservative growth curve, abalone that are 130 mm in length are on average over 30 years old (Breen 1980). The large size of abalone at the prison reserve appears to be a function of restricted catches over a long period (39 years), whereas the military site (8 years) and ecological reserve (18 years), having been closed for a shorter period, had smaller abalone on average. It is widely accepted that size and abundance of target species increases in reserve areas (Roberts and Polunin 1991, Rowley 1994). The question concerning most fisheries managers is the ability of reserves to both export larvae while sustaining the internal population (Roberts 1997a). Fecundity as simply a function of body size and abundance was shown to be greater in the enforced reserve areas compared to the coast-wide sites (Table 6.2). The study did not conduct surveys to assess the fate of exported larvae, or specifically look for recruitment into the sites, however, examining the age-frequency distributions there are differences between the study sites (Figure 6.3). For example, only 32%) of the prison reserve abalone population was under 100 mm whereas in the ecological reserve and military site, 57% and 53% of the population were under 100 mm. A number of combined factors potentially contribute to patterns of abalone recruitment, settlement, and survival (McShane 1992); including regional hydrodynamics (McShane and Smith 1991), population size (Prince et al. 1988), coastal topography (Shepherd et al. 1992), and substrata composition (McShane and Smith 1988). Teasing out the physical processes responsible for recruitment patterns between source and sink populations was beyond the scope of this study and, as 102 Roberts (1998) recently argued, perhaps should not be an immediate goal for marine reserve science as explained below. In British Columbia approximately 0.01% of coastal habitat is formally designated as 'no-take' marine reserve. The most important scientific information that can be contributed at the moment is evidence that areas closed to fisheries have ecological changes attributable to this exclusion. In terrestrial conservation, wildlife reserves were initially established to decrease human caused mortality to vulnerable hunted animals. If terrestrial conservation were to have been primarily concerned about the fate of seeds from trees in reserves, there would perhaps be fewer terrestrial protected areas. Justification of marine reserves exists without knowing the precise extent of larval dispersal outside the boundaries. For example, in the region of this study, abalone were once found in greater abundance (Breen 1986). Results from this research indicate that areas that receive protection support larger and more abundant abalone. Abalone are known to be broadcast aggregate spawners requiring high densities to ensure fertilization (Clavier 1992).The study region is influenced by strong tidal currents with daily maximum ebb and flood currents of 1.8 m/s and 1.5 m/s respectively, indicating the larvae wil l be transported away from their natal site, potentially replenishing depleted areas (Thomson 1981). From a practical management perspective, there is enough combined information available to warrant the implementation of marine reserves. What is a natural abalone population? The reserves examined for abalone in this study certainly have a role from a fisheries management perspective, but whether they help preserve abalone populations in their natural state is debatable. One subject which has repeatedly been brought to my attention is the absence of a critical component of the Southern Vancouver Island marine ecosystem, the sea otter. It is well documented that an area occupied by sea otters has very low abalone abundances (Estes and Palmisano 1974). Abalone in these areas are confined to deep crevices in high density aggregations. This life history strategy would ensure high levels of fertilization and hence recruitment. Functionally, abalone exploitation by humans is similar to sea otters with one important difference. Humans leave few refuges, as crevices are easily exploited using a knife. There are probably areas where abalone and otters did not overlap, but for the most part, they utilize the same habitats, and hence the abalone population at the prison reserve is not a natural population in the sense of natural predation. However, the point of the study was to examine how spatially removing the effects of human predation could result in an ecological change indicated by surveying an exploited species. Determining what is natural in the marine environment is a challenge facing marine conservation in general. One thing is certain, without marine reserves serving as baselines, there might never be an understanding of what are human impacts versus natural variation. Conclusion Justifying marine reserves on a species by species basis does provide needed evidence at a regional level but spatially managing single species has limitations comparable to other forms of single species management. Ecosystem benefits thought to emerge with the creation of marine reserves wil l be considerably more difficult to evaluate using quantitative studies. Designing reserves to account for scientific uncertainty while including ecosystem dynamics may be best accomplished using scientific principles of bio-geographic representation, replication, and network design (Ballantine 1997). These principles should underlie the science of marine reserves. Regional case studies such as the one described in this chapter are useful to decision-making institutions by providing evidence in support of the fundamental objectives of marine reserves. In political jurisdictions with no reserves, non-intentional closures resulting from either natural or human-created barriers provide an alternative method of evaluating marine reserve potential. 104 Chapter 7 The Role of Marine Reserves in the Conservation of Rocky Reef Fishes in British Columbia: The Use of Lingcod (Ophiodon elongatus) as an Indicator. INTRODUCTION The primary goal of this chapter is to understand how marine reserves can assist in conserving and rebuilding populations of depleted rocky reef fish in British Columbia. In other political jurisdictions, reserves have been shown to stabilize or enhance fishery resources (Roberts and Polunin 1991, Rowley 1994). Monitoring of reserves has revealed a world-wide trend which may be relevant to the conservation and enhancement of B.C. 's rocky reef fish populations. Refugia from fishing pressure result in an increase in size and/or abundance of a targeted species compared to an area where exploitation occurs. Until recently, no empirical studies had been conducted to examine the impact of reserves on species living in temperate rocky reefs in the northeast Pacific Ocean. Palsson and Pacunski (1995), who conducted the only study of this type on fish in this region, determined that reserves in Puget Sound demonstrated an increase in mean size and abundance in populations of quillback rockfish (Sebastes maligef), copper rockfish (S. caurinus), and lingcod (Ophiodon elongatus). The concept of reserves in B.C. and throughout Canada as tools for fisheries enhancement and biodiversity conservation is slowly gaining acceptance by fisheries managers, scientists, fishers, and the general public. Although acceptance is increasing, there is still a lot of opposition and uncertainty regarding the exact role of reserves. This is in part due to the lack of empirical evidence demonstrating the function of reserves within B.C. 's marine ecosystems. In this study, lingcod populations in two coastal reserves in Howe Sound, Strait of Georgia, are compared to exploited sites to demonstrate the potential role of reserves in B.C. Lingcod populations in the Strait of Georgia and Puget Sound are severely depleted (Beamish et al. 1994, West 1997). The extent of the decline can best be appreciated by examining traditional fishing techniques of the Coast Salish (Barnett 1955). Traditionally, one of the most accepted methods of catching the tooshqua or lingcod was by submerging a lure made of wood, using a long pole 5 8. When released, the lure would create erratic motions as it rose to the surface, thereby attracting lingcod. At the surface a fisher would be waiting with a spear or net to capture the fish. For this technique to have Early settlers also referred to lingcod as "Cultus cod", Cultus in Chinook language meant "little worth" as they presumably deemed it inferior to the true cod. It was also labeled "bastard cod" and "buffalo cod" (Canada Sessional Papers, 1887, No. 16, pg. 259). 105 developed and presumably be effective, would require lingcod in considerable abundance and of a large size. This technique would be ineffective today as the lingcod biomass in the Strait of Georgia has decreased to an estimated 3% of its historical level (Martell and Wallace 1998). Although a number of ecological factors are likely involved in maintaining the population at its current depleted level, it is generally accepted that decades of over-exploitation was the primary cause for the decline. It is rare in the world of fisheries science to have consensus on the cause of a population collapse. However, the lingcod fishery in the Strait of Georgia is an exception. Failure of lingcod to recover is in part due to continued recreational fishing but other factors may also be contributing. By comparing lingcod populations exposed to varying degrees of fisheries exploitation (i.e., reserves), insight into the relative contribution of fisheries in maintaining the low population levels can be acquired. Fisheries History While lingcod have been taken by aboriginal people in B.C. as early as 3,500-5,000 years BP (Barnett 1955), the commercial lingcod fishery in B.C. started only around 1860 as a handline fishery in the Strait of Georgia. In the 1940s a trawl fishery began and coastwide catches increased steadily from 630 t in 1945, to a maximum in 1985 of 5,000 t. The Strait of Georgia, which has been commercially closed since 1990 due to depleted populations, contributed a large portion of the total landings (Figure 7.1). Coast-wide trawl catches until recently were over 4,000 t, representing a geographical expansion of the fishery, not increased or stable population densities reflecting sound management. The decrease in landings since 1995 indicate that lingcod populations in other geographical areas are following the same trend as the Strait of Georgia (Figure 7.1). 106 1950 1960 1970 1980 1990 2000 Year Figure 7.1 Lingcod landings in the Strait of Georgia and all of British Columbia between 1951 and 1997. Increased fish catches in B.C. represent a geographical expansion of the fishery, not sustainable yields (DFO catch statistics). Although commercial lingcod fisheries are closed in the Strait of Georgia, there is still a substantial, albeit small, recreational fishery (Figure 7.2). In addition to targeted recreational fishing, incidental and undersized catches of lingcod in recreational and some commercial fisheries undoubtedly exist. Beamish et al. (1994) report that 40% of the lingcod caught by the recreational fishery in the Strait of Georgia are undersized (<65 cm.). 300 r 1980 1985 1990 1995 Year Figure 7.2. Estimated recreational lingcod landings in the Strait of Georgia (1980-1993) (Beamish et al. 1994). Life History Information Lingcod exhibit a number of life history characteristics which make them both a suitable indicator species of reserves and a species which could be better managed by including some form of spatial management. Most importantly, adult lingcod are considered to be non-migratory. Large scale tagging studies showed that the vast majority of lingcod stayed within 10 km of the release site. Exceptional travels of up to 370 km were observed, but contrary experimental and anecdotal evidence indicate that 107 adult lingcod typically stay in areas much smaller then 10 km (Mathews and LaRiviere 1987, Jagielo 1990, Smith et al. 1990, Mathews 1992). The resident behaviour of lingcod is critical for evaluating the effectiveness of reserves. It would be expected that lingcod, free from fishing pressures, would increase in size and/or abundance in reserves. With increased size there are a number of changes which increase the fitness of the lingcod. First, male lingcod guard their egg masses, so the larger the male, the better the protection. Protection is fundamental to egg mass survival. In one study where guarding males were removed, all the egg masses were consumed by predators within 22 days (Cass et al. 1990). This provides a clear indication that the presence of a male is essential for the protection of eggs. Although present fishing regulations prohibit the fishing of lingcod during the spawning season, fishing for rockfish, which share the same habitat, is permitted. Undoubtedly this results in both illegal catches and disrupted guarding behaviour in the event of male lingcod being caught and released. Adult size is also important in gamete production, as the number of eggs produced is correlated exponentially with body size. Larger female lingcod not only produce greater numbers of eggs, but also larger eggs compared to smaller females. In Atlantic cod, larger eggs yield larger embryos which may increase the chance of survival in certain spawning conditions (Trippel 1998). Larger females also spawn earlier and deeper (Cass et al. 1990), increasing the overall chances for year-class success. Larger males tend to establish territories in better spawning habitat which, when combined with the increased ability to fend off predators, makes size a significant factor for production of larvae. The long pelagic period of lingcod larvae (90 days) indicates that dispersal may be over a large area (Cass et al. 1990) and therefore lingcod spawning in protected areas may act as sources of larval export. Recent evidence suggests that lingcod are genetically similar through most of their geographic distribution from Baja California to Kodiak Island, Alaska with the exception of the Puget Sound-Strait of Georgia population (Jagielo et al. 1996). Lingcod in the Strait of Georgia are most likely a separate population and therefore must be managed accordingly. Previous management methods failed to maintain the population, and present methods are failing to enhance depleted populations. One management strategy, which would address fundamental life history characteristics, is the implementation of reserves. 108 Role of Lingcod in the Ecosystem Lingcod, occupying a trophic level of 4.3, feed primarily on herring and demersal fish (see Chapter 4) 5 9 . Once a lingcod reaches adult size, marine mammals are the only non-human predator of lingcod. It is estimated that lingcod comprise 3% of the overall diet of harbour seals and are preyed upon between November and April when males are defending egg masses (Olesiuk et al. 1990, Olesiuk 1993). Rationale, Goals, and Components of the Study Marine protected areas are gaining acceptance as a tool to assist in the management of fisheries and the conservation of marine biodiversity. This study is the first to empirically evaluate the potential of reserves in B.C. The primary research question is: Is there a change in lingcod demography attributable to protection from direct human exploitation in protected areas compared to adjacent non-protected areas in Howe Sound, British Columbia? To answer this question, a study consisting of three components was undertaken, each with a subset of questions and goals relevant to the primary research question. The first component was a comparative demographic study of lingcod in protected areas and exploited areas to determine whether there are differences in size and/or abundance of lingcod. The second component involved monitoring lingcod egg masses in protected and exploited areas. Information on reproductive output as well as female demography was ascertained using this method. The final component involved a tagging study to understand movement patterns and to test assumptions on resident behaviour. A l l three components were undertaken in Howe Sound. Introduction to Howe Sound Howe Sound is a fjord system within the Strait of Georgia (Figure 7.3). The sloping bedrock wall of the Sound extends to 300 m in places. Two major river systems influence the oceanography of the Sound. The Squamish River enters at the north end, and the Fraser River, although not entering directly into the Sound, also has a freshwater influence on some areas near the southern mouth. Wind is generally a mix of northerly outflow winds from the Squamish River valley, and south easterly or westerly winds from offshore weather systems. 5 9 Tor Miller, a commercial lingcod fisher in the Strait for over 50 years, described catching numerous 65 pound lingcod with 10 pound (4.5 kg) sockeye salmon in their stomachs during salmon migrations through the Southern Gulf Islands in the 1950s. 109 Figure 7.3 Map of Howe Sound showing the reserve sites, Whytecliff Park and Porteau Cove, primary survey sites east side (ES) 1. Porteau North, 2. Kelvin Grove, 3. Sunset Point, 4. Ansell Place, 5. Hole in the Wall, 6. Copper Cove, 7. Bird Islet, 8. Larsen Bay, 9. Eagle Island, 10. Juniper Point 11. Point Atkinson, 12. Passage Island reefs; and west side (WS) 1. Hutt III, 2. Popham (reef), 3. Popham Breakwater, 4. White Islets. 110 Howe Sound borders on the Greater Vancouver Regional District and is therefore used extensively for numerous activities. Only the east side of the Sound is accessible by car. The west side and islands are accessible only by boat. Commercial lingcod fishing in Howe Sound (fisheries management Area 28) was never as bountiful as other areas in the Strait. The greatest recorded 'modern day' catch in this area was 6.4 t in 1963. It is interesting to note that the early fisheries reports have recorded landings of Tooshqua from Howe Sound district being at a maximum of 250,000 pounds (113 t). 6 0 At present day, commercial fisheries in Howe Sound are limited to prawns and crabs. Recreational fisheries for salmon, lingcod, and rockfish comprise most of the fishing effort in the Sound. Description of Study Sites Thirty-five sites were examined in Howe Sound over three years. Each of these sites received various levels of survey effort (Appendix 7.1a-c) and all but one are found in Howe Sound. White Islets, being the only exception, is located 10 km south-west of Howe Sound on the east side of the Strait of Georgia. Two of the sites, Whytecliff Park and Porteau Cove are marine protected areas with complete closure to all fisheries all year. These two sites are collectively referred to as 'reserve' sites. A l l other areas are collectively referred to as 'exploited' sites. In addition to the regularly monitored exploited sites, there were also sites examined either only once, or on an irregular basis. Reserve Sites Whytecliff Park has been a reserve since 1993 (Solin 1993). The habitat consists of steep sloping bedrock descending to 250 m and includes a shoreline distance of approximately 1.2 km. For survey purposes the park was broken down into two transects, 'cut' and 'lookout' which are represented in the dive summaries in the appendices as Whytecliff (cut) and Whytecliff (lookout) respectively (Appendix 7.1a-c). In the analysis both of these survey locations are combined and referred to as Whytecliff Park. Porteau Cove is artificial reef habitat consisting primarily of metal boat hulls, concrete culverts, tires, and complex metal structures. In 1980 it was given a marine protected area designation primarily due to its value as a recreational dive site. Fishing restrictions were implemented in 1980 to minimize the risk of diving related accidents from entanglements with fishing line and from boats. Artificial reef structures are on sandy bottom and extend to a depth of 30 meters, but only habitat in the first 18 m (60 feet) was surveyed. 6 0 Canada, S i , 1892, no.HA, pg. 173. I l l Exploited Sites Exploited sites were chosen for a number of features including habitat, fisheries importance, accessibility for dive surveys, accessibility to recreational fishing, and proximity to reserve sites. It was critical for comparative purposes that surveys were conducted in sites of equal or better lingcod habitat than reserve areas. Anecdotal accounts from divers and fishers were used to identify historical lingcod 'hotspots' used in the study. M E T H O D S Data were collected for the three components of the study between the period of January 1996 and August 1998. A l l three studies were conducted in situ using scuba from two research vessels, a 21 ft (6.4 m) aluminium work boat and a 52 ft (16 m) luxury cruiser (Aquarius). A l l transects were conducted between the depths of 0 and 33 m, with most of the effort between 10 to 20 m for time and safety constraints. Shoreline geological features were used to identify the transect locations. Demographic Study The first component of the research was conducted to compare adult lingcod size (age) and abundance between study sites. Throughout the study period, 1996-1998, the method and frequency of sampling changed and therefore not all data can be directly compared between years. Table 7.1 shows a summary of the type of data collected with each sampling design. Table 7.1 Summary of information obtained in each component of the research between 1996-1998. Abundance measured as lingcod per hour diving (LPHD) or egg masses per hour diving (EPHD). Study Type Time Period (m/d/y) Abundance Size Total bottom time (min) Demographic A 1/7/96-10/15/96 LPHD Two classes 1,171 B 1/31/97-10/12/97 LPHD Three classes 3,292 C 10/12/97-8/27/98 L P H D Measurements 5,151 Spawning 1996-1998 EPHD Three classes -Tagging 1/13/98-8/18/98 n.a. n.a. -For all underwater visual census (UVC) surveys, a roaming diver technique was used (Thresher and Gunn 1986). This technique is preferred over fixed line transects because mobile species, such as lingcod and their prey, often vary their depth preference based on small scale temporal changes in oceanographic conditions. Survey depth therefore changes between and within dives. The aim of the 112 technique is to maximize one's encounter rate with the subject much the same way commercial spear-fishers would try to maximize their catch. Age Structure Data The data collected for evaluating population age structure changed over the period of the study. Between the period of January 1996 and October 1996, size data was collected by visually estimating the size of lingcod and assigning an age class in one of two categories, 0-2 years or 3+ years, which corresponds to respective lengths of under 50 cm, and 50+ cm (Cass 1990). With experience it became possible to assign lingcod as either 1,2, or 3+ years corresponding to lengths of 30-40 cm, 40-50 cm, and 50+cm (after age 3 there is too much ambiguity in size between years to accurately assign ages). This method was applied for the period of January 1997 to September 1997. During the period of October 1997 to August 1998, actual lengths of lingcod were recorded in situ using a measuring tape. Divers slowly approached a lingcod and noted features on the substrate representing the location of the lower jaw and the lower tip of the caudal fin. Distance between these points was then measured. In situations where measurements could not be obtained (i.e., i f the lingcod was swimming), a visual estimate of age was recorded. During surveys when both divers were collecting data (i.e., two different depth stratum), measurements were collected independent of the other diver.6 1 In the analysis all three forms of data are represented as three separate years despite not following a calendar year. Abundance Data Relative abundance between sites was determined as a function of the number of lingcod encounters per unit of search effort. E=("; 771) -60 Where E is the encounter rate of lingcod expressed in units of lingcod per hour diving (LPHD), n is the total number of lingcod encountered during dive i, and T is the bottom time of dive i in minutes converted to hours by multiplying by 60. The number of encounters most often equals the number of size/age observations recorded by each diver since every lingcod encountered was either measured or its age visually estimated. The only exception is on the occasional dive where only encounter data were collected. Abundance between sites was then compared as a relative index based on search effort. Each survey had a minimum Tof 20 minutes with an average of 39 minutes. 6 1 In some situations only one diver would collect data. Inexperienced divers would often not collect data, or sometimes each diver was involved with doing a separate task (e.g., one diver tagging fish, the other measuring). 113 Egg mass surveys During the spawning season, January through March, study sites were surveyed for egg masses to compare reproductive output of lingcod in each site and to gain understanding of female demographics. Typically female lingcod inhabit deeper waters than males (Gordon 1994) and are too deep for safe diving. Prior to spawning, females move into shallow inshore waters and select a mate. After a brief courtship, the female lays her eggs, which are fertilized by the male who then defends the egg mass from predators during a six week incubation period. After spawning the female returns to deeper waters. Egg mass size is proportional to female size, with a ratio of 26 eggs per gram of body weight (Giorgi 1981). Two different data sources were utilized to compare size and abundance of lingcod egg masses. The first source is from the volunteer based Annual Lingcod Egg Mass Survey, 6 2 and the second from research conducted by research divers at the Vancouver Aquarium. Egg mass size was categorized in situ as one of three categories, grapefruit (small), cantaloupe (medium), and watermelon (large)63. Relative comparison of egg mass abundance was brought to fruition using the same method as the adult lingcod surveys where the number of encounters (n) per unit of effort (T) was used to calculate an encounter rate (E) used as an index of abundance (egg masses per hour diving). 6 4 Locating important areas of spawning is necessary for management and for assessing the potential of reserves to act as areas of larval export (Plan Development Team 1990, Roberts 1998). In theory, an area which supports greater numbers of larger lingcod, will have greater potential for egg production. However, larval survival and transport depends on a number of physical factors which limits the ability to test the true effectiveness of reserves as tools to restore populations. For example, (Giorgi 1981) showed that in a laboratory, water current velocities of 10 cm per second were required to supply the egg mass with sufficient oxygen. Low current velocity resulted in egg masses with high egg mortalities. No assessment of egg mass survival or larval transport was conducted in this study. Tagging Study The final component of the research was an 8 month in situ underwater tagging program to evaluate the resident behaviour and population of lingcod in the study sites. Although mark-recapture studies are commonplace in fisheries biology to understand growth, movement, and habitat requirements, very few studies have been conducted underwater. Traditionally, tagging studies have relied upon hook and line, 6 2 Each February the Vancouver Aquarium supports the annual lingcod egg mass survey which is an annual count of egg masses collected by volunteer divers. This approach is similar to the Audubon Christmas Bird Count. 6 3 Fruit sizes were used as a standard for the egg mass count to ensure some consistency between volunteer divers. 6 4 During some egg mass surveys demographic data were also recorded. 114 nets, or electroshocking techniques (Hayes 1983, Hubert 1983). A l l of these methods require that the fish be brought to the surface for tagging. Generally, after tagging the fish are released at the surface, and then recapture data are contingent on reporting of tagged fish in commercial or recreational landings. Surface tagging procedures increase stress on fish during capture and handling. Release of stressed fish at the surface may subject them to increased predation risk before returning to their required habitat. Furthermore, in these studies, recapture data typically involves a single event as the capture involves killing the animal. There have been fourteen conventional tagging studies on lingcod populations ranging from California to the West coast of Vancouver Island (review in Cass et al. 1990). Prior tagging studies on lingcod have been used primarily to assess population size, age structure, growth, and large scale movement. Conventional tagging studies are not applicable to research in reserves for a number of reasons. First, protected areas by definition require that research be done with the utmost prudence so as to not be in conflict with the objectives of the protected area. Given the small size of the reserves used in this study, conventional tagging mortalities could drastically influence the demography of the populations. Furthermore, it was considered to be ethically unacceptable to fish for research purposes in the only two places in Canada where all forms of fishing are prohibited. Finally, as mentioned previously, recapture data in most recapture fisheries studies requires reports from people catching fish in recreational and commercial fisheries. Since this is not possible for fish within boundaries of reserves, recapture information has to be done by U V C . Aside from logistical and ethical reasons, underwater tagging was chosen for this study as it seemed to be the most effective technique to gain insight into small scale movement and habitat requirements important for marine reserve design (Roberts and Polunin 1991, Zellor and Russ 1998). Equipment Tagging commenced January 13, 1998. Initially, during the first 3 months, five colours of numbered plastic intramuscular spaghetti tags (FIM-96: F L O Y Intramuscular tag) were used, each colour representing one or more sites for a total of 13 sites. Tags were inserted into the dorsal musculature of adult lingcod using a homemade slingshot-style tagging pole (Figure 7.4).6 5 Only lingcod visually estimated to be greater than 50 cm length were tagged to ensure that they were of suitable size to withstand tagging stress. Tagging pole was developed by Steve Martell, Vancouver Aquarium, 1998. 115 Figure 7.4 Lingcod tagging procedure (not to scale). Lingcod diagram from Hart (1972). To insert a tag a diver would slowly approach a stationary fish from behind. The tip of the cocked pole with an attached tag was placed approximately 15 cm from the desired insertion point in the dorsal musculature. Once the pole was aligned properly, tension was released by opening the hand thereby inserting the anchor tag. Typically the tagged lingcod would dart off and then stop within 15 m. Larger lingcod (<60 cm) would often circle and return to the exact location in which they were tagged, indicating minimal tagging-induced stress. Lengths of tagged fish were only occasionally recorded at the time of tagging. In total, 352 lingcod were tagged during 2,492 minutes diving (Appendix 7.2). Resighting information was collected during subsequent U V C . 116 ANALYSIS AND RESULTS Comparison of Encounter Rates Between Years and Geographic Location Data are pooled into four categories: Whytecliff Park (WP), Porteau Cove (PC), all sites on the east side of Howe Sound (ES), and sites on the west side of Howe Sound (WS). 6 6 A n analysis of variance between years indicates that significantly more lingcod were sighted per hour of diving in all locations in 1997 and 1998 than in 1996 (Appendix 7.3, Figure 7.5A), and no difference in encounter rates of lingcod were observed between 1997 and 1998. Insufficient effort in 1996 prevented interannual statistical comparisons between locations, but comparisons between 1997 and 1998 were possible. (Figure 7.5B). There were no significant differences observed between sites and years. However, between sites within years, Whytecliff Park showed a significantly higher rate of encounter compared to the other locations in both 1997 and in 1998. A n analysis of variance conducted with 1998 data indicates a significant difference between WP and ES (p<0.05), but no other comparisons were significant (Appendix 7.3). Q 30 x a. 20 ~ 10 3 O O 1996 1997 Year 1998 Q 60 r X Q. 50 -. J <D 40 w 30 -O *-> c 20 -3 O o 10 -l5 0 • 1997 • 1998 4 • f i l i f t ES WS PC Location WP ALL Figure 7.5 (A) Lingcod encounter rates between years and all locations, and (B) between locations and year. The west side includes the White Islets. 117 Comparison of Size between Years and Location Comparison of size between years is not possible because of the type of data that was collected changed from year to year. In 1996 and most of 1997 size was recorded as categorical data. Two categories are used to describe the size of lingcod, category ' J ' refers to lingcod less than 50 cm (< 3 years of age, juvenile), category ' M ' refers to lingcod larger than 50 cm (>3 years, mature). The proportion of lingcod visually estimated as ' M ' was compared between the four sites for each year (Figure 7.6A) using a chi-squared test with Yates Correction for Continuity (Table 7.2, Fowler et al. 1998). 100 + t o 80 A •*-• 60 C CD O 40 L_ a 20 a. 0 • 1996 • 1997 ES WS PC WP ALL 70 60 50 40 rfi ES WS PC WP Total Location Figure 7.6 Comparison of lingcod size between locations: (A) 1996 and 1997 size as percentage of lingcod greater than 3 years old; (B) 1998 comparisons using mean lengths, error bars represent 95% confidence intervals. (ES and WS~East Side and West Side of Howe Sound, PC-Porteau Cove, WP-WhytecliffPark.) 118 Table 7.2 Survey effort (hours), number of lingcod encountered (n), and size of lingcod by year and general location. (A) Chi square tests based on categorical data of observed frequencies of lingcod >3 years; (B) mean size of lingcod based on 1998 data with 95% confidence intervals. A . Year Location t(h) n %>3 observed expected >3 >3 1996 ES 12.2 101 38 38 40 0.1 WS 5.1 12 50 6 5 0.2 PC 0.8 21 90 19 8 21.0 WP 0.8 49 18 9 19 8.0 T o t a l 18.9 183 39 72 - -1997 ES 20.4 360 20 72 73 0.01 WS 21.7 399 19 77 76 0.03 PC 2.5 40 58 23 8 31.95 WP 10.3 431 18 76 88 1.69 T o t a l 54.9 1,230 22 248 - -B. Year t(h) n Mean SD CI (cm) 1998 ES 39.4 650 49 9.2 0.7 WS 21.6 481 52 8.9 0.8 PC 7.2 171 63 13.9 2.1 WP 13.6 403 49 11.2 1.1 T o t a l 81.0 1,705 51 10.9 0.5 In 1996, 183 lingcod were categorized as either M or J, of which 39% were M . Therefore the statistical assumption was that the population at random would consist of 61% J and 39% M . Both Whytecliff and Porteau Cove showed significant differences from this expected frequency (Table 7.2A). The lingcod population at Porteau Cove had a significantly larger proportion of large lingcod than would be expected (90%), pO.Ol) . Whytecliff Park showed that it had a significantly smaller proportion of large lingcod than was expected (18%, p<0.01). In 1997 the survey effort increased nearly 3 times; as well, the total lingcod placed into categories increased to 1205. Based on an expected frequency of 22% M , the same tests, and same categories for describing the data, Porteau Cove had significantly larger lingcod (58%), p<0.01, Table 7.2A). In 1998 the data collected changed from categorical size data to continuous size data as a new method of underwater measurement was adopted, described in the methods section. Also in this year the survey effort allocated towards determining size increased to 78.9 hours in total from 53.5 hours in 1997, and 119 the number of lingcod measured increased to 1,703 (Table 7.2B). The mean length of lingcod in all of Howe Sound was found to be 51 ± .5 cm (CI 95%, Figure 7.6B) ranging from 26 cm to 106 cm. Using A N O V A , the means between the four locations were compared, followed by a Bonferroni multiple range test. It was shown that the lingcod at Porteau Cove are significantly larger than lingcod in all three of the other locations (p<0.05). It was also shown that the mean size of lingcod on the west side of Howe Sound was also significantly larger (p<0.05) than on the east side. The length frequency distributions between locations (Figure 7.7) imply differences in population age structure. The age structure at Porteau Cove is obviously different compared to the other locations. Thirty percent of the population at Porteau Cove is greater than 65 cm compared to only 4 % for the rest of the east side of Howe Sound. B East side 30 C West side o c a> 3 cr a> ..llll.. o CO o o o o o m T f in C D r-~ oo co E Whytecliff Park Length (cm) 30 20 10 D Porteau Cove .Mill . . . I o o o o o o m co -st in C D r- oo co Length (cm) Figure 7.7 Length frequency distribution of lingcod in (A) A l l of Howe Sound; (B) East side; (C) West side; (D) Porteau Cove; and (E) Whytecliff Park. Fishing Pressure Impacts In this analysis, the 1998 dataset is used to compare size and abundance of lingcod in areas receiving different fishing pressures. Twenty sites, excluding the two reserve sites, are categorized as having high, medium, or low fishing pressure. Placement into categories was based primarily on geographical and 120 logistical accessibility to fishing but also personal experience based on the amount of fishing line observed in the sites during the surveys. Any area which could be fished from shore with no need for boats was considered to suffer 'high' pressure, 'moderate' pressure required boat access, and 'low' pressure referred to areas that required a boat and were geographically further from access points. Figure 7.8A, shows the relationship between fishing pressure and abundance of lingcod. Areas with low fishing pressure did show more lingcod than other areas, but there is a large error associated with these numbers. The mean length of lingcod (53.2 ±0.9 cm) was shown to be significantly greater in areas with less fishing pressure (Figure 7.8B). 30 r Q X a. 25 = 20 15 A _ L O W MEDIUM HIGH 55 50 4 5 B -r L O W MEDIUM HIGH F i s h i n g P r e s s u r e Figure 7.8 Comparison of lingcod encounters (A) and mean size (B) in areas exposed to low, medium, and high fishing pressures (excluding two reserves). Error bars represent 95% confidence intervals; all data from 1998 surveys. 121 Demographic Study by Habitat Type A l l habitat surveyed consisted of sloping bedrock. The depth in which the bedrock was met by sandy bottom varied by site and was classified as either Shallow (0-15 m), Moderate (15-35 m), or Deep (>35 m). Porteau Cove is not included in the analysis as it is artificial reef. There were no significant differences in size between the sites, using 1998 length data, on the basis of bedrock depth (Figure 7.9). 53 r 52 51 -50 -49 I 1 1 1 1 L _ Deep Moderate Shallow Habitat Figure 7.9 Mean length of lingcod in sites with shallow (0-15 m), moderate (15-35 m), and deep (>35 m) bedrock. A l l data from 1998 surveys. Error bars represent 95% confidence intervals. Egg Mass Survey Three years of egg mass surveys are included in the analysis (Table 7.3). The two reserve sites are compared using a chi-squared test with expected frequencies derived from pooled data from all of Howe Sound. For all three years Whytecliff showed no significant difference in either size or abundance of egg masses when compared to the expected frequencies. However, Porteau Cove showed significantly higher encounter rates of egg masses per hour diving compared to other locations in both 1996 and 1997; and in 1998, although not significant (p<0.05), the rate was higher than the values for other sites. Egg mass size has not shown any noticeable trend, but there were proportionately more larger egg masses in Porteau Cove in 1996 than would be expected by chance alone. O) c 0) c ra CD 122 Table 7.3 Summary of spawning surveys by year, location, underwater visual census effort, and size frequencies. Location Time Total Encounters Small Medium Large % Large Encounters (min) (n) (EPHD) (%) (%) (%) 1996 Howe Sound 1867 109 3.5 14 40 46 - -Whytecliff Park 326 15 2.8 20 33 47 NS NS Porteau Cove 316 40 7.6 13 18 70 12.94 4.66 East Side Howe Sound 673 29 2.6 10 55 34 NS NS 1997 Howe Sound 2217 140 3.8 7 46 46 - -Whytecliff Park 120 7 3.5 0 57 43 NS NS Porteau Cove 265 40 9.1 8 55 38 NS 7.19 East Side Howe Sound 699 60 5.2 12 45 43 NS NS 1998 Howe Sound 1406 86 3.7 3 49 48 - -Whytecliff Park 80 5 3.8 0 60 40 NS NS Porteau Cove 277 30 6.5 0 47 53 NS NS East Side Howe Sound 764 45 3.5 7 56 38 NS NS Tagging Study In total, 41.2 diving hours were spent tagging lingcod in 17 different sites. A total of 348 tagged lingcod were used in the analysis resulting in a tagging rate of 8.7 lingcod per hour (Table 7.4). For logistical reasons, not all tagged lingcod were measured. Of the 348 tagged lingcod used in the analysis, 68 were measured at the time of tagging (Table 7.5). The mean length of these lingcod was 55 +2 cm (CI=95%). The mean length of re-sighted tagged lingcod was 61 ±2 cm (CI=95%). The extent of resident behaviour of tagged lingcod in each site was evaluated as a function of the encounter rate and the tagging rate (Table 7.4) expressed by the following ratio, Resident Behaviour=Resighting rate (R2) / Tagging rate (Ri) The resident behaviour at each site was ranked based on this ratio, where a higher value represents increased resident behaviour. Assuming zero tagging mortality and no tag loss, the ratio between the encounter rate of resighted tagged lingcod to the rate of tagging can be used as a crude indicator of resident behaviour. For example, i f there were 10 lingcod previously tagged at site X in one hour, and i f there was no mortality and no movement, than theoretically 10 lingcod could be resighted with the same U V C effort. The ratio served as an index to rank the sites to describe the differences in resighting rates, where a larger ratio value indicates a higher rate of resighting per unit of time. 123 Table 7.4 Summary of tagging, resighting, and ranking of lingcod resident behaviour by site. The ratio of R2/R1 represents the rate of tagging lingcod compared to the resighting rate. Larger ratio indicates less movement. Tagging Resighting Location No. of t No. Ri No. of t UVC n # R: R2/R, Rank events (min) tagged UVC (min) (obs) tagged Ansell Place 5 218 46 12.7 11 458 246 23 3.0 0.23 9 Bird Islets 3 123 16 7.8 4 162 68 3 1.1 0.14 11 Hole in Wall 2 93 6 3.9 3 133 20 0 0.0 0.00 13 Kelvin Grove 3 134 13 5.8 8 336 53 11 2.0 0.34 7 Point Atkinson 6 269 25 5.6 7 301 72 16 3.2 0.57 4 Popham (bay) 1 56 12 12.9 1 52 20 2 2.3 0.18 10 Popham (breakwater) 6 272 41 9.0 8 314 117 29 5.5 0.61 2 Popham (NE reef) 3 125 17 8.2 5 210 62 3 0.9 0.11 12 Porteau (North) 2 100 3 1.8 4 131 18 0 0.0 0.00 14 Porteau Cove 6 265 44 10.0 11 554 234 129 14.0 1.40 1 Sunset Point 4 217 25 6.9 7 331 120 22 4.0 0.58 3 White Islets 2 96 36 22.5 6 239 178 40 10.0 0.45 6 Whytecliff (cut) 6 247 36 8.7 9 415 192 30 4.3 0.50 5 Whytecliff (lookout) 4 181 28 9.3 7 312 182 13 2.5 0.27 8 TOTAL 53 2,396 348 8.7 91 3,948 1,582 321 4.9 0.56 Table 7.5 Summary of the number and mean size (L) of lingcod at time of tagging, during resighting events, and total by survey location recorded during 1998 underwater visual census surveys. Survey location Mean length at time of tagging No. L SD CI with (cm) (cm) (cm) tags Mean length at resighting No. with tags L SD CI (cm) (cm) (cm) Total No. L SD CI total (cm) (cm) (cm) Ansell Place Bird Islets Hole in Wall Kelvin Grove Point Atkinson Popham (bay) Popham (breakwater) Popham (NE reef) Porteau (North) Porteau Cove Sunset Point White Islets Whytecliff (cut) Whytecliff (lookout) 13 0 1 0 6 2 14 1 1 8 6 51 48 67 66 50 53 56 45 59 62 53 20 6 7 16 9 5 5 19 3 2 9 6 68 21 37 32 7 52 67 53 57 77 52 60 57 69 51 56 66 51 5 13 17 12 15 13 13 4 8 12 6 2 15 12 5 14 8 7 14 3 2 2 4 5 32 3 3 9 12 10 27 11 85 22 38 40 13 52 67 51 57 72 55 57 54 66 51 56 65 52 6 13 7 8 18 12 13 9 13 4 8 11 7 2 15 8 5 10 8 5 5 3 2 2 3 4 Total 68 55 10 233 61 13 305 60 13 From Table 7.4 it is seen that in total, R 2 /R i was 0.56. Within sites, Porteau Cove had the greatest rate of resighting (1.4) followed by Popham Breakwater (0.61). Both survey sites at Whytecliff, Cut and Lookout, had rates of 0.49 and 0.27 respectively. It should be noted that the length of time between 124 tagging and resighting data are not the same between or among sites (see Appendix 7.4). However, since this analysis is a test for resident behaviour the assumption is that every tagged fish can theoretically be observed during each U V C and that tagging is not influencing the mortality of the fish. Although there is natural mortality occurring between tagging and U V C events, this analysis assumes zero mortality. Previous lingcod tagging studies in the Strait of Georgia estimate movement rates of lingcod to be 500 m per day for males and 1,000 m per day for females (Smith and McFarlane 1990). The results of this study indicate that adult movement for at least portions of the population in Howe Sound may be considerably less than previously thought. However, sub-adults (2-3 year olds) appear to have high movement rates. To date there have been only two tag returns by recreational fishers: one was caught (by an unknowing poacher) in Whytecliff Park in the exact location where it was originally tagged 87 days prior and the other was caught approximately 10 km from the original tagging location 103 days after the tagging. Both of these fish were approximately 50 cm in length. DISCUSSION The original question forming the basis of this chapter was to determine i f there is a change in lingcod demography attributable to protection from direct human exploitation in protected areas compared to adjacent exploited areas in Howe Sound, British Columbia. Information from the commercial fishery has already shown that lingcod can be over-exploited at varying spatial scales. During an interview in May, 1998, Tor Miller, a commercial lingcod fisher in the Strait between 1932-1990 said that he always moved his fishing effort around so as to not overfish any given reef. His anecdotal evidence implies that he was well aware of the resident behaviour of lingcod. This is consistent with catch statistics in the Strait of Georgia fishery statistical areas which show that at a larger scale (100s km 2), overfishing also existed (Figure 7.10). This figure shows the lingcod landings from four of the most productive catch statistic areas. Many of the curves are defined by a peak, followed by either a gradual or abrupt decline. The current reserve system in Howe Sound is comprised of two small areas occupying less than 2 km 2 but even at this scale, changes in lingcod demography were observed during this three year study. 125 450 r 1950 1960 1970 1980 Year Figure 7.10 Commercial landings of lingcod in the Strait of Georgia broken down into DFO statistical regions. Area 13 is found at the Northern end of the Strait of Georgia near Campbell River. Areas 16-18 are found in the Southern Gulf Islands. Abundance The abundance of lingcod encountered during underwater visual censusing of study sites was significantly different between years. The encounter rate in 1997 and 1998 is twice that of 1996. The rate increased as a result of juvenile (1 year old) lingcod becoming present in the surveys due to strong year classes in 1995 and 1996. Juveniles were observed to arrive in the survey areas in late summer and typically reside on sandy bottoms near or adjacent to rocky reefs. In 1998, there were very few 1 year olds observed indicating that the 1997 year class is not as strong as the previous two years. Based on previous experiences with marine reserves, abundance of a target species should increase once fishing pressure is removed (Plan Development Team, 1990). In all three years, Whytecliff Park showed the highest encounter rate compared to the other locations. Due to small sample sizes in 1996 and large variances in 1997, statistics could not be used to compare locations. Regardless, Whytecliff was shown to be productive lingcod habitat. In each of the three years Whytecliff Park recorded the maximum total number of fish per dive. The greatest number of encounters of all sites, and all years was 72 lingcod in a 48 minute dive at Lookout Point in Whytecliff Park. Although fishing has likely decreased in Whytecliff with the establishment of the reserve, the high rate of encounter at this point is likely a factor of habitat and not fishing pressure as most of the fish encountered (63%) in 1998 were under 50 cm. This indicates that most of the fish in the park have only recruited since the establishment in 1993. The results do suggest that Whytecliff s location is a good choice of a reserve on the basis of it being suitable habitat for juveniles. Historically, there is anecdotal evidence that large lingcod were once common in the park 126 boundaries which suggests there is potential for the newly recruited juveniles to grow to larger sizes within the park. If future observations demonstrate a higher encounter rate combined with a larger mean size, then the evidence wil l be stronger in demonstrating the effect of the reserve. Since encounter rates of lingcod may simply be a function of suitable habitat availability within the transect sites, mean size may be a better indicator of the effects of fishing effort. In this study it was shown that Porteau Cove had significantly larger lingcod than all other sites for all three years (Figure 7.6). In 1998, only 18% of the lingcod encountered were less than 50 cm which means most of the fish are pre-1995 recruits. The low proportion of small fish suggests that areas with high concentrations of large lingcod exclude juveniles possibly through behavioural mechanisms such as territoriality or cannibalism. Territoriality was noticed at Porteau Cove not only during the spawning season as was previously thought (Cass et al. 1990), but throughout the year. Many of the tagged lingcod were resighted over a period of 8 months in the same location in which they guarded an egg mass. During the research there were two observational accounts of male lingcod guarding their egg mass in the same location in consecutive years. One male, identified by a missing section of the anterior portion of the dorsal fin, was recognized defending an egg mass in the same location in 1997 and in 1998. The second observation was of a male which was tagged while defending an egg mass in 1998. This same male was observed on several occasions at the same site throughout the year, and in 1999 was guarding an egg mass in exactly the same site indicating that the males may choose the spawning location or that they breed with the same females each year. These observations confirm that at least some portion of the lingcod population maintain territories throughout the year. Tag resightings were the highest at Porteau Cove indicating a high degree of resident behaviour compared to other sites. Alternatively, other sites may have larger populations with many tagged animals frequenting depths beyond scuba diving range. The average size of resighted individuals in all areas was shown to be larger than the average tagged fish. Unfortunately there are insufficient data for proper statistical analysis. However, the existing data and observational accounts do suggest that larger fish in all sites exhibit more resident behaviour than small fish. This would explain the high rate of resighting at Porteau Cove. The complete ban on fishing in Porteau Cove for over 19 years cannot from a scientific viewpoint be isolated as the variable governing the size of lingcod in the reserve. Porteau Cove is different from all 127 other sites in this study in that it is artificial reef on sandy bottom, whereas all other sites are of bedrock of varying depths. However, i f spearfishing were permitted, two divers could eliminate the population in one hour of diving. It is likely then, that the fishing ban is at least partly responsible for the observed population structure. Palsson and Pacunski (1995) describe similar lingcod demography in Puget Sound where the longest standing no-take reserve, Edmonds Marine Park, is also an artificial reef with nearly 30 years of protection. Assuming that fishing does have an impact on lingcod populations at small scales, then it would be expected that areas with less fishing would support larger lingcod and that encounter rates would be greater in areas with less fishing. When mean lengths of lingcod were compared between areas of high, moderate, and low fishing pressure, a significant difference was observed (Figure 7.8). Areas which receive low fishing pressure have on average significantly larger fish. This has important implications for both management and insight into the potential effectiveness of reserves. Although the study was not originally designed to test this effect, the results are meaningful. The results may simply be due to a larger scale ecological phenomenon such as food availability. Areas with low fishing pressure are also areas closer to the Strait of Georgia which may have more food sources available and therefore individuals may grow faster. It is noteworthy, as well, to mention that four of the sites considered to have low fishing pressure were in close proximity to large haul-out areas for harbour seals and migrant Steller sea lions. Encounter rates were also highest in areas with low fishing pressure, and lowest in areas with high fishing pressure. This is further evidence supporting the claim that lingcod populations are adversely affected by fishing pressure and that at least some portion of their population have small habitat requirements. There was no observable difference in lingcod demography between sites based on habitat classification. A l l sites were of bedrock or boulder habitat, but the depth at which the habitat ended varied between sites. A comparison of mean lengths of lingcod in habitats ending at different depths was made, excluding Porteau Cove but including Whytecliff. No differences were observed between habitat types, suggesting that fishing pressure, and not habitat, may be the dominant ecological factor affecting lingcod demography within sites in Howe Sound. These results indicate that in heavily fished regions, a reserve in any lingcod habitat has potential to result in a population of larger mean size. Further research and analysis are required to confirm this prediction. 128 Spawning Potential The ability of a reserve to contribute to the ecosystem or fishery in which it is embedded wil l depend on the amount of emigration of sub-adults and adults, or the export of larvae or eggs (Rowley 1994). In this study, the encounter rate of egg masses was used as an indicator of spawning potential of a site. In all three years encounter rates of egg masses at Porteau Cove were higher than other survey sites. In all years, Whytecliff showed an encounter rate of egg masses similar to other locations on the east side of Howe Sound. It is uncertain whether the encounter rate is a function of suitable habitat or a function of the number of spawning adults. Given the low numbers of large adults observed on the east side of Howe Sound it seems that it could be a function of the number of spawners. The fate of larvae produced in the reserve sites is unknown. Given that lingcod have a pelagic larval stage of approximately 90 days, there is tremendous potential for widespread export of larvae. However, designating an area as a reserve based on larval fate is not practical. Despite this, there is a lot of interest in source-sink relationships in the design of reserves (Carr and Reed 1993, Allison et al. 1998). However, the stochastic nature of the physical properties, combined with complex behaviours of larval fish make predictions of suitable location infeasible. As Roberts (1998) states, "If the identification of sources and sinks is allowed to drive reserve designation, then I doubt a single marine reserve could be established on current knowledge of connectivity patterns in the sea." For now, the simple prediction that more spawning leads to an increase in potential larval export will have to suffice. Humans, Seals, or Climate? Marine protected areas offer great potential as areas to conduct scientific research (Allison et al. 1998). In temperate waters commercial fish populations have been shown to be controlled not only by anthropogenic variables such as overfishing (Leaman 1991) and habitat destruction (Bergman et al. 1998), but also environmental variables such as climate (Beamish 1995, McGowan et al. 1998). An effective system of reserves could be used to isolate some of the causes underlying the dynamics observed in fish populations. This is especially true for marine waters adjacent to urban centres where numerous human activities potentially alter the natural course of marine ecosystems (Norse 1993). In the Strait of Georgia, blame for the loss of commercial fish resources has been directed towards water quality deterioration from land-based sources such as sewage outfalls and pulp mills, habitat destruction from urban development and log storage, overfishing, changes in climate, and seals (Levy et al. 1996). Strategically located 129 reserves could offer information on the relative importance of these influences. For example, a reserve embodying a fishing hotspot in close proximity to a pollution source or a seal haul-out would be useful in discerning the relative impacts. One area which fits these criteria is Popham Island. It has a large, permanent seal haul-out site, a research station, and historically was considered to be a lingcod hotspot. Without some form of baseline, isolation of relative anthropogenic impacts cannot be ascertained. Limitations of the Study A general obstacle which is present in any study of this type is the logistical difficulty in conducting the research. 1998 was the most intensive year of the research program. In that year, a total of 165 hours of bottom time was logged by all divers doing underwater visual censusing, tagging, or egg mass surveys. This research involved more diving than any other ongoing ecological research in British Columbia, but the observations represent only a small fraction of the overall time available to be sampled. Observation time is limited by the logistics of getting to the sites, the cost of conducting marine research, and limitations in human physiology. In this study surveys were rarely conducted below 18 m. This was for two reasons, one is that the allowable bottom time decreases with greater depths, and second, for liability purposes, all dives below 18 m require a standby diver (in addition to a dive tender) i f diving through an institution covered by British Columbia's Worker's Compensation. In many sites, only the top 18 m of the habitat was surveyed despite the fact that lingcod are known to commonly inhabit depths between 10-100 m (Cass et al. 1990). It is therefore not possible to accurately understand the demography of some sites, in particular Whytecliff Park which has habitat continuing to well over 100 m. The study was also limited by there only being one reserve site consisting of natural habitat. Comparing artificial reef with natural habitats incurs many difficulties. Artificial reef may contain structural complexity highly desirable for lingcod. If by chance a lingcod is moving along the shore when it encounters this form of habitat it may choose to stay. Once there, territorial behaviour ensures that only the largest fish wil l occupy the habitat. Alternatively, i f lingcod settle in the artificial reef by chance as juveniles, the isolated island nature of artificial reefs could possibly invoke a behavioural response preventing migration. A long-standing reserve site in natural habitat would provide very useful information in understanding the potential of marine reserves. One thing is certain, lingcod populations are a small fraction of their past abundance, which leads one to believe that there is ample suitable natural habitat currently unused. 130 Aside from Whytecliff being the only reserve site of natural habitat, it also only occupies approximately 1.2 km of shoreline. Using movement rates from previous studies suggests that passing lingcod would only be in the site for one day (Smith and McFarlane 1990). Tagging indicates that even at Whytecliff at least some of the population remains resident, but nonetheless, it is a small area to protect populations of fish with known daily movement rates larger than the size of the area. These results highlight the need for future research on lingcod movement. Poaching Non-compliance with fishing regulations is a problem in the management of any fishery (Hemming and Pierce 1997). There is indication that illegal fishing is taking place in the reserve sites. The best indicator is the amount of fishing line on the bottom. Porteau Cove Park consists of two sections. One section is artificial reef (Porteau Cove) which was the focus of this study, the second section (Porteau North) runs along the shore line. This area is comprised of larger boulder habitat resulting from the construction of the railroad along the east side of Howe Sound. Although it is officially part of the park, this site was not considered as protected area in the analysis due to the profusion of fishing line observed while scuba diving. This might be an indicator of higher catch rates predicted to occur due to spill over from the core of the reserve area (Russ and Alcala 1996), but likely it is just an indicator of easy fishing access. In Porteau (North), a home-made lure trap was deployed to assess the amount of illegal fishing. The trap consisted simply of 5 mm polyethylene rope suspended mid water with fishing floats and attached at either end to large boulders. The resultant U-shaped structure covered approximately 15 m of shoreline distance. In a period between May 27, 1998 and August 12, 1998, 14 lures were caught on the rope indicating considerable fishing pressure along this section. In the artificial reef section no fishing line was ever found during U V C but on one occasion a boat was seen fishing in the area. Evidence of illegal fishing in Whytecliff was indicated by consistent observations of new fishing line in the transect areas. Ironically, a tagged fish was caught and reported by a fisher unknowingly fishing in the reserve, further demonstrating that illegal fishing is occurring. More importantly, this incident demonstrated that some people are simply unaware of the restrictions. Whether or not the extent of poaching pressure is great enough to exert an influence on the observed demography is unknown. However, given the small size of the site, and the small numbers of large lingcod observed, it would not take much illegal fishing to influence the results. 131 Improving the Current System of No-Take Marine Reserves Considering that less than 1% of the water adjacent to Howe Sound's shoreline is considered a reserve, there is still considerable room for improvement. Both existing reserves could use better signage, in particular the shore side of Porteau Cove which is marked with an obscure, run-down marker delimiting the boundary of the park. Whytecliff Park needs further land-based stewardship in the form of a warden to educate people and to monitor activities. However, the most important improvement would be an expansion of the current system. From a conservation perspective, populations of lingcod and rockfish in Howe Sound and Burrard Inlet (Area 28) could benefit from a complete groundfish closure making the entire area a form of reserve. Since this is politically difficult, reserves in Howe Sound wil l inevitably be small due to their proximity to Vancouver and the number of resource users sharing the same body of water. Thus, future areas wil l need to be chosen carefully to maximize their ecological effectiveness. The potential effectiveness can be evaluated based on the (1) ecological goals of protection, (2) type of human activity restricted, and (3) to what degree are restrictions complied with or enforced (Allison et al. 1998). Furthermore, evaluation requires continuous and well designed biological monitoring. The only ecological goal that can be realistically achieved using small reserves is rebuilding populations of sedentary species (i.e., lingcod, rockfish species). Accepting this requires that areas be chosen based on their potential to rebuild populations, not necessarily protect existing populations. Potential can be determined by developing a list of traditional hot spots from anecdotal fishing accounts. Preferred sites would be ones where all continuous habitat is protected. Generally, this would be islands and reefs surrounded by deep water or sandy bottoms (e.g., Passage Island reefs, Bird Islets, Hurt Rocks, Popham Island reefs). The island effect would likely decrease the amount of emigration from the reserve area. However, for these small reserves to work will require compliance to restrictions of year round closures to all fishing. Incidental Observations During the course of this research incidental observations were recorded which support the value of reserves. In 1996, a school of newly recruited 1 year old yellowtail rockfish (Sebastes flavidus) were first observed in Whytecliff Park. Previous to this observation there had been no accounts of this species in the park since 1965.6 7 Don McPhail describes yellowtail rockfish at Whytecliff coming in by the thousands at dusk in the 1950s.68 Yellowtails have been shown to live up to 54 years (Shaw and 6 7 Andy Lamb (author of Coastal Fishes of the Pacific Northwest and co-founder of the Marine Life Sanctuaries Society), personal communication with author. 6 8 Don McPhail, University of British Columbia, personal communication with author. 132 Archibald 1981) and are considered to have limited movement (Pearcy 1992) and therefore their disappearance is likely linked to fishing. For the last three years this one small school of approximately 50 individuals has been repeatedly observed in the same location, and each year they are slightly larger. Based on life history information, it is likely that these are the same individuals observed each time. Whytecliff is one of the few places where yellowtail rockfish can be regularly seen in Howe Sound. Black rockfish {Sebastes melanops), the only known rockfish to feed on the surface, were once abundant enough in the Sound to support recreational flyfishing. Bernie Hanby describes Howe Sound black rockfish in the 1960s as being "all over the place". 6 9 At present they are virtually extirpated from this region. In the three years of diving in the Sound, I observed only 3 black rockfish, all at Point Atkinson, and most likely the same individual. The individual was spotted over a small boulder field (approximately 4 m wide and 8 m long). Black rockfish are generally found in large schools reflecting an evolutionary need for high populations (Kuzis 1986). For populations to have a chance of recovery, black rockfish wil l require some form of spatial protection. Yeiloweye rockfish (Sebastes ruberrimus) were at one time very common throughout the Strait of Georgia and in Howe Sound (see Chapter 4). Longevity in this species has been shown to be well over one hundred years in British Columbia waters (Kronlund et al. 1998). Adults are usually found in depths beyond diving range and not surprisingly none were encountered. However juveniles commonly inhabit depths between 20-30 m (Hart 1973). During the surveys only 4 juveniles where encountered, three found during one survey clustered together on a reef at Hutt III and an individual at Point Atkinson. Little is known about adult movement rates, but submersible observations of yeiloweye rockfish in Alaska found they utilize small refuges created from overhangs of boulders and crevices, indicating they have high site fidelity (O'Connell and Carlile 1993). Copper rockfish (Sebastes caurinus) and quillback rockfish (S. maliger) were shown by Palsson and Pacunski (1995) to be larger and more abundant in a reserve in Puget Sound. There were no formal surveys done for these species but observational data suggest that the copper rockfish at Porteau Cove are larger than at other locations. Quillbacks were most abundant at the White Islets site. Both species are resident, old-lived, and important for commercial and recreational fisheries in the Strait (Yamanaka and Kronlund 1996). 6 9 Bernie Hanby, Director of the Sport Fishing Advisory Board and co-founder of Marine Life Sanctuaries Society, personal communication with the author. 133 As mentioned previously, numerous lingcod were repeatedly sighted occupying the same location for up to three years. This occurrence was not only observed at Porteau Cove, but also at other locations. At Bird Islets, two lingcod were repeatedly sighted occupying horizontal crevices. At the Popham (breakwater) site, the same individual was seen during four different dives over a period of six months perching on a boulder. There were also repeated observations of lingcod pairs occupying the same crevice during non-spawning time. It is possible that these are spawning pairs. Given the territorial nature of lingcod it is unlikely that the pairs would be two males. Invariably all repeated observations of lingcod were of large individuals (>70 cm). A l l of these observations indicate that even small reserves wil l likely have an impact on the demography of resident, old-lived, targeted species. This is not to support establishing only 'postage stamp' sized reserves, but i f demographic changes can be observed at small spatial scales, it leads one to believe that larger areas wil l contribute to restoring and conserving a variety of marine species. Fisheries or Biodiversity Allison et al. (1998) make the distinction between 'fishing refugia' and 'biodiversity reserves'. This is an important distinction to make, as the ecological goals are quite different. The ultimate goal of refugia in fisheries management is to increase populations through emigration of surplus biomass from the refuge, or the export of larvae to replenish exploited areas (Plan Development Team 1990). Secondary objectives include diminishing the chances of management error (Lauck et al. 1998) and providing insurance in the event of management failure (Ballantine 1991). Although fishing refugia, by protecting species with important ecological roles wil l protect community structure (Castilla and Duran 1985), the management goals are quite different. Biodiversity reserves are more concerned with protecting threatened or unique species and ecosystems while establishing baseline research areas. Given the small size of the reserve sites in this study, they are not likely contributing much to rebuilding fish populations, nor are they conserving biodiversity. However the ecological structure of the areas was shown to be different, likely a result of removing the human predator from the system. The research benefit of having an area used as an ecological benchmark is beneficial for understanding how future, larger reserves can be used for these two general purposes. C O N C L U S I O N Humans are a powerful ecological force in the Strait of Georgia ecosystem. Although commercial fishing for lingcod is closed in the Strait, there is still a significant recreational fishery. It is estimated 134 that recreational angling effort in the Strait exceeds 600,000 boat trips annually, yielding approximately 1.2 million days of fishing effort (Brunt 1998). Annually 400,000 recreational licenses are sold. Fishing pressure in Howe Sound is likely the highest of anywhere in British Columbia, and therefore populations of resident fish are easily depleted. It was shown in this study that marine reserves offer a potential tool to re-build populations and protect at least some portion of lingcod populations. In Howe Sound, and for most marine waters exposed to heavy human influence, the word 'protected' in marine 'protected' area does not represent the management goal. Without exception, every published paper in the scientific literature referring to marine protected areas or reserves, in reality have only described the capacity of reserves to restore or rebuild populations of over-exploited species; not protect. Marine protected areas in Howe Sound wil l be used to restore and rebuild. Historical evidence suggests that the biomass of resident high trophic level species was at one time much higher throughout the Strait of Georgia (see Chapter 4) and also Howe Sound. Given the human population forecasts for the Georgia Basin, it is unforeseeable how populations of any resident fish can be restored, or even maintained at the present depleted level, without some form of marine rehabilitation area. 135 Chapter 8 Summary There is little question that fisheries exploitation impacts all three levels of biodiversity in British Columbia. Research presented in this thesis demonstrated many examples of drastic changes in population structure and size of targeted species, food web structure, and species composition of catches. As each population is embedded in a trophic structure, these effects have had far reaching ecosystem impacts. Summary of Ecosystem Models In Chapter 2, a data set of all known catches of marine organisms in B . C . from 1875 to 1996 was presented. Catches from all major fisheries including commercial, aboriginal, recreational, international, joint-venture, marine mammals, and bycatch were included in the data set. Combining these data demonstrated that catches rose steadily from the turn of the century until the 1970s at which time a crash in herring and an end of whaling resulted in a sudden decline of landings. However since the early 1970s catches steadily increased again to 1991 when it was near historic levels. Throughout the period covered in this database the species composition has changed dramatically. The early fishery, 1875-1900, was comprised primarily of salmon, dogfish, and fur seals. The next period, 1900 to 1925, was highlighted by the beginning of commercial whaling and industrial fishing of herring. By 1950, small pelagics consisting of herring and pilchard far outweighed other species caught in the fishery. The period between 1950 and 1975 was marked by extraordinary landings of herring and whales, until both fisheries, due to low populations, came to a close in the late 1960s. The present day fishery is the most diversified in terms of number of species targeted. This is primarily because of the expansion of the number of invertebrate species caught. The single most important species landed in terms of biomass is now hake. Catch data are good for illustrating changes in species composition in the fishery, but such data do not provide any ecosystem context for the landings. That is, a tonne of abalone is considered the same as a tonne of Steller sea lion, where in fact each have significantly different ecosystem roles both functionally and trophically. In Chapter 3 the data set compiled in Chapter 2 was used to evaluate ecosystem impacts by examining the trophic relationships of the catch. 136 Trophic levels were first assigned to each species group found in the catch and two analyses were carried out. The first analysis was designed to calculate the mean trophic level of the total catch over the period of the data set. It was found that overall there have been two separate periods of mean trophic level decline, each with separate causes. The first decline was due to an early fishery that changed from primarily dogfish, salmon, and fur seals, to one that targeted small pelagics and whales. This decline ended abruptly in 1963, at which time fishing for high trophic level groundfish, coupled with continued salmon catches, resulted in an increase in the mean trophic level. Since the 1970s, there has been a second decrease in the trophic level, but this time it is due to increases in the landings of hake (trophic level 3.3) and invertebrates (trophic level - 2 . 1 ) coupled with decreased landings of higher trophic level fish such as chinook, coho, and lingcod. The second analysis used only resident species. Resident species are those which are considered to spend their adult lives in B . C . waters. When only resident species are considered in the analysis, it was shown that there has been a steady decline in the mean trophic level since 1932, indicating the depletion of high trophic level, old-lived, resident fish such as lingcod, rockfish, and resident salmon. Mean trophic level, by itself, does not necessarily reflect ecosystem changes, as it may only be a consequence of management decisions or markets. To further the analysis, the primary production required to sustain the catch was determined. It was shown that the primary production required to sustain the fisheries in the 1990s, which is a measure of ecosystem support, was higher than any other period in B . C . history. However in recent years, the sharp decrease in trophic level combined with a decrease in the primary production required suggests that B.C. ' s fisheries are fully exploited with little or no chance of increased landings without further fishing down the food web. In doing so we preclude the opportunity to rebuild populations and jeopardize marine biodiversity. In Chapter 4 a detailed examination of the Strait of Georgia using mass balance ecosystem models revealed drastic changes in species abundance over the last century. These changes have had large scale trophic impacts on food web structure. In particular, overfishing of populations of baleen whales, sturgeon, halibut, lingcod, yellow-eye rockfish and other groundfish are well documented. The trophic niche left open from these depletions appears to be filled by hake, which is presently at historically high levels. Hake provides an abundant food source for seals, which in turn are consumed by transient killer whales. Because of this food web, coupled with large, albeit depleted populations of salmon, the Strait is considered a mature system in comparison with other systems. 137 Dynamic simulations made evident the potential widespread, long-term trophic impacts of fishing, and in particular, how fishing could lead to an ecosystem now extant. This change in structure due to fishing was in turn shown to have changed the fishery. A mean trophic level analysis of the Strait's fishery indicates that virtually all high trophic level, resident species have been overexploited. The remaining fisheries are now comprised predominantly of invertebrates. Modelled ecosystem impacts suggest that B.C. ' s fishery is unsustainable, and that sustainability as a present day goal would only be sustaining a depleted system. This was made evident by analyses utilizing historical data which indicate a coast-wide decline in resident, high trophic level species in fish landings, coupled with an overall increase in primary productivity appropriation (Chapter 3). Closer examination using the Strait of Georgia indicated profound impacts on food web structure. Marine reserves were suggested to be one tool to rebuild components of depleted ecosystems. Summary of Marine Reserve Case Studies Overall, the primary focus of the thesis was to understand how the ecosystem impacts from fishing could be better mitigated by the use of marine reserves or, in ecological terminology, what can be expected to happen i f a refuge is provided for species targeted by humans. Refuges are an integral component of any ecosystem in regulating predator-prey interactions (Conell 1970). In 1934, Gause conducted a simple experiment to test the functional role of refuges. In his study, the ecosystem consisted of three species; a bacteria, and two protozoans, Paramecium caudatum, and Didnium nasutum. Didnium preys upon Paramecium, and Paramecium feeds on the bacteria. In a test tube, Gause first introduced only Paramecium into the bacteria culture, and after a couple of days, the population had increased ten-fold, at which time he introduced the top-level predator, Didnium. Shortly thereafter the predator's population increased, followed by a decrease in the population of its prey, and eventually both populations died out as the Didnium ate every last prey and consequently starved. This experiment was repeated many times, and Gause (1934) reports, the quantities of the predator and prey at a certain time t could be exactly predicted with a comparatively small probable error. Using the same experimental setup, Gause introduced a refuge (sediment) for the Paramecium and in his words, "such a deterministic process disappears entirely when a refuge is introduced into the 138 microcosm." In these studies either species could die out first and any combination in between. Gause concludes by saying, When the microcosm approaches natural conditions (variable refuges) in its properties, the struggle for existence begins to be controlled by such a multiplicity of causes that we are unable to predict exactly the course of development of each individual microcosm. Based on Gause's observations of a simplified ecosystem, it seems improbable that the ecological outcome resulting from the establishment of marine reserves can ever be predicted precisely. Nonetheless, the objective of this thesis was to examine what would happen to populations of exploited species i f a refuge from human predation was intentionally introduced into our own microcosm. Empirical evidence worldwide has demonstrated that, in the absence of fisheries, ecosystems do structure themselves differently in accordance to processes of natural selection, and are therefore, to some degree, predictable. The most readily observed first-order effects include changes in species abundance, age structure, and overall biomass of targeted species (Plan Development Team 1990, Roberts and Polunin 1991, Roberts 1995, Alison et al. 1998). These effects are probable outcomes of establishing a marine reserve. Findings in this thesis indicate that marine reserves in British Columbia are consistent with worldwide observations of first-order effects of protection. In Chapter 6 it was demonstrated that abalone populations in well enforced reserves were larger and more abundant than those in adjacent exploited areas. Similarly, in Chapter 7, the average size of lingcod in a reserve population was shown to be significantly larger than populations in exploited areas, indicating a change in age structure. Furthermore, when exploited sites were categorized and compared by the amount of fishing effort they receive, it was found that less exploited sites had on average larger lingcod. A tagging study demonstrated that larger lingcod were more likely to be resighted, indicating that the larger fish tend to be more resident. Reserves therefore may be critical in protecting large spawning adults, which could benefit the surrounding areas by increased production of larvae. Many of B.C. ' s ecosystems are depleted of high trophic level, commercially valuable, resident species, which suggests that marine reserves may be important in rebuilding ecological structure. This is assuming an ecological process exists causing organisms to self-organize into a trophic 139 structure. Ecological structure may be rebuilt in the reserve area, but the extent to which this wil l contribute to non-reserve areas is unknown at this time. Marine Reserves as an Ecological Approach to Management Second-order effects of establishing reserves, which include most of the potential benefits to humans, are less easily predicted (see Appendix 8.1 for list of anticipated benefits of marine reserves). These include increases in adjacent fisheries catches (Russ and Alcala 1996), fate of larvae exported from reserve area and subsequent recruitment into the fishery (Roberts 1998), and decreased risk of management failure (Lauck et al. 1998). Although the theory and scant empirical evidence suggests that these benefits may accrue, in reality marine reserve science is a long way from making accurate predictions of this nature. These uncertainties have led to principled approaches to marine reserve establishment and fisheries management in general (Ballantine 1997). Ballantine's argument is that science wil l never predict with enough certainty to make proper fisheries management decisions while at the same time science wil l never fully understand ecosystem dynamics enough to implement a perfect network of marine reserves. Therefore, in his opinion, reserves should simply follow the principles of representation, replication, and network design to account for uncertainties in both fisheries and reserve creation. Implementation of marine reserves with this approach is consistent with the much-touted precautionary principle (Lauck et al. 1998). That is, i f there is uncertainty in the size of a fished population, the life history of the targeted animal, physical processes governing its population, and the impacts which fisheries may have, then it is best to have at least some portion of that population invulnerable to fisheries induced mortality. Fisheries management has been criticized because it has not confronted uncertainty directly by building insurance into management plans. Roberts (1997b) makes the analogy that engineers do not build bridges strong enough for the average flow of traffic. Reserves offer one of the most effective ways of providing a buffer. Fisheries management conventionally has not examined the role of refuges, but ironically, the role of refuges is well appreciated in pest management (Corbett and Rosenheim 1996, Murdoch et al. 1996). In pest management, refuges are considered as an annoyance because eradication of the pest becomes increasingly difficult with more refuges. The same principle could apply to fisheries management. In fisheries it has been acknowledged that nonintentional refuges are likely present in any successful fishery (Walters 1996, 1998), but implementation of intentional reserves has been slow. 140 Paradoxically, marine reserve science is confronted with having to provide evidence for justifying the implementation of reserves based on calculated potential benefits to humans rather than justifying them on the basis of what is unknown about the ecosystem in general. Consequently, research typically involves the comparison of a single or handful of indicator species in a reserve (treatment) to an exploited area (control), resulting in a reductionist single species approach to test first-order effects of protection. M y research was conducted in precisely the same manner. Abalone and lingcod were used as indicator species to demonstrate potential ecological effects of marine reserves. The analysis of the lingcod research was unable to conclusively determine i f the lack of a 'treatment' effect at Whytecliff Park was due to its small size, poaching, limited years of protection, or research limitations (i.e., depth). Similarly, at Porteau Cove, the large size of lingcod observed could not be attributed solely to protection because the artificial habitat confounded the results. However, coupling the known life history of the species, combined with results of the tagging study, strongly suggests that even small reserves have some effect. Results from the abalone research, which demonstrated that reserves were effective in protecting densities and age structure, were less contentious. In addition, incidental observations of other species described in Chapter 7 also suggest that many other species may benefit from the creation of reserves. The results of my research, not surprisingly, were consistent with the general trend shown in reserves. Species that are old-lived, resident, and heavily fished tend to be strongly affected by the creation of reserves, in terms of population structure and abundance. By deduction it is probable that these effects would be found in numerous indicator species in varied habitats and occupying all trophic levels. In British Columbia alone there are numerous exploited species aside from abalone and lingcod which could benefit from reserves based on known aspects of their life history. For example any of the 31 exploited species of rockfish 7 0, flatfish 7 1, skates, crabs, urchins, geoducks, horseclams, prawns, shrimp, and sea cucumbers could benefit from reserves. With any of these species, a reserve 7 0 Shaw and Archibald (1981) found the mean and maximum ages of ten commonly trawl caught Sebastes species (maximum age in brackets). S. aleutianus (101 years), S. alutus (76), S. brevispinis (80), S. crameri (47), S. entomelas (22), S.flavidus (54), S. pinniger (75), S. proriger (41), S. reedi (71), S. zacentrus (45). These species would likely show difference in age structure between heavily and lightly exploited populations. 7 1 There have been tagging studies done on at least three species of flatfish caught in B.C. which all indicate limited movement. Dover sole (Microstomus pacificus) (Rackowski et al. 1989), rock sole (Lepidopsetta bilineata) (Ketchen 1982), and starry flounder (Platichthys stellatus) (Nelson et al. 1993). 141 would demonstrate a change in age structure, as exemplified by Leaman's (1991) research on Pacific ocean perch, abundance, such as the catch per unit effort changes in the live rockfish fishery (Kronlund et al. 1998), or in average size, as represented by dungeness crab populations in Chapter 5. Populations of species comprising bycatch also undergo the same pressures from fishing, but since they have no economic value they are not considered overfished (Wallace 1997), and we have no benchmark to assess their decline (Pauly 1995). Furthermore, alterations in habitat from the effects of bottom trawling cause changes in the benthic community which have not yet been investigated in B . C . Discussion on individual species appears to be contrary to the notion of marine reserves as tools for ecosystem-based management as introduced in Chapter 1. But given that all species interact in a larger system, a change in demographics of one species due to protection must have greater ecological consequences, just as their depletions were shown to alter the trophic pathways in Chapter 4. When basic knowledge on movement and life history parameters of multiple species are combined with knowledge of fisheries history of abundance it is apparent that fisheries have had an impact on numerous species occupying a variety of habitats and trophic levels. A system of reserves is a practical ecological approach to management that acknowledges the breadth of habitat and trophic interactions within any ecosystem. A n ecological approach to management is different from ecosystem management. Ecosystem management implies that ecosystems can be managed, whereas an ecological approach acknowledges that there are connections, some of which can be managed. A n ecological approach, in my opinion, couples specific scientific knowledge with general scientific principles to deal with uncertainty according to precautionary and adaptive principles, which can in part be brought into reality by the establishment of marine reserves. A n ecological approach would utilize ecosystem knowledge, not just create it. This is well demonstrated by looking at the status of yellow-eye rockfish. It is known that they reach ages up to 120 years, that they are resident, and they were once found in far greater numbers (see Chapter 4). It is nonsensical that a fishery still targets them in areas where their populations are acknowledged in management reports to be "poor". Moreover, the mean age of yellow-eye rockfish in the Strait of Georgia fishery is currently 17 years, an age where only 50% of the stock is sexually mature (Yamanaka and Kronlund 1996). Because yellow-eye are one species in a multi-species fishery, a 142 closure would need to be in the form of a reserve for all species. Reserves are probably the only way to protect vulnerable and valuable species of this sort (Roberts 1997b). It has been pointed out that fisheries management is trapped by the notion that fishing should be allowed everywhere, all the time, until we can prove that it is having negative impacts on populations (Ballantine 1995, Walters 1998). Evaluation of fisheries impacts on species and ecosystems would be greatly strengthened with the implementation of reserves as control sites. This would also help isolate the relative importance of other variables such as climate and pollution critical in taking an ecological approach. Future of Mar ine Reserves in British Columbia Despite rapidly expanding evidence supporting the benefits of marine reserves there is still tremendous resistance to their creation. In 1990 the Canadian Council on Ecological Areas suggested that constraints to M P A establishment were scientific, legal, political and social (Graham 1990). Scientific obstacles are diminishing with growing empirical evidence and strong theoretical underpinnings. Legal obstacles have been to some degree lessened by the recently passed (January 1997) Oceans Act which specifically allows the Department of Fisheries and Oceans to designate Marine Protected Areas (Section 35(1)).7 2 Furthermore, pending legislation cited as the Marine Conservation Areas Act (Bil l C-48) by Parks Canada, wi l l assist in the designation of National Marine Conservation Areas. Both of these pieces of legislation wil l be useful from a legal point of view, but the largest obstacles are still social and political in origin and remain to be worked out. Establishment of marine protected areas in B .C. , of any form, have been heavily resisted since they were first suggested in 1970. 7 2 3 5. (1) A marine protected area is an area of the sea that forms part of the internal waters of Canada, the territorial sea of Canada or the exclusive economic zone of Canada and has been designated under this section for special protection for one or more of the following reasons: (a) the conservation and protection of commercial and non-commercial fishery resources, including marine mammals, and their habitats; (b) the conservation and protection of endangered or threatened marine species, and their habitats; (c) the conservation and protection of unique habitats; (d) the conservation and protection of marine areas of high biodiversity or biological productivity; and (e) the conservation and protection of any other marine resource or habitat as is necessary to fulfil the mandate of the Minister. 143 On October 5, 1970, Jacques Cousteau was quoted in the Vancouver Sun as saying, There wil l be no sea life in the Georgia Strait in 20 years unless it is set aside as a marine park. Another prominent scientist at the time, Howard Paish, was also quoted in the same article, What we have now are just enlarged campsites for the boating public...a marine park wil l include all the principles of land parks—protection and conservation, scientific, educational and recreational in many ways. Cousteau, was incorrect in saying there wil l be "no sea life", but he was correct in that certain components of the Strait's ecosystem have been lost which may have benefited i f a closure had been introduced in 1970. Nearly thirty years later, Paish's description of M P As still applies to the M P A system in B . C . Developing protected areas in marine ecosystems has lagged in comparison to protected areas in B.C.'s terrestrial ecosystems. Many environmental issues, including protected areas, are driven by public involvement and process. Marine issues are at an extreme disadvantage in that the interface of anthropogenic threats and ecological processes take place underwater and out of sight, and hence there is an obvious emotional detachment found in the public at large. People who are interested must rely on indirect sources of information generally originating from the scientific community. Therefore, without science and monitoring, coupled with public education, it is unlikely that M P As can ever be fully understood and supported by the public. Many scientific uncertainties still remain regarding the effectiveness of reserves but they are unknowable without actual implementation and monitoring of marine reserves. Enough ecological, biological, geological, fisheries, oceanographic, and theoretical information currently exists to experiment with marine reserves. It is only by creating reserves in a replicated and representative manner and then continually monitoring the reserves, that questions can be answered to reliably provide information. The research I presented in this thesis is an initial step in providing information, but needs to be expanded spatially and temporally in order to undertake reliable comparative studies needed to assess potential benefits of reserves. Furthermore, it is only by using long-term data sets collected in reserves that the confounding influences of climate, natural cycles, and human activities can be discerned. In conclusion, the research presented in this thesis involving ecosystem based models, and 144 empirical case studies monitoring marine reserves, proved to be an effective approach to understanding the effects of fishing on marine biodiversity and the role of marine reserves. 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Marine reserves: patterns of adult movement of the coral trout (Plectropmus leopardus (Serranidae)). Can. J. Fish. Aquat. Sci. 55: 917-924. 164 Appendix 2.1 Commercial landings (t) of all species from 1875-1997. Salmonids Pelagics Marine Mammals Year CHNK SCKY COHO PINK CHUM STHD HAKE HRNG PLCD SMLT ELCN MACK TUNA WHAL FUR SEAL HARB SEAL SEA LION 1873 - 295 - - - - - - - - - - -1874 - - - - - - - - - - - -1875 - - - - - - - - - - -1876 7 400 13 2 2 - - - - -1877 69 2733 106 12 13 - - - - - - - -1878 139 4321 340 18 19 - - - - - - - - -1879 109 2298 116 8 14 - - - - - - - -1880 237 1312 788 6 26 - - - 5 - ' - - -1881 527 6540 802 17 118 - - - - 23 - - - -1882 422 8380 1159 17 26 - - - 20 - • -1883 729 6552 1174 14 167 - - - - 27 - 912 • 1884 1543 4372 2246 19 674 - 16 - - 45 - 1535 • 1885 1082 4035 1569 12 622 - 42 - - 29 - 1856 -1886 597 3361 2612 10 56 - 19 - 9 41 - 2176 486 1887 1888 784 1017 6970 4918 1124 2373 14 15 136 151 • 100 59 - - 34 18 - 2167 1819 567 -1889 859 14578 1033 13 133 - 101 - - 45 - 1471 470 1890 1107 13253 1660 10 115 - 162 - 45 20 - 1936 - -1891 1014 8861 2667 5 141 - 166 - 36 57 - 2400 - -1892 1243 6649 2133 7 188 - 218 36 72 - 6225 486 -1893 1114 20831 1712 19 241 - 211 - 36 72 - 5408 567 1894 848 17333 1162 16 134 179 - 27 63 4477 567 1895 988 18383 2430 11 117 25 125 - 26 172 5371 1134 -1896 1077 19558 2064 8 83 29 96 - 25 167 7160 1652 -1897 972 35789 1494 17 475 29 218 - 32 200 - 8479 838 -1898 1021 15223 2293 9 2377 149 313 - 36 219 - 7418 1085 -1899 1297 25053 1918 154 2006 149 367 - 33 289 - 11173 672 -1900 1413 14083 1733 462 7756 154 518 - 39 360 - 15116 528 -1901 1465 40374 1911 1097 4008 100 517 - 52 357 - 3853 - -1902 1125 18763 2545 911 6198 100 950 - 167 466 - 3853 - -1903 1412 13090 2649 1050 3864 165 1895 - 204 484 - 3853 - -1904 1715 11903 3422 1212 8860 100 2403 - 226 466 - 3853 - -1905 1967 38684 3898 1061 8744 100 2117 - 174 321 11720 3853 -1906 2659 16471 4172 2285 8108 100 4128 183 312 - 3853 1907 2392 11388 4623 3872 7518 100 8841 208 204 - 3908 664 -1908 2376 12644 4155 2880 5216 74 20428 - 174 239 39375 2701 907 -1909 2545 28493 3891 2457 5807 8 26448 - 142 281 43969 2455 921 -1910 3967 20472 5198 1830 10661 100 12452 - 81 339 40600 2208 921 -1911 4501 14585 7485 11652 11391 100 24681 - 177 339 59500 2208 921 -1912 8887 16387 8661 9325 11695 100 33012 - 149 335 55450 1659 907 -1913 6267 35361 6718 6877 12546 100 29369 - 100 325 35032 864 544 -1914 7131 18980 10339 8297 16381 52 25493 - 97 371 28650 770 • -1915 6332 16449 12242 15836 9946 100 21152 - 118 330 13889 770 -1916 5614 7503 11066 11067 15970 100 22445 - 86 330 24049 677 31 -1917 5615 12588 10411 19771 23449 187 22047 62 48 23 18950 - - -1918 7368 9576 12321 17613 24492 100 28820 3291 102 23 25000 33 1070 1919 9048 14247 16772 13794 19974 171 25695 2969 52 5 29210 65 387 165 Commercial landings continued. Year CHNK SCKY Salmonids COHO PINK CHUM STHD HAKE HRNG 3elagics PLCD SMLT ELCN MACK TUNA WHAL Marine Mammals FUR SEAL HARB SEAL SEA LION 1920 7774 13404 8999 18591 7562 91 45310 3984 62 91 - 45577 56 - 401 1921 4776 5928 8924 8308 9285 46 42754 893 77 5 - - 70 362 2615 1922 6621 11031 8415 22021 19284 63 45363 920 18 5 - 11886 25 121 1538 1923 4487 12472 8919 17859 24079 67 46870 882 45 23 - 32462 35 127 -1924 4524 13990 10603 25581 33295 70 52381 1244 48 54 - 28118 14 121 -1925 7676 15035 11739 18412 31299 76 65062 14433 32 18 - 22773 11 - -1926 5928 13167 10840 28794 36910 82 58881 43890 50 23 - 17930 169 - -1927 6350 11392 10780 10087 28161 66 78020 61927 45 18 - 17674 376 -1928 5508 8009 12151 29301 46381 33 69462 72862 29 18 - 23993 149 118 1929 4807 10082 12111 18671 21849 26 59532 78138 27 14 - 25864 708 - 1358 1930 7867 18904 12169 40227 24570 63 55654 67937 61 32 - 17779 357 2098 1931 5491 11823 7209 13786 22085 55 67017 66610 63 5 - - 714 - 2138 1932 6482 12797 8480 9259 22772 55 45394 40134 43 5 - - 452 - 1427 1933 5650 9955 9114 21301 17847 55 48750 5476 23 14 - 12295 236 - 1251 1934 6832 13766 10592 18016 26070 55 37120 38919 45 14 - 20990 334 92 813 1935 6588 13372 14381 21598 24924 55 45634 41242 43 18 - 12475 541 520 1010 1936 6795 15549 12227 24563 31360 55 73331 40228 36 18 - 22427 368 963 888 1937 6254 12057 8865 23981 25373 32 87321 43506 16 126 - 18845 234 1022 1012 1938 5440 15769 13297 17149 26893 39 86335 46849 34 126 18914 286 986 603 1939 5442 9534 11165 25517 15086 30 93050 4998 31 126 128 - 317 697 608 1940 4136 12361 12115 8401 27637 46 134299 26036 31 126 2 14332 41 65 487 1941 6673 15345 16636 18623 28661 131 83457 26071 31 126 34 19546 135 - 392 1942 5023 23236 10937 10186 23965 177 94968 54409 31 126 - 9725 302 - 2667 1943 3936 5710 9369 21430 14451 118 70986 59693 31 126 13 5338 427 313 1645 1944 4593 7052 10600 12755 13586 149 84416 80399 31 126 210 - 219 696 2304 1945 5151 10391 15102 30057 15397 111 97846 53559 31 126 647 - 92 740 906 1946 6475 14549 10358 4807 27446 156 82498 31075 31 126 - - - 574 72 1947 5219 9791 8839 22989 26548 124 106480 3616 31 126 - - - - 59 1948 6127 8943 10103 12125 27329 215 148688 440 31 126 - 9801 - 532 111 1949 6574 8657 9503 25307 16287 90 166914 31 126 - 15258 - 189 24 1950 6108 13308 9404 18278 35953 145 161158 31 126 - 990 18702 162 52 1951 5889 13540 15977 27295 29749 184 164609 - 76 188 85 28678 - 156 157 1952 6528 13966 10056 23217 14453 229 85359 - 42 418 71 30842 - 320 163 1953 7095 16031 10402 28003 24688 209 134343 - 15 157 5 33228 - 266 147 1954 6112 21331 9369 11682 33749 253 162596 - 12 151 - 34188 - 444 60 1955 5680 7552 10675 28715 8247 109 137699 - 2 282 - 34686 - 436 121 1956 6212 9752 11408 13141 12342 103 221349 - 4 234 - 24321 - 414 1247 1957 5736 7136 10318 26082 12357 74 133052 - 27 194 - 39328 - 371 124 1958 6441 33618 11158 15384 17286 113 182488 - 20 91 8 53433 - 452 135 1959 6120 8192 8834 15884 10483 56 200014 39 131 74 53605 - 550 166 1960 4678 7022 6447 7707 9215 110 84539 - 29 83 211 - 528 100 1961 4123 12076 11199 22706 6627 92 201997 - 53 215 4 - - 702 94 1962 4110 8920 12058 42451 8189 108 200574 - 49 177 219 55312 - 646 223 1963 4608 5385 11543 20474 6997 65 257919 - 42 158 5 35295 - 555 279 1964 6063 10410 14353 16675 10755 106 227607 - 54 105 112 37417 - 657 675 1965 5743 7358 16633 10417 3019 60 200028 - 32 87 50 35112 - 606 2374 1966 6947 11659 17524 33322 6968 138 138582 - 34 101 264 33861 - 556 1132 1967 6968 16845 10244 23553 5517 114 52586 - 6 86 437 27662 - 466 439 166 Commercial landings continued. Year CHNK SCKY Salmonids COHO PINK CHUM STHD HAKE HRNG Pelagics PLCD SMLT ELCN MACK TUNA Marine Mammals WHAL FUR HARB SEAL SEAL SEA LION 1968 6943 19004 15357 35943 16652 99 - 2871 - 18 46 - 1186 381 783 1969 6483 10951 7965 6266 6077 64 1989 - 9 30 - 1443 343 555 1970 6587 11417 13601 24073 16771 56 3838 - 10 71 - 696 804 562 1971 8673 17325 13920 17615 5420 80 - 9947 - 0 34 1807 - 446 1972 8313 9485 10463 17856 29933 95 39102 144 53 3565 - 121 1973 7531 21453 11172 13295 32604 56 - 55741 - 4 53 - 1272 - 37 1974 7627 21685 10289 11206 12476 49 - 44763 - 1 75 - 1216 - 8 1975 7255 5682 7733 10234 4391 49 - 59764 - 27 28 - 101 - -1976 7750 12341 9303 17062 10925 46 - 81275 - 10 37 - 268 - -1977 7476 16383 9766 24720 6029 59 - 97375 • 7 32 - 53 - -1978 7877 22318 9144 15323 15847 57 - 81400 - 2 38 - 23 - -1979 6811 14456 10261 24659 4676 47 - 43465 - 1 22 - 289 - -1980 6660 7838 9155 14044 16966 51 - 25155 - 1 24 212 - -1981 5902 18902 7478 32601 6119 81 - 34014 - 1 21 5 - -1982 7074 29970 9211 3976 15086 104 - 28597 - 4 14 -1983 4734 14198 9174 38722 4873 57 - 39820 - 4 11 - 103 - -1984 6254 12877 10089 12058 9003 150 - 33703 - 2 12 - - -1985 5470 31568 8977 37701 23646 200 6002 25767 - 1 29 - 1 -1986 5007 30833 13238 29505 25197 158 6369 16341 - 1 50 - - -1987 5249 15035 8415 26921 11000 74 13112 37614 - 2 19 - - - -1988 5922 11943 7077 32217 30297 93 6361 31383 - 1 40 - 4 - -1989 5235 34383 8752 31004 9322 32 8604 40795 - 1 19 - 145 - -1990 5228 37134 10569 26240 17181 45 1160 41056 - 0 20 - 276 - -1991 5058 25211 10053 35096 10236 26 2280 39741 - 0 12 - 143 - -1992 5336 20938 7328 14913 17964 18 27415 34587 - 2 20 55 363 -1993 4817 42529 4316 16046 17274 8 15959 41048 2 9 - 329 -1994 3120 29773 6760 3277 20245 5 33313 40376 - 3 6 - 558 -1995 1323 10436 4205 18851 11858 4 57848 26780 - 1 12 821 - -1996 453 15360 3858 8447 6460 3 33034 22423 - 1 30 51 457 - -1997 1660 25324 751 12236 8677 1 54748 31992 - - 0 2 80 - -Total (t.103) 557 1809 970 1711 1627 9 266 6649 1017 5 13 0 19 1425 135 33 38 167 Commercial landings continued. Groundfish YEAR LING P.COD COD P. O. ROCK SABLE PLCK HLBT DOG FLNR SKTE SOLE TRBT STGN OTHER INDL SP. PRCH FISH FISH FISH FISH SP; 1873 - - - - - - - - . . . . . . . -1874 - - - - - - - - . . . . . . . . 1875 - - - - - - - - . . . . . . . . 1876 - 7837 - 2273 1877 4531 1 1314 1878 23 6517 - 1890 1879 1880 - 54 9 5192 6232 36 1506 1807 1881 4 7603 32 2205 1882 3 10481 36 3039 1883 11 11561 31 . - 3353 1884 68 2452 160 711 1885 109 3088 160 896 1886 25 37 2176 52 638 1887 175 4583 113 1329 1888 56 104 1558 98 452 1889 159 274 1377 144 399 1890 116 288 2241 179 650 1891 -• - 79 511 4455 147 1292 1892 87 614 4968 236 1441 1893 216 622 4797 149 1391 1894 149 850 4275 227 1240 1895 135 1170 4056 170 1176 1896 136. 1030 1985 172 576 1897 140 890 2204 515 639 1898 246 891 2726 339 791 1899 253 939 3211 126 931 1900 259 1928 2764 48 802 1901 224 2580 2632 29 763 1902 251 3809 3192 15 926 1903 300 4619 4360 14 1264 1904 354 6010 3714 16 1077 1905 302 4028 3752 9 1088 1906 324 5166 3847 11 1116 1907 337 6472 3581 45 1039 1908 285 7924 4189 81 1215 1909 490 9822 5054 226 1466 1910 920 9912 2071 249 600 1911 1134 8890 1720 234 499 1912 1290 11461 1938 229 562 1913 1322 1988 - 10112 1254 49 364 1914 2134 3209 - 9703 1282 52 319 1915 1623 2441 - 8819 304 37 88 1916 2867 4312 - 5568 1033 33 300 1917 3961 5956 - 5137 657 20 191 Commercial landings continued. EAR LING P.COD COD SP. P. 0. PRCH ROCK FISH SP. SABLE FISH PLCK HLBT DOG FISH FLNR SKTE SOLE TRBT STGN OTHER FISH INDL 1918 - - 3359 - 2039 8426 2682 - - - 15 778 1919 - 2618 - - 716 9537 2307 - - - - 10 - 669 1920 - - 1547 92 176 1754 16 10804 934 - 612 - 6 195 975 1921 - - 1335 98 116 1383 2 14745 2381 - - 224 - 9 177 1205 1922 - - 1279 81 98 1293 7 13266 1823 - - 583 - 15 70 1123 1923 - 1326 77 137 1135 6 15143 2957 - - 201 26 140 1363 1924 - - 1838 59 156 1238 4 14995 4642 - - 243 - 14 157 2013 1925 - - 1434 47 128 1017 8 14400 5891 - - 395 - 12 113 2292 1926 - - 1773 42 176 705 5 14257 4525 - - 348 - 12 135 1992 1927 2264 7 - 62 169 1118 4 12278 6521 - 556 - 16 146 2779 1928 2301 12 - 65 190 911 3 13702 12169 - 442 - 13 121 4402 1929 2199 28 - 99 236 1042 1 13752 14556 - - 604 - 14 74 5140 1930 2204 43 - 77 191 1124 1 11529 5363 - - 646 - 13 51 2472 1931 2313 73 - 43 120 397 3 8235 7191 - - 285 - 11 65 2908 1932 1812 125 - 32 124 436 2 7640 1595 43 29 251 - 9 43 1164 1933 1886 234 - 23 62 413 16 7729 5009 - - 275 - 17 85 2177 1934 2198 581 - 25 75 435 3 7959 8216 - - 322 - 10 110 3312 1935 2863 757 36 114 659 3 7750 5078 - - 293 20 123 2652 1936 3139 367 36 145 490 2 7597 7121 - - 347 - 6 95 3235 1937 2020 649 - 36 81 912 1 8490 6286 - - 284 - 4 57 2714 1938 2154 845 - 36 307 576 3 8754 10017 - - 382 - - 84 3985 1939 2184 740 - 36 97 617 10280 8525 - - 436 - - 190 3485 1940 2477 754 - 23 105 948 3 10816 8780 - - 631 - - 3456 3704 1941 2245 436 - 16 114 1188 1 5850 13949 - 392 - - 6291 4974 1942 2001 305 - 29 204 835 1 4990 17008 - - 558 - - 3909 5830 1943 2795 716 - 38 971 1426 - 5741 20544 - - 882 - - 134 7524 1944 3834 427 - 52 1424 1519 3 5958 31152 - - 2392 - - 857 11392 1945 3568 843 - - 1539 1428 2 6744 23347 - - 2946 - - 854 9350 1946 3393 1603 - - 1170 1619 4 8104 11404 - - 4537 344 6411 1947 2443 426 - - 34 905 - 10914 15072 - - 2733 - - 39 6005 1948 4152 417 - - 27 1483 3 8486 12164 - - 5188 - - 38 6365 1949 4579 763 - - 56 1895 - 8143 15992 - - 2685 - - 38 6982 1950 2924 1188 - - 92 648 1 8544 2211 - 4299 - - 60 3107 1951 2917 2469 29 378 854 - 9105 4000 211 53 4095 - 12 1807 4104 1952 1911 2032 - - 412 607 - 10580 3053 199 53 6494 - 12 854 4105 1953 1326 1437 - - 202 614 - 11208 3115 62 43 2765 - 12 1570 2595 1954 1760 2240 - 194 229 508 - 11351 2513 116 51 2445 - 12 1199 2769 1955 1633 1561 - 55 187 547 8864 2621 121 46 3150 - 16 3174 2718 1956 2146 1754 - 26 179 235 10503 1124 109 46 3740 - 15 5013 2646 1957 2140 677 - 106 262 680 - 10154 2473 138 55 3595 - 16 2174 2723 1958 1935 3453 - 336 271 259 - 10679 1606 105 55 3448 - 22 1410 3235 1959 1903 3200 - 265 462 264 - 10720 6401 97 55 2242 - 17 1846 4226 1960 2034 2362 - 382 251 470 - 12235 4370 146 55 3440 15 2683 3766 1961 2035 1549 - 116 299 301 - 11239 5929 172 55 2739 16 16 3470 3728 1962 1973 2022 568 539 279 - 11048 406 156 55 2832 9 13 3343 2467 1963 1440 3043 - 456 363 269 - 11682 222 142 55 2561 1 13 1737 2386 1964 1710 5409 - 446 450 427 - 14996 982 112 55 2733 - 16 2320 3434 1965 1988 8659 - 1402 363 440 14853 257 117 55 2887 - 12 1933 4545 Commercial landings continued. Groundfish YEAR LING P.COD COD SP. P. O. PRCH ROCK FISH SP. SABLE FISH PLCK HLBT DOG FISH FLNR SKTE SOLE TRBT STGN OTHER FISH INDL 1966 2264 9328 - 2403 317 632 14414 540 105 55 4720 - 12 2423 5706 1967 2245 5035 - 375 314 401 11811 584 105 47 4079 - 10 3534 3708 1968 2845 5114 - 870 400 402 13239 336 70 52 4520 - 11 2619 4120 1969 2234 3411 - 1355 929 263 15241 1 77 66 4719 - 44 3806 3710 1970 2073 2260 - 2085 898 222 13300 137 149 81 5400 4 18 1120 3795 1971 1955 3941 - 1331 938 223 - 11393 127 132 65 4811 - 15 1436 3857 1972 1650 6808 - 2322 1764 737 - 10038 116 206 84 3361 293 17 1533 4815 1973 1490 6031 - 1535 1267 652 - 6578 5056 65 85 3072 666 18 1419 5587 1974 1765 7087 - 2187 493 340 - 3391 1070 62 71 3263 407 17 769 4758 1975 1950 8325 12 3233 630 - 5157 713 92 162 4457 1045 21 293 5797 1976 1585 8069 - 7 3994 537 - 5455 242 51 185 5155 2621 22 594 6353 1977 1565 6140 - 15 7922 715 - 3715 1730 93 238 3786 2497 33 338 6956 1978 1308 5396 - 10305 556 2370 3864 3126 81 139 3075 2300 29 2515 8149 1979 1522 7602 - - 8776 1401 3386 2935 4757 309 175 4208 1806 23 1135 9437 1980 1454 6514 - - 9669 2374 2179 3305 4545 119 254 4655 1392 19 3450 8926 1981 1833 5375 - - 9460 3168 1130 2233 1782 208 240 4346 944 10 6461 7342 1982 4040 4689 - 5755 4610 3911 911 1690 2032 186 130 2897 529 8 2717 7476 1983 3752 4623 - 5731 6395 4319 1092 1865 710 66 345 2731 314 3 3000 7470 1984 3707 3459 - 7206 7489 3852 596 3110 985 169 390 3225 360 8 5159 8000 1985 5688 2345 - 6333 11481 4263 1689 4703 2680 66 370 2779 765 8 851 9917 1986 3860 3668 - 6047 18481 4686 598 4231 2983 54 517 2753 892 6 503 11557 1987 3540 13691 - 6275 17857 4717 86 5444 3767 124 751 3022 111 6 500 14239 1988 3444 11024 - 6787 20014 5291 460 5867 5314 141 589 5139 340 5 67 15443 1989 3979 9134 - 6068 18388 5495 43 4658 2774 123 352 6351 609 8 1423 13868 1990 5054 6233 - 5596 22143 5133 676 3783 4110 143 18 14064 2602 9 427 17585 1991 5366 11910 - 4295 19127 5546 2580 3240 3128 146 248 15459 2287 3 568 18718 1992 4334 10125 - 3990 21792 5372 3249 3441 2356 144 264 7944 3569 5 310 16752 1993 5234 8123 - 4609 20034 5310 8121 4796 830 108 249 9917 4132 3 555 17794 1994 3975 3351 - 4582 14655 4849 3838 4379 1714 99 508 7275 3365 2 658 12575 1995 3706 2129 - 5097 14715 4241 3295 4127 2689 75 961 7958 2675 4 1178 12557 1996 2379 692 - 6169 13513 3008 2066 4080 2828 23 1039 5051 4538 0 118 11106 1997 1492 1516 - 5780 12435 3806 1826 5132 1628 28 1287 4317 2893 - - 9629 Total (t.103) 186 247 37 110 317 146 40 816 559 6 11 253 44 5 104 517 Commercial landings continued. Invertebrates ABLN CLAM CRAB GDCK GSNK HRSE OTPS OYTR PRWN SHMP SCLP SEA CLAM CMBR 2 0 2 3 2 7 1 0 9 1 3 6 6 8 9 0 1 4 5 1 4 5 1 4 5 1 4 5 1 0 9 1 4 5 2 1 7 2 1 7 2 7 1 2 7 1 2 7 1 3 1 7 3 6 2 2 2 6 1 3 1 1 3 8 1 4 5 3 6 2 2 4 6 4 8 7 2 5 2 2 4 3 1 6 0 9 9 141 1 6 2 1 3 1 2 1 5 1 5 6 1 4 3 1 8 5 7 - - - - - 2 3 3 1 3 9 1 5 1 1 7 9 - - - - - 1 3 3 1 5 3 2 1 3 1 3 1 1 9 8 SEA OTHR URCH Commercial landings continued. YEAR ABLN CLAM CRAB GDCK GSNK HRSE CLAM OTPS OYTR PRWN SHMP SCLP SEA CMBR SEA OTHR URCH 1928 - 238 266 - 218 - - - -1929 - 177 267 382 - - - -1930 - 172 210 289 - - - -1931 - 116 230 - - 322 - - - -1932 - 145 141 - - 182 - 59 - -1933 - 196 - • 202 • 58 -1934 - 438 177 - - 298 - 57 - -1935 - 978 231 - - 304 - 91 - -1936 - 1529 230 - - 561 - 30 - -1937 - 1552 264 - - 211 - 39 -1938 - 2486 253 - - 270 59 -1939 1119 362 - - 1024 38 1940 1127 296 - 786 - 52 - -1941 - 1483 454 1276 - 26 - -1942 - 839 454 1356 - 23 - -1943 - 736 454 - 1366 - 34 - -1944 - 772 454 - 1800 - 34 - -1945 - 1925 454 - - 1275 - 78 - -1946 - 699 454 - - 2405 - 131 - -1947 - 419 454 - - 2199 - 157 - -1948 - 798 454 - - 1671 - 274 - -1949 - 454 - - 2163 - 289 - -1950 - 1213 454 • - 2297 - - - -1951 6 6691 816 - - 3343 21 225 -1952 5 2976 900 - - 2939 - 371 -1953 10 2066 1438 - - 2406 567 -1954 1700 1887 - 3108 428 1955 - 2497 2033 - - 3070 490 - -1956 0 1664 1610 - - 3257 548 -1957 1 1728 1365 - - 2439 720 -1958 5 1094 1896 2271 - 860 - -1959 0 1236 1947 2703 - 470 - -1960 2 2283 2283 2837 - 756 - • 1961 9 1052 2073 3083 - 543 - -1962 17 1785 1248 - - 3662 - 749 - -1963 7 1417 1534 - - 6167 - 805 - -1964 57 710 1960 - 28 5555 - 474 - -1965 3 945 1577 - 29 5454 - 790 - -1966 1 1114 2044 - 19 4863 - 758 - -1967 1 1243 2388 - 43 4646 - 764 - -1968 0 676 1969 - 30 3492 - 706 - -1969 1 577 1671 - 42 4407 955 1970 1 971 1500 - 27 4198 741 1971 15 971 1500 39 4198 741 - -1972 60 1563 898 - 31 3982 62 299 - -1973 203 716 1173 - 33 4766 77 709 - -Commercial landings continued. YEAR ABLN CLAM CRAB GDCK GSNK HRSE CLAM OTPS OYTR PRWN SHMP SCLP SEA CMBR SEA URCH OTHR 1974 26 1113 1138 - - - 35 3912 28 1176 - - - -1975 266 1175 1142 - - - 27 3231 75 711 - - - -1976 274 1181 997 • - - - 21 3231 81 3429 - - - -1977 429 1392 1032 246 - - 25 2985 166 2641 - - - -1978 433 1587 1176 1016 - 22 2781 220 1349 - - - -1979 186 1649 1179 2463 - 35 2222 324 392 - - 317 -1980 97 1632 808 2808 - 128 51 1914 368 288 - - - -1981 85 807 1315 2704 - 57 19 2634 325 615 - - - -1982 54 1159 895 3135 321 18 1579 274 415 8 - - -1983 56 1762 960 2636 - 21 37 2453 331 411 11 - - -1984 58 2615 1155 3483 - 7 25 2897 381 409 18 95 1764 -1985 42 2926 1165 5370 - 6 34 3420 514 678 53 346 1815 -1986 52 2851 1321 5006 - 96 53 2864 550 768 68 786 2067 247 1987 49 4280 1631 5735 32 656 130 3482 62 2644 66 1722 2223 216 1988 49 4519 1532 4567 49 326 209 3702 720 2561 67 1921 2559 404 1989 48 3565 1522 3964 30 116 217 3721 820 2299 75 1144 3269 429 1990 65 2885 2168 3992 4 125 197 4547 761 1940 69 870 3639 602 1991 - 1479 1887 3298 41 110 131 4482 961 3265 82 490 7576 566 1992 - 1340 3355 2874 38 2 117 4484 1168 2683 91 521 14056 473 1993 - 1352 6306 2455 30 23 145 4758 1215 3283 90 812 7102 66 1994 - 1811 5711 2235 28 62 88 4799 1225 2992 104 556 6153 508 1995 - 1727 4594 2056 7 1 89 5300 1300 6778 93 588 6262 638 1996 - 1415 4946 1768 12 - 139 6400 1723 7461 102 384 5867 594 1997 - 1206 3933 1657 10 4 206 4700 1910 5747 73 480 5449 245 Total 3 105 97 63 0 2 2 204 16 71 1 11 70 5 C10> Appendix 2.2 Aboriginal landings (t) between 1873 and 1996. YEAR CHNK SCKY COHO PINK CHUM STEEL HLBT STGN CLAM HEAD 1873-1905 1906-14 _ 7914 7914 272 113 4000 1915 12 7914 0.04 - 1 -1916 4 7914 0.01 - 0 -1917 40 7914 - - - -1918 19 7914 - - - -1919 - 7914 - - - -1920 7914 - 11 -1921 7914 90 - -1922 78 344 7 - 8 1923 18 3 3 - 3 -1924 27 9 8 - 3 -1925 296 1474 8 7 79 2 -1926 387 976 98 8 61 -1927 306 895 88 3 101 -1928 136 624 408 42 55 7 -1929 248 761 333 63 129 5 -1930 314 629 329 72 145 17 -1931 450 529 132 66 366 22 -1932 293 450 120 26 280 30 -1933 398 549 306 53 619 34 -1934 329 662 249 71 640 50 -1935 173 1059 205 109 254 20 -1936 287 858 310 105 601 46 -1937 204 2136 193 60 201 18 -1938 212 1519 233 32 209 32 -1939 212 497 315 85 1020 25 -1940 172 692 278 41 887 30 -1941 200 529 344 56 905 17 -1942 162 321 161 7 532 25 -1943 211 342 203 36 568 27 -1944 142 410 129 30 484 18 -1945 142 437 139 39 381 28 -1946 141 317 128 22 418 42 -1947 102 285 69 16 156 26 -1948 98 405 65 9 57 27 -1949 128 451 121 15 275 12 -1950 160 510 129 7 458 22 -1951 129 388 99 19 332 17 -1952 173 432 109 17 302 34 -1953 195 467 117 23 217 33 -1954 199 428 131 13 176 23 -1955 185 297 140 36 187 22 -1956 157 353 135 32 184 21 -1957 163 529 138 72 226 17 -1958 180 498 134 39 190 22 -1959 200 359 129 52 226 23 -1960 155 396 91 15 234 25 -Aboriginal landings continued. YEAR CHNK SCKY COHO PINK CHUM STEEL HLBT STGN CLAM HEAD 1961 154 568 123 78 179 33 -1962 149 544 145 28 187 32 -1963 144 758 118 100 160 32 -1964 155 601 159 18 191 31 -1965 149 550 211 79 169 23 -1966 130 634 199 32 170 28 -1967 133 527 88 65 157 17 -1968 151 566 183 25 269 18 -1969 171 670 106 58 162 13 -1970 237 667 161 57 195 14 -1971 196 751 165 85 175 16 -1972 208 628 153 26 225 21 -1973 168 786 124 122 229 63 -1974 230 967 188 19 350 17 -1975 272 1096 165 107 201 18 -1976 256 1026 214 43 279 20 -1977 341 1289 165 93 242 13 -1978 265 1146 227 35 231 10 -1979 243 1404 350 152 200 11 -1980 345 1195 467 21 268 28 -1981 320 1763 445 159 306 33 -1982 667 2146 541 79 368 58 -1983 508 1670 345 376 311 82 -1984 496 1727 549 111 441 142 -1985 561 2089 389 287 487 62 -1986 796 2160 422 82 588 64 -1987 752 2031 298 274 508 44 -1988 685 1848 311 37 505 44 -1989 768 2264 285 217 404 15 -1990 686 3138 277 94 696 12 -1991 941 2808 280 320 435 14 -1992 752 2390 388 137 927 2 -1993 1039 4159 434 68 2996 7 -1994 712 4307 552 32 2794 16 -Total (t) 21620 461479 15560 5002 28186 1874 Appendix 2.3 Recreational landings (t) between 1911 and 1996. Bold numbers for chinook (CHNK) are estimated based on the proportionate values in the figure below and represent all salmon species. Bold values for lingcod and Rockfish spp. are simply the average of the known values from 1981 to 1994). YEAR CHNK COHO SOCK EYE PINK CHUM HLBT DOG FISH LING COD ROCK-FISH SPP. 1911-20 472 - - - - - - - -1921-30 632 - - - - - - -1931-40 836 - - - - - - - -1941-50 985 - - - - - - - -1951 1403 - - - - - - 181 64 1952 1403 - 181 64 1953 673 589 - - - 181 64 1954 687 608 - - 181 64 1955 807 835 - - - - 181 64 1956 964 894 - - - - 181 64 1957 1211 1142 - 18 - - - 181 64 1958 1300 1185 1 6 - - 181 64 1959 1055 1100 - 67 - - 181 64 1960 837 1077 - 1 - - - 181 64 1961 603 711 0.14 48 - 181 64 1962 801 833 0.14 6 - - - 181 64 1963 767 893 0.14 201 - - - 181 64 1964 633 819 0.07 4 - - - 181 64 1965 656 853 0.14 17 - - - 181 64 1966 860 1145 - 9 - - 181 64 1967 759 766 - 53 4 - - 181 64 1968 871 989 - 10 - - 181 64 1969 900 651 4 66 - - 181 64 1970 1260 1072 1 19 - - - 181 64 1971 1110 1679 1 83 - - - 181 64 1972 2730 1562 5 22 - - - 181 64 1973 2607 1740 12 94 - - - 181 64 1974 2611 3566 9 30 - - - 181 64 1975 4044 2126 6 52 - - 181 64 1976 4745 1993 3 30 - - 181 64 1977 2308 1155 2 61 8 - 181 64 1978 2498 1714 1 12 22 - 181 64 1979 1710 1843 7 162 6 181 64 1980 1847 1781 - - - 181 64 1981 1785 1435 - - - 15 302 66 1982 1126 1863 - 5 - - 26 244 80 1983 1796 1828 - 99 - - 16 234 95 1984 4143 2034 - 19 - - 17 444 76 1985 2652 3440 8 202 14 17 265 67 1986 1994 2781 4 65 13 19 226 77 1987 1778 3338 90 232 25 6 15 240 73 1988 1779 4525 51 106 33 7 15 223 95 1989 2326 2678 41 269 42 21 13 194 101 1990 2222 3349 124 91 19 - 10 100 70 1991 1869 1052 292 539 26 - 18 28 84 1992 1987 3248 330 118 33 57 12 9 1993 2048 3979 356 328 20 96 - 11 2 1994 1366 1649 123 42 12 122 - 11 3 1995 1898 2655 245 224 22 - - -1996 1834 2517 269 250 23 - - -Total (t) 80187 77689 1987 3660 322 309 181 7965 2818 176 Appendix 2.3 Continued. Figure 1. Estimated recreational landings of salmon (chinook and coho) prior to 1950 based on human population growth in British Columbia and recorded landings. Landings were estimated for the years prior to 1951 by applying an average ratio between 1951 and 1991 of population to landings (1.4 kg per person). Triangles represent estimated values. 1901 1921 1941 1961 1976 1986 1996 Year 177 Appendix 2.4 Marine mammal landings reported as numbers of kills in British Columbia from 1877-1968. (BW=blue whale, F W = f i n , HW=humpback, SW=sperm, BBW=Baird's beaked, GW=grey, MW=minke, RW=right, U=unidentified, NF=northem fur seal, HS=harbour seal, SSL=Steller sea lion.) Cetaceans Pinnipeds Year B W F W H W SEI SW B B W G W M W R W U T O T A L N F HS SSL 1877 - - - - 5700 - -1878 - - - 9593 - -1879 - - - 11597 - -1880 - - 13600 3000 -1881 - - 13541 3500 -1882 - - 11368 - -1883 - - - 9195 2900 -1884 - - 12098 - -1885 - - 15000 - -1886 - - 38907 3000 -1887 - - 33800 3500 -1888 - - 27983 3500 -1889 - - 33570 7000 -1890 - - 44751 10200 -1891 - - 52995 5175 -1892 - - 46362 6700 -1893 - - 69832 4150 -1894 - - 94474 3260 -1895 - - 24079 - -1896 - - • - 24079 - -1897 - - 24079 - -1898 - - 24079 - -1899 - - 24079 - -1900 - - - 24079 - -1901 - - 24422 4100 -1902 - - - - 16883 5600 -1903 - - 15341 - -1904 - - 13798 5684 -1905 - - - 13798 5684 -1906 - - 10368 5600 -1907 - - 5397 3360 -1908 - - - - 4815 - -1909 - - - 4815 - -1910 - - 812 812 4232 190 -1911 - - 1190 1190 - - -1912 - - 1109 1109 205 - 2000 1913 10 93 372 - 11 219 705 404 - 723 1914 - - 573 573 352 - 750 1915 12 68 55 - 1 1 - 92 229 439 2237 4888 1916 15 . 94 64 - 11 1 - 228 413 159 749 2875 1917 - - 379 379 218 785 -1918 - - 500 500 88 748 -1919 37 217 65 74 35 4 432 70 - -1920 26 149 98 121 56 - 390 840 1058 - -1921 - - - - 2349 - -178 Appendix 2.4 Continued Year B W F W H W SEI SW B B W G W M W R W T O T A L 1922 4 94 50 1 38 - - - - 187 930 - 220 1923 62 166 78 53 94 2 - - - 455 4424 - 2539 1924 56 125 47 100 83 1 - - 2 - 414 2232 - 3921 1925 29 135 40 68 76 3 - - - 351 4465 - 3996 1926 14 124 25 25 80 - - - 1 269 2824 - 2667 1927 10 138 21 7 82 - - - - 258 1476 - 2338 1928 47 140 21 13 83 1 - - - 305 2090 567 1519 1929 16 168 9 67 146 1 - - - 407 3383 3209 1888 1930 10 62 12 89 147 - - - - 320 2297 5944 1660 1931 - - - - - - - - - - 1463 6308 1892 1932 - - - - - - - - - - 1787 6084 1128 1933 1 17 - 1 190 - - - - 209 1984 4300 1136 1934 - 71 14 - 265 - - - - 350 256 400 911 1935 6 20 1 - 175 - - - - 202 841 - 733 1936 3 48 14 2 311 - - - - 378 1888 - 4985 1937 1 44 7 - 265 - - - - 317 2671 1933 3075 1938 4 50 4 - 252 - - - - 310 1367 4295 4306 1939 - - - - - - - - - - 576 4569 1694 1940 2 90 2 - 126 - - - - 220 - 3546 134 1941 1 67 27 - 233 - - - - 328 - - 111 1942 1 25 7 - 130 - - - - 163 - 3282 208 1943 - 15 7 - 69 - - - - 91 - 1168 45 1944 - - - - - - - - - - - 1001 97 1945 - - - - - - - - - - - 961 293 1946 - - - - - - - - - - - 1978 304 1947 - - - - - - - - - - - 1639 275 1948 - 41 126 3 28 - - - - 198 - 2740 113 1949 2 105 76 3 69 - - - - 255 - 2693 227 1950 4 150 95 24 40 1 - - - 314 - 2556 2330 1951 9 216 51 5 153 1 1 - 1 437 - 2289 231 1952 16 240 61 22 126 - - - - 465 - 2791 252 1953 8 181 47 14 275 4 10 - - 539 - 3397 311 1954 11 150 106 134 226 3 - - - 630 - 3257 186 1955 11 120 37 139 320 3 - - - 630 - 4333 176 1956 14 168 28 37 127 1 - - - 375 - 3987 416 1957 15 284 49 93 190 4 - - - 635 - 3426 521 1958 8 573 40 39 112 2 - - - 774 - 4053 1261 1959 28 369 27 185 260 - - - 869 - 3741 4438 1960 - - - - - - - - - - - 3431 2115 1961 - - - ' - - - - - - - - 2878 821 1962 47 242 23 501 240 1 - - - 1054 - 2351 1463 1963 30 220 24 154 147 3 - - - 578 - 2118 1038 1964 12 141 10 616 106 - - - - 885 - 4962 1050 1965 9 83 18 604 151 - - - - 865 - - 834 1966 - 134 - 354 231 2 - - - 721 - - 227 1967 - 102 - 89 304 - - 1 - 496 - - 70 1968 - - - - - - - - - - - - 15 T o t a l 591 5739 1858 3637 6064 35 11 1 4 5496 23436 845005 196809 71406 N F HS SSL 179 Appendix 2.5 Summary of bycatch in the commercial ' A ' licensed trawl fisheries between 1996 and 1998 sorted from highest to lowest. Only species with totals greater than 1 tonne were included in the analysis. Groups refer to (/)ish, (/)nvertebrates, (m)ammals, and (s)harks. (Source: Department of Fisheries and Oceans Groundfish Management Unit) Common Name Scientific Name Group Total Retained Discarded Discard (0 (t) (t) (%) SPOTTED RATFISH H Y D R O L A G U S f 1716.4 18.2 1698.3 98.9 COLLIEI PACIFIC H A L I B U T HIPPOGLOSSUS f 1286.6 0.4 1286.2 100 STENOLEPIS PACIFIC H A K E M E R L U C C I U S f 1414.7 221.7 1193. 84.3 PRODUCTUS GRENADIERS M A C R O U R I D A E f 223.0 2.7 220.3 98.8 (FAMILY) STARFISH ASTEROIDEA i 215.7 0.2 215.5 99.9 (CLASS) MISSING D A T A f 163.7 2.8 160.9 98.3 MISSING f 120.8 7.5 113.2 93.8 T A N N E R C R A B S CHIONOECETES i 92.0 0.2 91.9 99.8 SPP PACIFIC HERRING C L U P E A P A L L A S I f 87.3 0.9 86.4 98.9 DUNGENESS C R A B C A N C E R i 63.6 0.6 63.1 99.1 M A G I S T E R SPONGES P H Y L U M i 30.3 0.0 30.3 100 PORIFERA PACIFIC S A N D D A B CITHARICHTHYS f 25.6 0.3 25.3 98.7 SORDIDUS EELPOUTS Z O A R C I D A E f 21.7 0.1 21.7 99.7 (FAMILY) SQUID TEUTHOIDEA i 20.7 1.0 19.6 95.1 (ORDER) BIGEYE THRESHER ALOPIAS s 17.7 0.5 17.2 97.1 SUPERCILIOSUS SPIDER C R A B S O X Y R H Y N C H A i 16.6 0.0 16.6 99.9 (SUPERFAMILY) LITHODES SPP i 16.3 0.1 16.2 99.6 WOLF E E L A N A R R H I C H T H Y S f 20.9 5.8 15.1 72.2 O C E L L A T U S A M E R I C A N SHAD A L O S A f 14.9 0.4 14.5 97.3 SAPIDISSIMA STONY C O R A L S M A D R E P O R I A i 13.9 0.0 13.9 99.9 (ORDER) C A L A R O U S SPONGES C A L C A R E A i 11.4 0.0 11.4 100.0 (CLASS) A N O M U R A i 8.7 0.0 8.7 100.0 (SECTION) PURPLE STARFISH PIS ASTER i 8.5 0.0 8.5 100.0 O C H R A C E U S J A C K M A C K E R E L T R A C H U R U S f 9.1 1.2 7.9 87.2 S Y M M E T R I C U S CHINOOK S A L M O N O N C O R H Y N C H U S f 7.6 0.5 7.1 93.0 T S H A W Y T S C H A REPIANTIA i 6.9 0.0 6.9 99.8 (SUBORDER) A N E M O N E i 6.7 0.0 6.7 99.7 180 Species in trawl bycatch continued. Common Name Scientific Name Group Total Retained Discarded Discard (0 (t) (t) (%) SEA URCHINS ECHINACEA i 5.6 0.0 5.6 99.6 (SUPERORDER) JELLYFISH SCYPHOZOA i 5.1 0.0 5.0 99.1 (CLASS) BRITTLE STARS OPHIURAE i 4.6 0.0 4.6 100.0 (ORDER) PYCNOPODIA PYCNOPODIA i 4.6 0.1 4.5 98.3 HELIANTHOIDES LUMPFISHES AND CYCLOPTERIDAE f 4.2 0.0 4.2 99.9 SNAILFISHES (FAMILY) STELLER SEA LION EUMETOPIAS m 3.5 0.0 3.5 100.0 JUBATUS SCULPINS COTTIDAE f 3.6 0.1 3.5 97.4 (FAMILY) PACIFIC SLEEPER SOMNIOSUS s 3.2 0.0 3.2 100.0 SHARK PACIFICUS SEA CUCUMBERS HOLOTHUROIDEA i 3.1 0.0 3.1 99.4 (CLASS) CHUB MACKEREL SCOMBER f 5.2 2.9 2.3 43.8 JAPONICUS RED SQUID (aka BERRYTEUTHIS i 1.9 0.0 1.9 99.6 SCHOOLMASTER MAGISTER GONATE SQUID) SEA PENS PENNATULACEA i 1.8 0.0 1.8 100.0 (ORDER) NORTHERN MIROUNGA m 1.6 0.0 1.6 100.0 ELEPHANT SEAL ANGUSTIROSTRIS BOX CRABS LOPHOLITHODES i 1.3 0.0 1.3 99.6 SPP GLASS SPONGES HEXACTINELLID i 1.2 0.0 1.2 100.0 A (CLASS) BASKING SHARK CETORHINUS s 1.2 0.0 1.2 100.0 MAXIMUS SPECKLED SANDDAB CITHARICHTHYS f 1.1 0.0 1.1 96.0 STIGMAEUS RAGFISHES ICOSTEIDAE f 1.1 0.0 1.1 100.0 (FAMILY) TOTAL 5695.4 268.3 5427.1 95.2 Appendix 2.6 International and Joint-venture fisheries landings (t) from 1965 to 1996. International Fishery Joint-venture Fishery YEAR HRNG DOG FISH HAKE PLCK SABLE FISH P.O. PERCH ROCK FISH YEAR DOG FISH HAKE PLCK ROCK FISH 1965 1966 493 175 174 36217 31419 29967 _ -1967 - 953 36713 188 1199 4579 31650 - - - - -1968 - 871 61361 181 2391 14839 11746 - - - -1969 744 92619 324 4738 11856 4241 - - - -1970 328 75009 13 5264 7196 1258 - - - -1971 - 304 26699 4 3169 4326 1525 - - - -1972 1028 1285 43413 25 4366 10374 1508 - - - - -1973 20 427 15125 7 2956 4934 7050 - - - - -. 1974 - 34 17146 12 3977 11123 12095 - - - -1975 - 117 15704 9 6248 5471 17335 - - - - -1976 - 242 5972 35 7348 3833 8959 - - - - -1977 77 5191 152 3140 2140 939 - - - -1978 - - 4650 26 2103 21 89 1978 33 1814 42 20 1979 - - 7900 103 1006 2 90 1979 91 5051 116 56 1980 - 1 5351 697 199 2 22 1980 237 13183 303 145 1981 - 3645 158 - 5 74 1981 411 22851 526 251 1982 - - 12480 504 - 7 226 1982 405 22501 518 248 1983 - - 13177 13 - 44 277 1983 554 30779 708 339 1984 - - 13203 1 - 42 363 1984 603 33506 771 369 1985 - 10534 2 - - 109 1985 241 13373 308 147 1986 - - 23742 15 - 38 204 1986 550 30570 703 336 1987 - 21455 86 - 192 381 1987 869 48261 1110 531 1988 - - 39715 - - 135 343 1988 898 49876 1147 549 1989 - 31577 8 - 197 1017 1989 1193 66253 1524 729 1990 - - 3976 1 - 5 123 1990 1419 78811 1813 867 1991 - - 6043 1 - 1 136 1991 1749 97162 2235 1069 1992 - - - - - - 1992 1254 69657 1602 766 1993 - - - - - - - 1993 835 46373 1067 510 1994 - - - - - - - 1994 1515 84154 1936 926 1995 - - - - - - - 1995 478 26580 611 292 1996 - - - - - - - 1996 1195 65596 2304 1079 Total (t.103) 1 6 592 3 48 118 163 Total (t.103) 15 806 19 9 Appendix 3.1 Mean trophic level of incidentally caught species. Discard weight based on three years of DFO observer data, trophic levels from Pauly et al. (1999). Species Group Discards (t) TL TL *Discard SPINY DOGFISH 3761 3.5 12508 FLOUNDER 56 3.5 64 WALLEYE POLLOCK 1538 3.3 1000 SKATES 2882 3.5 4235 SOLE 14243 3.5 9503 TURBOT 16093 3.6 24507 LINGCOD 3620 4.2 1204 PACIFIC OCEAN PERCH 15651 3.3 1570 ROCKFISH 35366 3.2 5819 PACIFIC COD 3052 3.9 919 T O T A L 96262 - 61333 M e a n t roph ic level _ 3.5 _ 183 Appendix 4.1 Ecopath inputs for marine mammals in the Strait of Georgia. (Source: Winship 1998). Species Mean wt. Daily ration Q/B Pop. Biomass Food Cons. (kg) (kg.day1) (year1) (N) (t.km2) (t.km2 .year') Orca (resident) - - - - - -Male 2587 53.73 3.178 40 0.0151 0.0479 Female 1974 43.28 3.354 40 0.0115 0.0386 Orca (transient) - - - - -Male 3068 61.59 7.327 6 0.0024 0.0179 Female 2761 56.60 7.483 6 0.0022 0.0165 Dall's Porpoise - - - - -Male 63.10 2.754 15.93 563 0.0051 0.0820 Female 61.40 2.695 16.02 563 0.0050 0.0803 F£br. Porpoise - - - - - -Male 32.60 1.624 18.18 250 0.0012 0.0215 Female 29.50 1.499 18.55 250 0.0011 0.0198 Harbour Seal - - - - - -Male 63.90 2.020 11.54 7163 0.0663 0.7654 Female 56.40 1.780 11.52 7163 0.0585 0.6745 Steller Sea Lion 458.0 13.45 6.225 1500 0.0996 0.6198 Male Cal. Sea Lion 188.0 6.597 7.439 1500 0.0409 0.3040 Male Total - - - 19043 0.3089 2.6882 Weighted mean 8.701 184 OO as T t T t CN T t t -in r o CN q vo in T f o m VO vo 00 CN O m r o o o VO VO as T t CN vq VO 00 00 O VO bo o d d o i r o T f d d CN VO CN CN in OS in T t °« .. q 00 in CN cn Os CN r o CN 00 00 r o - OS T t CN CN CN q O vq o O CN CO Os © as 00 vq un o vo CN © d CN CN ' 1 '*••' vd d T t CN VO in OS r o in d CN r~ in cn vd " N r o 00 rn Os VO CN 00 r o in r-; —c r o —1 q rN q T t r o vq in r o 00 in "a r o co OS VO CN r~ T f ' rS T t in Os r o in O T t r~ CN Os r> T t d in CO CN CN r-' OO —i r o 00 q 00 in in q r o r o r o r~ _ VO Os Os T t CN O r o oo CN r o in CN q r o as vo od q T t Os <n d T f Os T t CN • t d T t vd CN r-_ d T t T t . d CN 00 T t Os od CN vd OS d T t a vo Os Os ~^ T t T t 00 00 CN CN vd in CO d in od vd d CN d d T t as in d t \ Os Os "»< — — cn 00 T t r o 00 t - ; CN CN r-; T t CN r o r o „ OS q CN in in CN Os 00 T f d in CN CN 00 d r o d d CO in in d OS cn o CN CN T f CN in T f q VO r o T f o q T t CN Os Os in T t s r o O T t ' as cn r-' r o vo in CN r o vd o CN vd CN r o CN vo vd 00 o in t~ CN O r o r o CN © cn q CN T f CN q vq oo as _ CN in CN in o T t in as led Value 'lions $) Os Os r o cn T t CN CN CN 00 r o in Os r o T t CN CN CN r o VO d T t d T t T t CN CO d led Value 'lions $) ~ H led Value 'lions $) VO Os Os r~; q q in o q q q CN vq O VO 00 CN r o CN r-; m 00 T t 00 R S CN r o CN r o cn CN 00 mi d 00 r-T t T t CN CN d CO d T t r o r o CN CO CN d CN q q q q q o m 00 oq oq vo T t q q r o oo T t in r-- Os oo t \ Os Os od r o r o r o •— 1 CN T t ' in od oo vd vq in" T t d r o d d r o od CN r o r o Os d "-^ in —; Os o in in vq r o Os CO r o q T t r~; vq Os — VD 00 as "3 o VO in vo as cn Os os OS CN r o as m vd CN r~ in in in VO CO T t T t as T t in Os vd CN vd vo OS <u vq vq Os oo cn vq _ vo _ oo 00 T t CN T t CN CN Os oq as OS OS Os Os in T t d CN T t ' r o co CN Os CN CN 00 <n vd T t CN CN CN 00 r o in d T t T t in CN CO r o CN CN 5U C3 -S o v 5 O s O O C N r ^ o s i n r ^ oo CN O CN in vo vo co CN O T t —i CN q i n ^ q i n q q q r - ^ o o T t ' - ^ r o i n i n r o o d a s v d f ^ T t m CN r o m CO i n o r o Os m i n T J 1 r o CN CN VO VO CN T f ' d r o r o 00 T t d CN CN 00 00 O q o VD T t O O o O i n r o T t T t r o i n as T t T t d T t r o d T t T t T t T t CN T t VJ on ^ o a Q S T3 O •a u O o o ca oo .a ca h J OH O M o o OH Oi O o >s u o .5 co U U cyj £ " C ^ H CD cd T H cd CD B, o ca cs U co O O U S D O 'C ca ca CO CO CO 185 Appendix 5.1 Figure 1 Length frequency distributions of dungeness crab populations in Vancouver Harbour (Reserve) and Indian Arm (Non-reserve) before (June) and after (October) the crab season between 1994 and 1997. (Source: Data from Department of Fisheries and Oceans Shellfish Unit). 40 £ 30 I 20 IS -j= 10 0 1994 Before • Reserve • Non-reserve 130 140 150 160 170 180 190 200 40 30 20 10 0 1994 After d • Reserve • Non-reserve 130 140 150 160 170 180 190 200 1995 Before fijj • Reserve • Non-reserve 130 140 150 160 170 180 190 200 40 30 20 10 0 1995 After I • Reserve [3 Non-reserve n 120 130 140 150 160 170 180 190 200 1996 Before _d3_ • Reserve • Non-reserve 130 140 150 160 170 180 190 200 50 40 30 20 10 1996 After • Reserve • Non-reserve 130 140 150 160 170 180 190 200 40 £ 30 D) I 20 ™ 10 0 1997 Before ULJ • Reserve • Non-reserve i l l 130 140 150 160 170 180 190 200 50 40 30 20 10 0 1997 After • Reserve • Non-reserve 130 140 150 160 170 180 190 200 Size class (mm) Size class (mm) Appendix 7.1 a Summary of all underwater visual census surveys in 1996 by date, site, general location (L), bottom time of survey (t), the (total) number of lingcod encountered, encounter rate of lingcod per hour of diving (LPHD), the number of lingcod categorized as ages >2, or greater than 3 years, and percentage of 3+ in survey. Date Site V t (min) n total LPHD N>2 N3+ %3+ 07/04/96 Bird Islets ES 17 4 14.1 0 4 100 03/05/96 Brockton Point ES 59 2 2.0 0 2 100 01/09/96 Copper Cove ES 48 0 0.0 0 0 0 02/12/96 Copper Cove ES 43 0 0.0 0 0 0 02/19/96 Copper Cove ES 33 0 0.0 0 0 0 02/23/96 Deeks Creek ES 48 19 23.8 11 8 42.1 02/29/96 Eagle Island ES 11 0 0.0 0 0 0 07/04/96 Eagle Island ES 19 14 44.2 14 0 0 01/13/96 Finister Rock WS 51 0 0.0 0 0 0 03/07/96 Grace Islets WS 49 0 0.0 0 0 0 07/07/96 Grace Islets WS 63 0 0.0 0 0 0 02/28/96 Grebe Islets ES 61 0 0.0 0 0 0 01/15/96 Hermit Island WS 44 2 2.7 0 2 100 02/19/96 Hole in the Wall ES 52 5 5.8 0 5 100 02/29/96 Juniper Point ES 17 2 7.1 2 0 0 07/04/96 Juniper Point ES 23 15 39.1 13 2 13.3 02/29/96 Larson Bay ES 22 5 13.6 5 0 0 07/04/96 Larson Bay ES 18 11 36.7 9 2 18.2 03/28/96 Passage Island ES 41 12 17.6 0 12 100 01/19/96 Point Atkinson ES 25 1 2.4 1 0 0 10/15/96 Point Atkinson ES 33 1 1.8 0 1 100 08/06/96 Popham (bay) WS 20 0 0.0 3 0 0 08/06/96 Popham Island (breakwater) WS 20 5 15.0 1 4 80 08/06/96 Popham Island (reef) WS 30 3 6.0 0 0 0 07/23/96 Porteau Park PP 45 21 28.0 2 19 90 07/23/96 Porteau South ES 53 8 9.1 6 2 25 01/07/96 Telegraph Cove ES 53 0 0.0 0 0 0 02/15/96 Telegraph Cove ES 54 2 2.2 2 0 0 08/30/96 Whytecliff (lookout) WP 48 49 61.3 40 9 18.4 01/31/96 Woolridge Island WS 31 2 3.9 2 0 0 TOTAL 30 1131 183 11.2 0 111 72 a ES=East side of Howe Sound, WS=West Side of Howe Sound, PC=Porteau Cove Park, and WP=Whytecliff Park 187 Appendix 7.1b Summary of all underwater visual census surveys in 1997 by date, site, general location (L), bottom time of survey (t), the (total) number of lingcod encountered, encounter rate of lingcod per hour of diving (LPHD), the number of lingcod categorized as ages 1,2, or greater than 3 years, and diver. Date Site V t n LPHD 1 2 3+ Diver (min) total 03/02/97 Ansell Point ES 40 6 9.0 - 5 1 -02/11/97 Bird Islets ES 22 6 16.4 - 4 2 -07/22/97 Bird Islets ES 26 10 23.1 1 6 3 SM 07/30/97 Bird Islets ES 18 9 30.0 - 4 5 DK 07/30/97 Bird Islets ES 18 10 33.3 - 7 3 SW 03/03/97 Cape Roger Curtis WS 43 0 0.0 - 0 0 -03/13/97 Cape Roger Curtis WS 20 0 0.0 - 0 0 -02/25/97 Caulfield Cove ES 30 5 10.0 - 5 0 -02/18/97 Copper Cove ES 20 1 3.0 - 1 0 -06/06/97 Copper Cove ES 20 1 3.0 - 1 - JM 06/06/97 Copper Cove ES 20 4 12.0 1 3 - DK 07/11/97 Copper Cove ES 37 20 32.4 2 13 5 SM 07/11/97 Copper Cove ES 37 9 14.6 1 6 2 SW 08/06/97 Copper Cove ES 32 11 20.6 0 11 0 SW 08/06/97 Copper Cove ES . 32 3 5.6 - 3 - DG 10/12/97 Copper Cove ES 28 10 21.4 1 7 2 SM 10/12/97 Copper Cove ES 28 7 15.0 2 3 2 SW 02/13/97 Defence Islets WS 48 3 3.8 - 3 0 -02/11/97 Eagle Island ES 18 2 6.7 - 2 0 -06/06/97 Eagle Island ES 20 2 6.0 2 - - JM 06/06/97 Eagle Island ES 20 0 0.0 0 - - DK 07/22/97 Eagle Island ES 20 7 21.0 - 7 - SW 07/31/97 Flume Creek WS 41 16 23.4 3 11 2 SM 07/31/97 Flume Creek WS 41 9 13.2 1 7 1 SW 07/02/97 Grace Islets WS 46 14 18.3 2 12 0 SM 07/02/97 Grace Islets WS 46 6 7.8 1 5 0 DG 03/10/97 Hole in the Wall ES 28 8 17.1 - 7 1 -06/06/97 Hole in the Wall ES 20 9 27.0 - 7 2 JM 06/06/97 Hole in the Wall ES 20 7 21.0 - 4 3 DK 07/04/97 Hole in the Wall ES 23 6 15.7 - 4 2 SC 07/04/97 Hole in the Wall ES 23 4 10.4 - 4 - SW 07/14/97 Hole in the Wall ES 55 32 34.9 1 20 11 SM 07/14/97 Hole in the Wall ES 55 18 19.6 - 14 4 SW 09/20/97 Hole in the Wall ES 35 9 15.4 - 6 3 SC 09/20/97 Hole in the Wall ES 35 11 18.9 - 7 4 SM 09/20/97 Hut III WS 44 29 39.5 2 22 5 SC 09/20/97 Hut III WS 44 24 32.7 4 19 1 SM 02/11/97 Juniper Point ES 16 1 3.8 - 1 0 -06/06/97 Juniper Point ES 20 1 3.0 - 1 - JM 06/06/97 Juniper Point ES 20 1 3.0 - 1 - DK 07/30/97 Juniper Point ES 19 12 37.9 9 3 - DK 07/30/97 Juniper Point ES 19 8 25.3 6 2 - SW 02/11/97 Larson Bay ES 15 4 16.0 - 3 1 -06/06/97 Larson Bay ES 20 8 24.0 - 4 4 -06/06/97 Larson Bay ES 20 8 24.0 - 7 1 -07/22/97 Larson Bay ES 22 24 65.5 - 20 4 SM 02/24/97 Passage Island ES 39 11 16.9 - 10 1 -02/24/97 Point Atkinson ES 46 5 6.5 - 3 2 -188 02/06/97 Popham (bay) 07/24/97 Popham (bay) 07/24/97 Popham (bay) 07/02/97 Popham (breakwater) 07/02/97 Popham (breakwater) 07/23/97 Popham (breakwater) 07/23/97 Popham (breakwater) 08/18/97 Popham (breakwater) 08/18/97 Popham (breakwater) 07/23/97 Popham (breakwater) 07/23/97 Popham (breakwater) 01/31/97 Popham (NE reef) 07/02/97 Popham (NE reef) 07/02/97 Popham (NE reef) 07/24/97 Popham (NE reef) 07/24/97 Popham (NE reef) 08/18/97 Popham (NE reef) 08/18/97 Popham (NE reef) 07/18/97 Porteau North 07/18/97 Porteau North 03/08/97 Porteau Park 05/30/97 Porteau Park 07/18/97 Porteau Park 07/18/97 Porteau Park 03/10/97 Porteau South 07/18/97 Porteau South 07/18/97 Porteau South 07/31/97 White Islets 02/18/97 Whytecliff (cut) 02/18/97 Whytecliff (cut) 03/02/97 Whytecliff (cut) 06/02/97 Whytecliff (cut) 07/11/97 Whytecliff (cut) 07/11/97 Whytecliff (cut) 08/06/97 Whytecliff (cut) 08/06/97 Whytecliff (cut) 07/04/97 Whytecliff (lookout) 07/04/97 Whytecliff (lookout) 07/30/97 Whytecliff (lookout) 07/30/97 Whytecliff (lookout) 10/12/97 Whytecliff (lookout) 10/13/97 Whytecliff (lookout) 08/01/97 Woolridge (North end) 08/01/97 Woolridge (North end) 08/01/97 Woolridge (South end) 08/01/97 Woolridge (South end) TOTAL W S 52 5 5.8 - 3 2 -WS 42 36 51.4 7 24 5 S M WS 42 24 34.3 3 18 3 SW W S 42 16 22.9 2 11 3 DG WS 44 18 24.5 - 11 7 S W W S 39 6 9.2 - 5 1 AK W S 39 13 20.0 - 8 5 SW WS 32 1 1.9 - - 1 SW WS 32 2 3.8 - - 2 SC WS 61 7 6.9 4 3 - AK WS 61 12 11.8 1 8 3 S M W S 47 3 3.8 - 2 1 -W S 44 22 30.0 3 9 10 SM W S 44 17 23.2 1 12 4 SW WS 41 6 8.8 1 3 2 AK W S 41 24 35.1 5 17 2 S M WS 34 9 15.9 1 6 2 SW W S 34 14 24.7 2 9 3 SC E S 40 11 16.5 1 9 1 S M E S 40 15 22.5 - 12 3 S W PC 50 12 14.4 - 0 12 -PC 40 3 4.5 - - 3 S W PC 30 13 26.0 - 9 4 S M PC 30 12 24.0 - 8 4 SW E S 45 1 1.3 - 1 0 -ES 31 15 29.0 1 14 - S M ES 31 8 15.5 1 7 - SW WS 20 34 102.0 - 24 10 SM WP 28 7 15.0 - 6 1 -WP 57 20 21.1 - 15 5 -WP 28 12 25.7 - 6 6 -WP 41 14 20.5 - 7 7 S W WP 61 39 38.4 8 23 8 S M WP 61 36 35.4 4 25 7 S W WP 29 24 49.7 - 18 6 S W WP 29 20 41.4 - 17 3 DG WP 48 26 32.5 8 11 7 SC WP 48 22 27.5 - 16 6 SM WP 46 67 87.4 18 47 2 DK WP 46 72 93.9 9 54 9 SW WP 48 30 37.5 7 22 1 S W WP 49 42 51.4 11 23 8 SM WS 20 10 30.0 4 6 - JH WS 20 6 18.0 3 3 - PL W S 48 5 6.3 1 3 1 SW WS 48 8 10.0 - 7 1 DK 3292 1230 21.9 145 837 248 ES=East side of Howe Sound, WS=West Side of Howe Sound, PC=Porteau Cove Park, and WP=Whytecliff Park Appendix 7.1c Summary of all underwater visual census surveys in 1998 by date, site, general location (L), fishing pressure (F), habitat type (H), bottom time of survey (t), the total number of lingcod encountered (n), encounter rate of lingcod per hour of diving (LPHD), the number of lingcod measured, mean length, and diver. Date Site V F6 ff n LPHD n Mean Diver (min) (total) (measured) (cm) 12/11/97 Ansell Place ES H DB 31 8 15.5 8 51.4 JPD 12/11/97 Ansell Place ES H DB 31 12 23.2 7 44.7 SW 01/24/98 Ansell Place ES H DB 43 7 9.8 - - DL 03/21/98 Ansell Place ES H DB 44 7 9.5 7 47.3 DL 03/21/98 Ansell Place ES H DB 44 14 19.1 - - SM 04/24/98 Ansell Place ES H DB 45 11 14.7 - - SW 04/24/98 Ansell Place ES H DB 45 12 16.0 - - SM 05/30/98 Ansell Place ES H DB 41 23 33.7 23 49.9 NT 06/25/98 Ansell Place ES H DB 38 35 55.3 35 45.5 SM 06/25/98 Ansell Place ES H DB 38 32 50.5 32 52.9 SW 08/14/98 Ansell Place ES H DB 47 26 33.2 26 50.6 SW 08/14/98 Ansell Place ES H DB 47 21 26.8 - - SM 08/25/98 Ansell Place ES H DB 36 27 45.0 27 49.6 SM 08/25/98 Ansell Place ES H DB 36 22 36.7 22 48.9 SW 10/12/97 Copper Cove ES H SB 28 11 23.6 8 40.3 SM 03/07/98 Copper Cove ES H SB 33 1 1.8 1 50.0 SM&SW 06/02/98 Copper Cove ES H SB 38 9 14.2 9 46.0 SM 06/02/98 Copper Cove ES H SB 38 13 20.5 13 48.4 SW 11/23/97 Hole in Wall ES H DB 45 19 25.3 17 46.2 SM 11/23/97 Hole in Wall ES H DB 45 13 17.3 7 51.3 SW 01/24/98 Hole in Wall ES H DB 40 1 1.5 1 48.0 SM&SW 03/21/98 Hole in Wall ES H DB 53 5 5.7 5 46.8 DL 03/21/98 Hole in Wall ES H DB 53 6 6.8 - - SM 07/05/98 Hole in Wall ES H DB 40 10 15.0 10 52.7 SM 07/05/98 Hole in Wall ES H DB 40 4 6.0 4 49.3 SW 10/23/97 Juniper Point ES H SB 21 7 20.0 6 39.3 SM 10/23/97 Juniper Point ES H SB 21 9 25.7 6 43.8 SW 06/01/98 Juniper Point ES H SB 22 3 8.2 3 50.0 NT 06/01/98 Juniper Point ES H SB 22 3 8.2 3 51.0 SM 02/01/98 Kelvin Grove ES H DB 40 3 4.5 - - DG 04/23/98 Kelvin Grove ES H DB 37 2 3.2 1 48.0 SW 06/23/98 Kelvin Grove ES H DB 47 9 11.5 9 54.0 SW 06/23/98 Kelvin Grove ES H DB 47 8 10.2 - - SM 08/12/98 Kelvin Grove ES H DB 40 8 12.0 8 56.0 DG 08/12/98 Kelvin Grove ES H DB 40 10 15.0 10 47.0 SM 10/23/97 Larson Bay ES H MB 20 8 24.0 6 55.8 SW 10/23/97 Larson Bay ES H MB 20 16 48.0 14 43.8 SM 06/01/98 Larson Bay ES H MB 27 3 6.7 3 46.0 NT 06/01/98 Larson Bay ES H MB 27 11 24.4 11 47.8 SM 07/18/98 Larson Bay ES H MB 29 24 49.7 24 46.7 SM 07/18/98 Larson Bay ES H MB 29 12 24.8 12 46.1 SW 11/11/97 Porteau Cove North ES H MB 37 6 9.7 5 48.4 SM 11/11/97 Porteau Cove North ES H MB 37 10 16.2 9 46.3 SW 03/24/98 Porteau Cove North ES H MB 46 4 5.2 - - SM 07/17/98 Porteau Cove North ES H MB 25 7 16.8 7 61.7 SW 08/12/98 Porteau Cove North ES H MB 30 3 6.0 1 65.0 DG 08/12/98 Porteau Cove North ES H MB 30 4 8.0 4 53.5 SW 04/23/98 Sunset Point ES H DB 54 17 18.9 17 46.9 SM 05/30/98 Sunset Point ES H DB 52 17 19.6 17 48.4 NT 06/23/98 Sunset Point ES H DB 57 14 14.7 14 50.1 SW 06/23/98 Sunset Point ES H DB 57 20 21.1 - - SM 06/25/98 Sunset Point ES H DB 40 7 10.5 - - SW 06/25/98 Sunset Point ES H DB 40 8 12.0 - - SM 08/25/98 Sunset Point ES H DB 45 37 49.3 37 46.2 SM 190 08/25/98 Sunset Point ES H DB 40 16 24.0 16 51.4 SW 02/07/98 Popham (bay) WS L SB 56 11 11.8 11 52.0 DL 02/07/98 Popham (bay) WS L SB 56 20 21.4 - - SM 12/10/97 Popham (breakwater) WS L SB 42 14 20.0 11 54.5 DG 12/10/97 Popham (breakwater) WS L SB 42 21 30.0 20 55.8 SW 01/25/98 Popham (breakwater) WS L SB 48 9 11.3 8 49.5 S M & J P 03/08/98 Popham (breakwater) WS L SB 48 7 8.8 5 50.6 SM&SW 05/26/98 Popham (breakwater) WS L SB 40 11 16.5 - - SM 05/26/98 Popham (breakwater) WS L SB 40 8 12.0 5 52.4 NT 06/29/98 Popham (breakwater) WS L SB 20 14 42.0 - - SM 06/29/98 Popham (breakwater) WS L SB 20 16 48.0 - - TO 07/06/98 Popham (breakwater) WS L SB 41 24 35.1 11 53.5 SM 07/06/98 Popham (breakwater) WS L SB 41 13 19.0 13 51.7 SW 07/31/98 Popham (breakwater) WS L SB 53 26 29.4 26 56.0 SM 07/31/98 Popham (breakwater) WS L SB 53 5 5.7 5 60.8 SM&SC 12/10/97 Popham (NE reef) WS L MB 37 6 9.7 6 61.5 DG 12/10/97 Popham (NE reef) WS L MB 37 10 16.2 8 48.9 SW 01/25/98 Popham (NE reef) WS L MB 42 6 8.6 6 53.3 SM &JP 05/26/98 Popham (NE reef) WS L MB 45 5 6.7 5 55.6 NT 05/26/98 Popham (NE reef) WS L MB 45 9 12.0 - - SM 07/06/98 Popham (NE reef) WS L MB 41 23 33.7 23 44.5 SM 07/06/98 Popham (NE reef) WS L MB 41 14 20.5 14 51.8 SW 08/18/98 Popham (NE reef) WS L MB 38 9 14.2 9 46.6 SW 11/13/97 White Islets WS L DB 35 13 22.3 13 51.0 SM 11/13/97 White Islets WS L DB 35 12 20.6 12 54.7 SW 03/19/98 White Islets WS L DB 34 25 44.1 23 56.3 SW&JN 04/02/98 White Islets WS L DB 45 35 46.7 27 53.0 SM 07/14/98 White Islets WS L DB 42 35 50.0 35 51.6 SM 07/14/98 White Islets WS L DB 42 28 40.0 28 55.1 SW 08/27/98 White Islets WS L DB 38 31 48.9 31 53.6 SM 08/27/98 White Islets WS L DB 38 27 42.6 27 56.0 SW 10/23/97 Bird Islets ES M MB 20 12 36.0 11 48.8 SM 10/23/97 Bird Islets ES M MB 20 7 21.0 5 50.0 SW 03/17/98 Bird Islets ES M MB 44 14 19.1 - - JN 05/30/98 Bird Islets ES M MB 40 11 16.5 11 47.5 NT 05/30/98 Bird Islets ES M MB 40 12 18.0 - - SM 07/05/98 Bird Islets ES M MB 39 27 41.5 27 47.0 SM 07/05/98 Bird Islets ES M MB 39 15 23.1 15 54.6 SW 10/21/97 Columbine Point ES M DB 34 15 26.5 10 47.2 SM 10/21/97 Columbine Point ES M DB 34 8 14.1 5 45.6 SW 07/27/98 Columbine Point ES M DB 31 8 15.5 8 47.6 SM 07/27/98 Columbine Point ES M DB 31 5 9.7 5 49.6 SW 10/23/97 Eagle Island ES M SB 20 5 15.0 5 37.6 SM 10/23/97 Eagle Island ES M SB 20 7 21.0 4 38.5 SW 06/01/98 Eagle Island ES M SB 22 4 10.9 4 43.5 SM 10/21/97 Hurt III WS M DB 47 18 23.0 13 45.8 SW 08/07/98 Hutt III WS M DB 39 22 33.8 22 44.8 SM 08/07/98 Hutt III WS M DB 39 19 29.2 17 44.7 SW 11/12/97 Passage Island North ES M DB 35 6 10.3 6 48.4 SM 11/12/97 Passage Island South ES M DB 39 9 13.8 6 46.7 SW 11/12/97 Passage Island South ES M DB 35 12 20.6 8 38.4 SM 06/30/98 Passage Island South ES M DB 35 28 48.0 - - SM 12/03/97 Point Atkinson ES M MB 30 4 8.0 4 57.5 JPD 01/29/98 Point Atkinson ES M MB 43 12 16.7 - - SM 02/05/98 Point Atkinson ES M MB 49 9 11.0 9 78.0 SW 02/05/98 Point Atkinson ES M MB 49 14 17.1 - - SM 03/17/98 Point Atkinson ES M MB 37 5 8.1 - - SW&JN 04/30/98 Point Atkinson ES M MB 31 2 3.9 2 49.0 SW 05/14/98 Point Atkinson ES M MB 45 6 8.0 6 60.2 DG 07/18/98 Point Atkinson ES M MB 39 13 20.0 13 49.0 SM 07/18/98 Point Atkinson ES M MB 39 10 15.4 9 55.7 SW 08/07/98 Willies Reef WS M MB 35 11 18.9 11 50.5 SM 08/07/98 Willies Reef WS M MB 35 6 10.3 6 45.3 SW 11/11/97 Porteau Park PC PK. AR 44 16 21.8 16 62.8 SM 11/11/97 Porteau Park PC PK AR 44 8 10.9 7 58.1 SW 02/03/98 Porteau Park PC PK AR 52 25 28.8 19 60.3 SW 02/03/98 Porteau Park PC PK AR 52 27 31.2 - - SM 03/10/98 Porteau Park PC PK AR 56 19 20.4 - - SM 03/10/98 Porteau Park PC PK AR 56 13 13.9 - - SW 05/27/98 Porteau Park PC PK AR 50 16 19.2 15 75.9 NT 06/18/98 Porteau Park PC PK AR 44 13 17.7 13 58.5 SM 06/18/98 Porteau Park PC PK AR 44 14 19.1 14 64.4 SW 07/17/98 Porteau Park PC PK AR 48 23 28.8 23 61.4 SW 07/17/98 Porteau Park PC PK AR 48 21 26.3 - - SM 08/12/98 Porteau Park PC PK AR 56 37 39.6 37 60.7 SM 08/12/98 Porteau Park PC PK AR 48 27 33.8 27 63.4 SW 12/11/97 Whytecliff (cut) WP PK DB 31 11 21.3 11 47.5 JPD 12/11/97 Whytecliff (cut) WP PK DB 31 17 32.9 15 49.5 SW 02/05/98 Whytecliff (cut) WP PK DB 42 10 14.3 8 58.4 DG 02/05/98 Whytecliff (cut) WP PK DB 42 19 27.1 - - SW 03/07/98 Whytecliff (cut) WP PK DB 48 19 23.8 19 48.5 SM&SW 05/12/98 Whytecliff (cut) WP PK DB 45 21 28.0 21 49.5 SM 06/17/98 Whytecliff (cut) WP PK DB 44 15 20.5 15 56.3 SM 06/17/98 Whytecliff (cut) WP PK DB 44 12 16.4 12 54.8 SW 07/07/98 Whytecliff (cut) WP PK DB 47 32 40.9 32 56.1 SM 07/07/98 Whytecliff (cut) WP PK DB 47 21 26.8 21 55.0 SW 08/10/98 Whytecliff (cut) WP . PK DB 49 29 35.5 29 48.5 SM 08/10/98 Whytecliff (cut) WP PK DB 49 24 29.4 24 53.8 SW 10/12/97 Whytecliff (lookout) WP PK DB 47 42 53.6 37 44.4 SM 05/12/98 Whytecliff (lookout) WP PK DB 48 34 42.5 33 45.6 SW 06/02/98 Whytecliff (lookout) WP PK DB 49 24 29.4 24 46.6 SW 06/02/98 Whytecliff (lookout) WP PK DB 49 23 28.2 - - SM 07/07/98 Whytecliff (lookout) WP PK DB 47 27 34.5 27 42.9 SM 07/07/98 Whytecliff (lookout) WP PK DB 47 13 16.6 13 46.3 SW 08/10/98 Whytecliff (lookout) WP PK DB 49 35 42.9 35 48.7 SM 08/10/98 Whytecliff (lookout) WP PK DB 49 27 33.1 27 47.7 SW " ES=East side of Howe Sound, WS=West Side of Howe Sound, PC=Porteau Cove Park, and WP=Whytecliff Park b H=high fishing pressure, M=moderate, and L=low. c DB=deep bedrock, MB=middle bedrock, and SB=shallow bedrock. Appendix 7.2 Summary of 1998 tagging dives by date, location, bottom time, total number of lingcod tagged during diver, tag numbers, tag colour and diver. Date Location t (min) Total tagged Start # End # Tag Colour Diver 01/24/98 Ansell Place 43 8 226 234 Green SM 01/24/98 Ansell Place 43 6 201 207 Green sw 03/21/98 Ansell Place 44 6 276 282 Green SM 05/30/98 Ansell Place 41 13 313 326 Green (Y) SM 08/14/98 Ansell Place 47 13 351 364 Green (Y) SM 01/29/98 Bird Islets 39 7 11 18 Orange sw 03/17/98 Bird Islets 44 7 18 25 Orange SW 05/30/98 Bird Islets 40 2 76 78 Orange (Y) sw 01/24/98 Hole in Wall 40 1 234 235 Green SM 03/21/98 Hole in Wall 53 5 281 286 Green SM 01/22/98 Juniper Point 20 1 28 29 Orange SM 01/31/98 Kelvin Grove 46 1 235 236 Green SM 01/31/98 Kelvin Grove 46 6 251 257 Green SW 06/23/98 Kelvin Grove 42 6 326 332 Green SM 01/22/98 Point Atkinson 48 10 1 11 Orange SM 01/22/98 Point Atkinson 39 2 26 28 Orange SW 01/29/98 Point Atkinson 43 4 29 33 Orange SM 02/05/98 Point Atkinson 49 6 34 40 Orange SM 05/14/98 Point Atkinson 45 1 25 26 Orange (B) SM 05/14/98 Point Atkinson 45 2 41 43 Orange (B) SM 02/07/98 Popham (bay) 56 12 237 249 Green SM 01/25/98 Popham (breakwater) 48 10 207 217 Green SM 02/07/98 Popham (breakwater) 48 12 257 269 Green SM 03/08/98 Popham (breakwater) 48 3 223 226 Green SM 05/26/98 Popham (breakwater) 48 3 297 300 Green (Y) SM 05/26/98 Popham (breakwater) 40 3 301 304 Green (Y) SM 06/29/98 Popham (breakwater) 40 10 341 351 Green SM 02/09/98 Popham (main bay) 20 2 269 271 Green SW 01/25/98 Popham (NE reef) 42 6 217 223 Green SM 05/26/98 Popham (NE reef) 45 6 291 297 Green (Y) SM 08/18/98 Popham (NE reef) 38 5 364 369 Green (Y) SM 01/27/98 Porteau Cove 33 13 801 814 Pink SM 01/27/98 Porteau Cove 44 6 826 832 Pink SW 02/03/98 Porteau Cove 44 12 814 826 Pink SM 03/10/98 Porteau Cove 46 7 832 839 Pink SM 05/27/98 Porteau Cove 46 1 841 842 Pink (Y) SW 05/27/98 Porteau Cove 52 5 851 856 Pink (Y) SW 03/10/98 Porteau Ferry Dock 56 1 839 840 Pink SM 01/27/98 Porteau North 50 1 601 602 Yellow DL 01/27/98 Porteau North 50 2 626 628 Yellow SW 04/23/98 Sunset Point 54 2 249 251 Green (Y) SM 04/23/98 Sunset Point 54 5 286 291 Green (Y) SM 05/30/98 Sunset Point 52 9 304 313 Green (Y) SW 06/23/98 Sunset Point 57 9 332 341 Green SM 03/19/98 White Islets 48 23 602 625 Yellow SM 03/19/98 White Islets 48 13 628 641 Yellow SW 01/13/98 Whytecliff(cut) 42 5 401 406 White SW 01/13/98 Whytecliff (cut) 42 8 451 459 White SM 01/15/98 Whytecliff (cut) 38 3 408 411 White SW 01/15/98 Whytecliff (cut) 38 1 464 465 White SM 02/05/98 Whytecliff (cut) 42 11 411 422 White SW 05/12/98 Whytecliff (cut) 45 8 422 430 White (B) SW 01/13/98 Whytecliff (lookout) 42 1 406 407 White SW 01/13/98 Whytecliff (lookout) 42 6 459 465 White SM 05/12/98 Whytecliff (lookout) 48 15 486 501 White (B) SW 06/02/98 Whytecliff (lookout) 49 6 430 436 White (Y) SM TOTAL 2492 352 193 Appendix 7.3 Groups Count Sum Average Variance 1996 30 336.3 11.2 252.4 1997 94 2058.9 21.9 347.0 1998 150 3315.4 22.1 162.1 A N O V A Source of SS df MS F P-value F crit Variation Between Groups 3128.0 2 1564.0 6.64 0.001 3.03 Within Groups 63748.0 271 235.2 Total 66876.0 273 Fmax=Variance ( m a x )/Variance ( m i n ) =2.14, Fmax<Fcrit therefore significant to 0.001. Bonferroni multiple range test: t (.05,245) Comparison Absolute Value CD 1996-1997 -10.69 7.35 * 1996-1998 -10.89 7.10 * 1997-1998 -0.20 4.86 ns CD=Critical Difference, i f CD>Absolute value then comparison is significant (p=.05). Appendix 7.4 Summary of tagging recapture events in 1998 by date, location, bottom time (t), total number of lingcod observed, number of tags out at each location at time of census, number of lingcod observed with tags, percentage of tagged lingcod compared to the number of tags out, rate of recapture in tags per hour of diving, and diver. Date Location f (min) n obs #tags out # tags obs % rec Rate (recap) Diver 03/21/98 Ansell Place 44 14 14 2 14 2.7 SM 04/24/98 Ansell Place 45 11 20 1 9 1.3 SW 04/24/98 Ansell Place 45 12 20 0 0 0.0 SM 05/30/98 Ansell Place 41 24 20 0 0 0.0 SM 05/30/98 Ansell Place 41 23 20 0 0 0.0 NT 06/25/98 Ansell Place 38 32 33 3 9 4.7 SW 06/25/98 Ansell Place 38 34 33 2 6 3.2 SM 08/14/98 Ansell Place 47 26 33 1 4 1.3 SW 08/14/98 Ansell Place 47 21 33 3 14 3.8 SM 08/25/98 Ansell Place 36 22 46 4 18 6.7 SW 08/25/98 Ansell Place 36 27 46 7 26 11.7 SM 03/17/98 Bird Islets 44 14 7 0 0 0.0 SW 05/30/98 Bird Islets 40 12 14 1 8 1.5 SW 07/05/98 Bird Islets 39 15 14 2 13 3.1 SW 07/05/98 Bird Islets 39 27 14 0 0 0.0 SM 07/27/98 Columbine Point 31 8 0 0 0 0.0 SM 07/27/98 Columbine Point 31 5 0 0 0 0.0 SW 03/07/98 Copper Cove 33 1 0 0 0 0.0 SM 06/02/98 Copper Cove 38 13 0 0 0 0.0 SW 06/02/98 Copper Cove 38 9 0 0 0 0.0 SM 06/01/98 Eagle Island 22 4 0 0 0 0.0 SM 03/24/98 Furry Creek 51 2 0 0 0 0.0 SM 03/21/98 Hole in Wall 53 6 1 0 0 0.0 SM 07/05/98 Hole in Wall 40 10 6 0 0 0.0 SM 07/05/98 Hole in Wall 40 4 6 0 0 0.0 SW 06/01/98 Juniper Point 22 3 1 0 0 0.0 SM 02/01/98 Kelvin Grove 40 3 7 1 33 1.5 DG 02/27/98 Kelvin Grove 45 8 7 1 13 1.3 CS 02/27/98 Kelvin Grove 40 5 7 1 20 1.5 CS 04/23/98 Kelvin Grove 37 2 7 0 0 0.0 SW 06/23/98 Kelvin Grove 47 9 7 2 22 2.6 SW 06/23/98 Kelvin Grove 47 8 7 2 25 2.6 SM 08/12/98 Kelvin Grove 40 10 13 1 10 1.5 SM 08/12/98 Kelvin Grove 40 8 13 3 38 4.5 DG 06/01/98 Larson Bay 27 11 0 0 0 0.0 SM 07/18/98 Larson Bay 29 24 0 0 0 0.0 SM 07/18/98 Larson Bay 29 12 0 0 0 0.0 SW 06/30/98 Passage Island 35 28 0 0 0 0.0 SM 01/29/98 Point Atkinson 43 12 12 1 8 1.4 SM 02/05/98 Point Atkinson 49 14 16 6 43 7.3 SM 02/05/98 Point Atkinson 49 12 16 5 42 6.1 SW 03/17/98 Point Atkinson 37 5 22 1 20 1.6 SW 05/14/98 Point Atkinson 45 6 22 I 17 1.3 SM 07/18/98 Point Atkinson 39 13 25 1 8 1.5 SM 07/18/98 Point Atkinson 39 10 25 1 10 1.5 SW 02/07/98 Popham (bay) 52 20 10 2 10 2.3 SM 03/08/98 Popham (breakwater) 48 8 22 3 38 3.8 SM 05/26/98 Popham (breakwater) 40 11 25 1 9 1.5 SM 06/29/98 Popham (breakwater) 20 14 31 2 14 6.0 SM 06/29/98 Popham (breakwater) 20 16 31 3 19 9.0 TO 07/06/98 Popham (breakwater) 41 24 41 9 38 13.2 SM 07/06/98 Popham (breakwater) 41 13 41 4 31 5.9 SW 07/31/98 Popham (breakwater) 52 5 41 0 0 0.0 SC 07/31/98 Popham (breakwater) 52 26 41 7 27 8.1 SM 05/26/98 Popham (NE reef) 45 9 6 0 0 0.0 SM 05/26/98 Popham (NE reef) 45 7 6 0 0 0.0 NT 07/06/98 Popham (NE reef) 41 23 12 1 4 1.5 SM 07/06/98 Popham (NE reef) 41 14 12 1 7 1.5 SW 08/18/98 Popham (NE reef) 38 9 12 1 11 1.6 SW 03/24/98 Porteau (North) 46 4 3 0 0 0.0 SM 195 07/17/98 Porteau (North) 25 7 3 0 0 0.0 SW 08/12/98 Porteau (North) 30 4 3 0 0 0.0 SW 08/12/98 Porteau (North) 30 3 3 0 0 0.0 DG 02/03/98 Porteau Cove 52 27 19 14 52 16.2 SM 02/03/98 Porteau Cove 52 24 19 12 50 13.8 SW 03/10/98 Porteau Cove 56 19 31 10 53 10.7 SM 03/10/98 Porteau Cove 56 13 31 9 69 9.6 SW 05/27/98 Porteau Cove 50 16 38 9 56 10.8 SW 06/18/98 Porteau Cove 44 14 44 7 50 9.5 SW 06/18/98 Porteau Cove 44 13 44 7 54 9.5 SM 07/17/98 Porteau Cove 48 23 44 14 61 17.5 SW 07/17/98 Porteau Cove 48 21 44 15 71 18.8 SM 08/12/98 Porteau Cove 48 27 44 14 52 17.5 SW 08/12/98 Porteau Cove 56 37 44 18 49 19.3 SM 03/10/98 Porteau Ferry Dock 33 2 0 0 0 0.0 SM 04/23/98 Sunset Point 54 17 0 2 12 2.2 SM 05/30/98 Sunset Point 52 18 7 3 17 3.5 SW 06/23/98 Sunset Point 57 20 16 2 10 2.1 SM 06/23/98 Sunset Point 57 14 16 3 21 3.2 SW 06/25/98 Sunset Point 40 7 25 2 29 3.0 SW 06/25/98 Sunset Point 40 8 25 2 25 3.0 SM 08/25/98 Sunset Point 40 16 25 3 19 4.5 SW 08/25/98 Sunset Point 45 37 25 7 19 9.3 SM 03/19/98 White Islets 34 24 36 9 38 15.9 SW 04/02/98 White Islets 45 35 36 8 23 10.7 SM 07/14/98 White Islets 42 27 36 7 26 10.0 SW 07/14/98 White Islets 42 34 36 5 15 7.1 SM 08/27/98 White Islets 38 31 36 8 26 12.6 SM 08/27/98 White Islets 38 27 36 3 11 4.7 SW 02/05/98 Whytecliff (cut) 42 19 17 2 11 2.9 SW 03/07/98 Whytecliff (cut) 48 19 28 3 16 3.8 SM 05/12/98 Whytecliff (cut) 45 21 36 2 10 2.7 SM 06/17/98 Whytecliff (cut) 44 15 36 2 13 2.7 SM 06/17/98 Whytecliff (cut) 44 12 36 1 8 1.4 SW 07/07/98 Whytecliff (cut) 47 31 36 8 26 10.2 SM 07/07/98 Whytecliff (cut) 47 22 36 6 27 7.7 SW 08/10/98 Whytecliff (cut) 49 29 36 1 3 1.2 SM 08/10/98 Whytecliff (cut) 49 24 36 5 21 6.1 SW 05/12/98 Whytecliff (lookout) 48 34 7 1 3 1.3 SW 06/02/98 Whytecliff (lookout) 49 23 28 3 13 3.7 SM 06/02/98 Whytecliff (lookout) 49 24 28 2 8 2.4 SW 07/07/98 Whytecliff (lookout) 34 27 28 3 11 5.3 SM 07/07/98 Whytecliff (lookout) 34 13 28 0 0 0.0 SW 08/10/98 Whytecliff (lookout) 49 27 28 1 4 1.2 SW 08/10/98 Whytecliff (lookout) 49 34 28 3 9 3.7 SM T O T A L 4421 1721 2159 323 19 4.4 Appendix 8.1 List of benefits to be expected with an appropriate system of reserves accompanied by other management measures (From "No-take" Reserves working group meeting, Lee Stocking Island, Bahamas, September 25-30, 1995, unpublished). 1. Protect ecosystem structure, function, and integrity: physical structure of habitat ecological processes restore population structure and community composition biodiversity at all levels keystone species cascading effects vulnerable species threshold effects second order effects food web trophic structure incidental damage system resilience fishing gear impacts maintenance of high quality feeding areas 2. Improve fishery yields protect spawning fish stocks increase spawning stock biomass increase spawning density provide greater population fecundity (reproductive capacity) provides undisturbed spawning conditions, habitat, sites allows production of more eggs and larvae provides export of eggs and larvae enhances recruitment provides spillover of adults and juveniles reduces chances of recruitment overfishing reduces overfishing of vulnerable species protects diversity of fishing opportunities reduces adverse impacts on intraspecies genetics improves ability to recover from management failures reduces inadvertent fishing mortality reduces bycatch simplifies enforcement and compliance helps reduce conflicts among users maintains sport trophy fisheries provides better and more efficient management with limited resources increases understanding and acceptance of management facilitates stakeholder and user involvement in management provides information from unfished populations necessary for proper management 197 3. Increases knowledge and understanding of marine systems provides long term monitoring areas provides focus for study provides continuity of knowledge in undisturbed site provides opportunity to restore or maintain natural behaviours reduces risks to long term experiments provides synergism of knowledge, cumulative effect provides control areas for assessing anthropogenic impacts 4.Improves non-consumptive opportunities enhance and diversify economic activities enhance non-consumptive recreation improves peace of mind enhances aesthetic values improves wilderness opportunities spiritual connections social activity education enhances conservation appreciation increases sustainable employment opportunities diversifies and stabilises the economy creates public awareness leaves less room for irresponsible development encourages holistic approach to management 

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