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The role of abandoned stream channels as over-wintering habitat for juvenile salmonids Brown, Thomas Gordon 1985

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THE ROLE OF ABANDONED STREAM CHANNELS AS OVER-WINTERING HABITAT FOR JUVENILE SALMONIDS by THOMAS GORDON BROWN A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n THE FACULTY OF GRADUATE STUDIES DEPARTMENT OF FORESTRY We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA OCTOBER 1985 © THOMAS GORDON BROWN, 1985 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 l~ G <Z )- S T ^ V The University of British Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date OCT / / Sf S" D E - 6 ( 3 / 8 1 ) ABSTRACT The role of ephemeral swamps and intermittent t r i b u t a r i e s (off-stream habitat) located on the f l o o d - p l a i n of a west coast Vancouver Island stream (Carnation Creek), as over-wintering habitat, was examined for two winters. A l l trout (Salmo gairdneri and S_. c l a r k i c l a r k i ) and juvenile coho salmon (Oncorhynchus kisutch) off-stream habitat were i d e n t i f i e d and characterized. Within this habitat: seasonal movement of salmonids was noted, coho growth rates were measured, salmonid populations were enumerated and contribution of off-stream habitat to the t o t a l coho smolt production was estimated. Coho and trout did not occupy a l l winter flooded land. Trout occupied intermittent t r i b u t a r i e s , while coho occupied both intermittent t r i b u t a r i e s and ephemeral swamps. Salmonid use of flooded meadows was n e g l i g i b l e . The contribution of off-stream habitat to the watershed's t o t a l smolt production was at least 23% and more than 15% came from s i t e s devoid of water i n summer. Seasonal movement of juvenile coho followed a d i s t i n c t pattern and appeared dependent upon cl i m a t i c conditions such as magnitude and timing of the f i r s t f a l l (Oct-Nov) freshet. Climatic conditions i n spring (March-May) appeared to influence both growth and survival of coho within one small ephemeral swamp. i i i ACKNOWLEDGEMENTS I wish to express my appreciation to T. G. Northcote, G. F. Hartman, D. L. Golding and A. H. J . Dorcey f o r guidance throughout the course of t h i s study. Information and advice provided by members of the Carnation Creek Working Group: C. Scrivener, B. Andersen, K. King and P. Neaves; and support provided by f i e l d personnel: S. B a i l l i e , B. P a i s l e y , D. Claughton, M. Welby and G. Caw was e s s e n t i a l i n maintaining a good data base during adverse winter conditions. I d e n t i f i c a t i o n of plant species by D. McLennan and A. McGee was appreciated. I would e s p e c i a l l y l i k e to thank Bernice Morosoff, f o r her help i n c o l l e c t i n g data and her excellent d r a f t i n g of s i t e maps. iv TABLE OF CONTENTS Page Abstract i i Acknowlegements i i i Table of Contents iv List of Tables ix List of Figures x i i CHAPTER 1. INTRODUCTION 1. The Problem 1 2. The Purpose 5 3. Definitions 6 CHAPTER 2. STUDY AREA 1. Physical Features 8 2. Soils 10 3. Climate 11 4 Stream Discharge 11 5. Vegetation 11 6. Ecosystem Classification 12 7. Fisheries Resource 13 8. Logging Operation 13 9. Study Area Choice 14 CHAPTER 3. GENERAL FEATURES OF OVER-WINTERING SITES 1. Method of Site Selection 15 2. Site Description 16 3. Discussion 20 a) Common Features 20 b) Surface Area 20 c) Evolution of Off-stream Sites 21 V CHAPTER 4. SALMONID HABITAT CHARACTERIZATION 1. Methods 23 a) Theory 23 b) Vegetative Features 24 c) Surface Features 24 d) Water Table Depth 25 e) Fish Presence and Abundance 25 2. Results 26 a) Vegetative Features 26 (i) Plant Associations (ii) Vertical Spacing (Strata) b) Surface Features 29 (i) Woody Debris ( i i ) Surface Soil c) Water Levels ....33 d) Map Units 35 e) Habitat Units 38 3. Discussion 42 CHAPTER 5. SALMONID WINTER POPULATION DYNAMICS 1. Methods 44 a) Population Size 44 (i) Differentiation of Species (ii ) Method of Estimation ( i i i ) Comparison of Trapping with Other Methods b) Contribution to Total Smolt Run 48 2. Results 49 a) Coho Utilization 49 (i) Numbers (ii) Densities b) Contribution to Total Smolt Production 53 c) Population Change Over Winter 56 v i d) Trout Utilization 59 (i) Numbers (ii) Densities 3. Discussion 62 a) Coho Utilization of Off-stream Habitat 62 b) Off-stream Smolt Contribution 65 c) Winter Population Dynamics 66 d) Trout Utilization of Off-stream Habitat 68 CHAPTER 6. COHO MOVEMENT DURING THE WINTER PERIOD 1. Methods 71 a) Main-stream to Off-stream Movement 71 (i) . Timing ( i i ) Direction b) Winter Movement 72 c) Within Site Movement 72 2. Results 73 a) Main-stream to Off-stream Movement 73 (i) Timing (i i ) Mechanism ( i i i ) Direction b) Winter Movement 76 (i) Between Sites (i i ) Main-stream Replacement c) Within Site Movement 78 (i) Tributary Movement (ii) Swamp Movement 3. Discussion 79 a) Main-stream to Off-stream Movement 79 b) Winter Movement 83 c) Within Site Movement 85 v i i CHAPTER 7. WINTER GROWTH OF COHO JUVENILES 1. Methods 87 2. Results 87 a) Population Mean Length 87 (i) Size Dependent Mortality and Migration ( i i ) Growth b) Comparison of Sites 90 (i) Three Site Types (i i ) Intermittent Tributaries ( i i i ) Ephemeral Swamps c) Comparison of Years 96 3. Discussion 99 a) Winter Growth 99 b) Spatial Variation 101 c) Annual Variation 103 CHAPTER 8. SUMMARY 1. What is Off-stream Winter Habitat? 105 2. How Important is Off-stream Habitat? 106 3. Winter Ecology 107 CHAPTER 9. MANAGEMENT IMPLICATIONS 1. Introduction 109 2. Alteration of Access 109 3. Alteration of Winter Water Level 113 4. Importance of Large Woody Debris 115 5. Pool Formation and Destruction 117 6. Semi-Aquatic Vegetation 118 7. Changes Over the Forest Rotation 121 8. Trout Versus Coho (Management Differences) 123 v i i i 9. Means of Reducing Impacts 124 10. Cost to Forestry 125 11. Future Experimental Programs 126 12. Conclusions 127 BIBLIOGRAPHY 128 APPENDIX 1. Maps of Winter Flooded Land Located on Carnation Creek's Flood-plain (Scale 1:500) APPENDIX 2. Data Tables Used to Develop Map and Habitat Units APPENDIX 3. Salmonid Winter Population Estimates (Data Tables) APPENDIX 4 . Coho Winter Movement (Data Tables) APPENDIX 5. Coho Winter Growth (Data Tables) i x LIST OF TABLES TABLE PAGE 3.1 Description of flooded areas and coho over-wintering sites associated with the Carnation Creek flood-plain 17 4.1 Characteristic combinations of plant species, for plant associations located within winter flooded land, on the Carnation Creek flood-plain, 5-10 years after harvest 28 4.2 Groupings of plant communities, within winter flooded land located on the Carnation Creek flood-plain, 5-10 years after harvest, based on vertical spacing of the vegetation 29 4.3 Groupings of plots within winter flooded land located on the Carnation Creek flood-plain, 5-10 years after harvest, based on percentage of surface covered by woody debris 31 4.4 Groupings of plots, within winter flooded land located on the Carnation Creek flood-plain, 5-10 years after harvest, based on two soil features (% organic and % of particles <.25 mm)...33 4.5 Groupings of plots within winter flooded land located on the Carnation Creek flood-plain, 5-10 years after harvest, based on mean summer and winter water levels 35 4.6 Summary of discriminant groupings used to delineate map units located within winter flooded land on the Carnation Creek flood-plain 36 X 4.7 D e s c r i p t i o n of map u n i t s located w i t h i n winter flooded land on the Carnation Creek f l o o d - p l a i n . Plant constants include: L y s l c h i t o n americanum, Oenanthe sarmentosa and Epilobium sp.. .36 4.8 Desc r i p t i o n of salmonid habitat units located on the Carnation Creek f l o o d - p l a i n 41 5.1 Comparison of baited trapping (®"Gee" traps) estimates with estimates from e l e c t r o f i s h i n g and recovery at small fences. (Peterson mark/recapture) 48 5.2 Number of coho (Oncorhynchus kisutch) u t i l i z i n g off-stream s i t e s during: winter 1983, f a l l 1983 and winter 1984 51 5.3 Coho (Oncorhynchus kisutch) d e n s i t i e s within off-stream s i t e s and main-stream locati o n s for 1982 (main-stream values from Andersen 1984) 52 5.4 Coho (Oncorhynchus ki s u t c h ) d e n s i t i e s for a l l off-stream s i t e s based on: two estimates of area ( t o t a l flooded area and area of habitat unit 1 + 2 ) and mean coho population f o r two winters 52 5.5 Percentage of t o t a l off-stream over-wintering salmonid population represented by trout 59 5.6 Percentage of over-wintering salmonid population within two t r i b u t a r i e s represented by trout 60 5.7 Trout d e n s i t i e s for three i n t e r m i t t e n t t r i b u t a r i e s based on: two estimates of area ( t o t a l flooded area and area of habitat unit 1) and mean trout population for two winters 62 x i 6.1 D i r e c t i o n of j u v e n i l e coho movement from summer rearing s i t e s i n the main-stream to winter s i t e s off-stream 75 6.2 Percentage of marked juvenile coho moving to a new off-stream s i t e f o r two winter periods (1983-84) 76 6.3 Ratio of marked to unmarked juvenile coho and percentage replacement within off-stream s i t e s for two winter periods (1983-84) 77 6.4 F a l l movement of marked coho in t o the ephemeral (L1600m upper) and i n t e r m i t t e n t (L1600m lower) s e c t i o n of a t r i b u t a r y 79 7.1 Increase i n mean fork-length of 1 year old j u v e n i l e coho (Oncorhynchus ki s u t c h ) during the winter period 1983-84 94 x i i LIST OF FIGURES FIGURE PAGE 1.1 A generalized l i f e cycle of the coho salmon (Oncorhynchus  kisutch) 2 1.2 Map of Carnation Creek watershed showing locations of: tributaries, hydrographic weirs, fish counting fence and flood-plain 3 2.1 Map of Carnation Creek flood-plain showing locations of: tributaries, hydrographic weirs, fish counting fence, flooded areas mapped and salmonid over-wintering sites.......9 3.1 Succession of coho (Oncorhynchus kisutch) off-stream ephemeral over-wintering habitat on an alluvial flood-plain 22 4.1 Plant associations identified by reciprocal averaging ordination using "Ordiflex" (Gauch 1977). A l l sample plots are located on the Carnation Creek flood-plain within winter flooded lands 27 4.2 Groupings of sample plots by percentage cover per stratum (moss and herb layers). Plots containing shrubs are also indicated. A l l sample plots are located on the Carnation Creek flood-plain within sites flooded during winter 30 4.3 Groupings of sample plots by surface soil characteristics (particle size and % weight loss during ashing). A l l sample plots located on the Carnation Creek flood-plain within sites flooded during winter 32 x i i i 4.4 Groupings of plots located on the Carnation Creek flood-plain by mean seasonal water-levels (summer and winter) relative to plot surface 34 4.5 Relative success by sample plot (total number of fish captured and % of sampling dates on which fish were captured) for: (1) "trout", top graph (2) coho, bottom graph 39 4.6 Monthly water level (relative to the surface) for mapping units representing: intermittent tributaries (1), ephemeral muck swamps (2 and 3), seepage sites (4), and flooded meadows (5 and 6) 40 5.1 Placement of a baited minnow (®"Gee") trap within an ephemeral muck swamp site 46 5.2 Equipment used to mark (cold brand) juvenile coho. Includes: 1) acetone and dry-ice coolant In yellow thermos, 2) silver tipped brand with wooden handle, 3) anesthetizing bucket, 4) measuring board 46 5.3 The relationship between number of juvenile coho (Oncorhynchus kisutch) and two area estimations: (1) total flooded area, top graph (2) coho winter habitat (habitat units 1 and 2), bottom graph 54 5.4 Coho (Oncorhynchus kisutch) smolt contribution from off-stream sites as a percentage of the watersheds total smolt production. The ephemeral component of the tributaries was not enumerated separately in 1982-83 55 x i v 5.5 Change i n juvenile coho (Oncorhynchus kisutch) population over a winter period within one ephemeral swamp (R750m) 57 5.6 Regression of j u v e n i l e coho (Oncorhynchus kisutch) population within one ephemeral swamp (R750m) over time. Actual population and population corrected by +40 f o r Jan 4/1984 freshet 58 5.7 The r e l a t i o n s h i p between number of j u v e n i l e " t r o u t " and two area estimations: (1) area designated as coho winter habitat (habitat u n i t s 1 + 2 ) , top graph, (2) area designated as trout winter h a b i t a t (habitat unit 1), bottom graph 61 6.1 Movement of ju v e n i l e coho (Oncorhynchus kisutch) between main-stream and off-stream s i t e s f o r 2 years. Number of coho represents the sum of three small fences 74 6.2 I n d i v i d u a l movement of coho juv e n i l e s (Oncorhynchus  kisutch) within an ephemeral s i t e (R750m) for 6 periods during winter 1983-84. Upstream movement i s indicated by p o s i t i v e values, downstream movement i s indicated by negative values 80 7.1 Possible reasons for increase i n mean population length of ju v e n i l e coho (Oncorhynchus kisutch) during winter within an ephemeral muck swamp (R750m): (1) s i z e dependent m o r t a l i t y and/or migration, top graph (2) growth of i n d i v i d u a l s , bottom graph 89 XV 7.2 Growth of i n d i v i d u a l l y marked juvenile coho (Oncorhynchus  kisu t c h ) and increase i n mean population fork-length within an ephemeral swamp (R750m) during the winter period (1983-84). Three growth periods can be noted: f a l l (Oct-Nov), mid-winter (Dec-Jan) and spring (Feb-May) 91 7.3 Juvenile coho (Oncorhynchus k i s u t c h ) mean population fork-lengths f o r three habitat types ( i n t e r m i t t e n t t r i b u t a r y , ephemeral muck swamp and main-stream) during the winter period (1983-84) 92 7.4 Juvenile coho (Oncorhynchus k i s u t c h ) mean population fork-lengths f o r three intermittent t r i b u t a r y s i t e s during the winter period (1983-84) 94 7.5 Juvenile coho (Oncorhynchus kis u t c h ) mean population fork-lengths for s i x ephemeral muck swamp s i t e s during the winter period (1983-84) 97 7.6 Juvenile coho (Oncorhynchus kis u t c h ) mean fork-lengths for two winter periods, 1982-83 and 1983-84, within an ephemeral muck swamp (R750m). Weekly mean water temperatures (recorded at B weir on main-stream) are i l l u s t r a t e d f o r each winter...98 1 CHAPTER 1. INTRODUCTION 1. The Problem British Columbia's coastal watersheds support both an abundant fishery and a productive forest industry. However, the terrestrial and aquatic components of a watershed are closely linked. The forest plays an important role in regulating hydrologic, trophic and biotic systems which ultimately govern fish production by altering quantity, quality and use of fish habitat. Thus forest land managers must be able to identify areas of potential conflict between forestry and fisheries resource options and have sufficient understanding of natural processes to solve these conficts as they arise. Forestry activities conducted on west coast alluvial flood-plains have the potential of altering juvenile salmonid over-wintering habitat associated with small ephemeral swamps and intermittent tributaries. This off-stream habitat has never been clearly defined or evaluated and winter behaviour of species occuping this habitat is poorly understood. A freshwater residence of at least one year is required for completion of the coho salmon (Oncorhynchus kisutch) l i f e cycle (Figure 1.1). In winter within the Carnation Creek watershed (Figure 1.2), coho juveniles occupy both main-stream habitat (side pools, undercut banks and debris piles) and off-stream habitat (ephemeral swamps and intermittent tributaries), (Bustard and Narver 1975a; Tschaplinski and Hartman 1983; Forward 1984). Seasonal movement of coho and use of winter off-stream habitat in other Pacific Northwestern watersheds, 2 F A L L S P R I N G Figure 1.1 A generalized l i f e cycle of the coho salmon (Oncorhynchus kisutch). Figure 1.2 Map of Carnation Creek watershed showing locations of: t r i b u t a r i e s , hydrographic weirs, f i s h counting fence and f l o o d - p l a i n . is also well documented (Seeksick 1970; Mason 1976; Peterson 1980; Cederholm and Scarlett 1982). Off-stream habitat may be used by juvenile coho as a refuge to avoid adverse conditions within the main-stream such as high discharge and large volumes of suspended sediment (Skeesick 1970). "Trout" (rainbow, Salmo gardener! and cuttroat, S^. clarki clarki) also inhabit some of the off-stream sites during the winter (Bustard and Narver 1975a; Tschaplinski and Hartman 1983). At present our ability to identify potential off-stream winter habitat is poor. No clear delineation between flooded lands and winter fish habitat or between summer rearing habitat and winter habitat has been made. These off-stream areas are often ephemeral, lacking standing water in summer but retaining adequate water levels in winter to support fish, thus summer surveys based solely on the presence of adequate water levels would f a i l to identify many potential winter rearing sites. The value of winter off-stream ponds, swamps and tributaries for coho production may be highly underestimated. The only comment on their importance is that of Cederholm and Scarlett (1982), who estimated that 10% of a given watershed's coho smolt production can arise from off-stream migrants. The possibility that off-stream habitat may provide an alternate winter survival strategy must also be considered. Information on coho and trout winter ecology and processes occurring within off-stream sites is scarce. The difficulty in 5 conducting winter studies (cold, frequent disruptive storms, short days) may account for the lack of available information. 2. The Purpose The purpose of this study is to provide information essential to management of off-stream habitat. In order to achieve this goal the following objectives were established. 1 ) Identify and describe a l l winter off-stream sites utilized by coho and trout within a given watershed. 2) Characterize these sites in terms of readily identifiable features. 3) Calculate the importance of these sites to coho as a percentage of the watershed's total coho smolt production 4) Examine aspects of salmonid winter ecology ( population dynamics, movement and growth) and assess the value of off-stream habitat as an alternative survival strategy. Before proper management of any habitat can take place, i t must first be identified. The characterization of flooded areas located on the Carnation Creek flood-plain utilizes botanic, pedologic and hydrologic parameters. The development of habitat unit descriptions is intended to provide a guide to recognition of potential coho and trout winter habitat. Before a decision to manage habitat can be made its importance to the species utilizing i t must be assessed. The importance of off-stream sites must be considered in terms not only of total smolt ' 6 production, but also in terms of its biological importance as an alternative survival strategy for over-wintering coho. Before off-stream habitat can be managed certain aspects of the winter ecology of the fish species using i t must be clear. Means of reducing forestry impacts as well as possible methods of enhancing salmonid production require knowledge of fish population dynamics, movement and growth. 3. Definitions The basic terms used to describe the relationships between components of the flood-plain and their hydrology are: 1) Flood-plain — defined as a valley bottom land form deposited by running water, which is at least occasionally inundated by water from the stream (Cordes 1972) 2) Flooded land — those areas of the flood-plain (not including the main stream channel) covered by water or containing numerous pockets of standing water during winter base flow. 3) Ephemeral — those sites (sloughs, swamps, temporary channels) containing standing water during winter base flow, but completely dry in summer. 4) Intermittent — those sites (generally 1st order tributaries) containing visibly flowing water a l l winter but only isolated pools during the driest summer month. The basic terms used to describe the relationship between salmonids and their habitat are: 7 1) Off-stream — those sites removed from the main-stream, includes a l l tributaries, swamps and flooded lands. 2) Potential Habitat — areas lacking coho but capable of supporting coho if access was provided. 3) Winter Period — Generally extends from late October to early May. It starts with the first f a l l storms (coho movement into off-stream sites) and ends when the ponds and swamps become dry (cessation of coho movement out of the off-stream sites). 8 CHAPTER 2. STUDY AREA Carnation Creek i s a small stream flowing into Barkley Sound on the west coast of Vancouver Island (Figure 1.2). The Carnation Creek  Watershed Pro j e c t was i n i t i a t e d i n 1970 to in v e s t i g a t e f o r e s t r y -f i s h e r i e s i n t e r a c t i o n s and stream processes. This project w i l l continue to u t i l i z e the watershed u n t i l at l e a s t 1985. Numerous de s c r i p t i o n s of t h i s project and the watershed have been given (Narver and Chamberlin 1976; Symons 1978; Hartman 1981; Hartman 1982). 1. P h y s i c a l Features Carnation Creek drains an area of 10 km^, has a t o t a l length of 7.8 km and an acc e s s i b l e length f o r anadromous f i s h of approximately 3.2 km (Scrivener 1982). The creek flows from east to west and i s flanked by steep north and south-facing slopes. The t e r r a i n i s gen e r a l l y rugged with a maximum e l e v a t i o n of 880 meters (Hetherington 1982). The area of i n t e r e s t f o r t h i s study i s the f l o o d - p l a i n located i n the lower h a l f of the watershed (Figure 2.1). The f l o o d — p l a i n forms a narrow s t r i p 3000 meters long, ranges from 50 meters to 300 meters wide, covers an area of approximately 50 ha (5% of t o t a l watershed) and i s bounded by steep slopes ( o f t e n greater than 60%) on eit h e r s i d e . I t drops 62 meters to sea l e v e l i n the lower 3.2 km and has an average slope of 1.9% (Scrivener and Brownlee 1982). CARNATION CREEK WATERSHED PACIFIC OCEAN # Coho off - stream site m m Flooded areas mapped \ / Hydrologic weir Flood - plain boundary Figure 2.1 Map of Carnation Creek flood-plain showing locations of: tributaries, hydrographic weirs, fish counting fence, flooded areas mapped and salmonid over-wintering sites. The flood-plain contains no terraces and during storm flow conditions is often flooded for much of its length. Numerous old channels exist throughout the valley bottom and these are often the first areas to receive storm flow from the main channel. Where these old channels border the toe of the valley walls, seepage water from up-slope positions can maintain adequate winter water levels to support over-wintering fish populations. A general description of Sitka spruce flood-plains similar to the Carnation Creek flood-plain can be found in Cordes (1972). 2. Soils The soils of Carnation Creek have been described by Oswald (1973). These coarse textured soils are of volcanic origin. The parent S material of soils found on the flood-plain however, are of recent alluvium overlying gravel deposits as much as 4 meters deep (Scrivener and Brownlee 1982). The old channel scars collect vertical accretion material (fines and fine sands carried by slow moving flood waters) which covers the coarse lateral accretion materials (coarse sands and gravels left in channel scar) during periods of active flooding (Happ 1940). The fine vertical accretions combined with organic materials often produce muck blankets as much as a meter deep. These materials are stabilized by semi-aquatic vegetation and organic soil types are representative of most of the small ephemeral swamps. 3. Climate The area has a mild, wet winter with frequent frontal storms producing rapid increases in stream flow. Slightly over 75% of the precipitation occurs from October to March (Hetherington 1982) and less then 5% of the precipitation is in the form of snow (Scrivener and Brownlee 1980). Total precipitation ranges from 230 cm to 380 cm annually. Annual water temperatures recorded at B weir (location Indicated in Figure 0.3) range from 1°C to 18°C (Hartman 1982). 4. Stream Discharge Stream discharge is closely correlated to precipitation and the stream is considered to be "flashy" in nature (Hetherington 1982). Minimum flows generally occur in July or August (lowest recorded flow 0.017 m-Vsec.) and the two highest recorded flows were in January (50 m^/sec on Jan 28/1982; 65 m^/sec on Jan 4/1984; Carnation Creek Working Group 1984). 5. Vegetation Before harvest the dominant vegetation consisted of a dense overstory of western hemlock (Tsuga heterophylla), balsam f i r (Abies  amabilis), and western red cedar (Thuja plicata). A few isolated Douglas f i r (Pseudotsuga menziesii) grew on the well drained southern slopes and Sitka spruce (Picea sitchensis) was sparsely scattered throughout the alluvial flood-plain. Red alder (Alnus rubra) and broad-leaved maple (Acer macrophyllum) could be found bordering the main-stream at various locations, especially in the lower sections. The vegetation prior to logging has been described by Oswald (1973). After harvest the majority of the flood-plain was planted with Sitka spruce and western red cedar. Natural regeneration of western hemlock and balsam f i r has occurred. The rapid growth of salmonberry (Rubus spectabilis) and red alder has created a serious forest regeneration problem over much of the flood-plain. The application of the herbicide glyphosate (©Roundup) during September 1984 should eliminate much of the brush competition. 6. Ecosystem Classification A general description of British Columbia's west coast has been given by Krajina (1969) using the biogeoclimatic approach. A detailed description of climate, vegetation and zonal soils is given by Klinka et a l . (1979). The lower elevations (below 150m) lie within the Estevan submontane, wetter maritime, coastal western hemlock, biogeoclimatic variant. The remainder of the watershed (above 150m) falls within the West Vancouver Island submontane, wetter maritime, coastal western hemlock, biogeoclimatic variant. 13 7. Fisheries Resource From 1970 to 1982 Carnation Creek has supported an annual mean run of 2014 chum salmon (Oncorhynchus keta) and 251 coho salmon (0_. kisutch). Anadromous trout are few in number (less than 20 per year) and include both steelhead trout (Salmo gairdneri) and sea-run cuttroat trout (S_. clarki clarki). The occasional pink (Cj. gorbuscha), sockeye (0. nerka) and chinook (0_. tshawytscha) have been observed, but they are not present most years (Andersen 1983; Andersen 1984). The distribution of resident trout within the lower 3.2 km is very uneven. Trout account for 40-50% of the fish population in the upper 1200 meters and only 4-6% in the lower 2000 meters (Andersen 1983). Calculations made using 1982 data from a Carnation Creek report (Andersen 1984) indicate the late summer salmonid population consisted of 7557 coho juveniles, 1456 rainbow trout, and 205 cuttroat trout. Two sculpin species also inhabit the stream, prickly sculpin (Cottus  asper) and Aleutian sculpin (C_. aleuticus) (Ringstad 1974). 8. Logging Operations Road construction within the Carnation Creek watershed took place from 1974 to 1978 with 22 km of road being constructed during the winter months (MacMillan Bloedel Limited 1979). From 1975 to 1981, 388 ha (41%) of the watershed was clearcut in 12 settings (Dryburg 1982). Harvesting was conducted from September to May and total volume within the settings ranged from 438 mJ/ha to 1098 mJ/ha (MacMillan Bloedel Limited 1979). Yarding was done by mobile high lead spar or by grapple yarder. Approximately 25% of the volume removed was by direct loading from the road right-of-ways (Dryburg 1982). To date, a l l trees on the flood-plain have been harvested, but no roads were constructed on the flood-plain. No special consideration such as leave-strips were given to any of the off-stream sites examined in this study. Although much of the watershed was treated by broadcast burning, the alluvial flats received patchy burns due mainly to their continually high moisture status. A l l off-stream sites examined during this study were harvested between March 1976 and March 1979. 9. Study Area Choice Carnation Creek was chosen as a site for investigation of off-stream winter habitat for several reasons. First, experiments conducted within the Carnation Creek watershed can utilize facilities, equipment and support staff not readily available on other streams. Second, a long history of biological and physical data collection (14 years), including before harvest information, aids in interpretation of data obtained for this thesis. Third, Carnation creek has a sizeable flood-plain and is subjected to extreme flooding in response to winter storms. Fourth, utilization of off-stream sites by over-wintering salmonids has been documented by others (Bustard and Narver 1975a; Tschaplinski and Hartman 1983). CHAPTER 3. GENERAL FEATURES OF OVER-WINTERING SITES 1. Method of Site Selection During the months of November and December, 1982 the Carnation Creek flood-plain was examined in detail. A l l areas of flooded land were noted and limits of standing water were marked with survey tape. Six distinct flooded areas were marked and these were surveyed during the summer of 1983 using a 5 meter grid pattern. Maps of a l l 6 flooded areas were constructed using a 1:500 scale (see Appendix 1). From December to January 1982-1983, a l l flooded lands were examined for trout and juvenile coho presence. A series of 10 to 25 minnow ®"Gee" traps (see methods Chapter 5) were placed within each of the six flooded areas. If no fish were obtained after completion of three over-night trapping series the area was designated as non-habitat. If fish were obtained, the traps were moved to new locations within that area until the geographical limits of coho distribution were established. Based on fish presence and obvious natural physical features within the six flooded areas examined, 9 off-stream over-wintering sites and 2 non-habitat sites were delineated. Each of these sites was examined for general topographic and hydrologic characteristics. These sites are named on the basis of the following system. A symbol L or R indicates on which side of the creek the off-stream site can be found (left or right looking downstream). A number represents the distance in meters from the mouth of Carnation Creek (mean summer high-tide mark) to the confluence of a given site's outlet with the main-stream. A descriptive term may be added to clarify location of sites within the two tributaries. Thus, LI600m upper would indicate an off-stream site located on the left side of the creek, within the upper section of a tributary system, whose confluence with the main-stream is 1600 meters upstream from the creek's mouth. 2. Site Description The total area of land flooded during winter base flow (six areas mapped see Figure 2.1) was 12,807 m^ , while the area of the sites supporting salmonids was 9,845 m^  (Table 3.1). These values can not be directly equated to wetted area as raised mounds (hummocks) exist throughout the flooded lands. A l l discharge levels given in Table 3.1 are rough estimates of discharge recorded at a hydrologic weir located at approximately 350m (B weir). One flooded area (R250m) does not support a salmonid population. Fish access is restricted to periods of extreme flooding (>35 m^/sec at B weir). This area did flood during both winters of study, but only after coho winter distribution was established. Water levels within the R250m area respond very quickly to climatic conditions. During January 1984 only a few isolated shallow pools covered with thick ice remained. This is the first area to go completely dry in Feburary, well before coho out migration begins. If fish were present within this area i t is doubtful they could survive. Table 3.1 Description of flooded areas and over-wintering sites associated with the Carnation Creek flood-plain, (all flooding levels are estimates of discharge at "B weir") Flooded area Over-wintering site Description of formation Description of hydrologic characteristics R250m (1999m2) R750m ( 976m2) L1250-1550m (4107m2) R250m (1999m2) (non-habitat) R750m ( 976m2) LI400m ( 963m2) (non-habitat) LI 250m (1693m2) L1550m (1451m2) An ephemeral swamp, formed in a depression perched above the main-stream water-table. Located within a small basin bordered N. and E. by valley walls. Ephemeral swamp formed in an old channel, parallels a valley wall for its entire length. Series of ephemeral swamps and pools formed in old channel which parallels valley wall. The two sites are separated by a slightly higher section containing numerous small stagnant pools. Small ephemeral pools formed within an old channel. Ephemeral swamp bordering main-stream and a valley wall, formed within an old channel. Floods from main-stream at >35 m^/sec. Good seepage from upland slopes but no notable outlet. Area subject to early desiccation in spring and low water levels during periods of winter freezing. Floods through numerous old channel scars at >7m^ /sec. Only one major source of upland seepage. Confluence is perched and requires >7m3/sec. for access. Entire area connected and flowing at >18m3/ sec. Numerous small seepages from valley wall. Both sites have separate outlets to main-stream. Diffuse outlet may not permit access until >llm^/sec. Two deep pools contain stagnant water even in summer. Site floods at >9m^ /sec. and is in direct path of flood water. Good outlet. Table 3.1 continued Flooded Area Over-wintering Site L1600m (1960m2) L1600m lower (1144m2) LI600m upper ( 816m2) Rl500m R1500m ( 502m2) ( 502m2) R2600m R2600m lower (3272m2) (1688m2) Description of Formation A first order tributary, has a definable channel for most of its length. Borders a valley wall. Intermittent tributary in lower 350 meters of tributary course. Borders valley wall. Ephemeral tributary, in upper 150 meters of tributary course, bordering valley wall. Surface covered with thick layer of logging slash for much of length. Small ephemeral swamps formed within two separate old channel scars. Both parallel the valley wall. One channel is fairly recent and has gravel bottom for much of its length. Intermittent tributary associated with valley wall for its entire course. Channel indistinct in areas of deep muck soils where the main channel diffuses into a network of small channels. Description of Hydrologic Characteristics Tributary can be divided into two sites on the basis of differences in summer water levels. Contains isolated pools or flowing water at mouth for entire summer. Totally dry in summer, with numerous small seepages in winter. Receives flood waters from both main-stream and from "C weir tributary" at flows >20m3/sec. Totally dry in summer. Floods at low flows <6m^ /sec, receives high velocity flood waters and provides the least protection for over-wintering coho of a l l the sites. Outlet periodic during the winter. Flows at confluence a l l summer but various sections lack surface flow. No visual observation of flooding level was made (not observed but estimated at 23m^/sec). Table 3.1 continued Flooded Area Over-wintering Description of Site Formation R2600m upper Intermittent tributary forms in ( 777m2) canyon and flows onto the flood-plain. R2600m ponds Series of small ponds formed ( 807m2) in a depression within an old abandoned channel. Site flat with no relationship to valley walls. 12,807 m2 9,845 m2(habitat only) Description of Hydrologic Characteristics Continuous flow throughout the the year. Only part of this site can flood from main-stream. No upland seepage, depression may reeleve ground water from tributary. Floods from tributary at >7m3/sec and floods from the main-stream at an estimated level of >23m^ /sec (flooding never observed as unable to enter area under flooding conditions). 3. Discussion (a) Common Features Three sites were considered to be intermittent tributaries and six sites were named ephemeral swamps. Eight of the nine sites closely paralleled the valley walls for the majority of their length and seepage from upland surfaces was a major contributor to winter water levels. The majority of ephemeral swamp sites (5/6) were formed within abandoned main-stream channels. Access to a l l sites supporting over-wintering juvenile salmonids was available at flows of less then 11 m^ /sec (at B weir). Semi-aquatic vegetation was common to a l l flooded areas. A visual comparison of winter flooded land to surrounding higher land indicates an obvious lack of shrubs and trees rooted within the wet areas. Surface substrate within the ephemeral swamps consists of blankets or veneers of muck, overlying gravel left within the abandoned channels. Within the intermittent tributaries exposed sand and gravel surfaces dominated. (b) Surface Area The flood-plain covers an area of approximately 50 ha of which 3.0 ha is main channel (estimate of bankfull from Andersen 1984). The off-stream area flooded during winter base flow (estimate from area maps, see Appendix 1) is 1.3 ha. Only 0.98 ha of this off-stream 2 1 flooded land is inhabited by salmonid juveniles during the winter months. (c) Evolution of Off-Stream Sites Descriptions of fluvial processes have been written by several authors (Happ et al. 1940; Wolman and Leopold 1957) and the nature of flooding on a flood-plain has been modelled by Lewis and Hughes (1978). A good description of general processes occurring on west coast Sitka spruce alluvial flood-plains, similar to that of Carnation Creek's flood-plain, was written by Cordes (1972). The possible evolution of off-stream ephemeral swamp sites, as hypothesized in Figure 3.1, is based upon processes described by these authors and through consideration of features common to the sites observed during the course of this study. Lateral accretion and course channel material left within the abandoned channels is covered by fine vertical accretions deposited from the flood waters and fines displaced from the valley walls. Growth of semi-aquatic vegetation stabilizes the fines and permits accumulation of a blanket of muck soil. Depending on flooding characteristics and the relationship to upslope seepage, scour over time may create narrow deep channels within the muck blankets. These sites could eventually f i l l in and support tree growth or scour to the original sand and gravel stream bed left within the abandoned channels. a) within an abandoned channel, deposited vertical accretions are held by plants b) a muck pool holds water and supports over-wintering salmonids c) a deep narrow channel forms within a muck blanket (good habitat) d) shrub and tree growth or possible sedge meadow after f i l l - i n . Figure 3.1 Possible succession of coho (Oncorhynchus kisutch) off-stream ephemeral over-wintering habitat on an alluvial flood-plain. CHAPTER 4. SALMONID HABITAT CHARACTERIZATION 1. Methods (a) Theory Forty sample plots were established within the six flooded areas located on the Carnation Creek flood—plain. Each plot was 10 m2 (2 x 5 meters) and was placed within an area uniform in vegetative and surface characteristics. Plots were selected to represent a potential map unit; thus, their location was not chosen randomly. A l l plots were examined for debris, vegetation, surface characteristics, depth to water table and presence of fish (Appendix 2). Plots were analyzed for each biotic or environmental feature and those plots considered to have similar features were arranged into groups (discriminant analysis). Summarizing these groupings of plots for a l l distinctive features a set of map units was obtained. Those features characteristic of a given map unit were used both to name and describe that unit and also to delineate i t . Maps of a l l off-stream winter flooded land were prepared based on the map units established (Appendix 1). Once map units were established, they were grouped for potential management use into habitat units. This interpretive classification was based on the presence of trout and coho within the forty plots. Characteristics common to these units can be used to describe and identify off-stream salmonid habitat. (b) Vegetative Features The vegetation data taken for each plot includes a species l i s t and an estimation of the species significance (cover-abundance scale, Mueller-Dombois and Ellenberg 1974, p62). The percentage cover for each stratum (vertical layering) was also recorded. The field methods, including detailed listings of descriptive criteria are given in "Describing Ecosystems in the Field" (Walmsley e£ al. 1980) and the methods of analysis are described in "Aims and Methods of Vegetation Ecology" (Mueller-Dombois and Ellenberg 1974). A program to execute tabular comparison, "VTab" (Emanuel and Wong 1983) and an ordination program "Ordiflex" (Gauch 1977) were used to aid in establishing plant associations. Plant species characteristic of each plant association were identified using criteria established by Inselberg et al . (1982). No attempt was made to classify these early successional associations (5-10 years after harvest) within the existing ecological classification system used by the Ministry Forest, Vancouver Forest Region (Klinka et al . 1980; Inselberg et al. 1982) (c) Surface Features For each of the forty plots, five randomly selected subsamples of the top 10 cm. of soil were pooled into one composite sample. This composite sample was then fractionated into size classes (USDA soil particle size classification) by dry sieving (Lavkulich 1977, pl78). The percentage of organic material for each size class was obtained by ashing the soil samples. A slight modification to the method described in Lavkulich (1977) includes the gradual raising and lowering of furnace temperature from room temperature to 480 °C over a 12 hour period instead of placing the samples into a pre-heated oven for 1 hour at 300 °C and 4 hours at 480 °C. (d) Water Table Depth Water table wells were used to obtain a measure of water table depth relative to the surface of the plot. Water levels were recorded during the last week of every month for 14 months. At least 3 days without appreciable rain was required before measurements could be taken. This requirement delayed the May (1984) measurements until June 3. Water table wells were placed in the plots to best represent the average water table depth of the entire plot. Although the majority of plots were level, the few plots that were micromounded had a slight variation in water level over their surface. (e) Fish Presence and Abundance The presence and abundance of two fish groups, coho and trout (species differentiation of any live trout less then 80 mm in length was not reliable) were recorded for each of the forty plots on ten separate sampling dates. Eight of the sampling dates represented the winter period while the other two represented the summer period (summer sampling was confined to the intermittent tributaries). In those instances where a trap was not placed directly within a plot, the trap nearest to the plot and s t i l l within the same map unit, was treated as being representative of that plot. 2. Results (a) Vegetative Features (i) Plant Associations Four plant species groupings (plant associations) were identified using both reciprocal averaging ordination (Figure 4.1) and tabular comparison (Appendix 2). The characteristic species (plant species whose distribution is exclusively, selectively or preferentially associated with a given grouping) and constant species (plant species dominant within a given grouping but also dominant in a l l or nearly a l l other groupings) for these plant associations are listed in Table 4.1. ( i i ) Vertical Spacing (Strata) The percentage cover by stratum was estimated for each of the 40 plots. The strata categories (vertical spacing of vegetation) were similar to those indicated by Walmsley et^ al^. (1980). These include: 1. Trees (A1,A2,A3 strata), 2. Tall shrubs (Bl stratum) woody plants 2-10 meters in height, 3. Low shrubs (B2 stratum) woody plants <2 meters in height, 4. Herbs (C stratum) herbaceous species, 5. Mosses (D stratum). Figure 4.1 Plant associations i d e n t i f i e d by r e c i p r o c a l averaging o r d i n a t i o n using " O r d i f l e x " (Gauch 1977). A l l sample p l o t s are located on the Carnation Creek f l o o d - p l a i n w i t h i n winter flooded lands. 28 Table 4.1 Characteristic combinations of plant species, for plant associations located within winter flooded land, on the Carnation Creek flood-plain, 5-10 years after harvest. Group Temporary Name Characteristic Species Constant Species Group 1. Rush Scirpus microcarpus  Juncus ensifolius  Lecidea sp. Lysichiton americanum  Oenanthe sarmentosa  Epilobium (ciliaturn?) Group 2. Seepage Group 3. Grass-meadow Lecidea sp. Scirpus microcarpus  Sphagnum sp. Agrostis stolonifera  Maianthemum dilatatum  Aira sp. Rubus spectabilis  Polytrichum juniperinum  Juncus effusus  Anaphalis margaritacea  Blechnum spicant Sphagnum sp. Agrostis stolonifera  Viola palustris  Maianthemum dilatatum  Aira sp. Rubus spectabilis  Polytrichum juniperinum Athyrium filix-femina  Lysichiton americanum  Oenanthe sarmentosa  Epilobium (ciliatum?) Athyrium filix-femina  Lysichiton americanum  Oenanthe sarmentosa  Epilobium (ciliatum?) Group 4. Sedge-meadow Galium triflorum Athyrium filix-femina  Lysichiton americanum Carex obnupta  Fontinalis antipyretica Oenanthe sarmentosa Epilobium (ciliatum?) No vegetation greater than 10 meters in height (A stratum) was recorded on any of the plots and no plot had greater than 5% total shrubs (Bl + B2). The majority of vegetation was in the C and D strata (Figure 4.2). Four groupings of plots based on vertical spacing of the plant communities were identified (Table 4.2). Table 4.2 Grouping of plant communities, within winter flooded land located on the Carnation Creek flood-plain, 5-10 years after harvest, based on vertical spacing of the vegetation. Grouping Temporary Name Features Characteristic of Group Group 1. Bare <25% C and <10% D Group 2. Herbs >70% C and <10% D Group 3. Herbs and Moss >70% C and >10% D Group 4. Shrubs Present 25-70% C and >5% D and >1% B (b) Surface Features (i) Woody Debris A l l locations within the off-stream areas covered by more then 90% woody debris were mapped as a single entity (Table 4.3, woody debris). No plots were established and no further analysis was performed on this map unit. Piles of woody debris may in fact overlie each of the other map units, but recognition of these map units was impossible. No attempt was made to relate fish presence or abundance to off-stream woody debris. •30 100 80 E "5 a m 4) vt V) O i . V > o u 40 o s g e n d Shrubs pi •esenf 5) ® GR OUP 3 GROUP 4 D © 11 9) ®4iU 28 GROUP 32 (25) , 20 31 ZTZ6 18 19 3433 — , ^ GROUP 2 02 01 24 , 017 @ 1 6 20 40 60 80 100 % Cover Herbs (C Stratum) Figure 4.2 Groupings of sample plots by percentage cover per stratum (moss and herb la y e r s ) . Plots containing shrubs are also indicated. A l l sample plots are located on the Carnation Creek f l o o d - p l a i n within s i t e s flooded during winter. Woody debris, consisting mainly of intermediate sized material (limbs, bark and broken logs), accumulated at the base of the valley walls during yarding operations. This debris aggregated into piles, dependent upon the site's flooding characteristics. A l l plots chosen to represent the other map units were covered by less than 70% woody debris. Table 4.3 Grouping of plots within winter flooded land located on the Carnation Creek flood-plain, 5-10 years after harvest, based on percentage of surface covered by woody debris. Grouping Temporary Name Features Characteristic of Group Group 1. Exposed <90% Woody Debris Group 2. Woody Debris >90% Woody Debris (i i ) Surface Soil The 40 plots were divided into two groups (Figure 4.3) based on percent organic material and percent of soil sample smaller than fine sand (0.25 mm in diameter). A l l plots representing group 1 (Table 4.4) were located within the three intermittent tributary sites and were subjected to high discharge during winter. Organic and small inorganic soil particles were washed out of these plots leaving only coarse sands and gravels low in organic material. Thirty of thirty-four group 2 surface samples (Table 4.4), were classified as organic soils ( > 30% organic by weight, Canada Soil % Organic by weight Figure 4.3 Groupings of sample plots by surface soil characteristics (particle size and % weight loss during ashing). A l l sample plots located on the Carnation Creek flood-plain within sites flooded during winter. Survey Committee 1978). Only four plots had < 30% organic material by weight. One of these plots was partially scoured to clay and three of the plots had received fresh vertical accretions which covered the original organic substrate (high % fine sands, low % organic). Table 4.4 Grouping of plots, within winter flooded land located on the Carnation Creek flood-plain, 5-10 years after harvest, based on two soil features (% organic and % of particles <.25 mm.) Grouping Temporary Name Features Characteristic of Group Group 1. Gravel <5% Organic, <10% of Soil Particles smaller than 0.25 mm. Group 2. Muck >5% Organic, >10% of Soil Particles smaller than 0.25 mm. (c) Water Levels Four groupings of plots were identified based on differences In summer (June-Sept) and winter (Oct-March) mean water levels (Figure 4.4 and Table 4.5). Two of the groupings correspond to plots which maintained constant seasonal water levels ( < 10 cm change from winter to summer). These two groupings could be separated based on their relative height of standing water. If mean summer water level was maintained above 8 cm, the plot was considered to be constantly flooded. If mean winter water level was less than 8 cm, the plot was considered to represent a seepage site. The remaining two groupings correspond to plots which have variable seasonal water levels ( > 10 cm change from winter to summer). 34 E . o . 9) > 0) 1 -60 -40 -20 0 Summer Water-level (cm) 40 Figure 4.4 Groupings of p l o t s located on the Carnation Creek f l o o d - p l a i n by mean seasonal water-levels (summer and winter) r e l a t i v e to plot surface. 35 These plots tended to be flooded in winter and dry in summer. The two groupings could be distinguished based on their relative summer water levels. If mean summer water level f e l l below -25 cm, the plot was considered representative of a flooded-meadow. If mean summer water level was maintained above -25 cm the plot was considered representative of a muck-swamp. Table 4.5 Grouping of plots within winter flooded land located on the Carnation Creek flood-plain, 5-10 years after harvest, based on mean summer and winter water levels. Grouping Temporary Name Characteristic Water Levels Group 1. Flooded-meadows >10 cm seasonal change, summer water levels <-25 cm. Group 2. Muck-swamps >10 cm seasonal change, summer water levels >-25 cm. Group 3. Constant-seepage <10 cm seasonal change, water levels f a l l below 8 cm. Group 4. Exposed gravel <10 cm seasonal change, water levels remain above 8 cm. (d) Map Units A summary of the various plot groupings (discriminant analysis based on a l l environmental and biotic factors) permitted recognition of seven distinct map units (Table 4.6). Each of these map units was described (Table 4.7) and identified (see maps Appendix 1) by utilizing the characteristics unique to each plot grouping best representing that Table 4.6 Summary of discriminant groupings used to delineate map units located within winter flooded land on the Carnation Creek flood-plain. Map unit Discriminative Factor Grouping Plant association Veg. Stratum Debris Soil Water level Unit 1. 1. 1. 1. 1. 4. Unit 2. 1. 1. 1. 2. 2. Unit 3. 1. 2. 1. 2. 2. Unit 4. 2. 4. 1. 2. 3. Unit 5. 3. 4. 1. 2. 1. Unit 6. 4. 3. 1. 2. 1. Unit 7. - 2. - -Table 4.7 Map unit Description of map units located within winter flooded land on the Carnation Creek flood-plain. Plant constants include: Lysichiton americanum, Oenanthe sarmentosa, and Epilobium sp. Name Description Unit 1. Exposed gravel Vegetation covers <25% of surface, dominated by Oenanthe sarmentosa and isolated Scirpus  microcarpus. Surface consists of gravels and coarse sands washed clean of fine organic material. Water levels are constant throughout the year and standing water is always present. Unit 2. Exposed muck Vegetation covers <25% of surface, dominated by Oenanthe sarmentosa, Zannichellia  palustris and isolated Scirpus microcarpus. Surface consists of an organic muck blanket. Water levels are seasonally variable but are always within 25 cm of the surface, thus through capillary rise the surface may appear wet even in summer. 37 Unit 3. Bullrush-cattail Vegetation covers >70% of surface, dominated by thick beds of Scirpus microcarpus and Juncus ensifolius. Other species often present include Lecidea sp., Typha latifolia and Scutellaria lateriflora. Shrub and moss layers absent or poorly developed. Water levels similar to map unit 2. Unit 4. Juncus-seepage Vegetation covers 25-70% of surface and as the surface may be micromounded considerable variation in water levels and plant species may result. Plant species such as Juncus  effusus, Maianthemum dilatatum, Agrostis  stolonifera, Anaphalis margaritacea and Blechnum spicant dominate while the wettest pockets may contain isolated Scirpus  microcarpus and the driest mounds may support growth of Rubus spectabilis. Sphagnum sp. Is always present. Water levels are constantly at or near the surface. Unit 5. Sedge-meadow Surface covered by thick beds (>70%) of Carex obnupta and the moss Fontinalis antipyretica. Galium triflorum and Athyrium filix-femina may be present. Water levels are highly variable, sites are often flooded to depths >40 cm in winter and dry (<-60 cm) in summer. Surface soil is organic muck. Unit 6. Grass-meadow Surface covered (25-70%) by grasses (Aira sp. and Agrostis stolonifera) herbs, (Maianthemum  dilatatum and Viola palustris) mosses, Sphagnum sp. and Polytrichum juniperinum) and by isolated shrubs (Rubus spectabilis). Water levels and soil similar to map unit 5. Unit 7. Woody debris Surface covered by >90% woody debris. This map unit may overlie a l l other mapping units preventing their delineation. 38 map unit. No single environmental or biotic feature could be used to distinguish a l l seven map units. (e) Habitat Units The map units described above were further grouped into habitat units based on their ability to support over-wintering coho and trout. Map unit 1 was ascertained to be trout habitat (Figure 4.5 top), while map units 1, 2 and 3 consistently supported over-wintering coho and were therefore considered to be important as coho habitat (Figure 4.5 bottom). These three map units maintained the most constant and deepest water levels over the winter period (Figure 4.6). Although coho were trapped in map units 6 (2/6 plots) and 5 (1/6 plots), the catch was sparse and these map units were considered non-habitat. Map units 5 and 6 were subject to both an early spring and a mid-winter drop in water level (Figure 4.6). The mid-winter drop in water level may have been the result of freezing. Map unit 4 never maintained water levels adequate to support over-wintering fish. Coho were captured within map unit 1 during September (5/6 plots); thus, map unit 1 must be considered as coho summer habitat as well as winter habitat. This map unit maintained a constant water level throughout the year, but lacked a visible flow during much of the summer. The three habitat units identified were described based on the characteristics of the map units of which they were composed (Table 4.8). MAP UNITS REPRESENTING TROUT HABITAT 10-1 3 . o ,k_ 0) E 3 2 40 60 Trapping Success (%) 80 100 MAP UNITS REPRESENTING COHO HABITAT 30-| O • • •• o • o • • 20 40 60 80 Trapping Success (%) Legend • Map Unit 1. O Map Unit 2. • Map Unit 3. + Map Unit 4. A Map Unit 5. V Map Unit 6. 100 Figure 4 . 5 Relative success by sample pl o t ( t o t a l number of f i s h captured and % of sampling dates on which f i s h were captured) f o r : ( 1 ) "trout", top graph ( 2 ) coho, bottom graph. 40 40-30-IHT. TRIBUTARIES 20-E « > <X) cr 10--10-Z - 2 0 -> HI _i v. -30 H I -40--50-U E A 0 O W S A-Legend • M A P UNIT 1 O M A P J J N I T S 2 j 3 X M A P UNIT 4 A M A P U N I T S 5 , 6 "A -60; * V ^ 0# ^ ^ & iS* ^ & ^ ° 4* 1982 Months 1983 Figure 4.6 Monthly water level (relative to the surface) for mapping units representing: intermittent tributaries (1), ephemeral muck swamps (2 and 3), seepage sites (4), and flooded meadows (5 and 6). Table 4.8. Description of salmonid habitat units located on the Carnation Creek flood-plain. Name Description Habitat Unit Unit 1. Intermittent tributaries (coho and trout winter and summer habitat) Unit 2. Ephemeral swamps (coho winter habitat) Unit 3. Seepage sites and flooded meadows (non-habitat) Described by map unit 1. Subject to winter water velocities capable of scouring away fine materials and rooted vegetation. Surface consists of exposed gravel and sand. Supports both coho and trout for the entire year. Described by map unit 2 and 3. Summer water levels are near the surface (>-25 cm) and winter water level is adequate to support juvenile coho. Trout do not utilize this habitat. Surface consists of an organic muck blanket* Plants characteristic of this unit include Scirpus  microcarpus, Juncus ensifolius and Zannichellia palustris. Shrubs and mosses are generally absent. Described by map unit 4, 5 and 6. Although water levels are highly variable these map units lack a water level adequate to maintain a fish population over the winter period. Coho may move across this unit during winter floods. Surface consists of an organic muck layer similar to habitat unit 2. Vegetation tends towards sedges, grasses and isolated shrubs. A well developed moss layer may be present. 3. Discussion One of the objectives of this study was to characterize coho and trout off-stream winter habitat within the early successional eco-systems located on the Carnation Creek flood-plain. The flooded lands were described and mapped based on easily recognizable environmental and biotic factors. Seven map units were delineated and no single environmental or biotic factor is unique in each of the seven units. A combination of factors must be used to identify a given mapping unit. Three habitat units were established on the ability of the mapping units to support over-wintering salmonids. The development of habitat units should assist watershed managers in differentiating salmonid habitat from flooded non-habitat during the winter and in recognizing potential salmonid habitat during summer when most sites are dry. Trout did not utilize a l l habitat occupied by coho. Trout inhabited intermittent tributaries (habitat unit 1), while coho occupied both intermittent tributaries and ephemeral swamps (habitat unit 1 and 2). The natural successional trend for the flood-plain should end with the development of a climatic climax western hemlock and western red cedar forest (Klinka e_t al_. 1979). The flood-plain has been planted with western red cedar, western hemlock and Sitka spruce (Cameron Division, MacMillan Bloedel Limited 1979), but will never reach a climatic climax state before the next harvest. The small ephemeral swamps and intermittent tributaries located on the flood-plain may represent an edaphic climax as some sites existed in a similar condition prior to harvest (Bustard and Narver 1975a; Tshaplinski and Hartman 1982). Caution in applying the habitat and map units developed for the Carnation Creek watershed to other watersheds and other successional stages must be emphasized. Few west coast streams have as extensive a flood-plain and as the watershed lacks major storage elements (lakes and ponds), the flooding characteristics of Carnation Creek might not apply to other systems. Although ephemeral swamps and tributaries may be considered an edaphic climax stage, harvesting has eliminated the canopy and altered water levels on the flood-plain (Hetherington 1982; Hartman and Holtby 1982) and this should alter the presence, vigour and significance of the plant species forming the various plant associations. CHAPTER 5. SALMONID WINTER POPULATION DYNAMICS 1. Methods (a) Population Size (i) Differentiation of Species Three species of juvenile salmonid over-winter within the Carnation Creek watershed; coho salmon (Oncorhynchus kisutch), rainbow or steelhead trout (Salmo gairdneri) and coastal cuttroat trout (Salmo  clarki clarki). It Is difficult to differentiate the two trout species, especially the smaller individuals (less than 80mm). For this reason both trout species were treated as one and were termed "trout". Main-stream enumeration conducted by Andersen (1984) indicated that rainbow trout consituted 88% of the total trout population, however this may not be valid for the minor tributaries (i i ) Method of Estimation Estimates of coho population size within a l l off-stream sites (see Appendix 3) were obtained using a mark-recapture method. The formula (Begon 1979) used to estimate the population size was: N = r (n + 1) / (m + 1) (1) where N is the estimate of population size, r is the number of marks at risk, n is the total number of juveniles captured and m is the total number of marks recovered. This estimate has been named the "simple Peterson estimate" and uses "Bailey's correction" to give a less biased estimate (Begon 1979). The standard error of the estimate was obtained using the following formula: where SEJJ is the standard error of the estimate of N and a l l other variables are similar to those used in formula (1). The method used for both i n i t i a l capture and recapture was by minnow ®"Gee" traps (Figure 5.1). Each trap was baited with a spoonful of canned herring contained within a perforated plastic sandwich bag and left for 24 hrs to attract fish. A l l traps were placed with openings parallel to the direction of any apparent flow and required a depth of 8 cm before openings were accessible. Traps were scattered throughout the sites independent of cover or substrate types and a trapping density of greater than 1 trap/25 m2 of water surface was maintained. Coho were marked (Figure 5.2) using a cold branding technique (Everest and Edmondson 1967). Four methods of capture are available for estimating salmonid populations: baited traps, netting, electrofishing and recovery at small fences during the downstream migration. Capture by any method other than baited traps is almost impossible during winter. Some of (2) ( i i i ) Comparison of Trapping with Other Methods Figure 5.1 Placement of a baited minnow trap (®"Gee") within an ephemeral muck swamp s i t e . Figure 5.2 Equipment used to mark (cold brand) juvenile coho. Includes: 1) acetone and dry-Ice coolant i n yeLlow thermos, 2) s i l v e r tipped brand with wooden handle, 3) anesthetizing bucket, 4) measuring board. the reasons why the other methods are not usable include: 1) large area to enumerate in a short time, 2) large volume of woody debris within sites, 3) frequent storms and flooding, 4) poor visibility due to aquatic vegetation, 5) low conductivity of water and 6) shortage of man-power. When using mark-recapture as a means of estimating the population i t is advisable to use two different techniques, the first for the i n i t i a l capture, the second for the recapture. This was impossible under the conditions mentioned above. A comparison of population estimates obtained by use of baited traps with estimates obtained by electrofishing (Table 5.1) indicated the two methods did not significantly differ (paired t-test, P > 0.5). Electrofishing locations were not selected at random. These locations represent the only areas capable of being reasonably estimated. A comparison of population estimates obtained by use of baited traps with estimates obtained by recapture of coho juveniles at the small fences (Table 5.1) indicated the two methods did not differ significantly (paired t-test, P < .20)1, however a trend towards higher estimates from the small fences is noted. The slightly higher estimates obtained by the small fences was not surprising. The number of marks recorded depended upon the technicians ability to read and recognize marked coho (marks not recorded would increase the population 1 Where .10 >P< .20 then P will be indicated by P < .20 and where .05 >P< .10 then P will be indicated by P < .10. The null hypothesis will only be rejected i f P < .05, but if P < .20 the results will be examined. estimate). Estimates made at the small fences required a longer time period between marking and recapture. The number of marks at r i s k declined as unmarked f i s h from the main-stream replaced marked f i s h and poorly marked brands became unreadable with time. Table 5.1 Comparison of baited trapping (®"Gee" traps) estimates with estimates from electrofishing and recovery at small fences (Peterson mark/recapture) Site 3 (r) (n) Trapping <*) (h (SEN) Electroshocking (n) (m) (N) (SE«j) L1600m lower (100m) 45 37 15 107 20 31 20 69 9 L1250m (total) 53 50 25 104 14 26 15 89 14 R2600 ponds (total) 35 23 16 49 6 13 7 61 13 L1600m upper (150m) 32 26 14 58 10 21 10 64 13 TOTAL 165 136 70 318 26 91 52 286 25 Site b (r) (n) Trapping (m) (N) (SEN) (n) Small (m) fences (N) (SEN) R750m total 1983 102 59 25 235 34 44 15 287 56 L1600m total 1983 107 92 21 452 82 68 16 434 89 R2600m total 1983 117 129 32 461 68 94 24 445 75 TOTAL 1983 326 280 98 1148 75 206 55 1166 136 Site c (r) (n) Trapping (m) (N) (SEN) (n) Small (m) fences (N) (SEu) R750m total 1984 111 101 50 222 22 92 45 224 23 L1600m total 1984 192 171 80 408 33 66 23 536 86 R2600m total 1984 217 162 82 426 49 83 35 506 63 TOTAL 1984 520 434 212 1056 52 241 103 1266 89 a marks placed March 2-3/1984, recovered March 10-14/1984. b marks placed Feb/1983, recovered Feb-March/1983. c marks placed March/1984, recovered March-May/1984. (b) Contribution to T o t a l Smolt Run The Carnation Creek working group operated a downstream fence ( L i l l and Sookachoff 1974) from March to September. During this period a l l emigrating juvenile coho (smolts) were captured at the downstream fence and were enumerated. A l l coho were examined for marks placed on them within the off-stream sites. The following formula was used to calculate the contribution of each off-stream site to the watershed's total coho smolt production: C% - [(m2 (n x / m i ) ) / N2] x 100 (3) where C% is the percentage contribution of a given site in terms of the entire watershed above the main-stream fence, m2 is the number of marks placed within a given site recovered at the main-stream fence, (ni / mi) is the number of coho each marked fish represents within a given site and N2 is the total number of coho examined at the main-stream fence. 2. Results (a) Coho Utilization (i) Numbers Differences in annual utilization of specific off-stream sites for the two years examined appeared governed by environmental rather than density dependent factors. Population estimates conducted within the main-stream before f a l l redistribution were similar (7557 for 1982 and 10,171 for 1983; Andersen 1985) however, magnitude of stream discharge caused by the first f a l l storms (period of redistribution of coho from main-stream to off-stream sites) differed for the two years (35 m3/sec for 1982 and 8 m3/sec for 1983; Carnation Creek Working Group 1984). Access to the various sites utilized as over-wintering habitat was dependent upon stream discharge level (Table 5.1). Total winter use of a l l sites (Table 5.2) was not significantly different for the two years (paired t-test, P > 0.5). Total numbers utilizing off-stream sites were very similar for the two winters (1982-83: 1517 * 114, 1983-84: 1619 * 86). Estimations of 1982-83 populations were taken two months later than were the 1983-84 estimates. The 1982-83 estimates could be slightly lower because of the earlier sampling date. Although no significant difference in total number of juvenile coho inhabiting the off-stream sites for the two years was apparent, differences in numbers residing within specific sites did occur (Table 5.2). Sites L1250m and L1550m were connected during the f a l l of 1982, however during the f a l l of 1983, storm flow magnitude was not high enough to connect the sites and redistribution of coho into LI250m from L1550 could not take place. The difference in storm flow magnitude may account for the increase in numbers occupying L1550m and decrease in numbers occupying L1250m. No explanation for the difference in annual distribution between L1600m lower and L1600m upper is available. No apparent change in coho population within the intermittent components of the two tributaries before redistribution (Sept 1983) and after redistribution (Nov 1983) was observed (Table 5.2). The net movement of coho into the tributaries (fences Oct-Nov, N = 290) is slightly larger than the November 1983 coho population estimated within the ephemeral components of these tributaries (N « 220). 51 Table 5.2 Number of coho (Oncorhynchus kisutch) utilizing off-stream sites during winter 1983, f a l l 1983 and winter 1984. (Jan-Feb 1983) (Sept 1983) (Nov 1984)  Off-stream site _N SE N _N SEN _N SEN Ephemeral R750m 235 34 0 227 40 LI250m 103 29 0 23 5 L1550m 147 23 0 360 28 L1500m — 0 110 17 L1600m upper 208 46 0 159 18 R2600m ponds 70 22 0 62 11 Intermittent LI600m lower 239 67 353 52 393 65 R2600m lower 253 45 355 40 287 77 R2600m upper 113 34 76 16 69 20 Total Ephemeral 892a 74 0 979 54 Total Intermittent 621 89 821 71 768 103 Total (All Sites) 1517a 114 1619 86 estimates corrected by 110 for missing data point. ( i i ) Densities A comparison of coho winter densities (Table 5.3) indicated that off-stream sites have a greater density of coho than do main-stream locations (t-test, P < 0.05). The main-stream densities were obtained from Andersen (1984) and field measurements of wetted area were used in his calculations. Area estimates used to calculate off-stream densites, were obtained from maps (Appendix 1) and represent an over-estimate of total wetted area because raised hummocks are included. 52 Table 5.3 Coho (Oncorhynchus kisutch) densities within off-stream sites and main-stream locations for 1982 (main-stream values from Andersen 1984) Description Date of estimates Density SE (coho/m2) main-stream locations Nov.23-25 5 0.072 0.018 off-stream sites Jan-Feb 8 0.156 0.025 Off-stream sites exhibit considerable variability in juvenile coho densities (Table 5.4). One site, L1250, had a low density compared to the other sites. Coho could enter this site only during high freshets (> 18 m3). The relatively low density was likely due to access problems rather than to habitat quality. Table 5.4 Coho (Oncorhynchus kisutch) densities for a l l off-stream sites based on: two estimates of area (total flooded are? and area of habitat unit 1+2) and mean coho population for two winters. Off-stream site Density (total area) Density (winter habitat) R750m 0.24 coho/m2 0.32 coho/m2 L1250m 0.04 0.11 R1500m 0.22 0.34 L1550m 0.18 0.28 L1600m upper 0.22 0.40 L1600m lower 0.28 0.39 R2600m lower 0.16 0.44 R2600m upper 0.12 0.22 R2600m ponds 0.08 0.27 Mean 0.17 (SE=0.03) 0.31 (SE=0.03) Coho were not distributed equally throughout the flooded land and a poor correlation (r < .01) was evident between total flooded area for each site and juvenile coho over-wintering population size (Figure 5.3 top). A significant correlation existed between area delineated as coho winter habitat (see Chapter 4) and coho over-wintering population size (Figure 5.3 bottom, r = .96, P < .001). This illustrates the importance of identifing coho winter habitat rather than simply using flooded land as an indication of over-wintering coho presence. (b) Contribution to Total Smolt Production The contribution of off-stream sites to the total coho smolt production was estimated for two years (Figure 5.4). Ephemeral sites located within the two tributaries were not separately marked during winter 1982-83. Thus, the ephemeral component of these tributaries was not measured for that winter. Total coho production from the watershed was similar for the two years of study, 3544 smolts for 1982-83 and 3200 smolts for 1983-84 (Carnation Creek Working Group 1984). A difference in percentage of coho smolts produced from the off-stream sites was noted for the two years, 14.5% for 1982-83 and 22.8% for 1983-84. These estimates must be considered minimum values because any marks missed by the technicians recording them at the main fence from March to May, would decrease the estimate of contribution. The increase in percentage contribution in 1983-84 may have been due to differences in production from ephemeral sites. Although the production of coho smolts from ephemeral sites was not significantly 54 COHO / TOTAL AREA FLOODED 400-1 o o o 300-1_ a> E 3 200-100- O o soo - O r -1000 1500 2000 Area (Square mefers) Figure 5.3 The relationship between number of juvenile coho (Oncorhynchus kisutch) and two area estimations: (1) total flooded area, top graph (2) coho winter habitat (habitat units 1 and 2), bottom graph. WINTER 1982-83 Main-stream 56.2% WINTER 1983-84 Non-recovered 21.9% Main-stream 55.3% Int. Tributaries 7.1% Eph. Tributaries 4.2% Ephemeral 10.4% NRB 1.1% Figure 5.4 Coho (Oncorhynchus kisutch) smolt contribution from off-stream sites as a percentage of the watersheds total smolt production. The ephemeral component of the tributaries was not enumerated separately in 1982-83. different (paired t-test, P < .20) there was a trend towards greater production in 1983-84 from the sites examined. Observations indicate differences in spring climatic conditions may have been responsible. In spring 1982-83, the ephemeral sites went dry early due to a warm, dry March and April. Stranding and mortality of coho within the sites was noted. In spring 1983-84, the swamps remained wet until late May. (c) Population Change Over Winter The number of juvenile coho inhabiting an off-stream site changed over the course of a winter (Figure 5.5). In September 1982, the ephemeral muck swamp was dry and no fish were present. With the onset of the first winter storms (late October), water level rose and access from the main-stream was available. The population reached its maximum level immediately following the first storms and numbers declined continuously through the winter. The rapid decline noted in April-May was due primarily to coho out-migration (smolts). The decline in juvenile coho population noted from November to March was due to net emigration and mortality. This loss of juvenile coho from the one ephemeral swamp examined (R750m) was constant and independent of a l l mid-to-late winter storms with the possible exception of a storm event occurring on Jan 4/1984, a 25 year flood event (Figure 5.6). An estimated net loss of 40 coho (15%) occurred at this time. The net loss from time of entrance (October) until April was estimated at 35% of the in i t i a l population. 57 Figure 5.5 Change in juvenile coho (Oncorhynchus kisutch) population over a winter period within one ephemeral swamp (R750m). 58 3 5 0 - . 3 0 0 -2 5 0-1 O JZ o o _© 'C 2 0 0 o > 3 O »_ 150 o -O. £ 3 Z 100-1 5 0 Y = 265 - 0.43 X r = .97 P < .001 Y = 269 - 0.76 X r = .96 P < .001 Legend O ACTJUAL_POPUL_ATJO_N X CORRECTED FOR JAN.4/84 i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — - i — i — r — i — i — i — i — i — i — i — r - 1 — i — r 19 22 2t • 13 U 17 ) 10 17 U 1 • 19 22 2* 1 11 II i l ! • If 29 1 • 19 22 2* 9 S E P O C T N O V D E C J A N F E B M A R A P R 1 9 8 3 1 9 8 4 12 1* 21 3 10 17 MAY Date Figure 5.6 Regression of juvenile coho (Oncorhynchus kisutch) population within one ephemeral swamp (R750m) over time. Actual population and population corrected by +40 for Jan 4/1984 freshet. (d) Trout Utilization (i) Numbers A comparison of the percentage of trout residing within a l l ephemeral swamps, intermittent tributaries and main-stream locations examined during this study (Table 5.5), indicates that at least one of the types differs from the others (One-way Anova, P < .05). Trout use of ephemeral sites is significantly lower than both intermittent and main-stream sites (Scheffe's, P < .05). Considering trout densities are higher in the upper half of the flood-plain (Andersen 1984), only those sites located within the two tributaries (L1600m and R2600m) and main-stream locations above 1600m were compared (Table 5.6). A significant difference (One-way Anova, P < .01) between ephemeral and intermittent sites (Scheffe's, P < .01) and between ephemeral and main-stream sites (Scheffe's, P < .01) was obtained. Trout use of ephemeral muck swamps when compared to coho use was extremely limited (< 1%) while use of intermittent tributaries and main-stream locations above 1600m was much greater (25-36%). Table 5.5 Percentage of total off-stream over-wintering salmonid population represented by trout Site types examined Jan-March/1983 Jan-March/1984 N trout N coho %trout N trout N coho %trout Ephemeral (5-6 sites) 6 591 1.0% 12 1445 0.8% Intermittent (3 sites) 171 298 36.4% 373 1099 25.3% Main-stream (2 locations) 48 96 33.3% 40 117 25.5% 60 Table 5.6 Percentage of over-wintering salmonid population within two tributaries represented by trout Site type Location % Trout 1983 1984 Ephemeral L1600m upper 0% 0% R2600m ponds 6.5 4.0 Intermittent L1600m lower 28.8 24.5 R2600m lower 35.9 18.1 Main-stream @ 1700 m 24.4 12.5 @ 2600 m 43.9 28.8 (i i ) Densities Trout were not distributed evenly throughout the flooded lands. Three intermittent tributary sites supported over 95% of the total trout population over-wintering off-stream. Almost a l l of habitat unit 1 (see Chapter 4) was located within these sites. No correlation existed between number of trout and either total flooded area for each site or area of coho winter habitat (habitat unit 1 + 2 ) . A significant correlation (r = 0.98, P < .001), however, did exist between number of trout utilizing a site and area delineated as habitat unit 1 (Figure 5.7 bottom). For a l l three intermittent sites, trout densities (Table 5.7) were lower than coho densities (Table 5.4). 61 TROUT / AREA OF HABITAT UNIT 1 + 2 3 O 125 100-75-L. © -| 50 3 25-OO -O r O — O r - O O - , O , O , 0 200 400 600 800 1000 Area (Square meters) TROUT / AREA OF HABITAT UNIT 1 Area (Square meters) Figure 5.7 The relationship between number of juvenile "trout" and two area estimations: (1) area designated as coho winter habitat (habitat unit 1 + 2 ) , top graph, (2) area designated as trout winter habitat (habitat unit 1), bottom graph. 62 Table 5.7 Trout densities for three intermittent tributaries; based on two estimates of area (total flooded area and area of habitat unit 1) and mean trout population for two winters. Site Density (total area) Density (habitat unit 1) L1600m lower 0.10 trout/m2 0.15 trout/m2 R2600m lower 0.06 0.17 R2600m upper 0.08 0.14 Mean 0.08 (SE=.01) 0.15 (SE=.01) 3. Discussion (a) Coho Utilization of Off-stream Habitat Carnation Creek is unproductive compared to other small coastal streams (Holtby and Hartman 1982). Small streams on the east coast of Vancouver Island produce approximately 0.73 coho smolts/m2 (Mundie and Traber 1983). The Carnation Creek watershed produces approximately 0.20 coho smolts/m2 (assuming 3000 smolts/year from 15,000 m2 of wetted area within the main-stream channel, Andersen 1984). A much higher total smolt output was obtained through the main-stream fence than was expected, based on winter main-stream population estimates plus estimates of off-stream smolt contribution. A Nov/1982 main-stream estimate of approximately 1000 coho juveniles (0.07 coho/m2 for 15,000 m2, Andersen 1984) plus an estimated off-stream smolt contribution of 500 smolts for spring 1983 (see Appendix 3) was less than the fence counted spring 1983 output of 3500 smolts (Andersen 1984). An underestimation of 2000 smolts or 57% was evident. The large reduction in coho population, observed following the first winter storms (Tshaplinski and Hartman 1983; Forward 1983), was not fully accounted for by coho utilization of off-stream winter habitat. Our inability to sample the main-stream under winter conditions is the most plausible explanation for this severe underestimation of coho smolt production. Using electroshocking, seine netting and the removal method of population estimation, Andersen (1984) captured a total of only 117 coho from over 300 meters of main-stream during a Nov/1982 estimate. This removal method may not be suitable for estimating winter coho populations within the main-stream. One single trapping of three small main-stream debris piles (20 traps) during the following winter (Nov/1983) yielded 153 juvenile coho. The movement of coho into debris piles (Tshaplinski and Hartman 1983; Hartman 1965; Bustard and Narver 1975a) reduces the accuracy of any main-stream winter estimate which uses methods incapable of sampling such sites. Although off-stream coho density (0.16 coho/m2) appears significantly greater than main-stream coho density (0.07 coho/m2, P < .05), this result must be suspect for the reasons mentioned above. Coho densities within the main-stream may have been much higher then indicated by Andersen (1984). Coho are not evenly distributed throughout the flooded lands. A significant correlation (P < .001) existed between numbers using a site and the area within that site delineated as coho winter habitat. No such correlation existed between coho use and total flooded area. In identification of coho over-wintering habitat care must be taken to use the characteristics that correctly indicate winter habitat rather than simply defining a l l flooded land as habitat. Although total number of coho juveniles using off-stream sites was similar for the two winters of study, considerable variation occurred within two closely linked sites (L1250m and Ll550m). This variation lends considerable support to the argument for passive movement of coho with the flood-waters. Potential coho winter habitat within L1250m was under utilized while potential coho winter habitat within L1550m was fully utilized (Table 5.4). The inability of coho to move across the flood-plain from L1550m to LI250m and to redistribute evenly between the two sites during the first winter floods of 1983 could account for the observed variation. Thus, coho utilization of winter habitat was as follows: 1) September main-stream juvenile coho population estimates were similar for the two years and the number of coho juveniles over-wintering within off-stream sites were similar for the two winters. Winter off-stream population ranged from 1500 to 1600 coho. 2) Coho winter off-stream densities were higher than main-stream densities (P < .05), however, serious sampling problems within the main-stream makes this conclusion dubious. 3) A significant correlation (r = .98, P < .001) existed between area of coho winter habitat (as defined in Chapter 4) and number of coho using each off-stream site. No correlation existed between area flooded within each site and number of coho. In identifying coho winter habitat i t is important to use the habitat units defined in Chapter 4. 4) The utilization of off-stream over-wintering sites appears to be dependent upon accessibility during the first winter storms. (b) Off-stream Smolt Contribution Published literature on the relative contribution of off-stream habitat to a watershed's total coho smolt production is not available. Cederholm and Scarlett (1982) citing unpublished information from the Washington Department of Fisheries indicated that as much as 10% of the total coho smolt yield from the Clearwater River may have been from coho moving off-stream into "riverine" ponds. They also speculated that off-stream contribution may be greater in rivers with more pond-fed tributaries (Cederholm and Scarlett 1982). Smolt contribution from a l l off-stream sites located on the Carnation Creek flood-plain ranged from 14.5% (1982-83) to 22.8% (1983-84) of the total watershed production. These must be considered minimum values due to the potential of missing marked coho at the main counting fence. The 1983-84 smolt contribution from ephemeral sites was estimated at 15% of the watershed's total smolt yield. The variation in annual smolt output from the ephemeral sites can be explained by differences in spring (April-May) climatic conditions. Smolt production was low and survival was poor during the warm dry spring of 1983. Coho juveniles were noted within small, drying, isolated pools well before emigration could occur. Smolt production was much higher during the wet cool spring of 1984. No stranding was noted and emigration proceeded to mid May. The contribution of off-stream sites to Carnation Creek's total coho smolt production is as follows: 66 1) Total smolt output from off-stream sites for the two years was variable. Minimum values ranged from 14.5% to 22.8%. 2) Coho production from ephemeral sites was not significantly different for the two years examined (P < .20) however, the trend towards higher production in 1984 may have been due to a cool wet march-May versus the warm dry March-May in 1983. 3) Ephemeral sites, totally devoid of standing water in summer, can yield at least 15% of the watershed's total coho smolt output. (c) Winter Population Dynamics Juvenile coho seasonal redistribution from summer rearing habitat in the main-stream to off-stream winter habitat, coincides with the fir s t f a l l freshets (Tshaplinski and Hartman 1983; Cederholm and Scarlett 1982). The number of coho juveniles occupying off-stream sites peaked with the first f a l l freshets (1 to 2 weeks) and later storms of even greater magnitude did not increase the numbers residing off-stream. A steady decline in population was recorded in spite of these mid-to-late winter storms. Numerous authors have speculated that the reason for juvenile coho f a l l off-stream movement is to avoid adverse winter conditions within the main-stream (Skeesick 1970; Bustard and Narver 1975a; Tshaplinski and Hartman 1983; Cederholm and Scarlett 1982). The hypothesis that off-stream movement is caused by displacement of individuals during the freshet events must be questioned as the timing and numbers of juvenile coho moving off-stream showed no relationship to storm-flow magnitude. Movement occurred on the first f a l l freshets and may be in response to the first storms rather than to an avoidance of adverse main-stream conditions created by them. If coho redistribution was solely due to displacement, then mid to late winter storms producing higher main-stream discharge levels should increase the population of coho rearing off-stream. This increase did not occur. The steady decline in coho population from time of entrance (October) until commencement of smolt downstream emigration (April), indicates no specific period of time was critical to winter survival. The most dramatic decline in number of coho residing off-stream (15%) was due to a major storm event (25 year flood). During this event, the water velocities within the normally placid off-stream sites may have been high enough to displace some off-stream over-wintering fish. The fate of coho elimininated from the R750m site is unknown. The small fence at the outlet was over-topped and destroyed by flood-waters on three occasions during winter 1983-84. After fence repair, marked individuals were observed below i t . Thus, not a l l of the decline in off-stream population can be attributed to mortality. The rapid decline in off-stream population observed in April and May coincides with the annual smolt downstream migration. Both "parr" and "smolt" forms of coho were captured at the small outlet fence during this period. The winter population dynamics of one specific off-stream ephemeral swamp site (R750m) can be summarized by: 1) The off-stream population peaked following the first f a l l freshets (1-2 weeks). 2) Mid-to-late winter storms of greater magnitude did not increase the number of coho over-wintering off-stream. 3) The population showed a steady decline until commencement of smolt downstream migration. 4) At least 65% of the i n i t i a l population size was maintained until April. 5) The inability to operate the small outlet fence prevented an estimation of the relative contribution of emigration and mortality to this decline. Some emigration did take place on major storm events. 6) A major (catastrophic) flood on Jan 4/84 may have been responsible for the most dramatic mid-winter population decline observed. Approximately 15% of the total juvenile population was eliminated at this time. (d) Trout Utilization of Off-stream Habitat Coho and trout use of the two off-stream site types (intermittent and ephemeral) was significantly different (P < .01). Unlike trout, coho occupied the muck bottom ephemeral sites. Trout were confined to the intermittent sites with sand and gravel substrate. This difference is further emphasized by the correlation between number of trout over-wintering within a site and the area of habitat unit 1 (r = .98, P < .001) and the lack of a correlation between number of trout over-wintering within a site and area delineated as coho winter habitat (r = .42, P > .20). This interspecific difference in off-stream winter habitat utilization may have been the result of differences in behavioural response to f a l l freshets. The close relationship between over-wintering steelhead trout and rubble substrate is well documented (Chapman 1966; Bustard and Narver 1975a(b); Chapman and Bjornn 1969; Edmondson et a l . 1968). Other salmonid species such as chinook salmon (Oncorhynchus tshawytscha) (Chapman 1966) and cuttroat trout (Bustard and Narver 1975a) also over-winter in rubble. Atlantic salmon juveniles (Salmo salar) use "substrate chambers" beneath the streambed surface (Rimer and Paim 1983). Juvenile steelhead movement in f a l l may be in response to the absence of suitable rubble refuge (Bjornn 1971). The use of rubble by coho juveniles has not been clearly demonstrated. Coho tend to seek refuge in woody debris piles or side pools along the channel margins (Hartman 1965; Bustard and Narver 1975a(b); Mason 1976; Tshaplinski and Hartman 1983). Coho remained within sidepools regardless of bottom type as long as suitable cover was available (Bustard and Narver 1975b). In response to low stream temperatures and higher flows, coho were less closely associated with the stream bottom than were trout species (Bustard and Narver 1975a). The differences in behavioural response to such stimuli as low temperature and high velocity water could account for the eventual differences In winter habitat utilization. Coho juveniles by maintaining a higher position in the water column would tend to move passively and laterally onto the flood-plain. Coho have been noted within riparian vegetation on freshet events (Bustard and Narver 1975a; Bisson and Nielsen unpublished). During these events, trout would remain within the intermittent tributaries and main-channel where the only suitable rubble substrate exists; whereas, coho would become established within isolated off-stream muck bottom ephemeral swamp sites. Thus, the utilization of off-stream habitat by trout in winter can be summarized as follows: 1) Coho and trout showed marked differences in use of off-stream habitat (P < .01). Trout over-wintered only within sand and gravel bottom tributaries while coho utilized both tributaries and muck bottom ephemeral sites. 2) The difference in utilization may be due to differences in response to low temperatures and f a l l storms. Trout seek shelter within rubble substrate while coho move laterally on to the flood-plain. CHAPTER 6. COHO MOVEMENT 1 Methods (a) Main-stream to Off-stream Movement (i) Timing The timing of movement between the main-stream and off-stream sites was determined using three small wooden and wire mesh fish fences placed at the confluence of the sites with the main-stream. Two of these fences (R750m and L1600m) were used on previous occasions (Bustard and Narver 1975a; Tschaplinski and Hartman 1983), but the third fence (R2600m) was built in August 1982 for this study. At a l l three sites the fences were incapable of trapping the total number of moving fish. It was impossible to maintain trapping facilities in locations where flood-waters could not be confined and where high velocities destroyed structures built on muck substrate. The small fences were useful however, In studying the timing and direction of movement between the main-stream and off-stream sites. (Ii) Direction In September 1982 the Carnation Creek Working Group marked a total of 1358 juvenile coho within ten main-stream locations. Coho at each location were marked with a different symbol by cold branding. These marked fish were recovered either by trapping within the off-stream sites (®"Gee" traps) or at the three small fish fences described above (Table 6.1). There was no significant difference (Chi-square, P > .99) between the two methods of recovery. Few main-stream marked fish (4%) were recovered, possibly due to the method of marking. A short interval of contact between the brand and the coho's side produces a mark readable for only 5 to 6 weeks (Everest and Edmundson 1967). (b) Winter Movement Different symbols for each of nine off-stream sites on each of four enumerations (1983-84) were placed upon the captured coho. Using these markings movement between various sites and exchange of coho off-stream populations with main-stream populations during the winter period, after f a l l redistribution, could be examined (see Appendix 4). (c) Within Site Movement Resident coho (juveniles rearing within the intermittent section of L1600m tributary through the summer) and migrant coho (juveniles moving from summer main-stream locations to over-winter within L1600m), were marked in Sept 1983 and Oct 1983, respectively. Recovery of marked individuals in; Nov 1983 indicated the relative f a l l redistribution of each group within a small tributary. Within one site (R750m), 257 coho were individually marked, using a combination of cold brand symbols in different orientations and in different positions upon the fish. The mark and location of each trapped coho (®"Gee" traps) was recorded on each of 12 trapping series to an accuracy of 5 meters. 2. Results (a) Main-stream to Off-stream Movement (i) Timing Coho juveniles entered off-stream sites in October-November and returned to the main-stream in March-May (Figure 6.1). During these periods some movement in the opposite direction was observed, but no explanation for this is available. Little to no movement in either direction occurred during the remainder of the year. Care must be taken in interpretation of this pattern of movement. Only coho juveniles counted at three small fences were considered, coho moving across the flood-plain with the flood-waters were not included. For off-stream sites lacking a good main-stream connection at lower flows movement would tend to occur on freshets or periods of high water. In 1983-84 immigration into R750m site occurred on the first f a l l freshet while 83% of the spring emigration took place on four separate periods of high water (total of 14 days) in April and May. (ii ) Mechanism On October 22, 1983 a freshet of 8 m3/sec (first f a l l storm) marked the first appearance of standing water and coho within R750m site. A small fence at the outlet to this site recorded only 4 coho 300 1983 MONTH 1984 Figure 6.1 Movement of juvenile coho (Oncorhynchus kisutch) between main-stream and off-stream sites for 2 years. Number of coho represents the sum of three small fences. moving upstream. The small fence was thoroughly examined and considered to be completely impenetrable to fish. Water levels were not high enough to over-top the fence, however overland flow into the site from the main-stream through old abandoned channels was noted. A trapping series within the site on October 24 (®"Gee" traps) yielded 65 coho. The movement of coho over 150 meters across the flood-plain into the site during the flood was the only plausible explanation for their existence within this site. ( i i i ) Direction The relative frequencies of marked juvenile coho entering off-stream sites from main-stream locations, below (-150m), adjacent (within 150m) and above (+150m) these sites (Table 6.1), differed significantly (Chi-Square, P < .001). No appreciable movement of coho into off-stream over-wintering sites from summer main-stream rearing areas below these sites occurred. The movement of coho into off-stream sites from adjacent main-stream locations was significantly greater than from locations above these sites (Chi-Square, P < .01). Table 6.1 Direction of juvenile coho movement from summer rearing sites in the main-stream to winter sites off-stream. Method of Movement Up No Movement (150m) Movement Down Recovery (m) (r) Freq (m) (r) Freq (m) (r) Freq "G" Trapping total 1 3225 .0003 17 1242 .0137 16 3682 .0043 Small fences (3) 1 1792 .0006 13 505 .0257 14 1777 .0079 (b) Winter Movement (i) Between Sites The major freshet (Jan 4/1984) did not redistribute coho from one site to another (Table 6.2). Less then 3.0% * 1.1% of the coho moved to a new off-stream location. In the period after the freshet (Jan-March), 1.7% * 0.6% of the coho relocated to a different site. Most of the winter movement occurred between two closely related sites (L1550m and L1600m). Seven of eight coho relocated during the October-November to January period moved from L1550m to L1600m. One coho moved over 400 meters upstream in L1600m tributary. Upstream movement may have been facilitated by strong eddies along the valley wall during the flood of Jan 4/1984. Eight of nine marked coho relocated during the January to March period moved from L1600m to L1550m and three of these coho were first marked within the L1550m site in October-November. Thus, some of the coho juveniles displaced from L1550m to L1600m during the Jan 4/1984 flood, returned to L1550m during the later winter period. Table 6.2 Percentage of marked juvenile coho moving to a new off-stream site for two winter periods (1983-84) Date marked/ Moved to a Held within % Movement to a recovered New site same site new site (ml) (m2) ml / (ml + m2) Oct.-Nov./Jan. 8 255 3.0% (SE=1.1) (before/after storm) Jan/March 9 512 ,1.7% (SE=0.6) (after storm) 77 ( i i ) Main-stream Replacement Juvenile coho which had entered off-stream sites during November were replaced through the winter by main-stream coho (Table 6.3; One-way Anova-Correlated Data, P < .05). From November to March 34.9% * 9.1% of the off-stream rearing coho were replaced. The majority of replacement (33.1% * 11.3%) occurred during the early period (Nov-Jan; Scheffe's P < .10) and i t is likely the catastrophic storm of Jan 4/84 was a major factor. No replacement occurred between January and March (Scheffe's, P > .20). Table 6.3 Ratio of marked to unmarked juvenile coho and percentage replacement within off-stream sites for two winter periods (1983-84). Site Ratio (m/n) % Replacement Nov. Jan. Mar. Nov.-Jan. Nov.-Mar. R750m .46 .39 .36 15.2% 21.7% LI250m .60 .57 .33 5.0 45.0 Ll550m .50 .39 .45 22.0 10.0 R1500m .39 .07 .12 82.1 69.2 LI600m .28 .20 .23 28.6 17.9 R2600m .22 .12 .12 45.5 45.5 Mean .41 .29 .27 33.1 34.9 (SE-11.3) (SE=9.1) It must must be noted that considerable variation in % replacement exists between the various sites (10% to 69%). The Ll500m site (69% replacement) floods on minor freshets and is subjected to high velocity waters on major freshets. The L2600m tributary (46% replacement), especially the lower 1/2, may have been subjected to the effects of a debris torrent. The R1250m site, although well protected from flood waters, has a very small population (N < 30) and was therefore sensitive to sampling error. The reasons given above may account for some of the variability observed, but i t also appears that the ability of coho to remain within a given site is dependent upon specific characteristics of the site (i.e., flooding characteristics). (c) Within Site Movement (i) Tributary Movement The eventual over-wintering location of juvenile coho, either within the intermittent section (L1600m lower) or ephemeral section (L1600m upper) of a tributary, was dependent upon their summer location Table 6.4). Resident coho (marked within the intermittent section during September) remained within this lower section and did not contribute greatly to the upper ephemeral section (Chi-square, P < .01). Coho migrating through the small fence from the main-stream (migrants) showed no preference to either upper or lower sections (Chi-square, P > .20). After f a l l redistribution migrants comprised 78% of the coho population within the ephemeral section and only 44% within the intermittent section. 79 Table 6.4 Fall movement of marked coho into the ephemeral (L1600m upper) and intermittent (L1600m lower) section of a tributary. Location marked Number Location observed (m/n) % of Total marked lower upper lower upper Ll600m fence 119 17/95 = 17.9 16/104= 15.4 44% 78% Nov./1982 (Migrants) L1600m lower 80 29/192= 15.1 6/200= 3.0 56% 22% Sept.1982 (Resident) (ii ) Swamp Movement The movement of marked individuals was recorded for 6 periods during the winter 1983-84 (Figure 6.2). During the first f a l l period (Oct 23 to Dec 1), a mean movement downstream of 8.4 m * 1.4 occurred, (Chi-square, P < .10). A significant mean downstream movement of 23.4m * 14.2 was recorded during the spring period (March 10-28 to May 3-4; Chi-square, P < .01). No significant mean movement during the remaining four winter periods was observed. From December until March, 81% of the marked coho remained within 10 meters of their i n i t i a l trapping location. 3. Discussion (a) Main-stream to Off-stream Movement The immigration of coho into small tributaries and swamps in the f a l l (October to November) and emigration of coho in the spring (March 6-2 Individual movement of coho juveniles (Oncorhynchus kisutch) within an ephemeral site (R750m) for 6 periods during winter 1983-84. Upstream movement is indicated by positive values, downstream movement is indicated by negative values. to May) has been well documented (Skeesick 1970; Bustard and Narver 1975a; Mason 1976; Peterson 1980; Cederholm and Scarlett 1982; Tshaplinski and Hartman 1983). Fall immigration coincides with the firs t freshets of winter (Tshaplinski and Hartman 1983) and corresponds to a notable decline in coho juvenile population within the main-stream (Tshaplinski and Hartman 1983; Forward 1983). Spring emigration is not as closely related to freshets, although peak movement tends to occur on the higher spring flows (Bustard and Narver 1975a). Movement into off-stream sites may occur by two methods. First, movement of juvenile coho from the main-stream into small tributaries by actively moving upstream within the tributaries is well known (Skeesick 1970; Bustard and Narver 1975a; Cederholm and Scarlett 1982; Tshaplinski and Hartman 1982) and is strongly supported by coho movements recorded at the three small fences used in this study. Second, displacement of juvenile coho from the main-stream by lateral movement onto the surrounding flood-plain and passive movement with the flood waters across the flooded lands, has not been documented for coho. On tropical flood-plains lateral migrations are very common and may be either active or passive (Welcomme 1979). The origin of juvenile coho entering off-stream sites is strongly dependent upon their summer rearing locations within the main-stream. The majority of immigrants originate from locations up-stream, moving down-stream into their over-wintering sites (Cederholm and Scarlett 1982). Peterson (1980) documented the f a l l downstream movement of juvenile coho into "riverine ponds" in the Clearwater River, Washington. Their location up-stream relative to over-wintering sites may also have been an important determinate of which off-stream site was utilized. Coho rearing within the main-stream in locations bordering an off-stream site were preferentially captured within that off-stream site (P < .01). Lateral movement of coho juveniles from the main channel into riparian vegetation and overflow ponds along the channel margins has been reported (Bisson and Nielsen unpublished). Obtaining information on movement across the flood-plain during freshets is extremely diff i c u l t . The probability of observing coho juveniles stranded within the terrestrial vegetation after a freshet is low. On only two occasions were stranded juveniles noted within small drying pockets of water, access to which required both a lateral and a passive movement with the flood-waters. The trapping of coho within one ephemeral site (R750m), after an apparent movement of over 150 meters across the flood-plain through old channel scars (vegetated), provides evidence for the passive movement of juvenile coho with the flood-waters. Further studies should be undertaken in other systems to obtain definitive support for this method of movement. In summary, the pattern of juvenile coho movement between off-stream sites and main-stream locations was: 1) Coho juveniles immigrated from summer rearing locations in the main-stream to winter off-stream rearing sites in October and November. 2) Movement occurred during freshets and the first f a l l freshets produced the largest immigration (Tshaplinski and Hartman 1983) 3) The origin of juvenile coho over-wintering in off-stream sites was from main-stream locations adjacent or upstream. Coho residing in main-stream locations directly adjacent to the off-stream site contributed a greater relative number of coho than main-stream locations up-stream (P < .01). 4) Movement into the sites may be either active (moving upstream against the outflow from the off-stream site) or passive (moving with the flood-waters into the site). 5) Coho returned to the main-stream (emigrated) from March to May. Periods of higher water may have been preferred. 6) Little to no movement between off-stream sites and the main-stream occurred from December to February. (b) Winter Movement Unless coho entering the off-stream sites in f a l l are marked or the small fence's operation is uninterrupted i t is difficult to assume that the coho emigrating in spring are the same coho. Skeesick (1970), used fin clips to mark coho entering a tributary and reported a 62.6% recovery of marked coho emigrating from that tributary in spring. Other authors have assumed the catch of moving coho at small fences to be reliable indicators of total movement (Bustard 1975a; Tshaplinski and Hartman 1983). This assumption is valid provided the small fences remain in operation during major freshets and only one route is available to moving coho. The use of off-stream habitat may be considered as an alternative survival strategy for over-wintering juvenile coho salmon (Cederholm and Scarlett 1982). Severe freshets can remove or destroy certain life-stages of salmonid species from main-stream locations (Needham and Jones 1959; Elwood and Waters 1969; Seegrist and Gard 1972). The use of off-stream habitat as a refuge from winter freshets has been considered by many authors (Skeesick 1970; Bustard and Narver 1975a; Mason 1976; Tshaplinski and Hartman 1983; Cederholm and Scarlett 1982). For the entire Carnation Creek watershed, winter mortalities were not related to winter flow conditions (Holtby and Hartman 1982). During freshets, much of the flood-plain was flooded and coho movement between off-stream sites and movement between off-stream sites and the main-stream was facilitated by the availability of numerous interconnected water courses. Coho which entered a given site on the f a l l storms however, did not move to a new site (97% remained associated with a given site) and 65% of the coho recovered in March were present in November. These results indicate the permanent use of a specific off-stream site as winter habitat, rather than a temporary residence lasting only for the period of high main-stream flows followed by a return to the main-stream. Only a catastrophic event (major storm) will move a small percentage of coho juveniles to a new off-stream site and displace main-stream over-wintering fish into off-stream sites. A severe storm (Jan. 4/84) was considered responsible for the majority of movement between main-stream locations and off-stream sites. During this freshet as much as 1/3 of the coho over-wintering off-stream were replaced by main-stream fish. Considerable variation in percent replacement from the sites was noted. Those sites subjected to the highest velocity flood—waters had the highest percent replacement. Little to no replacement occurred during the relatively calm late winter period. There is some evidence that a few coho displaced during the severe storm returned to their i n i t i a l f a l l locations during later storm events. Thus, the anticipated movement of juvenile coho from and between sites during the winter period was as follows: 1) Coho juveniles occupied a specific off-stream site from November to March with l i t t l e to no exchange between sites, 2) During the Jan 4/84 freshet some exchange of coho between main-stream and off-stream sites did occur (33% * 11.3), 3) The percentage of coho replaced by main-stream fish during the Jan 4/84 freshet was highly variable and appeared dependent upon site specific characteristics, 4) There is some evidence coho displaced on Jan 4/84 returned to their i n i t i a l off-stream site. (c) Within Site Movement A small tributary system (L1600m) has both an intermittent lower section and an ephemeral upper section. A population of juvenile coho reared through the summer within the lower section (residents) and during the f a l l a population of juvenile coho immigrated into the tributary from the main-stream (migrants). The origin of coho over-wintering within the ephemeral upper section of L1600m site was not an equal composite of resident and migrant coho. Resident coho did not move up-stream into! the ephemeral section of the tributary (P < .01); whereas the migrant coho distributed themselves throughout the entire system. Although within the entire tributary resident coho are are more numerous, within the ephemeral section the migrants comprised 78% of the coho population. Bustard and Narver (1975b) found that coho remained within experimental pools even when free access to the main-stream was available (provided shelter was present). In winter as temperature drops and coho activity is reduced, main-stream over-wintering fish seek shelter (overhanging banks and debris piles) (Hartman 1965; Bustard and Narver 1975a(b); Mason 1976) and may be associated more closely with the bottom (Bustard and Narver 1975a). Little to no individual winter movement of coho within main-stream locations or within off-stream sites was expected. Within one ephemeral site (R750m) no significant movement of individual coho occurred from Dec. 1/83 to March 28/84. Over 80% of the marked individuals were consistently recaptured within a 20 meter section of swamp. These results were consistent with the patterns of movement recorded at the small fences and further demonstrate that coho maintained stable positions for the entire winter period even within low velocity off-stream sites. Thus, movement within a site during the winter period was: 1) In a tributary with a sizable population of summer residents (1983-84; N = 353 * 52) the summer residents remained within the intermittent section and the ephemeral section was populated largely by main-stream migrants. 2) Movement within the placid off-stream sites was extremely limited during the winter period (December to March). Individual coho maintained stable positions within a small area (specific pool, debris pile or weed-bed). 87 CHAPTER 7. WINTER GROWTH OF COHO JUVENILES 1. Methods During each trapping series within each of nine sites, the fork-length of every fish captured was measured to the nearest millimeter (see Appendix 5). A separation of 1 year-old juvenile coho from 2 year-olds was made by plotting the length frequency, obtaining a bimodal distribution and separating the two groups at a given length. This method of age separation was double checked by scale data from one site (R750m). Coho individually marked during the f a l l within R750m swamp were divided into six size classes. Recovery of individuals within these classes in spring indicated differences in size response to emigration and mortality. A measurement of individual length over time (growth) was also obtained. 2. Results (a) Population Mean Length An increase in population mean fork-length was noted for R750m site from Jan 15/1983 to Feb 23/1983 (Z-test, P < .001). During this mid-winter period, the mean population fork-length increased from 73.9 mm * 1.1 to 80.1 mm * 1.1. Hypotheses for this increase are: 1) size dependent mortality (larger coho have higher survival rates), 2) size dependent migration (small coho immigrate, large coho emigrate or a combination of the two), 3) growth of individuals. During the following winter (1983-84), 257 coho juveniles were individually marked within R750m site. This permitted testing of the three hypothesis for explaining the observed increase in a coho population's mean fork-length. (i) Size Dependent Mortality and Migration Coho individually marked in early winter (200 coho branded before Dec. 1) were divided into six size classes. The percentage of marked individuals recovered within each size class during early spring (March to May) was calculated and a regression of % recovery versus mean size class (indication of size dependent mortality and migration combined, Figure 7.1) was not significant (r = -.65, P < 0.2), but does indicate a trend towards small individuals remaining within the site; while large individuals either emigrated or died. This trend was contrary to in i t i a l expectations. The observed winter increase in mean fork-length of the population can not be explained by either size dependent migration or size dependent winter survival. 70-89 RECOVERY OF SIX SIZE-CLASSES S 6 ° -O I a> N i/> 4 0 50-o >-k. > o o 0) Ct. t£ 10-30-20-X X r = = - .65 P = 0.16 70 i — 80 55 —r-60 65 i 75 i 85 Mid-Point of Size Class (mm) INDIVIDUAL GROWTH / POPULATION LENGTH 25-i Population Mean Length (mm) Figure 7.1 Possible reasons f o r increase i n mean population length of ju v e n i l e coho (Oncorhynchus kis u t c h ) during winter within an ephemeral muck swamp (R750m): (1) s i z e dependent m o r t a l i t y and/or migration, top graph (2) growth of i n d i v i d u a l s , bottom graph (ii) Growth A linear regression of the mean length of the population versus cummulative increase in length of individuals within that population (growth) (Figure 7.1) yields a significant correlation (r = .99, P < .001). Considering size dependent migration and mortality did not contribute to the increase in population mean length, the growth of individuals through the winter period was likely responsible for the observed increase in mean fork-length of the population. This correlation is further illustrated in Figure 7.2. Three growth periods can be noted: 1) f a l l period (Oct-Nov) growth of .11 mm/day, 2) mid-winter period (Dec-Jan) no measurable growth, 3) spring period (Feb-May) growth of .17 mm/day. (b) Comparison of Sites (i) Three Site Types Increase in mean length (1 year old juveniles only) varied for 3 site types (Figure 7.3). Unfortunately, only one main-stream location was examined and a statistical comparison of the three site types was impossible. It appears the two off-stream sites had a higher growth rate than the main-stream. In the main-stream, growth in the spring (Feb-May) was delayed, possibly due to colder water. 91 13 2 2 2 3 • 13 2 0 2 7 3 10 17 2 4 I • 13 2 2 2 1 3 12 l » 2 3 2 * 13 2 3 1 9 13 2 2 2 3 3 12 19 2 3 3 10 17 S E P O C T N O V D E C J A N F E B M A R A P R MAY 1 9 8 3 1 9 8 4 Date Figure 7.2 Growth of individually marked juvenile coho (Oncorhynchus  kisutch) and increase in mean population fork-length within an ephemeral swamp (R750m) during the winter period (1983-84). Three growth periods can be noted: f a l l (Oct-Nov), mid-winter (Dec-Jan) and spring (Feb-May). 92 Figure 7.3 Juvenile coho (Oncorhynchus kisutch) mean population fork-lengths for three habitat types (intermittent tributary, ephemeral muck swamp and main-stream) during the winter period (1983-84). Assuming the change in mean length was the result of growth (Table 7.1), total winter growth within ephemeral sites may have been greater than within intermittent sites (t-test, unequal variances, P < .10). Although total winter growth for the two site types was not significantly different, a trend towards higher growth rates within ephemeral sites during the early winter was apparent (t-test, unequal variances, P < .20). Much of this possible difference in total growth may have been due to the difference in early winter growth. Caution in equating increase in mean fork-length to growth for the various sites must be emphasized. A difference in sampling dates of a week in November or March may have made an appreciable difference in mean-fork length. Sample size for Ll250m site was small (n = 12) and mean lengths had a large standard error. It can not be assumed that the same fish are being measured at a future sampling date, this was especially true for main-stream locations. Error in separating one-year-old from two-year-old juveniles will alter the mean size of both age classes. Although the relationship between change in population mean length and individual growth has been shown for one site (R750m), other sites may not have responded in a similar manner. ( i i ) Intermittent Tributaries Coho length may have differed (two-way anova, P < .10) between the three intermittent sites (Figure 7.4). Juvenile coho within R2600m upper had a slight, but consistently greater mean fork-length (1.5 mm * 0.6) than did juveniles within R2600m lower (Scheffe's, P < .10). Date Figure 7.4 Juvenile coho (Oncorhynchus kisutch) mean population fork-lengths for three intermittent tributary sites during the winter period (1983-84). 95 Table 7.1 Increase in mean fork-length of 1 year old juvenile coho (Oncorhynchus kisutch) during the winter period 1983-84. Site Period during winter 1983-84  Sept.20-Nov.10 Nov.10-Jan.10 Jan.lO-MarchlO Main-s tream @2700m 1.8 (mm) 2.0 (mm) Ephemeral R750m 1.6 5.2 Ll250m 1.7 7.0 Ll550m 5.6 4.1 Rl500m 7.7 5.1 L1600m upper 3.0 7.0 R2600m ponds 1.6 7.0 Intermittent LI600m lower 4.8 (mm) 0.9 5.7 R2600m lower 8.4 1.2 5.6 R2600m upper 6.0 1.8 5.0 Mean Ephemeral 3.5(SE=>1.0) 5.9(SE=0.5) Mean Intermittent 6.4(SE=1.1) 1.3(SE=0.3) 5.4(SE=0.2) Mean increase in fork-length from November 10 to March 10 for the 3 intermittent sites was 6.7 mm * 0.1 (Table 7.1). The highest growth rate occurred during the later winter period, January 10 to March 10, (two-way anova 2 x 3, P < .01). No differences in growth rates were evident between the populations residing within the 3 intermittent sites (two-way anova 2 x 3, P > .20). ( i i i ) Ephemeral Swamps Considerable differences in fork-length between the various ephemeral sites was evident (two factor anova 3 x 6, P < .001). The largest deviation, 16 mm in November, existed between L1250m and L1550m (Figure 7.5). The difference in November fork-lengths clearly demonstrates that, based on size, the coho populations entering each of the ephemeral off-stream sites is unique. The mean increase in juvenile coho fork-length (growth) for the six ephemeral sites from November 10 to March 10 was 9.8 mm * 0.8. No, difference between early winter and late winter growth was observed (two-way anova 2 x 6, P > .20). A difference in growth rates between the sites may have existed (two factor anova 2 x 6, P < .10) however, no relationship between upper and lower sites or between northern and southern exposures was observed. The two sites with the greatest early winter growth (L1550m and Rl500m, Nov 10 to Jan 10 noted in Table 7.1) are also the two sites with the smallest coho upon entry. Repeated capture of salamanders in baited traps during the winter period, even beneath 5 cm thick ice, indicates these two sites also contain large amphibian populations (Taricha granulosa granulosa and Ambystoma  gracile gracile) during the winter period. No explanation can be given for the possible difference in growth rates between the various sites. (c) Comparison of Years The shape of the two winter growth curves for R750m site (Figure 7.6) showed considerable variation especially during the late January to May period. The shape of each curve corresponded to observed differences in annual climatic conditions and variations in winter growth may therefore be dependent upon these conditions. 97 Figure 7.5 Juvenile coho (Oncorhynchus kisutch) mean population fork-lengths for s i x ephemeral muck swamp si t e s during the winter period (1983-84). 98 Figure 7.6 Juvenile coho (Oncorhynchus kisutch) population mean fork-lengths for two winter periods, 1982-83 and 1983-84, wi t h i n an ephemeral muck swamp (R750m). Weekly mean water temperatures (recorded a t B weir on main-stream) are i l l u s t r a t e d f o r each winter. The shape of the two curves was similar from November to late January (Figure 7.6). From late January to late Feburary the 1982-83 curve had the greatest rate of increase, but this curve plateaued by early March and l i t t l e to no further increase in fork-length was recorded. The mean size of coho during 1983-84 increased steadily from mid February and by early April exceeded the mean size of coho for 1982-83, overcoming an in i t i a l size discrepancy of 4 mm. The months of January and February were warmer in 1983 than in 1984. This may have accounted for the accelerated growth rates observed for February 1983. Warm dry conditions continued during 1983 and coho remaining within the site were stressed (stranding and mortality was observed) and growth was impaired. The months of March to May 1984 were cool and wet enough to maintain standing water levels within the site and the high growth rate continued. It appears that spring climatic conditions strongly influenced the eventual size (mean fork-length) of the coho produced from an isolated off-stream site. 3. DISCUSSION (a) Winter Growth Salmonid activity does not cease with the onset of the winter period. Coho have been observed actively feeding at temperatures below 2.5 °C. (Bustard and Narver 1975a). Rainbow trout have been observed feeding in supercooled water (Needham and Jones 1959) and have been caught on bait at 0 °C. (Maciolek and Needham 1952). During the course of this study, coho and trout were captured in baited traps at water temperatures below 1 °C. No difference in trapping efficiency was noted between relatively warmer f a l l and spring enumerations and colder mid-winter enumerations. An Increase in a coho population's mean fork length from the time of f a l l immigration until spring emigration has been observed by various authors (Skeesick 1970; Bustard and Narver 1975a; Peterson 1980). In one off-stream site (R750m), an increase of 22.1 mm was recorded from Oct.24/83 until May 5/1984. Growth of individual members of the population was responsible for this increase (P < .001). Size dependent mortality and migration did not contribute to the increase in mean fork-length. There was a trend towards smaller individuals remaining within the off-stream sites and larger individuals emigrating or dying (P < .20). Larger coho may have higher maintenance costs during the winter period (Elwood and Waters 1969) and higher energy costs of over-wintering may be a cause of early salmonid emigration (Riddell and Leggett 1981). The majority of coho off-stream winter growth took place during two periods, f a l l (Oct-Nov) and spring (Feb-March). A mid-winter (Dec-Jan) lag period in which no significant growth was noted, distinguishes these two periods. Winter growth rate corresponded closely with water temperature (Fig 7.6) and for both years of study, no growth was apparent when water temperatures were less than 5-6 °C. The components of winter growth can be summarized as follows: 101 1. Coho continued to feed during the winter period. 2. Increase in mean fork-length of the coho population during the winter period was due to growth of individuals (P < .001) and not due to size-dependent factors. 3. Growth took place in two periods; f a l l (Oct-Nov) and spring (Feb-May). In mid-winter (Dec-Jan), when weekly average water temperatures were below 5-6 °C, no growth was observed. 4. Total growth for the entire winter period (Oct-May 1983-84) for one off-stream site (R750m) was 22.1 mm. Spring (Feb-May) growth rate for R750m site was 0.17 mm/day. (b) Spatial Variation The quality of each site as winter habitat will influence the growth of over-wintering coho. Intrinsic differences in size and condition of the individuals comprising the various populations entering the specific off-stream sites in f a l l , could also affect growth rates of these populations. Thus, i f i t can be shown that each site i n i t i a l l y supports a distinct population of coho, i t can not be concluded habitat quality is responsible for observed differences in growth rates. There was considerable evidence for the uniqueness of populations entering each of the off-stream sites during f a l l redistribution. Unique populations of coho (based on fork-length only) existed within the various main-stream sections sampled by Andersen (1984). Coho movement off-stream was not a random displacement of individuals. Certain main-stream September populations were more likely to enter a specific off-stream site (see Chapter 6.). A difference in coho fork-lengths may have existed between the three intermittent sites (P < .10) and did exist between the six ephemeral sites (P < .001). Riddell and Leggett (1981) noted that Atlantic salmon inhabiting two tributaries of the Miramichi River had similar growth rates. The two populations had different behaviour (migration timing) and different body morphology and thus were unique populations. Within the three intermittent tributary sites and six ephemeral swamp sites examined in this study, no significant differences in growth rates were measured. The total number of sites examined was small however, and a difference in growth rates may have existed between the ephemeral sites (P <.10). Increase in coho mean fork-length (growth) varied between site types. From Nov 10/83 until March 10/84 coho growth averaged: 9.4 mm * 0.8 within ephemeral sites, 6.7 mm * 0.1 within intermittent sites and was only 3.8 mm within the one main-stream site examined. This evidence strongly suggests the small, s t i l l , ephemeral, off-stream ponds provided some of the best over-wintering habitat for coho juveniles. These ephemeral sites may have had a higher growth rate (t-test, P < .10) than did the intermittent tributary sites. Much of this difference in total growth was due to higher early winter (Nov 10 to Jan 10) growth. Ephemeral sites showed a trend towards a higher growth rate than intermittent sites during this period (P < .20). The two ephemeral sites with the highest (Nov 10 to Jan 10) growth were also the two sites with the smallest coho immediately following f a l l redistribution. It is speculated the small i n i t i a l size (uniqueness of these populations) may have contributed in part to the higher growth rates noted for the ephemeral sites. 103 The geographic variation in coho off-stream populations of over-wintering coho juveniles can be summarized as follows: 1. Off-stream sites contained unique populations of coho juveniles (based on variation in fork-length) immediately following f a l l redistribution. 2. Difference in habitat quality was impossible to isolate as a single factor. Change in fork-length (growth) must be considered the product of both intrinsic characteristics of the population and the quality of the habitat. 3. Winter growth of coho juveniles appears to be best in ephemeral sites followed by intermittent tributaries and main-stream locations. (c) Annual Variation Coho emigration from off-stream sites corresponded to spring smolt downstream migration. Many of the individuals emigrating through the small fences however, had no visible indication of smoltification (silver colour). The mechanisms triggering movement from off-stream sites to the main-stream are unknown. It may be speculated that one possible reason for emigration is the general decline in off-stream habitat quality as water levels are reduced, followed by a spring freshet which permits access to the main-stream. In spring (March to May), maintenance of growth may be dependent upon the quality of the habitat. Differences in growth rates which corresponded to differences in climatic conditions were observed for the two years of study (Figure 7.6). A warm dry spring may stress off-stream rearing coho and reduce growth rates. Annual variation in growth within off-stream sites may be summarized as follows: 1) Growth of juvenile coho varied from winter to winter for a given off-stream site. 2) A major factor influencing growth appears to be spring (March-May) climatic conditions. A warm dry spring may reduce habitat quality and lower growth rates within off-stream sites. 105 CHAPTER 8. SUMMARY 1. What is Off-stream Winter Habitat? Salmonid off-stream winter habitat was readily identifiable on an early successional (5-10 years after harvest) west coast alluvial flood-plain. Characteristics considered important in identifying this habitat included: general location and topographic features, substrate type, vegetative associations, percentage cover by vegetative stratum, and seasonal water table. Although coho were found within sites containing trout, coho also inhabited sites devoid of trout. Trout utilized over-wintering habitat located within intermittent tributaries (habitat unit 1). Standing water was present throughout the year and a directional flow was present in winter. Fines (organic and inorganic) had been washed from the surface and the substrate consisted of sand and gravel. Less than 25% of the surface was covered by vegetation rooted within the site and plants were restricted to strong rooting, highly water tolerant species, such as: Oenanthe  sarmentosa, Lysichiton americanum and Scirpus microcarpus. Plants grew only where they were protected from higher velocity water. Coho were found not only within the intermittent tributaries, but also within the ephemeral muck swamps. Standing water was not present in summer but water levels were generally within 25 cm of the surface. In winter, the level of standing water was sufficient to support juvenile coho. The surface consisted of organic muck soils often held in place by roots from semi-aquatic plants. Vegetative cover varied 106 from muck pools (< 25% cover) to dense beds (> 70% cover) of Scirpus  microcarpus. Other herb species present included: Oenanthe  sarmentosa, Lysichiton americanum, Typha la t i f o l i a , Juncus ensifolius, Lecidea sp. and Zannichellia palustris. Mosses and shrubs were generally absent. The majority of salmonid habitat identified in this study was located at the base of the valley walls, often within a section of abandoned channel. Winter water levels were maintained by seepage from upslope locations. 2. How Important is Off-stream Habitat? Coho smolt production from off-stream habitat ranged from 15% to 23% of Carnation Creek's total smolt output. Smolt production from sites totally devoid of standing water in summer accounted for more than 15% of the watershed's total smolt output in 1984. Annual smolt output appears dependent upon spring climatic conditions. Trout use of off-stream sites was limited to intermittent tributaries and the proportion of the total watershed's population using these sites is unknown. Trout have been reported to use these minor tributaries for spawning (Tschaplinski and Hartman 1982). Off-stream habitat, especially the placid ephemeral swamps, may provide the highest quality juvenile coho over-wintering habitat available on the flood-plain. Growth (P < .10), density (P < .01) and possibly survival (Tshaplinski and Hartman 1982; Bustard and Narver 1975a) were higher within ephemeral off-stream sites than within either small intermittent tributaries or the main-stream. The concept of off-stream sites as marginal habitat utilized by individuals displaced by f a l l and winter storms must be questioned. Off-stream habitat may provide over-wintering juvenile coho with an alternate survival strategy. High discharge peaks in association with unstable debris, may dislocate main-stream fish and possibly lower winter survival (Hartman and Holtby 1982). In years with frequent high discharge producing storms, placid off-stream sites may contribute a high proportion of the watershed's smolts. In years with a dry warm spring, few coho will survive within the off-stream sites due to inadequate water levels but main-stream survival may be high. Coho utilization of two habitat types (main-stream and off-stream), each with its own distinct potential for producing coho smolts under different climatic conditions, may aid in stabilizing total smolt production from a west coast watershed. 3. Winter Ecology Redistribution of coho and trout took place during the first major freshet in f a l l (Oct-Nov). The magnitude of the first freshet appeared responsible for the eventual over-wintering distribution of coho within the off-stream sites. Coho movement into off-stream habitat was either active (utilizing the outlets of small off-stream tributaries and swamps) or passive (lateral displacement with the flood water). The f a l l redistribution of trout differed from that of coho (P < .01). One possible explanation for this difference in distribution may be a difference in behavioural response to f a l l storms. Trout tended to remain within the sand and gravel bottomed systems and may respond to the first storms by seeking protection on or within this substrate, while coho may tend to move laterally away from the center of the stream channel. Thus, trout may not have been subjected to the same passive displacement as were coho. Fall redistribution was not a random displacement of coho juveniles from the main-stream. Movement was from upstream and adjacent main-stream locations (P < .001) and those coho rearing adjacent to a given off-stream site in summer were more likely to enter that site in f a l l (P < .01). The number of coho within an ephemeral swamp was at its maximum after the first f a l l storms and numbers steadily declined independent of later winter storms. During the winter, coho juveniles exhibited l i t t l e to no movement and often remained from November to May within a specific pool or weedbed. Emigration took place from April to May and tended to occur at higher water levels but not. necessarily under freshet conditions. Coho actively fed during the winter period, even at low water temperatures. Growth occurred in both f a l l (Oct-Nov) and in spring (Feb-May). Coho juveniles inhabiting one off-stream site grew 22 mm from October 1983 to May 1984. No measurable growth was recorded in mid-winter (Dec-Jan) when water temperatures were lowest. Differences in growth rates may have existed between various ephemeral sites (P < .10). Growth, however could not be directly equated to habitat quality, as the various sites supported distinct populations (based on fork-length) immediately following f a l l redistribution (P < .001). 109 CHAPTER 9. MANAGEMENT IMPLICATIONS 1. Introduction Salmonid use and survival within off-stream habitat are dependent upon both annual climatic conditions and forestry activities. Management practices that maintain or enhance fisheries values by reducing the harmful impacts of forestry practices while utilizing the beneficial effects of logging activites, should be considered. The main objective of this section is to discuss how various forestry activities can affect off-stream production of salmonids on west coast alluvial flood-plains and because coho tend to utilize the most marginal of this habitat (muck swamps), they will be stressed. Means of reducing the harmful impacts of forestry activities as well as possible methods of enhancing fish production will be considered. It must be recognized that much of this section is highly speculative as few publications have considered either winter off-stream juvenile coho production or the impacts of forestry activities on their habitat. 2. Alteration of Access Juvenile coho move off-stream either passively with the flood-waters or by actively moving up through the outlets to the off-stream sites. The majority of this movement occurs during the first f a l l storms (Tschaplinski and Hartman 1982). Access to off-stream sites can be affected by forestry activities. Road building and harvesting could alter the magnitude of peak flows (especially the first peak), alter the nature of main-stream flooding at a specific location or change migration patterns from the main-stream through construction of engineering structures such as culverts or bridges. Considerable variation in response of peak flows to forestry practices is apparent from studies conducted in the Pacific Northwest. In watersheds where severe soil disturbance and considerable road building has occurred, an increase in the magnitude of peak stream flow during winter storms was noted (Harr 1976). Other studies (Carnation Creek included) have not detected statistically significant increases in size of peak flows without soil disturbance (Hetherington 1982; Rothacher 1973). In one study conducted in Southwestern British Columbia (Cheng et a l . 1975), a reduction in magnitude and an increase in duration of storm flow was measured after clearcut logging. The largest increases in peak flows attributable to forestry practices occur during the first f a l l storm In the years following harvest (Harr et a l . 1975; Harr 1976). At this time, transpiration losses are less and soil moisture content is higher than It would be before harvest. Changes in the first f a l l storm's magnitude can have a profound effect on utilization of off-stream coho habitat by altering access. It appears that mid-winter and late-winter storm events do not cause a redistribution of juvenile coho even i f the storm discharge is greater. The relationship between stormflow magnitude and coho production is unclear; i t may be negatively correlated (Knight 1980) or statistically unmeasurable (Hall and Knight 1981). Total flow during the winter I l l period (Nov-May) was found to be significantly related to increased catch of adult coho two years later (Scarnecchia 1981). It may be more desirable to maintain the existing hydrologic state rather than attempt to manage for either reduced or increased peak flows. Forestry practices will have profoundly different effects on different watersheds (e.g. rain dominated systems will respond to forestry practices differently then either snow dominated systems or watersheds subject to periodic rain-on-snow events). Two forest management practices are capable of altering the magnitude of f a l l and winter peak flows. The first is rate-of-cut. If clearcut size is reduced and harvesting schedules are lengthened, effects of logging activities on peak flows would be negligible. The second practice relates to soil disturbance and interception of storm-runoff by roads. If road construction is kept to a minimum and soil disturbance is reduced through proper placement of landings used in high-lead operations, alteration of peak flow magnitude should be negligible. Debris jams located within the main channel may be important in redirecting stormflow across the flood-plain. This would permit access to winter off-stream habitat located within the stormflow's path. Coho moving with the floodwater would be swept into quiet, back-water areas, capable of supporting winter populations of juvenile coho. The literature does not support the concept of juvenile coho down-stream movement across the flood-plain on storm events. In studies conducted to date, there has been a tendency to select sites to monitor fish migrations where winter storms will not destroy the small trapping fences and where a l l migrating fish can be enumerated. These conditions are not met in areas where annual flooding would produce flows strong enough to allow fish movement across the flood-plain. The location, size and number of debris jams capable of redirecting storm flow from the main channel to off-stream winter sites would vary depending upon the logging practices, age and condition of the stands harvested and time since harvest. Cross-stream yarding destabilizes woody debris and permits its rapid down-stream movement (Toews and Moore 1982), while a buffered stream maintains large woody debris for longer periods. It is expected "second growth timber" logged during the next rotation will produce less and smaller woody debris (Toews and Brownlee 1981). The amount of large woody debris present would be at a maximum immediately following harvest of an old growth stand. The more mobile pieces would quickly come together to form jams during the first 5-10 years, but with few new pieces entering the system, with time the number of debris jams should decline due to removal of debris from the main channel by storms, burying of logs by bedload and changes in location of the main channel by diversion around jams. Debris jams on small streams should be managed and not removed. Where a debris jam is not considered detrimental to fish movement within the main channel and where that debris jam promotes flooding into a critical winter habitat, removal of that jam could prove detrimental to coho production. The importance of large debris as main channel refuge during winter storms has been established (Hartman 1965; Bustard and Narver 1975a; Tschaplinski and Hartman 1982). Its importance in creation of migration* routes to off-stream sites is not as clear. ...... Culverts and stream crossings designed solely for migrating adult salmon may not be adequate to facilitate access to winter off-stream habitat by smaller juvenile coho. The swimming ability of salmonids is size dependent (Reiser and Bjornn 1979). A culvert designed for easy passage of large adults may have too fast a flow or be too long to allow access by smaller fish. Off-stream juvenile coho winter habitat can not be equated to adult spawning habitat. If access to spawning habitat is the only criterion for culvert or crossing design then many high quality winter habitat sites will be lost. Thus both swimming ability and habitat requirements of juvenile coho must be considered when designing, locating and constructing culverts and stream crossings. 3. Alteration of Winter Water Level The level of water within an off-stream site during the winter period is important for juvenile coho salmon. The higher the water level the more space is available to protect the fish from ice formation, predation and water draw-down during dry periods. Road building can redirect water courses into or away from winter rearing sites. Harvesting activities can alter winter water levels by disrupting the hydrologic cycle. Silvicultural activities such as site rehabilitation (wet land drainage) could completely eliminate winter habitat. Road construction in coastal B.C. watersheds is generally conducted on the side-hills above the valley bottoms. Roads running parallel to the contour lines can divert water from one minor drainage to another neighbouring drainage i f long ditches and few cross-road culverts are used. In general, good road construction would be consistent with maintenance of the existing drainage patterns. Diversion of water away from seepage sites and ephemeral water courses feeding small off-stream ponds and swamps utilized by coho during the winter could be considered detrimental, however diversion of unutilized water into winter habitats could enhance these sites. The dependence of small off-stream ephemeral swamps on minor upslope seepages should be considered before roads are constructed. Clearcut logging has been shown to increase total water yield from a watershed with largest relative increases in summer and largest absolute increases in winter (Harr 1976). Harvesting activities cause soil compaction (Rothacher 1973), destruction of sub-surface macro-channels (Cheng et^ a l . 1975) and plugging of the soil matrix by fines. This may result in a reduction in the rate of water loss from off-stream wet-land sites through subsurface flow. An increase in volume of water entering the sites combined with a reduction in rate of outflow might raise and maintain the winter water level for a longer period of time thus enhancing coho production in off-stream sites. West coast flood-plains are some of B.C.'s best forest land. Growth potential of commercial species is excellent on the nutrient rich, flat terrain provided adequate drainage is available. Poor drainage leads to chlorotic growth and high mortality of even the most water tolerant species, Sitka spruce and western red cedar. Temporarily flooded lands can be rehabilitated through ditching and draining to provide high quality growing sites. Draining of these sites would prove detrimental to coho. It is extremely important to be able to identify winter off-stream coho habitat and to estimate its ablity to produce fish. A l l flood-plain sites scheduled for draining by forest managers should be examined for possible fishery value. Sites without the potential of supporting over-wintering juvenile coho could be drained. Those sites with the potential for supporting coho would become subject to negotiation between forestry and fisheries concerns. Mutual use by these concerns would appear unlikely. The presence of standing water through the winter insures the survival of juvenile coho and the destruction of commercial tree species. Removal of winter standing water insures the survival of the trees and destruction of the coho. For Carnation Creek, 2% of the flood-plain (1 ha / 50 ha) can be considered to support juvenile coho over-wintering off-stream. The loss to forestry however, is far less then 2%. The off-stream sites tend to be long and thin (often less then 2 m wide) and when the forest canopy closes over these sites, l i t t l e to no growing space will be lost. 4. Importance of Large Woody Debris The importance of large woody debris as winter refuge for trout and salmon in flowing streams is well documented (Hartman 1965; Bryant 1983; Bustard and Narver 1975a). Its value in coho production for 116 off-stream sites is not as clear. Although undocumented, large woody debris may be important in the following ways: 1 . A cover of woody debris could reduce predation. 2. On those occasions when flooding occurs, scouring of mud under and around logs would create deep pools providing refuge during drier periods and during ice formation. 3. Logs could aid in stabilization of water levels, water dammed behind them would be trapped by an impenetrable barrier. 4. Half rotted large logs produce a hummock (raised mound within a wet swamp). Vegetation requiring a drier microsite can grow on this hummock thus providing additional site cover and possible diversity in food source. The production of large woody debris is dependent upon the structure of the stand harvested (e.g. old cedars and western hemlock within climax stands contain a high percentage of non-merchantable logs due to a high rot factor) and location of the off-stream sites relative to the location of the landings (e.g. flood-plain sites directly below landings will accumulate the largest volume of debris). Standing timber containing high volumes of rot (designated as non-commercial) should remain within the sites and not be yarded to the landings. This could prove beneficial to both fishery and forestry concerns as off-stream sites would be enhanced due to the increase in large woody material and forestry costs would be reduced through the elimination of unnecessary yarding. Large woody debris already present within the sites should not be removed or relocated through yarding activities. Yarding patterns could be designed to minimize disturbance of known winter habitat sites. 5. Pool Formation and Destruction As indicated earlier, pools can be created through the washing action of running water under and around obstructions such as large logs. Pools can also be lost through the deposition of fines. The loss of rearing space, especially the deeper off-stream pools, would be detrimental to salmonid production. Forestry activities may increase the rate of surface erosion. The generated sediments are carried down steep slopes and deposited on the flat valley floor. Thick blankets of muck (over 1 meter of organic and inorganic sediment) have been noted to cover the alluvial parent material common to the Carnation Creek flood-plain. Although much of this material may have been generated from the main channel, upslope erosion is also responsible. Any forestry activities designed to reduce production of inorganic fines could be considered beneficial not only to main channel habitat but to off-stream habitat as well. The creation of pools through blasting can enhance coho and trout production (Anderson and Miyajima 1975; Bustard 1983). This technique applied to ephemeral muck swamps may enhance winter coho habitat, however the mechanism of spring emigration from ephemeral off-stream habitat to the main channel is not clear. Deep pools created in these areas may prove to be traps destroying fish rather than improving production. The utility of a blasted pool may be very short. Ephemeral swamps are subjected to constant settling of suspended sediments under conditions of reduced water velocity and blasted pools may f i l l in very quickly. 6. Semi-aquatic Vegetation Forestry activities can have both a direct and an indirect impact on vegetation rooted within the off-stream sites. Direct impacts include mechanical removal and physical destruction through yarding and felling of timber and chemical destruction of aquatic vegetation through use of herbicides. Indirect impacts include changes in light intensity through removal of riparian vegetation, changes in nutrient regime through both timber removal and prescribed burning and changes in substrate quality through addition of organic fines and woody debris. The importance of semi-aquatic vegetation rooted within the off-stream sites is presumed to be as follows: 1. Provides stability to the muck substrate through anchoring roots. 2. Provides refuge from avian predators. 3. Possibly represents a major component in the food web of ponds and swamps. 4. Dissipates the destructive energy of flood waters. 5. Possibly produces a chemical cue to the location of suitable off-stream habitat thus aiding juvenile coho migration. The elimination of disturbance to vegetation rooted within off-stream sites by yarding and felling activities is impossible. Many off-stream sites have veneers of organic muck over coarse alluvial rocks and gravel. These sites are extremely vulnerable to mechanical disturbance. The position of landings and season in which felling and yarding are implemented are important in minimizing disturbance. Landings should be positioned such that maximum l i f t is achieved over the areas deemed sensitive. Most west coast alluvial flood-plains are an integral part of winter logging operations thus yarding during periods of high water conditions can't be avoided. However, i f sensitive areas are felled and yarded late into winter, then at least some of the early winter floods can be avoided. A major concern of west coast foresters is the elimination of competing alder (Alnus rubra) and salmonberry (Rubus spectabilis) from the productive flood-plains. At present only 2-4-D and glyphosate (©Roundup) are licensed for aerial application in B.C. To date the majority of herbicide testing has been to establish the toxicity and hazard of a given herbicide to a given fish species. Little consideration as to possible indirect effects of herbicides on coho through destruction of non-target plants (semi-aquatic vegetation) has ever been given. The importance of such a study is indicated by the use of herbicides such as glyphosate to destroy vegetation bordering drainage ditches (Norris et a l . 1983). Removal of riparian vegetation will increase the availability of light to vegetation rooted within narrow off-stream habitat. This increase is expected to be temporary ( less then 15 years) as riparian vegetation will quickly become re-established. Immediately following both harvest and prescribed burning an increase in nutrient levels can be expected (Brown 1980; Scrivener 1982). This increase combined with the increase in light can be expected to enhance the growth of established vegetation within the off-stream sites. As sedges and rushes (Scirpus sp., Juncus sp., Typha sp. and Carex sp.) are rapid colonizers, newly created sites will quickly become vegetated. The production of small and intermediate sized woody debris during felling and yarding activities can be expected to alter the substrate within the off-stream swamp sites. The decomposition of organic fines combined with the already highly anerobic conditions within the saturated muck soils can be expected to increase H2S and reduce 0 2 levels. Rooting depth will be reduced and the range of plant species capable of surviving will be narrowed. Immediately following logging a large volume of small woody debris (pieces less then 3 meters in length) is present on the flood-plain (Toews and Moore 1982). Reduced velocities within the ephemeral swamps and intermittent tributaries prevents removal of this debris which may collect and cover the bottom. Debris blankets will not permit the germination or growth of vegetation requiring an exposed soil surface. Large accumulations of small debris can be noted immediately below landings situated on hill-sides above the flood plain* As timber is yarded off the valley floor maximum breakage will occur on the slope directly below the yarder tower. Debris will r o l l back down the slope (depending on gradient) and accumulate on the valley floor below. If landings are positioned on the c l i f f face directly above winter off-stream coho habitat, a vast accumulation of intermediate sized debris will cover the habitat's surface impeding growth of semi-aquatic vegetation and altering the site's ability to produce coho. 7. Changes Over the Forest Rotation During the winter of harvest a reduction in habitat quality and coho production can be expected. Increased sedimentation, reduction in chemical quality (H2S), increased scour and destabllization of large debris will occur. A small fence at the outlet of R750m swamp was monitored through the specific period of active yarding (Log April/1976; Carnation Creek Working Group 1985). At this time water flowing from the site was turbid and an out-migration of 117 juvenile coho was noted however, the time of migration coincided not only with the period of yarding but also with juvenile coho's normal seasonal period of out-migration (April). A movement of trichopteran larvae (Limnephilidae sp.) was also observed, the cases of which were so numerous they completely plugged the small fence. This is the only time these trichopteran larva have been noted in such numbers. In general an improvement in quality and possibly quantity of off-stream habitat should occur during the early successional stages. More water is available due to reduction in evapotranspiration and interception, growth of semi-aquatic vegetation is enhanced due to increased light and nutrients and an increase in deciduous growth should enhance the allochthonous energy pathway. Fall storms will remove much of the organic matter and sediments deposited in the year of active logging, although some f i l l i n g in of deep pools can be expected. On the unterraced alluvial flood-plain the main channel will begin to rapidly alter its position as stabilizing material is lost. As new channels are created old channels will become temporary flood channels forming ephemeral muck swamps. There may be an increase in large woody debris after the harvest of an old growth forest. This would provide additional cover and aid in creation of deep pools. After crown closure the nutrient loss from the terrestrial component of the watershed will be reduced, solar radiation available to semi-aquatic vegetation will decline, evapotranspiration and rainfall interception will increase, the input of large woody debris from new stands will be non-existent and the main channel will begin to stabilize. Thus the level of standing water and quantity of semi-aquatic vegetation within the sites will decline. The formation of new sites will be minimal. A decline in off-stream coho production can be expected. Thus within an active flood-plain new swamps are being created through the abandonment of channels and old swamp sites are slowly lost as potential fish habitat. The system is dynamic and logging destabilizes the flood-plain further. It is unknown if the creation of new habitat will exceed the loss of old habitat. This would depend upon the individual watershed and the intensity of harvest. The cumulative effects of various forestry practices on the quality of off-stream habitat is very complex. Some practices may enhance habitat while others destroy habitat. Using only two sites (R750m and L1600m) Tschaplinski and Hartman (1983) have indicated no difference in numbers and no apparent difference in survival of coho utilizing off-stream habitat before and after logging. However, the fi r s t year of active logging may show the greatest net loss (it was not examined) and some forestry practices such as drainage have an obvious detrimental effect on habitat quality. 8. Trout Versus Coho (Management Differences) Differences in species presence, season of residence and possible use of the various minor drainages exists. Trout inhabited intermittent tributaries, while coho juveniles occupied both intermittent tributaries and ephemeral swamps. Populations of trout and juvenile coho where found within intermittent tributaries in a l l seasons, while ephemeral habitat supported coho juveniles only for the winter period. Use of minor drainages by trout and coho for spawning has been reported (Tshaplinski and Hartman 1983) however, use of muck bottom drainages is unlikely and during the course of this study numerous trout in spawning condition were noted moving into the tributaries (trapped at small fences) but, no adult coho were observed. These interspecies differences imply basic differences in management strategies directed towards either trout or coho habitat protection. Intermittent tributaries were easier to identify as fish habitat than were ephemeral swamps. For management purposes such as: design of bridges and culverts, delineation of buffer zones and specific recommendations during harvesting activities; i t would be easier to locate and argue for protection of trout habitat than coho habitat. Unavoidable disturbances to ephemeral habitat could be directed towards the driest summer months when no coho juveniles are present. Within intermittent tributaries however, there may be no preferred season in which potentially disturbing forestry activities can take place. The use of tributaries by spawning trout requires the maintenance of substrate quality and forestry practices which reduce peak flows (prevent flushing and scouring of rooted vegetation). Increases in sedimentation and increases in small debris loading, may lower trout production. If spawning by coho within these minor tributaries is not as prevalent, their production may not be impaired. 9. Means of Reducing Impacts The fundamental problem in reducing the impacts of forestry practices on off-stream habitat is the inability of watershed managers to identify this habitat type. Even if an off-stream site is recognized its importance may be underestimated. Its importance is not only in number of fish. Juvenile coho use of this habitat represents an alternative winter survival strategy. Only through proper identification and evaluation can the habitat type be managed. Various forestry practices can be modified to maintain the quality of the habitat and protect the coho utilizing the site: 125 1. Locate landings such that: a) the least amount of yarding occurs within the swamp sites; b) l i f t is at its maximum over the swamps; c) the volume of small and intermediate sized debris is reduced (cleanup). 2. Water is not diverted away from the sites during road building. 3. Engineering structures allow juvenile coho access. 4. Herbicide use within the sites is reduced. 5. Large woody debris is left within the sites and is not hauled out to the landings. 6. Soil erosion is minimized. These areas should not be thought of as catch basins to protect the main-stream. 7. Active logging should take place in the drier season when juvenile coho are absent from the ephemeral sites. 10. Cost to Forestry The incremental cost of environmental regulations necessary to protect off-stream winter habitat is that cost to the forestry resource sector over and above the cost otherwise incurred. The lack of quantitative cost or benefit estimates reduces both the accuracy and precision of any total incremental figure derived from summation of these estimates. Only the relative magnitude and direction of the major additional costs imposed on the forest resource sector can be estimated. These additional costs are: 126 1. Low elevation west coast flood-plains are an integral part of winter logging patterns. It would be extremely difficult and costly to postpone the harvest of sensitive sites on the flood-plain to a drier season. 2. Costs would be higher if more landings or additional settings were required to avoid sensitive areas. The exact cost would be highly variable and specific to a particular watershed. 3. The additional costs incurred if herbicide free buffer zones were required on a l l seasonal water courses may be extremely high. If ten meter wide buffer zones were required on the long narrow sites common to the Carnation Creek flood-plain, the aerial application of herbicide to approximately 7 ha (15% of the flood-plain) would not be permitted. 4. Costs would be higher if site specific structures such as baffled culverts were required to permit juvenile salmonid passage. Costs would also be higher if additional culverts were required to maintain the natural drainage into an off-stream site. 11. Future Experimental Programs Within this later chapter, various speculative statements were made. Future experimental programs could increase our understanding of processes occurring within off-stream winter habitat and remove much of this speculation. Future programs should consider: 1. The potential of habitat creation through blasting of deep holes within sites. 2. The potential of improving access to off-stream sites. 3. The role of large woody debris within ephemeral sites. 4 . The direct impacts of winter felling and yarding on water quality and juvenile salmonid survival within winter habitat which lacks a constant directional flow. 5. The potential of stabilizing exposed muck surfaces through seeding with various species of semi-aquatic plants. 12. Conclusions The use of off-stream habitat by coho is a major component of their winter survival strategy. On west coast flood-plains the quality and quantity of off-stream winter habitat changes over time with annual variation, forest succession and fluvial processess. Forestry activities can alter the quality of this habitat, the ability of the juvenile coho and trout to access this habitat and processes and cycles occurring within this habitat. Through careful management practices many harmful effects can be avoided and some enhancement techniques may be utilized to improve fish production. This study can not be considered in isolation. Other li f e stages, habitat types, seasons and species must be examined and incorporated into any decision making process concerning forestry activities within this rain dominated coastal watershed. Salmonid behaviour within other watersheds, especially snow dominated systems may be completely different (Bustard in press) and extrapolation of findings made in this thesis to other forested regions must be done with extreme care. The potentially high cost to the forestry resource sector of additional environmental regulations designed to protect off-stream salmonid winter habitat, must also be considered. 128 BIBLIOGRAPHY Andersen, B.C. 1983. Fish populations of Carnation Creek and other Barkley Sound streams 1970-1980. Can. Data Rep. Fish. Aquat. Sci. 415. 267p. Andersen, B.C. 1984. Fish populations of Carnation Creek and other Barkley Sound streams 1981-1982. Can. Data Rep. Fish. Aquat. Sci. 435. 63p. Andersen, B.C. In press. 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Corvallis Environmental Research Lab., Oregon. 85p. Happ S.C, G. Rittenhouse and G.C. Dobson. 1940. Some principles of accelerated stream and valley sedimentation. USDA. Tech. Bull. 695, p.22-31. Harr, R.D. 1976. Hydrology of small forest streams in western Oregon. USDA For. Serv. Gen. Tech. Rep. PNW-55. 15p. Harr, R.D., W.C Harper and J.T. Krygier. 1975. Changes in storm hydrographs after roadbuilding and clearcutting in the Oregon Coast Range. Water Resour. Res. 11:436-444. Hartman, G.F. 1965. The role of behaviour in the ecology and interaction of underyearling coho salmon (Oncorhynchus kisutch) and steelhead trout (Salmo gairdneri). J. Fish. Res. Bd. Can. 22:1035-1081. Hartman, G.F. 1981. Carnation Creek Report for 1979 and 1980. Pacific Biological Station, Nanaimo, B.C., Canada. 21p. Hartman, G.F. 1982. The study area: an in i t i a l description. Page 15 in G.F. Hartman editor. Proceedings of the Carnation Creek workshop, a ten year review. 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February 24-26, 1982. 404p. Inselberg, A.E., K. Klinka, and C. Ray. 1982. Ecosystems of MacMillan Park on Vancouver Island. British Columbia Ministry of Forests. Victoria, B.C. Canada. Land Management Report Number 12, ISSN 0702-9861. 113p. Klinka, K., F.C. Nuszdorfer, and L. Skoda. 1979. Biogeocllmatic units of central and southern Vancouver Island. British Columbia Ministry of Forests. Victoria, B.C. Canada. 120p. Klinka, K., W.D. van der Horst, F.C. Nuszdorfer, and R.G. Harding. 1980. An ecosystematic approach to a subunit plan: Koprino River watershed study. Land Management Report Number 3. British Columbia Ministry of Forests, Victoria. B.C., Canada. 118p. Knight, N. J. 1980. Factors affecting smolt yield of coho salmon (Oncorhynchus kisutch) in three Oregon streams. MSc. thesis. Oregon State Univ., Corvallis. lOlp. Krajina, v.J. 1969. Ecology of forest trees in British Columbia. Ecology of Western North America 2:1-146. 132 Lavkolich, L.M. 1977. Methods Manual. Pedology Laboratory, Dept. Soil Sci. University of B.C., Vancouver, B.C. 224p. Lewis, J. and D Hughes. 1978. Welsh floodplain studies. II. Application of a qualitative endunation model. J. Hydrol. 46:35-49. L i l l , A.F. and P. Sookachoff. 1974. The Carnation Creek counting fence. Can. Fish. Mar. Ser. Southern Operations Branch, Pac. Reg. Tech. Rep. PAC-T-74-2. 23p. Maciolek, J.A. and P.R. Needham. 1952. Ecological effects of winter conditions on trout and trout foods in Convict Creek, California. Trans. Am. Fish. Soc. 81:202-217. MacMillan Bloedel Limited. 1979. MacMillan Bloedel Limited Logging Operations in Carnation Creek Watershed, 1975-1978. Fisheries and Marine Service. Data Report 157. 22p. Mason, J.C. 1976. Response of underyearling coho salmon to supplemental feeding in a natural stream. J. Wildl. Mgmt. 40:775-788. Mueller-Dombois, D. and H. Ellenberg. 1974. Aims and Methods of Vegetation Ecology. John Wiley and Sons, New York. 545p. Mundie, J.H. and R.E. Traber. 1983. The carrying capacity of an enhanced side-channel for rearing salmonids. Can. J. Fish. Aquat. Sci. 40:1320-1322. Narver, D.W. 1974. Carnation Creek experimental watershed project. Annual report for 1973. Report submitted to the Carnation Creek Coordinating Committee by the Working Group. March 1974. Pacific Biological Station, Nanaimo, B.C. 24p. Narver, D.W. and T.W. Chamberlin. 1976. Carnation Creek—An experiment towards integrated resource management. Fish. Mar. Ser. Pac. Biol. Sta. Circ. 104. 20p. Needham P.R. and A.C. Jones. 1959. Flow, temperature, solar radiation, and ice in relation to activities of fishes in Sagehen Creek, California. Ecology, Vol. 40, No. 3:465-474. Norris L.A., H.W. Lorz, and- S.V. Gregory. 1983. Influence of forest and rangeland management on anadromous fish habitat in Western United States and Canada. 9. Forest chemicals. USDA. Forest Service. PNW-149. 95p. Oswald, E.T. 1973. Vegetation and soils of Carnation Creek watershed, a progress report. Dept. Env., Canadian Forest Service, Pacific Forest Research Centre, Victoria, B.C. Internal Report BC-43. 38p. Peterson, N.P. 1980. The role of spring ponds in the winter ecology and natural production of coho salmon (Oncorhynchus kisutch) on the Olympic Peninsula, Washington. MS. thesis, Univ. Wash. Seattle. 96p. Reiser, D.W. and T.C. Bjornn. 1979. Influence of forest and rangeland management on anadromous fish habitat in Western United States and Canada. 1. Habitat requirements of anadromous salmonids. USDA. Forest Service. PNW-96. 54p. Riddell B.E. and W.C. Leggett. 1981. Evidence of an adaptive basis for geographic variation in body morphology and time of downstream migration of juvenile Atlantic salmon (Salmo salar). Can. J. Fish. Aquat. Sci. 38:308-320. Rlmmer, D.M., U. Paim, and R.L. Saunders. 1983. Autumnal habitat shift of juvenile Atlantic salmon (Salmo salar) in a small river. Can. J. Fish. Aquat. Sci. 40:671-680. Ringstad, N. 1982. Carnation Creek watershed project freshwater sculpins: genus Cottus a review. Pages 289-305 in G.F. Hartman, editor. Proceedings of the Carnation Creek workshop, a ten year review. Pacific Biological Station, Nanaimo, B.C. February 24-26, 1982. 404p. Rothacher, J. 1973. Does harvest in west slope Douglas-fir increase peak flow in small forested streams? USDA. For. Ser. Res. Pap. PNW-163. 13p. Scarnecchia, D.L. 1981. Effects of streamflow and upwelling on yield of wild coho salmon (Oncorhynchus kisutch) in Oregon. Can. J. Fish. Aquat. Sci. 38:471-475. Scrivener, J.C. 1982. Logging impacts on the concentration patterns of dissolved ions in Carnation Creek, British Columbia. Pages 64-99 in_ G.F. Hartman, editor. Proceedings of the Carnation Creek workshop, a ten year review. Pacific Biological Station, Nanaimo, B.C. February 24-26. 1982. 404p. Scrivener J.C. and M.J. Brownlee. 1980. A preliminary analysis of Carnation Creek gravel quality data, 1973-1980. In proceedings from the conference, Salmon-spawning gravel: a renewable resource in the Pacific Northwest?, Oct. 6-7, 1980. Seattle, Washington. Seegrist, D.W. and R. Gard. 1972. Effects of floods on trout in Segehen Creek, California. Trans. Am. Fish. Soc. 101:478-482. 134 Skeesick, D.G. 1970. The f a l l immigration of juvenile coho into a small tributary. Ore. Fish. Comm. Res. Rep. 2(l):90-95. Symons, P.E.K. 1978. Carnation Creek annual report for 1976. Pacific Biological Station, Nanaimo, B.C. 14p. Symons, P.E.K. 1979. Carnation Creek annual report for 1978. Pacific Biological Station, Nanaimo, B.C. 20p. Toews, D. and M. Brownlee. 1981. A handbook for fish habitat protection in British Columbia. Habitat Protection Division, Dept. of Fisheries and Oceans, Vancouver, B.C. 173p. Toews, D.A. and M.K. Moore. 1982. The effects of three streamside treatments on organic debris and channel morphology in Carnation Creek. Pages 129-153 in G.F. Hartman, editor. Proceedings of the Carnation Creek workshop, a ten year review. Pacific Biological Station, Nanaimo, B.C. February 24-26, 1982. 404p. Tshaplinski, P.J. and G.F. Hartman. 1983. Winter distribution of juvenile coho salmon (Oncorhynchus kisutch) before and after logging in Carnation Creek, British Columbia, and some implications for overwinter survival. Can. J. Fish. Aquat. Sci. 40:452-461. Walmsley, M., G. Utzig, T. Void, D. Moon, and J. van Barneveld. 1980. Describing ecosystems in the field. RAB. Technical Paper 2, Land Management Report No. 7. British Columbia Ministry of Forests. Research Branch. 225p. Welcomme, R.L. 1979. Fisheries Ecology of Floodplain Rivers. Longman, New York, USA. p. Wolman G. and L.B. Leopold. 1957. River flood plains: some observations on their formation. Geological Survey Professional Paper. 282-C. p87-107. I B S Content: APPENDIX 1. MAPS OF WINTER FLOODED LAND LOCATED ON CARNATION CREEK'S FLOOD-PLAIN 1. Swamp System R250m 2. Swamp System R750m 3. Swamp System L1250m - L1550m 4. Swamp System R1500m 5. Tributary System Ll600m 6. Tributary System L2600m SWAMP SYSTEM R 250 m Scale 1^6 LEGEND M A P UNITS Map Unit I Map Unit 2 ( exposed gravel ) ( exposed muck ) Map Unit 3 ( bullrush — cattail ) Map Unit 4 (juncus — seepage ) Map Unit 5 ( sedge — meadow ) Map Unit 6 ( grass — meadow ) Map Unit 7 (woody debris) R E F E R E N C E 28 study plots small fence ^ ^ log t = E P non flooded land ^— seepage I A M A / I A * . m a i n - stream flooding trail site boundaries SWAMP SYSTEM R 750 m Scale Map Unit 5 ( s e d g e — m e a d o w ) " site boundaries Map Unit 6 ( g r a s s meadow ) WW* Map Unit 7 (woody d e b r i s ) SWAMP S Y S T E M L 1250 m - L 1550m X / / Scole 5m o 10m 2 0 m \ \ L 1250m L E G E N D MAP UNITS Map Unit ( exposed gravel) Map Unit b , ( exposed muck ) Map Unit Map Unit Map Unit Map Unit Map Unit [3 ( bullrush — cattail) 4 (juncus — seepage ) 5 ( sedge — meadow ) 6 ( grass — meadow) 7 ( woody debris) REFERENCE study plots I 2 8 I small fence 5 ( log i i non flooded land o seepage -vvwuvw main- stream flooding trail site boundaries L 1550 m SWAMP S Y S T E M R 1500m \ 5 m 0 m 1 0 m 2 0 m LEGEND MAP UNITS REFERENCE km Map Unit I ( exposed gravel ) Map Unit 2 ( e x pos e d muck ) Map Unit 3 ( bul lrush — cat ta i l ) Map Unit 4 ( juncus — seepage ) Map Unit 5 ( sedge — meadow ) M a p Unit 6 ( g rass — m e a d o w ) Map Unit 7 ( w o o d y debr is ) study plots smal l fence log non f l o o d e d land seepage m a i n - s t r e a m f looding trail site boundar ies 28 TRIBUTARY S Y S T E M L 1600 m Scale / / / I Map Unit Map Unit 2 Map Unit 3 Map Unit 4 Map Unit 5 Map Unit 6 Map Unit 7 ( exposed gravel ) ( exposed muck ) ( bullrush — cattail ) (juncus — seepage ) ( sedge — meadow ) ( grass — meadow ) ( woody debris) REFERENCE study plots L l f _ small fence ) ( log i i non flooded land o seepage main-stream flooding —"""" troil site boundaries TRIBUTARY S Y S T E M R 2 6 0 0 m l HI L E G E N D i MAP UNITS Map Unit I ( exposed gravel) Map Unit 2 ( exposed muck ) Map Unit 3 ( bullrush — cattail ) Map Unit 4 (juncus — seepage ) Map Unit 5 ( sedge — meadow ) Map Unit 6 ( grass — meadow) Map Unit 7 ( woody debris) REFERENCE study plots mm small fence ) ( log • ' non flooded land .: O seepage MVWWI*. main-stream flooding —" trail site boundaries R2600 lower R 2600 upper APPENDIX 2. DATA TABLES USED TO DEVELOP MAP AND HABITAT UNITS Content: 1. Surface Cover / Plot 2. Soil Analysis / Plot 3. Water Level / Plot 4. Soil pH / Plot 5. Vegetation Species List 6. Vegetation Table 7. Coho Catch / Plot 8. Trout Catch / Plot 9. Surface Cover / Map Unit 10. Percentage Organic Soil / Map Unit 11. Percentage Particle Size / Map Unit 12. Water Level / Map Unit 13. Fish Catch / Map Unit 14. Surface Area / Map Unit TABLE 1 SURFACE COVER OF SAMPLE PLOTS BY PERCENT (Summation of % by strata may be greater then 100%) Plot % Vegetative cover by strata % Soil % Woody Bl B2 C D Total debris 01 % % 99% 6% 99% 95% 5% 02 95 7 95 95 5 03 99 60 99 85 15 04 1 95 60 95 60 40 05 2 95 35 98 75 25 06 65 35 99 85 15 07 99 80 99 85 15 08 1 35 12 45 90 10 09 99 6 99 98 2 10 80 2 80 95 5 11 99 30 99 85 15 12 1 1 55 1 55 90 10 13 1 30 6 30 95 5 14 1 35 4 35 90 10 15 2 30 20 50 90 10 16 99 99 99 1 17 80 1 80 95 5 18 5 5 60 40 19 5 5 45 55 20 5 5 30 70 21 20 5 20 90 10 22 1 95 1 95 95 5 23 1 1 70 10 70 90 10 24 80 4 80 90 10 25 1 10 2 10 70 30 26 1 50 65 90 98 2 27 25 25 50 50 28 1 90 17 95 95 5 29 10 1 10 90 10 30 50 3 50 98 2 31 5 5 90 10 32 5 5 90 10 33 10 1 10 95 5 34 10 10 35 65 35 1 4 60 30 70 80 20 36 10 2 10 40 60 37 99 1 99 95 5 38 1 65 8 70 95 5 39 5 40 75 95 85 15 40 1 1 40 15 40 95 5 TABLE 2 RESULTS OF SURFACE SOIL ANALYSIS FOR SAMPLE PLOTS (% Organic represents loss on ignition at 450 C.) (Particle sizes based on USDA sieve sizes) Plot % Particle size (100%) % Organic CG FG VCS CS MS FS VFS FIN CG FG VCS CS MS FS VFS FIN TOT 01 0 5 3 11 24 28 18 12 79 49 47 46 40 37 36 43 02 0 4 1 11 17 30 21 15 - 68 61 42 40 36 31 26 36 03 0 29 6 12 23 18 9 4 - 38 39 49 52 49 48 40 43 04 0 25 13 27 17 13 5 1 - 70 51 67 61 63 63 50 64 05 0 7 3 13 21 27 20 8 - 47 62 75 67 59 45 44 58 06 0 23 4 9 24 18 16 7 - 95 82 82 80 71 59 62 78 07 0 25 8 17 17 18 11 5 41 50 55 51 56 48 41 49 08 0 18 3 13 22 24 12 9 - 7 28 5 31 32 32 29 23 09 0 14 8 7 18 39 10 7 - 76 51 59 44 39 33 31 46 10 0 24 18 18 19 16 5 2 - 74 60 50 47 34 23 46 53 11 0 6 2 13 23 25 15 17 — 70 51 48 48 49 49 44 49 12 0 11 8 14 27 21 12 7 - 55 57 55 56 49 43 41 52 13 0 2 2 20 27 24 15 11 - 73 70 61 62 63 60 54 61 14 0 3 2 21 25 28 13 9 - 83 77 73 73 73 75 66 73 15 0 13 4 20 24 22 12 5 92 88 82 82 80 77 65 82 16 0 7 1 8 15 30 23 16 - 68 77 57 52 42 30 27 42 17 0 6 1 6 18 31 25 14 - 77 41 26 18 24 13 15 22 18 29 43 3 5 15 5 1 T 2 1 3 3 3 4 9 T 2 19 46 40 7 4 2 1 T T 1 1 2 3 5 9 T T 1 20 62 26 3 2 3 3 1 T 1 1 3 5 5 6 10 T 1 21 0 13 9 15 13 27 14 10 — 65 63 63 50 48 48 43 53 22 0 3 2 5 34 31 15 11 - 82 55 45 36 30 31 32 35 23 0 T T 3 21 33 28 14 - 12 80 68 68 61 69 48 63 24 0 3 5 13 24 25 18 11 - 78 70 63 52 39 30 24 45 25 0 2 5 13 24 29 17 11 - 65 50 51 40 48 38 40 44 26 0 6 7 9 16 29 22 12 - 87 80 95 78 66 60 55 70 27 22 58 14 5 1 T T T 1 1 2 3 8 T T T 1 28 0 14 5 17 21 21 14 8 - 80 83 75 63 55 57 49 65 29 36 46 9 5 3 1 T T 1 2 2 2 4 6 12 11 2 30 0 T 1 8 22 26 28 15 — 58 59 47 49 48 31 32 41 31 0 16 3 10 16 21 14 21 82 56 57 72 51 49 44 58 32 30 13 28 22 7 1 T T T 2 1 2 3 10 29 16 2 33 0 4 3 10 20 31 21 11 - 90 59 57 58 52 45 37 52 34 0 3 7 12 20 37 16 5 - 82 75 64 44 20 14 17 35 35 0 5 6 7 10 23 23 27 - 17 5 5 8 9 8 7 8 36 0 27 22 22 15 9 3 2 - 70 67 54 66 65 62 51 64 37 0 5 1 8 11 40 21 15 - 45 33 66 43 18 21 26 28 38 0 10 6 14 26 20 15 9 - 44 33 36 32 28 22 13 30 39 0 7 3 7 21 27 20 15 - 87 75 72 72 73 69 57 71 40 0 8 6 13 16 25 19 13 - 72 56 54 53 42 36 39 47 TABLE 3 WATER TABLE DEPTH RELATIVE TO PLOT SURFACE (0 = at surf a c& . -r above sur face , - belo v su; rface ) PLOT WATER LEVEL ( cm ) JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG 01 -21 -20 -19 39 35 27 17 24 24 25 23 -36 ^f5 -51 02 -15 -13 -19 10 11 09 07 08 09 08 03 -20 -24 -29 03 -60 -60 -60 15 09 -09 10 16 21 07 -31 -60 -60 -60 04 -60 -60 -60 21 19 -02 21 22 31 08 -33 -60 -60 -60 05 -60 -25 -60 11 03 -16 06 12 19 -04 -30 -60 -60 -60 06 -60 -60 -60 25 21 0 20 28 33 16 -26 -60 -60 -60 07 -60 -60 -60 48 45 20 45 48 58 38 08 -60 -60 -60 08 -38 -31 -28 06 09 -03 02 03 02 04 -26 -31 -30 -50 09 -18 -18 -26 14 17 20 15 17 18 14 13 -21 -24 -37 10 -04 -01 -04 04 05 05 03 02 02 02 01 -02 -02 -03 11 -02 -12 -01 18 21 20 17 21 23 22 14 -16 -50 -60 12 02 03 01 07 07 06 05 06 08 08 04 02 04 01 13 -03 -04 -05 02 07 01 -02 -01 02 02 -03 -01 -05 -05 14 -28 -17 -08 02 01 -04 02 02 0 01 -01 -03 -05 -10 15 -03 0 0 13 06 07 06 07 09 09 03 0 -04 -04 16 15 20 16 21 20 21 17 19 20 19 16 14 05 0 17 11 12 06 19 26 22 27 30 31 30 22 09 06 02 18 20 30 29 30 23 29 12 12 15 16 14 13 13 14 19 10 09 09 14 13 15 15 17 22 20 16 13 12 10 20 19 20 19 22 20 18 16 19 20 20 19 16 17 16 21 -07 -06 -08 12 08 16 17 20 22 16 03 -04 -07 -07 22 -12 -26 -22 05 06 07 10 10 13 11 07 01 -09 -21 23 -11 -05 -07 10 07 12 11 08 15 12 05 -03 -16 -06 24 -14 -13 -47 10 14 14 23 23 29 29 16 •18 06 -15 25 -12 -06 -14 04 27 04 06 09 09 08 05 05 03 -09 26 -15 -16 -17 -05 -10 -05 -11 -08 -08 -07 -12 -09 -12 -14 27 12 12 09 16 16 23 15 18 21 22 15 11 10 08 28 -08 -12 -13 -04 04 -03 -03 -03 -03 -05 -01 -02 -13 -40 29 11 11 08 11 09 11 08 06 06 06. 05 04 06 06 30 -24 -51 -48 09 14 34 10 13 17 16 09 -36 -60 -60 31 05 06 -07 18 24 18 13 16 17 16 17 16 -05 -26 32 26 26 20 26 27 32 26 33 37 39 31 25 26 23 33 -05 -04 -10 20 20 21 18 21 26 26 21 22 15 -04 34 20 22 16 35 30 27 32 34 37 34 26 11 08 10 35 -45 -18 -11 -11 -12 -05 -06 -01 -09 -04 -25 -12 -09 -14 36 22 23 21 24 30 31 30 32 32 37 30 27 26 23 37 -11 -02 -05 20 15 07 17 18 27 19 07 -05 -08 -15 38 -60 -60 -60 24 19 -03 . 23 28 41 14 -15 -60 -60 -60 39 -40 -21 -16 -01 02 -02 -01 02 -01 -02 -07 -22 -23 -34 40 0 -02 -02 01 04 01 -02 01 01 01 -03 -02 -02 -05 TABLE 4 SOIL pH OF SAMPLE PLOTS (Samples taken during March 1984) Plot pH of soil 01 5.15 02 5.15 03 4.39 04 4.64 05 3.89 06 4.53 07 4.44 08 4.81 09 5.21 10 5.13 11 4.55 12 5.03 13 5.51 14 4.30 15 4.91 16 4.83 17 5.70 18 4.97 19 5.78 20 5.67 21 4.89 22 5.04 23 5.08 24 4.52 25 4.82 26 4.91 27 5.03 28 5.00 29 5.43 30 4.92 31 4.80 32 5.28 33 4.88 34 4.98 35 5.25 36 5.29 37 5.07 38 4.40 39 4.76 40 4.95 TABLE 5 SIGNIFICANCE OF PLANT SPECIES PER PLOT (COVER- ABUNDANCE SCALE, MUELLER-DOMBOIS AND ELLENBERG 1974, p62) PLOTS ST SPECIES PRES LYSI A ME 90 0 • EN* SAR 90 0 EPIL C1L 77 .5 ZANN PAL 20 O SCUT LAT 17 .5 MNIU INS 15 .0 TVPH LAT 10 .0 ELEO PAL 10 .0 JUNC ENS 35 .0 EOUI PAL 30 .0 LECI DEA 37 .5 SCIR MIC 62 .5 AGRO STO 45 .0 ATHY FIL 57 .5 SPH» GNU 57 .5 GAL I TRF 42 5 CARE OBN 27 .5 FONT ANT 20 0 VIOL PAL 25 .0 MA IA DIL 35 0 AIRA 35 .0 RUBU SPE 27 5 POLY JUN 25 0 JUNC EFF 25 .0 ANAP MAR 22 .5 BLEC SPI 20 .0 GEUM MAC 12 .5 HERA SPH 12 5 LUZU PAR 12 .5 SALI SIT 15 0 PELT IGE 12 5 TIAR UNI 12 5 OSMO RHI 10 .0 CARE LIV 7 .5 PICE SIT 7 .5 RICC NAT 7 .5 CARE FLA 5 0 CLAY SIB 5 0 DISP TRA 5 0 HYLO SPL 5 0 JUNC US 5. 0 LACT UCA 5. 0 MALU FUS 5 0 MITE PEN 5 0 MNIU GLA 5 0 THUJ PL I 5 0 VACC OVA 5 0 VACC PAR 5 0 AO IA PEO 2 5 AINU RUB 2 5 A RUN CUS 2 .5 CARE MER 2 5 EPIL ANG 2 5 HYPO RAD 2 5 MENZ FER 2 5 PETA FRI 2 5 POLY MUN 2 5 PRUN VUL 2 5 RISE SAN 2 5 RORI PPA 2 5 RUBU PAR 2 5 SALI LAS 2 5 SAMB RAC 2 5 SPAR AME 3 5 SPIR OOU 2 5 STAC COO 2 5 T 1 AR TR 1 2 5 TSUG HE T 2 5 19 20 37 29 33 21 25 31 33 34 36 02 9? 10 12 1 1 3 1 1 1 1 1 4 i 3 5 3 3 5 1 4 1 2 1 4 4 1 5 1 1 1 1 2 1 1 3 1 1 1 1 3 1 2 3 B 5 1 2 3 4 5 1 1 1 2 1 3 5 5 2 2 1 3 2 3 4 1 1 3 1 1 2 1 2 3 3 1 1 3 1 2 1 8 9 8 7 33 34 37 14 15 26 13 35 40 1 4 3 3 i 4 5 3 1 1 3 5 3 4 3 3 3 4 1 1 1 1 1 1 1 1 3 3 8 3 5 1 1 1 3 2 3 4 3 4 8 9 1 1 1 1 1 1 3 1 1 3 2 1 1 1 1 3 4 1 4 3 3 2 1 3 5 8 1 5 3 3 2 3 1 1 1 3 3 3 1 2 4 3 1 3 1 1 1 1 1 1 2 1 1 3 3 1 5 3 5 1 5 5 1 1 2 1 3 2 1 1 1 1 3 3 2 1 3 2 1 1 4 1 4 1 3 1 3 4 1 4 1 3 5 2 4 1 6 2 5 4 2 1 1 1 1 2 2 9 1 9 1 8 4 9 2 9 2 8 6 3 3 8 8 9 6 3 3 7 1 4 1 1 4 1 9 4 4 1 5 3 • 4 2 1 1 3 3 1 1 2 1 1 1 2 5 3 + 2 2 1 3 3 1 1 -i-TABLE 6 VEGETATION SPECIES LIST 1 ADIAPED 2 AGROSTO 3 AIRA 4 ALNURUB 5 ANAPMAR 6 ARUNCUS 7 ATHYFIL 8 BLECSPI 9 CAREFLA 10 CARELIV 11 CAREMER 12 CAREOBN 13 C L A Y S I B 14 DISPTRA 15 ELEOPAL 16 EPILANG 17 E P I L C I L 18 EOUIPAL 19 FONTANT 20 GALITRF 21 GEUMMAC 22 HERASPH 23 HYLOSPL 24 HYPORAD 25 JUNCEFF 26 dUNCENS 27 JUNCUS 28 LACTUCA 29 LECIDEA 30 LUZUPAR 31 LYSIAME 32 MAIADIL 33 MALUFUS 34 MENZFER 35 MITEPEN 36 MNIUGLA 37 MNIUINS 38 OENASAR 39 OSMORHI 40 P E L T I G E 41 PETAFRI 42 P I C E S I T 43 POLYJUN 44 POLYMUN 45 PRUNVUL 46 RIBESAN 47 RICCNAT 48 RORIPPA 49 RUBUPAR 50 RUBUSPE 51 S A L I L A S 52 S A L I S I T 53 SAMBRAC 54 SCIRMIC 55 SCUTLAT 56 SPARAME 57 SPHAGNU 58 SPIRDOU 59 STACCOO 60 THUdPLI 61 T IARTRI 62 TIARUNI 63 TSUGHET 64 TYPHLAT 65 VACCOVA 66 VACCPAR 67 VEROAME 68 V IOLPAL 69 ZANNPAL Ad1 anturn pedatum A g r o s t i s s t o l o n i f e r a A 1 r a s p A l n u s r u b r a A n a p h a l l s m a r g a r 1 t a c e a A r u n c u s s p A t h y r i u m f 11 l x - " femlna B l e c h n u m s p l e a n t C a r e x f l a v a C a r e x 11 v i d a C a r e x m e r t e n s 1 1 C a r e x o b n u p t a C l a y t o n l a s l b i n c a D l s p o r u m t r a c h y c a r p u m E l e o c h a r l s p a l u s t M s E p i l o b i u m a n g u s t l f o H u m E p i l o b i u m d l l a tum E q u l s e t u m p a l u s t r e F o n t m a l l s a n t l p y r e t l c a G a l i u m t r l f l o r u m Geum macrophy11um H e r a c l e u m s p h o n d y l i u m H y l o c o m l u m s p l e n d e n s H y p o c h o e n s r a d i c a t a d u n c u s e f f u s u s d u n c u s e n s l f o l i u s d u n c u s s p L a c t u c a s p L e c i d e a s p L u z u l a p a r v l f l o r a L y s i c h i t o n amer icanum Maianthemum d i l a t a t u m MaIus f u s c a M e n z l e s l a f e r r u g l n e a M i t e l l a p e n t a n d r a Mnlum g l a b r e s c e n s Mnlum m s l g n e O e n a n t h e s a r m e n t o s a O s m o r h l z a sp P e l t i g e r a s p P e t a s l t e s f r l g l d u s P 1 c e a s l t c h e n s l s P o l y t r i c h u m j u n i p e r i n u m P o l y s t l c h u m munltum P r u n e l l a v u l g a r i s R l b e s s a n g u i n e u m R l c c l o c a r p o s n a t a n s R o r l p p a s p Rubus p a r v l f l o r u s Rubus s p e c t a b l 1 1 s S a l I x l a s l a n d r a S a l I x s l t c h e n s l s Sambucus r a c e m o s a S c i r p u s m i c r o c a r p u s S c u t e l l a r i a l a t e r i f l o r a S p a r g a n l u m amer icanum Sphagnum s p S p 1 r a e a doug1 a s 11 S t a c h y s c o o l e y a e T h u j a p i i c a t a T l a r e l l a t r i f o l l a t a T l a r e l l a u n l f o l l a t a T s u g a h e t e r o p h y l l a T y p h a l a t l f o l 1 a Vacc1n1um ova11fo11um Vacc1n1um p a r v 1 f o 1 1 u m V e r o n i c a a m e r l c a n a V i o l a p a l u s t M s Z a n n l c h e l l l a p a l u s t r l s TABLE 7 RELATIONSHIP BETWEEN COHO TRAPPING SUCCESS AND SAMPLE PLOTS Plot Trapping success /Sampling period Number (2 "G" Trappings/Period) Feb/1982 Sept/1983 Nov/1983 Jan/1984 March/1984 N % 01 1 4 D D - 0 0 1 0 0 6 33% 02 1 4 D D 6 6 4 3 6 2 32 80 03 0 - D D 0 - 0 - 0 - 0 0 04 0 - D D 0 - 0 - 0 - 0 0 05 0 - D D 0 - 0 - 0 - 0 0 06 0 - D D 0 - 0 - 0 - 0 0 07 0 - D D 0 - 0 - 0 - 0 0 08 0 0 D D 0 3 0 0 1 0 4 20 09 1 3 D D 0 4 1 1 0 0 10 50 10 0 2 D D 1 1 2 2 3 1 12 70 11 2 1 D D 0 0 0 0 1 2 6 40 12 2 1 D D 2 0 1 1 2 0 9 60 13 0 0 D D 0 0 N N 0 0 0 0 14 0 0 D D 0 0 N N N N 0 0 15 0 0 D D N N N N N N 0 0 16 2 0 D D 3 2 0 - 1 1 9 56 17 2 2 D D 4 2 0 - 1 0 11 67 18 0 1 1 2 1 2 - - 2 0 9 75 19 0 1 1 3 1 0 - - 0 0 6 50 20 1 0 2 2 1 1 0 - 1 1 9 78 21 2 4 D D 1 1 0 - 3 4 15 67 22 2 1 D D 2 4 - 4 1 2 16 78 23 1 0 D D 0 0 - 1 1 0 3 33 24 3 4 D D 3 3 3 1 2 1 20 80 25 - 0 D D 2 0 1 1 1 1 6 56 26 N - N N N N N N N N 0 0 27 2 1 5 2 0 1 - 3 2 1 17 89 28 N N D D N N - D D D 0 0 29 1 2 1 2 1 0 1 2 1 2 13 90 30 0 0 D D 0 - 0 0 0 0 0 0 31 0 0 D D 0 0 0 0 1 0 1 10 32 P - - - 1 1 - 0 3 P 7 83 33 4 6 D D 4 2 3 2 5 2 28 80 34 6 0 N N 2 1 0 - 1 0 10 44 35 0 0 D D 0 0 - - N N 0 0 36 1 1 D D 1 1 1 1 1 1 8 80 37 - - D D 1 2 0 1 2 3 9 63 38 0 - D D 0 - 0 - 0 - 0 0 39 N N D D N N N N N N 0 0 40 N N D D N N N N N N 0 0 TABLE 8 RELATIONSHIP BETWEEN TROUT TRAPPING SUCCESS AND SAMPLE PLOTS p l o t Trapping success/Sampling period Number (2 "G" Trappings/Period) Feb/1982 Sept/1983 Nov/1983 Jan/1984 March/1984 N % 01 0 0 D D - 0 0 0 0 0 ~0~ ~0% 02 0 0 D D 0 0 0 0 1 0 1 10 03 0 - D D 0 - 0 - 0 — 0 0 04 0 - D D 0 - 0 - 0 - 0 0 05 0 - D D 0 - 0 - 0 — 0 0 06 0 - D D 0 - 0 - 0 — 0 0 07 0 - D D 0 - 0 - 0 - 0 0 08 0 0 D D 0 0 0 0 0 0 0 0 09 0 0 D D 0 0 0 0 0 0 0 0 10 0 0 D D 0 0 0 0 0 0 0 0 11 0 0 D D 0 0 0 0 0 0 0 0 12 0 0 D D 0 0 0 0 0 0 0 0 13 0 0 D D 0 0 N N 0 0 0 0 14 0 0 D D 0 0 N N N N 0 0 15 0 0 D D N N N N N N 0 0 16 0 0 D D 0 0 0 - 0 0 0 0 17 0 0 D D 0 0 0 - 0 0 0 0 18 0 0 0 0 0 1 - - 1 0 2 25 19 1 0 1 1 0 0 - - 1 0 4 50 20 1 0 3 1 0 1 2 — 0 0 8 56 21 0 0 D D 0 0 0 — 0 0 0 0 22 0 0 D D 0 0 - 0 0 0 0 0 23 0 0 D D 0 0 - 0 0 0 0 0 24 0 0 D D 0 0 0 1 0 0 1 10 25 - 0 D D 0 0 0 0 0 0 0 0 26 N - N N N N N N N N 0 0 27 2 0 1 0 0 0 - 1 0 0 4 33 28 N N D D N N - D D D 0 0 29 0 0 1 1 1 0 1 1 1 1 7 70 30 0 0 D D 0 — 0 0 0 0 0 0 31 0 0 D D 0 0 0 0 0 0 0 0 32 - - - - 0 0 - 0 1 - 1 25 33 1 0 D D 2 0 0 0 0 0 3 20 34 0 0 N N 0 0 0 - 0 0 0 0 35 0 0 D D 0 0 - - N N 0 0 36 0 0 D D 0 0 0 0 0 0 0 0 37 - - D D 0 0 0 0 0 0 0 0 38 0 - D D 0 - 0 - 0 - 0 0 39 N N D D N N N N N N 0 0 40 N N D D N N N N N N 0 0 TABLE 9 SUMMARY OF SURFACE COVER FOR (6) MAP UNITS Map Unit Variable % Vegetative Cover By Strata % S o i l % Woody Debris 39.2 24.6 10.0 30.0 26.6 10.9 5.8 3.2 1.0 15.8 12.8 5.2 12.8 8.8 3.6 8.7 6.4 2.6 B l B2 C D TOTAL 1. BG X 0 0 9.2 0.2 9.2 S 8.0 0.4 8.0 SE 3.2 0.2 3.2 2. BM X 0 0.2 10.8 1.7 10.8 S 0.4 4.9 1.9 4.9 SE 0.2 2.0 0.3 2.0 3. SC X 0.2 0.3 85.2 3.3 85.2 S 0.4 0.5 14.9 3.3 14.9 SE 0.1 0.2 4.7 1.1 4.7 4. CA X 0 0.3 96.8 42.2 97.7 S 0.5 3.7 28.8 2.1 SE 0.2 1.5 11.8 0.8 5. GA X 0.3 1.3 57.5 21.7 67.0 S 0.5 1.5 21.6 12.3 26.4 SE 0.2 0.6 8.8 5.0 10.8 6. JU X 0.3 1.7 40.8 23.3 52.5 S 0.5 1.2 12.0 22.5 23.2 SE 0.2 0.5 4.9 9.2 9.5 TABLE 10 SUMMARY OF % ORGANIC FOR THE VARIOUS PARTICLE SIZES Map Coarse Fine Very coarse Coarse Medium Fine Very fine Total Unit Variable gravel gravel sand sand sand sand sand Fines 1. BG X 0.7 1.4 2.0 2.8 4.4 7.5 T T 1.4 S 0.4 0.5 0.6 1.1 2.0 2.8 0.3 SE 0.2 0.2 0.3 0.5 0.8 1.1 0.1 2. BM X 75.5 61.7 57.7 54.8 47.1 42.6 38.8 51.0 S 10.4 8.8 5.1 12.5 14.6 15.8 11.8 10.4 SE 4.2 3.6 2.1 5.1 5.9 6.4 4.8 4.2 3. SC X 63.4 58.3 53.0 46.3 37.2 32.4 31.6 42.2 S 21.5 14.9 12.6 11.6 12.2 15.1 10.4 12.3 SE 6.8 4.7 4.0 3.7 3.8 4.8 3.3 3.9 4. CA X 62.9 53.7 56.6 53.5 52.0 50.2 43.3 52.1 S 18.6 14.9 11.6 6.9 7.7 9.0 5.3 9.8 SE 7.6 6.1 4.7 2.8 3.1 3.7 2.2 4.0 5. GR X 49.3 48.7 44.7 48.0 43.5 35.1 35.5 42.5 S 33.2 27.5 33.3 25.7 21.6 16.9 18.2 24.9 SE 13.6 11.2 13.6 10.5 8.8 6.9 7.4 10.2 6. JU X 77.7 70.5 69.8 66.5 63.8 60.5 51.7 64.5 S 17.7 19.3 20.1 18.2 18.5 20.2 19.6 18.2 SE 7.2 7.9 8.2 7.4 7.6 8.2 8.0 7.4 TABLE 11 SUMMARY OF PARTICLE SIZE (%), FOR TOP 10 CM OF PLOT SURFACE, (5 subsamples/plot) FOR (6) MAP UNITS Coarse Fine Very coarse Coarse Medium Fine Very fine Map Unit Variable gravel gravel sand sand sand sand sand Fin« 1. BG X 37.6 37.7 10.7 6.9 4.9 1.7 T T S 14.6 16.2 9.3 7.2 5.1 1.7 SE 6.0 6.6 3.8 2.9 2.1 0.7 2. BM X 0 10.6 8.0 13.6 17.9 25.6 14.1 10.1 S 9.9 7.3 4.4 4.1 9.7 5.8 6.4 SE 4.0 3.0 1.8 1.7 3.9 2.4 2.6 3. SC X 0 7.6 4.7 9.0 20.3 29.5 17.7 11.2 S 6.9 5.5 4.6 6.5 7.4 7.4 4.6 SE 2.2 1.7 1.5 2.1 3.4 2.3 1.4 4. CA X 0 17.1 6.2 16.0 20.8 20.4 11.8 7.7 S 10.5 4.0 5.8 3.1 5.7 4.6 5.9 SE 4.3 1.6 2.4 1.3 2.3 1.9 2.4 5. GA X 0 10.1 3.8 10.5 19.2 23.8 19.7 13.2 S 8.6 1.9 2.8 5.2 3.2 5.5 7.4 SE 3.5 0.8 1.1 2.1 1.3 2.3 3.0 6. JU X 0 6.8 4.0 15.2 23.2 25.0 16.2 10.2 S 4.2 2.1 6.1 4.1 3.6 4.0 3.4 SE 1.7 0.9 2.5 1.7 1.5 1.6 1.4 TABLE 12 SUMMARY OF MONTHLY WATER TABLE DEPTH FOR MAPPING UNITS Map Unit Variable JULY AUG. SEP. OCT. NOV. DEC. JAN. FEB. MAR. APR. MAY. JUNE JULY AUG. 1. BG X 16.3 18.0 15.7 19.8 S 6.3 8.7 8.4 7.4 SE 2.6 3.6 3.4 3.0 2. BM X 3.8 5.8 -00.3 18.8 S 14.4 13.7 14.9 10.6 SE 5.9 5.5 6.0 4.3 3. SC X -05.7 -04.3 -10.7 12.0 S 11.4 13.9 18.2 6.2 SE 3.6 4.4 5.8 2.0 4. CA X -35.2 -37.3 -35.5 22.8 S 27.9 25.0 27.5 18.5 SE 11.3 10.2 11.3 7.6 5. GA X -47.2 -41.3 -45.3 12.3 S 15.4 17.8 19.0 10.3 SE 6.3 7.3 7.8 4.2 6. JU X -15.7 -09.5 -07.2 0.3 S 17.8 8.3 6.2 8.0 SE 7.3 3.4 2.5 3.3 18.0 6.6 2.7 23.2 8.4 3.4 12.8 6.9 2.2 22.2 15.5 6.3 18.0 15.2 6.2 21.3 8.2 3.3 19.5 9.4 3.8 12.3 6.6 2.1 8.8 15.2 6.2 1.7 16.8 6.9 15.3 6.0 2.5 19.3 10.0 4.1 13.5 7.8 2.4 17.8 15.8 6.5 10.0 9.7 4.0 17.5 9.0 3.7 22.0 9.5 3.9 14.1 8.7 2.8 21.3 16.4 6.7 14.3 11.5 4.7 20.2 10.1 4.1 23.8 10.1 4.1 17.2 9.7 3.1 25.7 19.6 8.0 18.5 16.6 6.8 1.6 -00.8 -02.2 9.6 4.8 5.9 3.9 2.0 2.4 0 -00.8 4.9 6.7 2.0 2.7 20.5 16.7 13.7 14.0 12.8 10.7 8.5 6.9 6.9 6.2 4.4 3.5 2.8 2.8 2.5 22.8 17.0 12.8 6.7 -03.0 11.4 11.0 11.3 12.5 17.3 4.6 4.5 4.6 5.1 7.1 15.2 9.4 -00.7 -06.2 -12.3 9.1 6.9 12.8 12.0 13.5 2.9 2.2 4.0 3.8 4.3 15.8 -03.3 -39.0 -48.0 -55.2 15.4 23.6 25.4 18.3 8.3 6.3 9.6 10.4 7.5 3.3 7.3 -15.8 -44.8 -48.8 -54.0 9.2 14.9 17.2 17.4 10.6 3.8 6.1 7.0 7.1 4.3 0.3 -06.8 -04.5 -02.8 -08.7 5.5 10.2 4.8 9.5 4.6 2.2 4.2 2.0 3.9 1.9 TABLE 13 SUMMARY OF NUMBERS OF FISH AND TRAPPING SUCCESS FOR (6) MAP UNITS Map Unit Variable COHO TROUT  Number % Success Number % Success 1. BG X 10.2 77.5 4.3 43.2 S 4.1 14.7 2.7 18.4 SE 1.7 6.0 1.1 7.5 2. BM X 11.3 56.2 0.5 3.3 S 9.4 26.6 1.2 8.1 SE 3.8 10.9 0.5 2.6 3. SC X 13.1 63.7 0.2 2.0 S 8.0 14.9 0.4 4.2 SE 2.5 4.7 0.1 1.3 4. CA X 2.0 12.2 0 0 S 3.1 19.0 SE 1.3 7.7 5. GA X 0.7 3.3 0 0 S 1.6 8.2 SE 0.7 3.3 6. JU X 0 0 0 0 S SE TABLE 14 AREAS OF MAPPING UNITS FOR 11 LOCATIONS ON THE CARNATION CREEK FLOOD-PLAIN (9 Overwintering Sites and 2 Flooded Areas) Location Mapping Units 1 2 3 4 5 6 7 Total R250m 0 0 0 0 808 642 549 1999 R750m 0 177 554 14 38 131 63 976 Rl500m 0 215 104 0 9 149 25 502 LI250m 0 264 290 223 75 290 551 1693 L1400m 0 9 43 227 140 488 56 963 LI550m 0 310 583 148 40 236 134 1451 L1600m lower 407 142 261 38 0 18 278 1144 L1600m upper 46 194 215 6 0 26 329 816 R2600m lower 250 89 272 70 218 523 302 1688 R2600m upper 185 99 177 0 0 197 119 777 R2600m ponds 0 140 101 15 108 412 31 807 Total 888 1639 2600 741 1427 3112 2437 12807 APPENDIX 3. SALMONID WINTER POPULATION ESTIMATES (DATA TABLES) Coho Population Estimates 1982-83 and 1983-84 by Site Trout Population Estimates 1982-83 and 1983-84 by Site Estimation of Smolt Contribution by Site Estimations by ®"Gee" Trapping and Electrofishing Estimations by ®"Gee" Trapping and Small Fences TABLE 1 ESTIMATION OF COHO POPULATION SIZE FOR SITES LOCATED ON THE CARNATION CREEK FLOOD-PLAIN (Peterson mark/recapture) 1982-1983 Site Date branded Marks Total # # of marks m/n N SEN /recovered at risk recovered recovered (r) (n) (m) 750m Dec.30/Jan.l5 62 102 28 .27 220 34 Jan.l5/Feb.23 102 59 25 .42 235 34 Apr.l6/May 7 46 13 6 .46 92 23 1250m Jan.1/Jan.18 27 22 4 .18 124 45 Jan.l8/Feb.l8 22 38 7 .18 108 32 Feb.l8/Feb.24 38 18 6 .33 103 29 July 3/July 7 8 13 4 .31 22 7 1550m Feb.l8/Feb.26 62 51 21 .41 147 23 1600m Feb.19/Feb.26 50 42 8 .19 239 67 lower 1600m Feb.20/Feb.27 57 50 13 .26 208 46 upper 2600m Feb.22/Mar.l 33 23 6 .26 113 34 upper 2600m Feb.21/Feb.28 64 86 21 .24 253 45 lower 2600m Feb.21/Feb.28 20 20 5 .25 70 22 ponds 1983-1984 750m Oct.23/Nov.5 65 107 26 .24 260 43 Nov.5/Dec.1 81 96 28 .29 271 41 Dec.1/Dec.31 96 76 29 .39 246 34 Dec.31/Jan.2 55 94 22 .23 227 40 Jan.l4/Jan.20 103 65 35 .54 189 21 Site Date branded Marks Total # # of marks m/n N SEN /recovered at risk recovered recovered (r) (n) (m) Jan.20/Mar.l 59 101 32 .32 182 26 Mar.1/Mar.10 77 108 49 .45 168 17 Mar.l0/Mar.27 92 79 43 .54 167 17 Mar.27/May 3 65 36 14 .39 160 31 May 3/May 5 27 43 13 .28 85 20 May 5/May9-ll 38 31 12 .39 94 19 1250m Nov.30/Jan.l6 14 12 7 .58 23 5 Jan.l6/Jan.21 12 11 7 .64 18 8 Mar.5/Mar.13 12 8 3 .38 27 9 1550m Nov.7/Nov.l3 180 167 83 .50 360 28 Jan.l8/Jan.21 103 76 40 .53 193 20 Mar.1/Mar.11 97 106 41 .39 247 29 1500m Nov.12/Nov.15 49 46 20 .43 110 17 Jan.l8/Mar.2 20 53 11 .21 90 22 Mar.2/Mar.ll 53 50 25 .50 104 14 1600m Sept.l7/Sept.l9 80 149 33 .22 353 52 lower Nov.l3/Nov.28 93 113 26 .23 393 65 Jan.l9/Jan.23 126 77 32 .38 298 39 Mar.3/Mar.l2 103 106 40 .38 269 33 1600m Nov.l3/Nov.28 52 152 49 .32 159 18 upper Jan.l9/Jan.23 53 44 25 .57 92 11 Mar.3/Mar.l2 89 65 40 .62 143 14 2600m Sept.20/Sept.22 144 115 46 .40 355 40 lower Nov.26/Nov.29 39 80 10 .13 287 77 Jan.22/Jan.30 98 160 51 .32 303 34 Mar.4/Mar.10 108 96 38 .40 269 33 2600m Sept.21/Sept.23 32 30 12 .40 76 16 upper Nov.26/Nov.29 15 36 7 .19 69 20 Jan.22/Jan.30 40 37 22 .59 66 9 Mar.3/Mar.l2 74 43 28 .65 112 12 2600m Nov.26/Nov.29 36 25 14 .56 62 11 ponds Jan.l6/Jan.21 21 17 9 .53 38 8 Mar.2/Mar.10 35 23 16 .57 49 7 I CO TABLE 2 ESTIMATION OF TROUT POPULATION SIZE FOR SITES LOCATED ON THE CARNATION CREEK FLOOD-PLAIN (Assuming equal catchability, estimations based on ratio trout/coho) 1982-1983 Site Date Trout Coho Ratio Coho Trou marked/recovered (n) (n) trout/coho N N 750m Dec.30/Jan.15 0 184 0 220 0 Jan.l5/Feb.23 0 161 0 235 0 1250m Jan.1/Jan.18 0 49 0 124 0 Jan.l8/Feb.l8 0 60 0 108 0 Feb.l8/Feb.24 0 56 0 103 0 July3/July7 0 21 0 22 0 1550m Feb.l8/Feb.26 3 113 .03 147 4 1600m Feb.l9/Feb.26 39 92 .42 249 106 lower 1600m Feb.20/Feb.27 0 107 0 208 0 upper 2600m Feb.22/Mar.1 48 56 .86 113 97 upper 2600m Feb.21/Feb.28 3 43 .07 70 5 ponds 2600m Feb.21/Feb.28 84 150 .56 253 142 lower Feb.28 Main@ Mar. 6 19 59 .32 1700m Main@ Mar.7 2100m 29 37 .78 TABLE 2 (continued) ESTIMATION OF TROUT POPULATION SIZE FOR SITES LOCATED ON THE CARNATION CREEK FLOOD-PLAIN (Assuming equal catchability, estimations based on ratio trout/coho) 1983-1984 Site Date Trout Coho Ratio Coho Trout Marked/recovered (n) (n) trout/coho N N 750m Oct.23/Nov.5 0 172 0 260 0 Nov.5/Dec.1 2 161 .01 271 2 Dec.l/Dec.31 4 172 .02 246 5 Dec.31/Jan.2 3 149 .02 227 5 Jan.l4/Jan.20 0 168 0 189 0 Jan.20/Mar.l 4 160 .03 182 5 Mar.l/Mar.10 4 185 .02 168 4 Mar.lO/Mar.27 0 171 0 167 0 Mar.27/May 3 3 101 .03 160 5 May 3/May 5 3 „ 70 .04 85 3 1250m Nov.30/Jan.16 1 26 .04 23 1 Jan.l6/Jan.21 0 23 0 18 0 Mar.5/Mar.13 1 20 .05 27 1 1550m Nov.7/Nov.l3 0 347 0 360 0 Jan.l8/Jan.21 0 179 0 193 0 Mar.l/Mar.ll 0 203 0 247 0 May 7 0 27 0 1500m Nov.l2/Nov.l5 0 95 0 110 0 Jan.18/Mar.2 0 73 0 90 0 Mar.2/Mar.ll 0 103 0 104 0 Mar.14 0 26 0 1600m Sept.l7/Sept.l9 86 229 .38 353 133 lower Nov.l3/Nov.28 70 206 .34 393 134 Jan.19/Jan.23 46 203 .23 298 68 Mar.3/Mar.l2 88 209 .42 269 113 1600m Nov.l3/Nov.28 2 204 .01 159 2 upper Jan.19/Jan.23 0 97 0 92 0 Mar.3/Mar.l2 0 154 0 143 0 2600m Nov.26/Nov.29 1 61 .02 62 1 ponds Jan.16/Jan.21 3 38 .08 38 3 Mar.2/Mar.l0 1 58 .02 49 1 1983-1984 (continued) Site Date Trout Coho Ratio Coho Trout marked/recovered (n) (n) trout/coho N N 2600m Sept.20/Sept.l9 65 273 .25 355 89 lower Nov.26/Nov.29 26 119 .22 287 63 Jan.22/Jan.30 42 258 .16 303 49 Mar.4/Mar.10 60 204 .29 269 79 Mar.14 7 31 .27 2600m Sept.21/Sept.27 23 62 .37 76 28 upper Nov.26/Nov.29 19 51 .37 69 26 Jan.22/Jan.30 33 77 .43 66 33 Mar.3/Mar.12 97 117 .83 112 93 Main@ Nov.30 17 111 .15 2700m Jan.31 23 41 .56 Mar.10 13 48 .27 May.7 14 43 .32 MainC? Nov.30 1 41 .02 1600m Jan.31 2 12 .17 Mar.3 2 16 .13 TABLE 3 NUMBER OF COHO SMOLTS PRODUCED BY OFF-STREAM SITES (Marks recovered at main fence) 1982 -1983 (3544 coho examined out of a total run of 3544) Site Marks Mark Marks Coho % of c % of brand: at risk ratio recovered produced total recovered 750m 102 .42 14 33 0.9% 14% 1250m 38 .33 6 18 0.5 16 1550m 62 .41 28 68 1.9 45 1600m total 107 .23 39 170 4.8 36 2600m total 117 .25 46 184 5.2 39 NRB. 5 17 0.5 Total 425 .29 138 490 13.8# 32% .« ••! » 1- — — #(0.7 assumed for 1500m)= 14.5% 1983 -1984 (2461 coho examined out of a total run of 3200)* 750m 111 .48 51 106(138)* 4.3% 46%(61%)* 1250m 12 .38 7 18( 23) 0.7 58 (76 ) 1550m 97 .39 38 97(126) 3.9 39 (51 ) 1500m 53 .50 18 36( 47) 1.5 34 (44 ) 1600m upper 89 .62 47 76( 99) 3.1 53 (70 ) 1600m lower 103 .38 31 82(107) 3.3 30 (39 ) 2600m main 182 .48 45 94(122) 3.8 25 (32 ) 2600m ponds 35 .57 15 26( 34) 1.1 43 (52 ) NRB. 13 28( 36) 1.1 Total 682 .47 265(345)* 563(732) 22.8% 40%(51%) 1600m total 192 .47 78 166(216) 6.7 41 (53 ) 2600m total 217 .49 60 122(159) 5.0 28 (36 ) TABLE 4 COMPARISON OF TWO METHODS OF CAPTURE, "G" TRAPPING AND ELECTROSHOCKING (Peterson mark/recapture, marks placed March 2-3/1984) (marks recovered March 10-14/1984) Site "G" Trapping Electroshocking (r) (n) (m) (N) (SE») (n) (m) (N) (SEN) 1600m (lower 100m) 45 37 15 107 20 31 20 69 9 1500m (total) 53 50 25 104 14 26 15 89 14 2600 ponds (total) 35 23 16 49 6 13 7 61 13 1600m (upper 150m) 32 26 14 58 10 21 10 64 13 Total 165 136 70 318 26 91 52 286 25 TABLE 5 COMPARISON OF TWO METHODS OF CAPTURE, "G" TRAPPING AND MOVEMENT THROUGH SMALL FENCES (Peterson mark/recapture, marks placed Feb. 1983 or March 1984) (Marks recovered Feb.-March 1983 or March-May 1984) Site "G" Trapping Small fences (r) (n) (m) (N) (n) (m) (N) (SEM) 750m total 1983 102 59 25 235 34 44 15 287 56 1600m total 1983 107 92 21 452 82 68 16 434 89 2600m total 1983 117 129 32 461 68 94 24 445 75 TOTAL 1983 1148 75 1166 136 750m total 1984 111 101 50 222 22 92 45 224 23 1600m total 1984 192 171 80 408 33 66 23 536 86 2600m total 1984 217 162 82 426 49 83 35 506 63 TOTAL 1984 1056 52 1266 89 (6$ APPENDIX 4. COHO WINTER MOVEMENT (DATA TABLES) Content: 1. Movement Main-stream — Off-stream 2. Recovery of Marks by ®"Gee" Trapping 3. Recovery of Marks by Small Fences 4. D i r e c t i o n of Movement from Main-stream 5. Movement Within T r i b u t a r i e s 6. Movement from Oct/83 to Jan/84 7. Movement from Jan/84 to March/84 8. Replacement of Marks by a Freshet 9. In d i v i d u a l Movement Within a Muck Swamp TABLE 1 NUMBER OF COHO JUVENILES MOVING BETWEEN MAIN-CREEK AND OFF-STREAM SITES BY MONTH (Coho moving through small fences) Date 750m fence 1600m fence 2600m fence Total OUT IN OUT IN OUT IN OUT IN 1982 Sept 0 0 0 3 0 1 0 4 Oct 1 12 11 96 3 6 15 114 Nov 19 1 47 77 1 25 67 103 Dec 1983 9 1 7 6 3 3 19 10 Jan 14 6 0 3 0 1 14 10 Feb - - 8 7 0 1 8 8 March 18 19 48 10 47 2 113 31 April 1 1 7 2 29 2 37 5 May 13 0 6 0 18 0 37 0 June 0 0 0 0 1 3 1 3 July 0 0 6 10 0 2 6 12 Aug 0 0 1 0 0 0 1 0 Sept 0 0 0 21 6 0 6 21 Oct 0 4 8 204 2 63 10 271 Nov 9 12 45 179 2 28 56 219 Dec 1984 0 9 7 3 0 7 7 19 Jan - - - - 0 5 0 5 Feb 7 2 - - 2 1 9 3 March 9 1 - - 15 4 24 5 April 9 0 52 16 41 5 102 21 May 74 2 63 8 37 0 174 10 June 0 0 4 0 0 0 4 0 July 0 0 0 0 0 1 0 1 Aug Sept Oct Nov Dec 1985 Jan Feb TABLE 2 RECOVERY OF MAIN-STREAM MARKED JUVENILE COHO IN OFF-STREAM SITES, DEC-MARCH 1982-1983 (All marks placed Sept. 1982 in main-stream) Site Location # of marks Direction of Distai recovered marked recovered movement 750m 1400m 4 DOWN 650m 700m 1 NONE 0 1250m 950m 1 UP 250 1550m 1600m 1 NONE 0 1800m 2 DOWN 300 2200m 3 DOWN 650 2400m 1 DOWN 850 1600m upper 1600m 1 NONE 0 2200m 5 DOWN 600 1600m lower 1600m Trib. 3 NONE 0 1600m 1 NONE 0 1800m 1 DOWN 200 2600m lower 2500m 2 NONE 100 2700m 5 NONE 100 2600m upper 2500m 1 NONE 100 2600m 2 NONE 0 Summary 1 12 21 UP (+151m) NONE (+-150m) DOWN (-151m) TABLE 3 RECOVERY OF MAIN-STREAM MARKED JUVENILE COHO AT SMALL FENCES, OCT.-NOV. 1982 (All marks placed Sept. 1982 in main-stream) Site of Location # of marks Direction of Distance fence marked recovered movement (meters) 1600m 1600m 9 NONE Om 1800m 7 DOWN 200 2200m 7 DOWN 600 2600m 1800m 1 UP 800 2700m 4 NONE 100 Summary 1 13 14 UP (+151m) NONE (+-150m) DOWN (-151m) TABLE 4 DIRECTION OF MOVEMENT OF MAIN-STREAM MARKED COHO AFTER THE FIRST WINTER STORMS 1982-1983 (All marks placed Sept. 1982 in main-stream recovered In sites) Site # above # at # below Total recovered (m) (r) (m) (r) (m) (r) (m) (r) R 750m 4 1222 1 136 0 0 5 1358 R 1200m 0 794 0 259 1 305 1 1358 R 1500m 0 555 0 239 0 564 0 1358 R 1550m 6 555 1 239 0 564 7 1358 L 1600m 6 555 5 132 0 671 11 1358 R 2600m 0 0 10 237 0 1121 0 1358 Total 16 3682 17 1242 1 3225 34 (Marks placed Sept. 1982 in main-stream recovered at small fences) R 750m 0 1222 0 136 0 0 0 1358 L 1600m 14 555 9 132 0 671 23 1358 R 2600m 0 0 4 237 1_ 1121 5 1358 Total 14 1777 13 505 1 1792 28 TABLE 5 MOVEMENT OF MARKS WITHIN TWO TRIBUTARIES Location Date Marks Location Date m/n Ratio marked marked at risk recovered recovered 1600m fence 1982/Oct-Dec 119 1600m lower Feb. 19 11/50 .22 Feb. 27 6/45 .13 1600m upper Feb. 19 12/57 .21 Feb. 27 4/47 .08 2600m fence 1982/Oct-Dec 25 2600m lower Feb. 21 0/57 Feb. 26 2/65 2600m upper Feb. 21 0/33 Feb. 26 0/23 2600m ponds Feb. 21 0/22 Feb. 26 1/20 1600m lower 1982/Sept.24 28 1600m lower Feb. 19 1/50 Feb. 27 1/45 1600m upper Feb. 19 1/57 Feb. 27 0/47 1600m lower 1983/Sept.l7 80 1600m lower Sept.19 33/149 .22 Nov. 14 16/79 .20 Nov. 28 13/113 .12 1600m upper Sept .19 DRY Nov. 14 2/48 .04 Nov. 28 4/152 .03 TABLE 6 MOVEMENT OF MARKED JUVENILE COHO BETWEEN OFF-STREAM SITES FROM OCT-NOV. 1983 to JAN. 1984 (Marks recovered (m) within sites) Site (placed) 750m 1250m 1500m 1550m 1600m 2600m. .covered) '.' • (r) . (n). 198 14 49 180 146 81 750m . 176 68 0 0 1 0 0 1450m . 23 0 13 0 0 0 0 Jside '. 27 0 0 2 0 0 0 1550m . 179 0 0 0 69 0 0 1600m . 300 0 0 0 7 60 0 2600m .' 373 0 0 0 0 0 43 TABLE 7 MOVEMENT OF MARKED JUVENILE COHO BETWEEN OFF-STREAM SITES FROM JAN. 1984 TO MARCH 1984 (Marks recovered (m) within sites) Site (placed) 750m 1250m 1500m 1550m 1600m upper 1600m lower 2600m main 2600m ponds (recovered) V • ( O • (n). 111 12 20 103 53 126 138 35 750m . 288 139 0 0 0 0 0 0 0 1450m . 12 0 7 0 0 0 0 0 0 Jside . 103 0 0 8 0 1 0 0 0 1550m . 203 0 0 0 82 4 4 0 0 1600m upper . 154 0 0 0 0 64 0 0 0 1600m lower . 209 0- 0 0 0 9 80 0 0 2600m main . 319 0 0 0 0 0 0 106 1 2600m ponds . 73 0 0 0 0 0 0 5 26 TABLE 8 MARK RATIOS WITHIN SITES BEFORE AND AFTER A MAJOR STORM (2200 cfs.) ON JAN.4/1984 BEFORE AFTER Site Date Marks Date (m)/(n) Date (m)/(n) marked at risk recovered ratio recovered ratio 750m Oct. 23 147 Dec. 1 (44/96) - .46 Dec.31 (39/75) - .52 Jan. 2 (39/94) - .42 Jan. 14 (41/111)- .37 Jan. 20 (27/65) - .42 March 1 (36/101)- .36 March 10 (40/108)- .37 March 27 (28/79) - .35 1250m Nov. 30 14 Dec. 30 (3/5) - .60 Jan. 16 (7/12) - .58 Jan. 21 (6/11) - .55 March 5 (4/12) - .33 March 12 (4/12) - .33 1500m Nov. 12 49 Nov. 15 (18/46)- .39 Jan. 16 (2/20) - .10 Jan. 20 (0/7) - 0 March 2 (6/53) - .11 March 11 (7/50) - .14 March 14 (2/26) - .08 1550m Nov. 7 180 Nov. 13 (83/167)= .50 Jan. 18 Jan. 21 March 1 March 11 (42/103)= (27/76) • (48/97) • (38/106)» .41 .36 .49 .36 1600m Nov. 13 146 Nov. 28 (75/265)= .28 Jan. 19 Jan. 23 March 3 March 12 2600m Nov. 26 91 Nov. 29 (31/140)- .22 Jan. 22 Jan. 30 March 4 March 10 (33/171> (27/129)= (47/192)= (35/171)= .19 .21 .25 .20 (24/159)= (19/214)= (25/217)= (20/165)= .15 .09 .12 .12 TABLE 9 LOCATION OF INDIVIDUALLY MARKED JUVENILE COHO WITHIN 750m SITE (Distance upstream from confluence of 750m swamp system with main-stream) (hard to read marks are indicated by ) CODE INDIVIDUAL LOCATION (+- 5 meters) AT DATE OF RECOVERY — — 0ct23 Nov 5 Dec 1 Jan 1 Jan 2 Janl6 Jan20 Feb29 MarlO Mar28 May 3 May 5 001 50 101 90 002 57 5 003 68 50 50 50 31 50 004 68 62 87 31 005 2 33 35 38 45 40 006 2 2 1 6 4 8 007 15 2 19 6 008 18 55 31 35 44 009 68 010 68 011 76 76 68 012 76 14 14 013 18 19 19 014 18 015 18 50 50 39 016 22 25 31 44 8 43 14 5 6 017 76 49 018 76 79 34 42 019 76 112 020 76 79 021 22 49 112 112 022 24 21 31 28 37 37 39 023 24 25 31 31 37 024 24 025 76 106 113 112 0 39 026 76 027 76 87 92 86 95 028 83 029 24 29 49 030 24 21 20 27 14 031 30 45 032 30 15 34 033 35 58 140 140 140 44 034 45 91 10 39 035 45 15 036 45 037 83 90 90 86 038 83 98 75 60 67 82 80 039 83 87 90 88 91 92 040 83 31 TABLE 9 (continued) CODE INDIVIDUAL LOCATION (+- 5 meters) AT DATE OF RECOVERY Oct23 Nov 5 Dec 1 Jan 1 Jan 2 Janl6 Jan20 Feb29 MarlO Mar28 May 3 May 5 041 45 15 042 45 50 49 52 043 45 85 80 76 8 044 50 49 49 045 83 72 76 046 83 45 46 49 047 83 101 102 048 83 30 40 31 34 40 37 049 91 90 90 92 89 050 91 90 051 81 052 91 90 90 88 053 102 5 054 102 32 2 055 102 102 056 102 49 49 057 91 49 058 91 102 059 91 98 102 103 101 060 91 102 102 107 103 061 102 102 107 34 40 062 102 124 140 063 102 102 110+15 -064 106 102 065 137 137 1 1 066 6 5 067 6 068 15 069 15 25 21 6 4 90+35 070 15 071 15 31 37 19 072 15 15 8 6 073 15 2 074 15 31 4 18 19 075 24 076 24 077 21 078 21 34 079 25 21 16 080 25 TABLE 9 (continued) CODE INDIVIDUAL LOCATION (+- 5 meters) AT DATE OF RECOVERY Oct23 Nov 5 Dec 1 Jan 1 Jan 2 Janl6 Jan20 Feb29 MarlO Mar28 May 3 May 5 081 25 25 25 1 14 082 25 28 083 28 30 29 084 32 49 085 32 113 117 117 117 112 19 086 32 30 31 34 37 35 087 40 088 45 089 45 49 49 14 090 45 34 091 45 40 092 45 65 093 49 094 49 49 49 52 50 61 0 65 095 49 50 096 49 097 49 113 138 124 098 49 19 15 63 099 49 33 25 55 100 49 45 49 14 49 34 101 49 37 45 46 43 102 50 37 34 36 35 103 50 50 1 104 50 50 50 52 49 55 105 50 18 106 50 19 107 50 60 57 61 61 14_ 108 50 109 50 25 5 4 14 110 55 111 55 112 55 113 55 114 55 116 124 124 130 139 138 138 117 6 115 58 40 31 37 37 116 62 33 8 52 5 48 117 62 49 60 67 57 118 62 119 62 48 4 3 120 62 TABLE 9 (continued) CODE INDIVIDUAL LOCATION (+- 5 meters) AT DATE OF RECOVERY 0ct23 Nov 5 Dec 1 Jan 1 Jan 2 Janl6 Jan20 Feb29 MarlO Mar28 May 3 May 5 121 62 83 55 122 62 19 123 79 83 124 79 125 79 126 85 85 90 127 85 128 90+8 46 92 35 106 129 90+8 55 48 31 45 49 130 90+8 37 52 50 131 90+24 87 82 82 80 76 84 132 90+24 133 90 60 42 43 134 90 67 50 135 90 0 19 136 94 137 94 6 4 18 138 94 49 60 49 139 94 140 98 10 141 98 142 101 124 112 112 143 101 106 107 112 124 144 102 45 40 34 49 49 49 49 49 145 102 113 113 112 124 146 112 147 2 148 19 149 19 150 19 35 14 151 19 14 6 152 15 153 15 22 154 21 7 19 35 22 8 155 25 31 36 37 156 25 21 25 26 26 157 25 3 158 25 30 159 30 36 31 160 33 1 I 7 4 TABLE 9 (continued) CODE INDIVIDUAL LOCATION (+- 5 meters) AT DATE OF RECOVERY — _ Oct23 Nov 5 Dec 1 Jan 1 Jan 2 Janl6 Jan20 Feb29 MarlO Mar28 May 3 May 5 161 37 42 17 34 162 37 45 43 163 37 43 46 45 43 164 37 43 31 37 45 35 43 165 45 43 31 42 166 50 52 49 167 50 60 34 57 61 61 19 34 168 50 50 46 169 50 19 170 49 49 53 49 171 49 49 45 49 92 49 172 49 49 173 49 174 49 175 76 74 68 66 69 74 176 76 74 68 66 55 177 83 80 86 86 86 86 90 86 178 87 179 87 87 76 8 180 87 34 92 181 87 90 90 182 95 183 105 112 112 112 184 105 185 105 105 106 107 102 186 105 105 107 107 107 187 106 113 113 112 117 108 112 112 188 106 106 107 31 189 106 116 112 112 14 190 116 110+10 110+10 112 44 191 116 117 117 6 192 116 110+10 110+10 67 65 193 118 117 124 112 112 194 124 124 125 125 195 124 124 125 124 125 124 196 124 124 140 139 197 132 140 135 137 112 198 139 135 135 137 138 199 7 0 200 7 31 36 38 35 39 I 1 7 TABLE 9 (continued) CODE INDIVIDUAL LOCATION (+- 5 meters) AT DATE OF RECOVERY __ 0ct23 Nov 5 Dec 1 Jan 1 Jan 2 Janl6 Jan20 Feb29 MarlO Mar28 May 3 May 5 201 7 202 7 203 7 204 7 205 7 6 16 0 3 18 206 16 19 8 207 28 31 37 208 37 31 43 209 36 14 210 36 34 211 36 4 212 36 31 22 40 38 10 213 36 31 69 37 14 14 214 36 31 37 37 42 10 39 215 45 46 216 75 217 89 218 90 91 219 90 89 86 220 90 95 , 221 90 89 91 28 92 222 92 90 92 35 39 223 102 107 224 102 106 103 108 107 225 106 106 107 107 107 52 226 106 107 106 107 90 227 110+10 112 138 228 113 113 112 112 229 113 112 138 230 113 113 112 112 112 231 232 233 234 235 236 237 238 239 240 124 2 6 6 27 44 44 31 31 31 125 4 22 124 8 22 42 25 125 0 8 26 21 40 124 6 18 26 64 124 124 6 35 40 TABLE 9 (continued) CODE INDIVIDUAL LOCATION (+- 5 meters) AT DATE OF RECOVERY Oct23 Nov 5 Dec 1 Jan 1 Jan 2 Janl6 Jan20 Feb29 MarlO Mar 2 8 May 3 May '. 241 31 26 48 242 46 10 43 243 46 45 43 49 23 244 52 86 245 76 86 76 86 246 76 86 102 14 247 49 248 49 49 35 49 249 49 49 250 49 86 92 10 23 251 87 76 86 252 87 117 253 102 254 107 255 113 117 256 113 112 112 117 5 257 113 112 110+17 117 APPENDIX 5. WINTER GROWTH (DATA TABLES) Coho Fork-Lengths 1982-83 Coho Fork-Lengths 1983-84 Length/Weight Individual Coho Fork-Lengths / Time TABLE 1 MEAN LENGTHS OF JUVENILE COHO WITHIN OFF-STREAM SITES WINTER 1982-1983 SITE DATE ALL JUVENILES 1 YEAR OLDS ONLY (n) X SD SE (n) X SD SE 750m Nov. 1-8 17 75.88 10.35 2.51 13 71.54 7.29 2.02 Dec. 12 17 76.52 10.30 2.50 12 71.83 8.33 2.41 Dec. 30 62 73.60 9.76 1.24 59 72.59 8.80 1.16 Jan. 15 102 73.90 10.60 1.10 92 71.85 9.05 0.94 Feb. 23 59 80.08 8.50 1.11 52 78.00 6.59 0.91 Mar. 28 13 80.31 7.33 2.03 12 79.08 6.11 1.76 April 16-•17 46 81.22 6.73 .99 43 80.30 5.91 0.90 1250m Jan. 1 27 82.74 12.12 2.33 19 76.58 5.36 1.23 Jan. 18 22 82.58 10.58 2.26 16 77.69 6.48 1.62 Feb. 18 38 85.95 10.33 1.68 28 81.50 6.76 1.28 Feb. 24 18 84.00 12.06 2.84 15 80.13 8.50 2.19 July 3-7 17 93.82 7.84 1.90 9 87.78 4.79 1.60 1550m Feb. 18 62 78.14 10.39 1.32 56 76.09 8.58 1.15 Feb. 26 51 76.51 7.73 1.08 48 75.60 7.02 1.01 1600m lower Feb. 19 50 79.04 9.12 1.29 47 77.85 7.94 1.16 Feb. 26 42 80.50 8.01 1.24 37 78.43 5.97 0.98 1600m upper Feb. 19 57 78.98 8.38 1.11 53 77.62 6.86 0.94 Feb. 27 50 78.16 6.67 0.94 47 77.28 5.81 0.85 2600m upper Feb. 22 33 75.61 7.45 1.30 32 75.13 7.03 1.24 March 1 23 76.21 6.67 1.39 23 76.21 6.67 1.39 2600m lower Feb. 21 64 76.27 11.01 1.38 53 72.18 6.75 0.93 Feb. 28 86 76.05 9.06 0.98 77 73.84 6.43 0.73 2600m ponds Feb. 21 20 75.00 9.11 2.04 18 73.11 7.42 1.75 Feb. 28 20 71.90 6.62 1.48 20 71.90 6.62 1.48 Main-channel March 6 96 78.43 10.27 1.05 85 76.07 7.45 0.81 TABLE 2 MEAN LENGTHS OF JUVENILE COHO WITHIN OFF-STREAM SITES WINTER 1983-1984 SITE DATE ALL JUVENILES 1 YEAR OLDS ONLY (n) X SD SE (n) X SD SE 750m Oct. 23-24 65 68.09 10.59 1.31 Nov. Dec. Dec. Jan. Jan. Jan. March March 10 March 27 May 3 May 5 5 1 31 2 14 20 1 107 96 76 94 103 65 101 108 79 36 43 70.11 69.81 71.58 73.27 71.10 70.54 74.79 75.98 78.87 87.36 88.70 9.65 6.90 8.21 9.14 7.20 7.99 7.42 7.45 7.72 5.98 5.95 0.93 0.70 0.94 0.94 0.71 0.99 0.74 0.72 0.87 1.00 0.91 59 99 94 70 85 98 62 93 101 73 32 39 65.61 68.17 69.46 69.96 71.19 70.17 69.65 73.46 74.87 77.49 86.03 87.67 6.88 6.68 6.52 6.08 6.22 6.04 7.03 6.09 6.32 6.23 4.89 5.22 0.90 0.67 0.67 0.73 0.67 0.61 0.89 0.63 0.63 0.73 0.86 0.84 1250m Nov. 7 5 88.60 15.95 7.13 3 77.33 1.53 0.88 Nov. 30 12 87.00 15.22 4.39 6 74.33 7.09 2.90 Jan. 16 12 86.33 11.73 3.39 7 78.29 4.61 1.74 Jan. 21 11 83.45 12.12 3.65 8 77.38 5.85 2.07 March 5 12 87.92 10.70 3.09 7 81.00 6.71 2.54 March 13 8 94.25 8.28 2.93 4 88.00 2.58 1.29 1550m Nov. 7 180 59.55 6.56 0.49 175 59.05 5.93 0.45 Nov. 13 167 59.59 6.71 0.52 165 59.38 6.47 0.50 Jan. 18 103 65.76 7.55 0.74 99 65.05 6.79 0.68 Jan. 21 76 67.07 7.96 0.91 72 66.11 7.01 0.83 March 1 97 68.06 7.44 0.76 95 67.65 6.95 0.71 March 11 106 70.56 8.37 0.81 101 69.70 7.61 0.76 May 7 27 71.00 6.42 1.24 27 71.00 6.42 1.24 1500m Nov. 12 49 62.51 12.45 1.78 45 59.58 6.90 1.03 Nov. 15 46 65.93 13.51 1.99 41 61.98 6.03 0.94 Jan. 18 20 71.65 10.77 2.41 18 69.11 7.60 1.79 Jan. 20 7 69.00 6.90 2.61 7 69.00 6.90 2.61 March 2 53 75.23 8.68 1.19 47 73.13 6.47 0.94 March 11 50 75.18 8.63 1.22 45 73.31 6.67 0.99 March 14 26 76.00 8.65 1.70 24 74.54 7.25 1.48 TABLE 2 (continued) WINTER 1983-1984 SITE DATE (n) ALL JUVENILES SD SE 1 YEAR OLDS ONLY (n) SD SE 1600m lower Sept. 17 80 64.28 10.11 1.13 73 62.03 7.08 0.83 Sept. 19 149 65.98 11.19 0.92 127 62.50 7.82 0.69 Nov. 13 93 68.99 9.18 0.95 86 67.29 7.02 0.76 Nov. 28 113 67.67 8.70 0.82 108 66.68 7.50 0.72 Jan. 19 126 68.18 7.29 0.65 121 67.31 5.97 0.54 Jan. 23 77 71.45 10.65 1.21 67 68.43 7.41 0.91 March 3 103 73.05 9.95 0.98 102 72.82 9.73 0.96 March 12 106 75.52 8.96 0.87 100 74.29 7.59 0.76 1600m upper Nov. 13 52 69.50 11.66 1.62 47 66.49 6.89 1.01 Nov. 28 152 68.36 7.72 0.63 148 67.68 6.51 0.54 Jan. 19 53 69.09 5.48 0.75 53 69.09 5.48 0.75 Jan. 21 44 71.47 6.69 1.01 43 70.88 5.47 0.83 March 3 89 75.85 6.88 0.73 87 75.33 6.02 0.65 March 12 65 76.03 7.14 0.89 63 75.29 5.85 0.74 2600m lower Sept. 20 158 60.72 10.03 0.80 148 59.03 7.84 0.64 Sept. 22 115 61.34 10.07 0.94 106 59.38 7.63 0.74 Nov. 26 39 68.85 6.93 1.11 38 68.45 6.56 1.06 Nov. 29 80 68.58 9.41 1.05 73 66.59 7.09 0.83 Jan. 22 98 70.18 9.80 0.99 93 68.68 7.80 0.81 Jan. 30 160 69.07 9.20 0.73 151 67.68 7.36 0.60 March 4 108 73.60 10.06 0.97 100 71.78 7.91 0.79 March 10 96 73.68 7.68 0.78 93 73.01 6.80 0.71 Sept. 21 32 61.50 9.16 1.62 31 60.84 8.50 1.53 Sept. 23 30 62.73 9.72 1.77 30 62.73 9.72 1.77 Nov. 26 15 68.47 8.90 2.30 15 68.47 8.90 2.30 Nov. 29 36 67.08 8.32 1.39 36 67.08 8.32 1.39 Jan. 22 40 72.43 7.59 1.20 39 71.97 7.12 1.14 Jan. 30 37 69.95 9.40 1.55 36 69.39 8.89 1.48 March 3 74 71.96 9.49 1.10 74 71.96 9.49 1.10 March 12 43 74.40 8.99 1.37 42 73.98 8.67 1.34 TABLE 2 (continued) WINTER 1983-1984 SITE DATE ALL JUVENILES 1 YEAR OLDS ONLY (n) X SD SE (n) X SD SE 2600m ponds Nov. 26 36 67.61 9.46 1.58 33 65.73 7.28 1.27 Nov. 29 25 67.92 8.53 1.71 24 66.88 6.89 1.41 Jan. 16 21 69.43 8.93 1.95 20 68.30 7.47 1.67 Jan. 21 17 67.59 7.29 1.77 16 66.06 3.80 0.95 March 2 35 75.26 7.84 1.32 32 73.38 4.77 0.84 March 10 23 74.04 5.48 1.14 22 73.27 4.14 0.88 Main-channel Nov. 30 111 65.90 6.05 0.57 109 65.50 5.23 0.50 (32700m Jan. 31 41 68.51 7.84 1.22 40 67.88 6.78 1.07 March 10 48 68.85 7.59 1.10 47 68.40 7.00 1.02 May 7 43 77.14 8.80 1.34 40 75.83 7.57 1.20 Main-channel Nov. 30 42 61.81 8.07 1.25 41 61.32 7.51 1.17 @1500m Jan. 31 12 70.00 9.53 2.75 10 67.70 8.71 2.75 March 3 16 72.94 10.12 2.53 13 68.85 3.89 1.08 750m fence May 1 19 87.89 5.57 1.28 17 86.59 4.18 1.01 May 9 39 90.28 5.88 0.94 32 88.22 4.16 0.74 1600m fence Oct. 23 108 65.25 9.67 0.93 99 62.93 5.65 0.57 Oct. 27 43 64.07 8.69 1.33 40 62.33 5.74 0.91 Nov. 2-4 78 67.73 8.44 0.96 71 65.80 5.94 0.71 Nov. 12-14 41 66.85 7.48 1.17 39 65.82 6.01 0.96 A p r i l 18-22 26 84.54 8.58 1.68 23 82.17 5.32 1.11 May 9-11 24 87.46 7.16 1.46 20 85.40 5.77 1.29 TABLE 3 LENGTH/WEIGHT RELATIONSHIP (March 27/1984 @ 750m Sit e ) LENGTH WEIGHT (mm) (gm) 58 2.25 69 3.30 71 3.60 71 3.65 73 3.55 74 3.55 74 4.20 74 4.30 75 4.55 76 4.15 76 4.90 77 4.80 78 4.20 79 5.75 79 6.35 80 5.30 80 5.70 80 5.70 81 6.65 83 4.80 83 6.05 85 4.10 88 7.25 88 7.45 89 7.35 91 7.00 91 8.45 93 7.75 94 8.80 95 7.90 96 9.15 97 9.90 99 9.05 TABLE 4 CHANGE IN LENGTH OVER TIME FOR INDIVIDUALLY BRANDED COHO JUVENILES (750m Site) CODE INDIVIDUAL LENGTH (mm) AT DATE OF RECOVERY Oct23 Nov 5 Dec 1 Jan 1 Jan 2 Janl6 Jan20 Feb29 MarlO Mar28 May 3 May 5 001 109 109 112 002 57 60 003 69 74 76 77 78 84 004 70 71 73 82 005 83 86 90 91 98 98 006 78 78 85 86 87 92 007 75 77 80 81 008 65 70 72 78 82 009 76 010 71 O i l 58 65 66 012 58 71 72 013 70 73 78 014 68 015 63 68 69 72 016 63 69 72 71 76 78 80 85 86 017 56 56 018 63 62 76 78 019 62 68 020 52 55 021 72 72 80 83 022 78 83 84 85 85 85 91 023 60 66 67 68 70 024 68 025 67 71 73 73 91 91 026 66 027 55 57 67 69 70 028 55 029 59 65 66 030 59 65 67 68 76 031 59 60 032 71 71 74 033 70 70 77 78 80 95 034 70 75 98 98 035 77 77 036 74 037 67 70 71 77 038 58 59 64 67 68 69 68 039 70 74 74 74 77 82 040 65 68 TABLE 4 (continued) CODE 0ct23 Nov 5 Dec 1 Jan 1 Jan 2 Janl6 Jan20 Feb29 MarlO Mar28 May 3 May '. 041 89 88 042 65 67 68 69 043 59 61 61 66 66 044 86 90 96 045 58 66 69 046 56 58 65 70 047 61 68 69 048 65 68 69 70 75 76 76 049 71 73 73 76 92 050 73 83 051 70 052 80 83 84 88 053 71 74 054 88 89 90 055 64 66 056 71 72 74 057 69 70 058 63 63 059 57 57 61 71_ 72 060 57 60 63 64 64 061 63 67 74 75 84 062 63 68 89 063 65 66 69 064 76 77 065 100 101 102 102 066 75 79 067 83 068 69 069 77 79 80 80 81 81 070 83 071 67 72 74 74 072 67 74 79 80 073 73 76 074 57 67 70 74 83 075 66 076 102 077 71 078 74 77 079 68 70 77 080 74 1 ^ TABLE 4 (continued) CODE INDIVIDUAL LENGTH (mm) AT DATE OF RECOVERY Oct23 Nov 5 Dec 1 Jan 1 Jan 2 Janl6 Jan20 Feb29 MarlO Mar 2 8 May 3 May 5 081 75 78 78 78 79 082 65 66 083 70 77 77 084 80 82 085 68 72 74 77 77 80 91 086 71 72 74 74 78 86 087 68 088 81 089 89 90 91 95 090 82 90 091 74 75 092 67 71 093 68 094 59 61 62 62 64 65 83 84 095 65 68 096 90 097 82 86 90 97 098 68 71 72 76 099 73 73 73 79 100 60 65 71 77 82 8 3 101 74 77 78 78 82 102 74 76 77 77 78 103 74 79 95 104 64 65 65 65 68 70 105 72 74 106 69 72 107 59 68 68 72 74 70 108 65 109 64 68 68 71 71 110 66 111 72 112 76 113 60 114 65 66 67 67 68 69 76 78 80 88 115 56 58 59 59 61 116 64 66 70 72 85 85 117 70 72 72 72 73 118 81 119 65 66 70 71 120 68 TABLE 4 (continued) CODE INDIVIDUAL LENGTH (mm) AT DATE OF RECOVERY  Oct23 Nov 5 Dec 1 Jan 1 Jan 2 Janl6 Jan20 Feb29 MarlO Mar28 May 3 May 5 121 65 66 67 122 64 66 123 73 74 124 69 125 59 126 85 88 89 127 56 128 73 74 129 68 72 72 74 130 64 67 69 131 59 63 64 65 64 67 71 132 62 133 64 68 71 71 134 65 67 135 67 76 76 136 63 137 64 66 66 73 138 61 64 65 65 139 58 140 76 82 141 65 142 69 71 82_ 83 143 64 70 71 71 76 144 66 68 68 68 68 69 70 70 72 145 65 68 70 74 146 66 147 72 148 73 149 84 150 77 84 83 151 152 153 154 155 156 157 158 159 160 68 70 63 73 71 70 69 65 62 75 74 61 74 69 67 76 69 66 75 73 64 77 75 71 77 72 73 79 78 74 TABLE 4 (continued) CODE INDIVIDUAL LENGTH (mm) AT DATE OF RECOVERY Oct23 Nov 5 Dec 1 Jan 1 Jan 2 Janl6 Jan20 Feb29 MarlO Mar28 May 3 May 5 161 56 67 81 82 162 56 72 73 163 68 70 71 75 76 164 63 63 64 64 66 67 80 165 65 65 66 73 166 74 76 78 167 75 76 76 78 82 84 84 92 168 68 69 69 169 68 87 170 68 68 69 71 171 76 76 77 76 79 79 172 84 85 173 72 174 68 175 69 70 71 71 74 76 176 65 66 68 68 72 177 50 51 50 52 53 58 72 74 178 84 179 70 72 73 74 180 79 79 81 181 65 64 69 182 83 183 87 90 93 94 184 65 185 69 70 71 72 80 186 58 59 61 69 74 187 69 69 70 75 75 77 90 91 188 67 67 68 68 189 64 69 70 72 83 190 73 74 83 88 92 191 64 70 77 80 192 71 72 76 81 92 193 82 83 83 89 100 194 82 82 81 84 195 65 65 66 72 74 75 196 72 72 75 74 197 67 69 69 71 71 198 66 68 69 71 80 199 75 78 200 87 87 89 89 92 92 TABLE 4 (continued) CODE INDIVIDUAL LENGTH (mm) AT DATE OF RECOVERY Oct23 Nov 5 Dec 1 Jan 1 Jan 2 Janl6 Jan20 Feb29 MarlO Mar 2 8 May 3 May 5 201 88 202 77 203 79 204 76 205 65 65 65 66 67 70 206 72 74 75 207 70 72 73 208 73 74 81 209 99 99 210 87 88 211 81 82 212 74 74 75 75 75 82 213 74 75 79 79 78 92 214 69 70 72 72 74 86 87 215 71 72 216 82 217 86 218 73 76 219 69 74 75 220 78 77 221 64 65 73 75 79 222 72 71 73 73 88 223 67 67 224 65 66 75 67 83 225 67 68 68 78 77 90 226 58 59 59 68 70 227 61 68 69 228 70 72 76 99 229 73 76 81 230 63 64 65 70 70 231 58 59 67 70 74 85 86 232 72 71 79 233 82 86 87 88 93 234 59 71_ 234 68 69 71 72 74 236 70 237 75 78 238 67 68 83 239 73 73 73 88 240 65 68 / 9 / TABLE 4 (continued) CODE INDIVIDUAL LENGTH (mm) AT DATE OF RECOVERY  Oct23 Nov 5 Dec 1 Jan 1 Jan 2 Janl6 Jan20 Feb29 MarlO Mar28 May 3 May 5 241 64 69 74 242 71 84 85 243 71 76 77 78 88 244 70 80 245 62 62 68 71 246 57 57 60 61 247 82 248 92 91 95 94 249 78 80 250 78 79 80 87 87 251 57 62 64 252 82 86 253 63 254 63 255 80 81 256 62 62 65 66 88 257 64 64 75 75 NRB 0 0 0 0 0 1 2 2 3 3 4 5 

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