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Distributional ecology of the calanoid copepod Pareuchaeta elongata esterly Evans, Marlene Sandra 1973

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»S 1.14-THE DISTRIBUTIONAL ECOLOGY OF THE CALANOID COPEPOD PAREUCHAETA ELONGATA ESTERLY by Marlene Sandra Evans A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n the Department of Zoology and I n s t i t u t e of Oceanography We accept t h i s thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA January, 1973 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f the requirements f o r an advanced degree at the U n i v e r s i t y o f B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e copying o f t h i s t h e s i s f o r s c h o l a r l y purposes may be g r anted by the Head of my Department or by h i s r e p r e s e n t a t i v e s . I t i s understood t h a t c o pying or p u b l i c a t i o n of t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be allowed without my w r i t t e n p e r m i s s i o n . Department o f The U n i v e r s i t y o f B r i t i s h Columbia Vancouver 8, Canada ABSTRACT Many f i e l d and laboratory studies t e s t i n g the growth of phytoplankton and the s u r v i v a l of the early developmental stages of zooplankton and benthic organisms have shown that sea waters that are a l i k e i n s a l i n i t y and temperature are nevertheless d i f f e r e n t i n other properties ( q u a l i t i e s ) . These differences i n q u a l i t y may be associated with v a r i a t i o n s i n the concentrations of dissolved trace elements and organics. The concentration of a trace element or or-ganic may have b e n e f i c i a l or harmful e f f e c t s on marine organisms. Bary (1963) suggested t h a t , i n c e r t a i n areas, these v a r i a t i o n s i n the properties of sea waters may be s u f f i c i e n t l y great, and the tolerance, of zooplankton s u f f i c i e n t l y s m a l l , .for species to be r e s t r i c t e d to various waters. These waters, c a l l e d water bodies, were described by t h e i r temperature and s a l i n i t y c h a r a c t e r i s t i c s and the d i s t r i b u t i o n of species was described i n r e l a t i o n to these water bodies. Many of the species Bary.(1963) studied were at the northern' most or southern-most boundaries of t h e i r geographic ranges. It was the purpose of t h i s study to investigate whether or not, within the geographic range of an organism, v a r i a t i o n s i n water q u a l i t y are an important environmental v a r i a b l e i n determining a species '• abundance and d i s t r i b u t i o n . The study organism was the calanoid copepod Pareuchaeta elongata. Lewis and Ramnarine (1969) had shown t h a t , i n the laboratory, the egg and the prefeeding naupliar stages were se n s i t i v e to v a r i a t i o n s i n water q u a l i t y . The b i o l o g i c a l p ortion of th i s study consists of three p a r t s . The f i r s t part i s the r e s u l t s of three survey cruises of the waters of the i n l e t s of the B r i t i s h Columbia mainland, .the west coast of Vancouver Island, the connecting passages, and the P a c i f i c Ocean. Six groups of water were i d e n t i f i e d on the basis of the s i m i l a r i t y i n the temperature-salinity c h a r a c t e r i s t i c s of t h e i r subsurface waters. The r e s u l t s i n d i c a t e that P. elongata i s capable of breeding i n a l l the waters studied, thus suggesting that v a r i a t i o n s in. the species' abundance are unrelated to va r i a t i o n s i n water q u a l i t y . Variables which may a f f e c t the species' abundance were suggested as being asso-ciated with the primary production of that area, and the o r i g i n and the residence time of the water i n that area. The one-year laboratory study, t e s t i n g P.',elongata egg c l u s t e r s i n various natural sea waters, .indicated that there were differences i n the s u r v i v a l among egg clu s t e r s from various areas. It was also shown, by t e s t i n g egg cl u s t e r s from one area i n a number of seawaters of s i m i l a r s a l i n i t i e s , - that there were va r i a t i o n s i n the q u a l i t y - o f these waters. Egg clusters were c o l l e c t e d from G.S.-l (in the S t r a i t of Georgia) and Indian Arm, and were tested i n t h e i r home water once a month over a 12-month peri o d . F i e l d c o l l e c t i o n s were made at these two stations over a 29-month peri o d . The laboratory data were evalua-ted i n terms of the f i e l d data.. The number of n a u p l i i i n the water was correlated with the number of eggs i n the water, and was apparently not s i g n i f i c a n t l y affected by va r i a t i o n s i n the s u r v i v a l of the egg i i i -i n i t s home water (as measured i n the laboratory). . This lack of any s i g n i f i c a n t e f f e c t of v a r i a t i o n s i n s u r v i v a l was probably due to the very large e f f e c t of v a r i a t i o n s ; i n egg production. There was a high mortality from the hatched nauplius to the adult . (approximately 97%), i n d i c a t i n g that the mortality of the egg due to i t s i n t e r -action with the water had a small r o l e i n determining the f i n a l po-pul a t i o n s i z e . The data suggested that v a r i a b l e s , isuch as prey a v a i l a b i l i t y , and predation;/, are probably the most e f f e c t i v e variables i n r e g u l a t i n g the abundance of the species i n these two areas. In conclusion, while the data showed that the species was more abundant i n some areas than others, these differences could be ex-plained by considering the primary production of the area, and the o r i g i n and residence time of the water. Although seawaters within the study area may vary i n q u a l i t y , these v a r i a t i o n s probably do not s i g -n i f i c a n t l y a f f e c t the abundance and d i s t r i b u t i o n of the species. i v TABLE OF CONTENTS Page ABSTRACT ..... I.i TABLE OF CONTENTS ..... l i v LIST OF TABLES ..... v i LIST OF FIGURES v i i i ACKNOWLEDGEMENTS ..... i x INTRODUCTION ..... 1 (i) The concept of v a r i a t i o n s i n the q u a l i t y of sea water . . . . . 2 ( i i ) The d i s t r i b u t i o n a l biology o f P_. elongata • 7 CHAPTER I: Physical' Oceanography of the Study Area INTRODUCTION 10 Materials and Methods ..... 11 (i) Survey Cruises 11 ( i i ) The 2-Year Study 14 Results • . ..... 15 (i) The Survey Cruises 15 ( i i ) The 2-Year Study . 18 Summary . . . . '. • 22 CHAPTER I I : P_. elongata Temperature-Salinity Asso-c i a t i o n s as Determined by the Three Survey Cruises 24 INTRODUCTION ..... 24 Materials and Methods ..... 25-(i) F i e l d Procedures. ..... 25 ( i i ) Treatment of the P. elongata f i e l d Data ..... 26 Results .. .'. . 28 (i) The abundance of P_. elongata i n the Six Groups of Waters 28 ( i i ) The Temperature-Salinity Associationyof the Developmental Stages of P. elongata (July 1970) . . . ./. 34 Discussion 37 Conclusions ..... 41 CHAPTER I I I : The Laboratory Study-An Examination of the Hatching Success of P_. elongata egg clusters i n various natural sea waters 43 INTRODUCTION 43 V Table of Contents (cont'd) Page Materials and Methods ..... 44 Tests ..... 46 Results ..... 48 (i) Variations i n the concentrations of dissolved z i n c , manganese, copper, and n i c k e l ..... 48 ( i i ) Fluctuations i n the s u r v i v a l o f G.S.?1 and Indian Arm egg clusters i n Indian Arm, G.S.-l, and Juan de Fuca deep waters ..... 51 ( i i i ) Survival of P a c i f i c Ocean egg c l u s t e r s i n four natural sea waters ..... 58 (iv) Bute, A l b e r n i , and Seymour Experiments 61 (v) G.S.-l 20-meter water 65 Summary ..... >65 CHAPTER IV: An evaluation of the r o l e of v a r i a t i o n s i n water q u a l i t y i n the d i s t r i b u t i o n of P_. elongata at Indian Arm and G.S.-l 70 INTRODUCTION ..... 70 Materials and Methods ..... 72 Results ..... 76 (i) The v e r t i c a l d i s t r i b u t i o n of the nauplius and the t h i r d copepodite (October 1970 to October 1971) . 76 ( i i ) Temporal v a r i a t i o n s i n the abundance of the developmental stages ..... 78 ( i i i ) C o r relation between the number of n a u p l i i and (i) the s u r v i v a l of the egg, and ( i i ) the number of eggs 79 (iv) The estimated mean m o r t a l i t i e s of the develop-mental stages 81 '(v) S t a b i l i t y Analysis -83j Conclusions . . '.. . • 86 BIBLIOGRAPHY ..... 89 APPENDIX ...... 1.99 The species and generic name of the study organism 99 An examination of Patten's analysis of s t a b i l i t y 106 v i LIST OF TABLES Page TABLE 1 The depth of the water column, the depth of the deepest sample, and the month of sampling f or the stations occupied dur-ing the three survey c r u i s e s . ..... 13 TABLE 2. The estimated number of developmental stages of P_. elongata i n a l-m^ column of water at the stations occupied during the May 1970 survey c r u i s e . ..... 29 TABLE 3. The estimated number of the.developmental stages of P_. elongata i n a l-m^ column of water at the various stations occupied during the JuGiy 1970 survey c r u i s e . ..... 30 TABLE 4. The estimated number of the developmental stages of P_. elongata i n a l-m^ column of water at the various stations occupied during the February 1971 survey c r u i s e . ...... 31 TABLE 5. Results and the analysis of variance of the percentage hatching of.Indian Arm egg clusters i n Indian Arm 200-m water, Juan de Fuca 200-m, water, and d i l u t e d Juan de Fuca 200-m water. • 53 TABLE 6. Results and the analysis of variance of the percentage hatching of G.S.-l and In-dian Arm egg cl u s t e r s i n Indian Arm 200-m water and G.S.-l 350-m water. ..... 56 TABLE 7. Analysis of variance of (a) the s u r v i v a l of Indian Arm egg clusters i n Indian Arm water and G.S.-l water. (b) The su r v i v a l of G.S.-l egg clusters i n Indian Arm water and G.S.-l water, and (c) the s u r v i v a l of G.S.-l egg cl u s t e r s i n Indian Arm water, G.S.-l, and Juan de Fuca water. ..... 57 TABLE 8. Results and the analysis of variance of the percentage hatching of Pac-6 egg clus t e r s i n four d i f f e r e n t sea waters. ..... 59 v i i L i s t of Tables ' (cont'd) Page TABLE 9. Results and the analysis of variance of the percentage hatching of Pac-8 egg clusters i n four d i f f e r e n t sea waters. ..... 60 TABLE 10. Results and the analysis of variance of the percentage hatching of Bute Inlet . egg clusters i n Bute water and G.S.-l w water. ..... 62 TABLE 11. Results and the analysis o f variance of the percentage hatching of Alberni Inlet egg c l u s t e r s i n Alberni water and Juan de Fuca water. 63 TABLE 12. Results and the analysis of variance of the percentage hatching of Seymour Inlet and Indian Arm egg clu s t e r s i n water c o l -lected from these two areas. ..... 64 TABLE 13. Results of the percentage hatching of G.S.-l and Indian Arm egg c l u s t e r s i n G.S.-l near-surf ace f20-m) water and G.S.-l deep (350-m) water. ..... 66 TABLE 14. The estimated mean time spent by P. elongata i n the egg, the s i x naupliar stages, and the s i x copepodites stages. ..... 7.4 TABLE 15. The mean number of developmental stages at G.S.-l and Indian Arm i n a 1-m^  c o l -umn of water, and the estimated between-stage and cumulative m o r t a l i t i e s . 82 TABLE 16. The analysis o f the s t a b i l i t y of the b i o l o g i c a l , chemical, and physical variables measured at G.S.-l. ..... 84 TABLE 17. The analyses of the s t a b i l i t y of the b i o l o g i c a l , chemical, and physical variables measured at Indian Arm. ..... 85 v i i i LIST OF FIGURES Page FIGURE 1. The study area showing the positions of the s t a t i o n s . 12 FIGURE 2; The temperature-salinity curves for the s i x groups of stations studied during the Ju l y 1970 survey c r u i s e . 17 FIGURE 3; The temperature, s a l i n i t y , and dissolved oxygen concentrations of the water at Juan de Fuca S t r a i t , Haro S t r a i t , Boundary Passage, G.S.-l (in the S t r a i t of Georgia) and Indian Arm during the study p e r i o d . • 20 FIGURE 4: The temperature-salinity associations of the developmental stages of. P_. elongata during the J u l y 1970 survey c r u i s e . • • 35 FIGURE 5. The concentrations of dissolved z i n c , manganese, copper, and n i c k e l i n Juan de Fuca, G.S.-l and Indian Arm deep waters •. 49 FIGURE 6. • The mean percentage hatching of P_. elongata egg clusters c o l l e c t e d from G.S.-l and Indian Arm i n Juan de Fuca, G.S.-l, and Indian Arm deep waters (March 1971 to February 1972) . , 5 2 FIGURE. 7. The v e r t i c a l d i s t r i b u t i o n of the n a u p l i i and of the t h i r d copepodites at G.S.-l and Indian Arm (October 1970 to October 1971). ..... 77 FIGURE 8. The estimated number of the developmental stages of P_. elongata i n a l-m^ column of water at G.S.-l and at Indian Arm during, the study p e r i o d . ..... ,80 FIGURE 9. A hypothetical system i n which the measured v a r i a b l e has p h y s i c a l s t a b i l i t y . ^l'l'O ACKNOWLEDGEMENTS I would l i k e to thank my supervisor, Dr. A.G. .'Lewis, f o r his constant willingness to guide 'and help me throughout my study. Thanks are also extended to Dr; B. McK. Bary, who suggested many i n t e r e s t i n g ideas during the early part of my study, and to my committee who provided valuable c r i t i c i s m s of the f i r s t d r a f t of the t h e s i s . • The help of Mr. A. Ramnarine was very much appreciated both at sea and i n the laboratory.. Without his assistance, the c o l l e c t i o n of the data' would have been considerably less enjoyable. Mr. M. Storm provided good i n s t r u c t i o n i n the,.collection of oceanographic data during the early part of my study, was of great assistance i n many of the survey c r u i s e s , and was responsible f o r performing most of the s a l i n i t y estimates. I also wish to thank him for the many times he went out of his way to help me, .often without my asking. The assistance of Mr. G.. Bromley, Mr. U. Borgmann, and Mr. G. Gardner at sea was very much appreciated. Special thanks are extended to Mr: G. Gardner f or c o l l e c t i n g sea water and egg clusters during the autumn and winter of 1971-72, and f o r making a v a i l a b l e the oceanographic data he c o l l e c t e d during these c r u i s e s . I am also g r a t e f u l to Dr. P.H. LeBlond who conducted a cr u i s e for my b e n e f i t . I would l i k e to thank Dr. E.V. G r i l l and Mr. F.A. Whitney who ran a l l the analyses of the trace element concentrations, Mr. B. de Lange Boom who wrote the computer program f o r the analysis of s t a b i l i t y and Mr. P.H. W h i t f i e l d who drew the i l l u s t r a -t i o n s . The help and suggestions given by Dr. T.R. Parsons during the l a t t e r part of my studies were very much appreciated. I would also l i k e to thank the Department of Zoology f o r providing me with a teaching a s s i s t a n t s h i p during my f i r s t winter and spring session, Dr. B. McK. Bary f or providing me with support during my second session, and the I n s t i t u t e of Oceanography for providing me with support during my f i r s t two summer sessions. The assistance, co-operation, and courtesy extended to me by the o f f i c e r s and men of the research vessels C.S.S. Vector, and C.N.A.V. Laymore and Endeavour during the course of my study was very much appreciated. I wish to thank a l l the remaining people with whom I have been associated during my study, and who have helped or advised me i n a v a r i e t y o f ways. F i n a l l y , I wish to extend my sincere gratitude to my parents f o r , i n my early l i f e , providing me with the opportunities to con-tinue my education, and for t h e i r encouragements which they w i l l i n g l y offered throughout my studies. 1 INTRODUCTION A planktonic organism i s c a r r i e d by the water i n which i t l i v e s from one area to another, and i s incapable of swimming against t h i s current. Because the range of such organisms i s , by n e c e s s i t y , dependent upon currents, descriptions of a species' range have f r e -quently been made i n terms of some of the physical c h a r a c t e r i s t i c s ' of the water i n which i t lives.• These physical c h a r a c t e r i s t i c s have been described from measurements of temperature and s a l i n i t y , and de-f i n i t i o n has been given to water masses, domains, and the various mechanisms which transport water from one area to another. Species may be associated with p a r t i c u l a r water masses ( B i e r i 1959; Kriss 1960; Kriss ejt . a l . 1960a, 1960b; McGowan 1960; Brinton 1962; Fager and McGowan 1963; Johnson and Brinton 1963)... They may also be associated with smaller volumes of water, and the currents adjacent to coasts (Russell 1935, 1936, 193.7, 1939; Fraser 1937, 1939, 1952; Marumo 1957; Sheard 1965). Marine organisms possess a range of tolerances for temperature and s a l i n i t y (Kinne 1963, 1964). Within the oceanic environment, s a l i n i t y i s probably not l i m i t i n g to oceanic plankton (Hopper 1960), although i t may be l i m i t i n g i n estuaries (Gunter 1961). Temperature may l i m i t the v i a b i l i t y or fecundity of zooplankton . (Hutchins 1947), and i s l i m i t i n g to ce r t a i n species c a r r i e d from warm t r o p i c a l waters into the colder temperate and polar regions (Somme 1929; Berner and Reid 1961; Woodhouse 1971). However, while temperature and s a l i n i t y may l i m i t a planktonic species at the boundaries of i t s range, i t i s less l i k e l y that temperature and s a l i n i t y v a r i a t i o n s , per se. are s i g n i f i c a n t variables i n determining a species' abundance within i t s range. (i) The concept of• v a r i a t i o n s i n the 'q u a l i t y ' of sea waters Sea waters of s i m i l a r s a l i n i t i e s may\have d i f f e r e n t concen-tration s of the minor elements, although the eleven major elements, which account for 99.9% (by weight) of the s a l t i n oceanic waters, occur i n constant proportions (Sverdrup.et a l . , ,1942). Many of these minor elements are involved i n the more important inorganic, and biochemical reactions i n the marine environment (Goldberg 1965). These reactions may be important i n determining the concentrations of these dissolved elements. The concentrations of dissolved nitrogen and phosphorous i n the euphotic.zone are l a r g e l y dependent upon these r e a c t i o n s , and l a r g e l y independent of v a r i a t i o n s i n s a l i n i t y . The concentrations of dissolved copper (Atkins 1953), s i l i c o n e (Armstrong 1954), i r o n (Armstrong 1959), and dissolved organic carbon, nitrogen and phosphorous (Duursma 1961) vary seasonally i n c e r t a i n waters. Many of the elements present i n sea water are concentrated by marine organisms (Goldberg 1957; Bowen.1966), and have known functions (Lehninger 1950; Williams 1953). Nitrogen and phosphorous are the general l i m i t i n g factors to growth i n the sea (Redfield 1958), and have been studied at various l e v e l s i n the marine ecosystem (Clowes 1938; Marshall and Orr 1927; King and Demond 1953; Sette 1955; Holmes et a l . 1957; Steeman and Jensen 1957; Bogorov 1958; Heinrich 1962; 3 Reid "19.62). However, i n c e r t a i n areas, other trace elements may l i m i t phytoplankton growth, both i n lakes (Lund 1950; Goldman 1960, 1961) and i n the marine environment (Harvey 1947; Ryther and G u i l l a r d 1959; Johnston 1963). The concentration of dissolved copper may be important to the s e t t i n g of oyster larvae (Prytherch 1934). Dissolved organics may have several e f f e c t s upon the b i o t a within the marine environment (Lucas 1938, 1947, 1949, 1961), being toxic (Bainbridge 1953; Gunter et a l . , 1948; Procter 1957),or b e n e f i c i a l (Chu 1946, C o l l i e r et a l . , 1953; Rodhe 1955; Pfovasoli 1963; Stephen e i al..: 1961; Barber and Ryther 1969). Johnston (1963, 1964) indicated that sea waters'of s i m i l a r s a l i n i t i e s (and temperatures) may vary i n q u a l i t y , t h i s q u a l i t y being associated with the a v a i l a b i l i t y of dissolved trace elements. He determined these v a r i a t i o n s i n q u a l i t y by examining the growth of phytoplankton i n several sea waters c o l l e c t e d from d i f f e r e n t areas and at d i f f e r e n t times. Wilson (1951) and Wilson and Armstrong (1952, 1954, 1958, 1961) also indicated that there were v a r i a t i o n s i n the q u a l i t y of sea waters c o l l e c t e d from d i f f e r e n t areas. However, they were unable to determine the source of v a r i a t i o n . G i l f i l l a n (1970) showed that the zooplankter Euphausia p a c i f i c a . c o l l e c t e d from two areas, exhibited d i f f e r e n t r e s p i r a t i o n rates i n waters of s i m i l a r temperatures and s a l i n i t i e s . Few. studies have, however, investigated the r o l e of v a r i a t i o n s i n the q u a l i t y of natural sea waters i n the d i s t r i b u t i o n a l ecology of zobplankton; a "notable; exception has been the work of Bary- (1963). 4 Bary (1963) surveyed the surface waters around Great B r i t a i n , and subdivided them into 'water bodies' on the basis of t h e i r temper-a t u r e - s a l i n i t y c h a r a c t e r i s t i c s . Certain species of zooplankton were associated with p a r t i c u l a r water bodies, e.g., Pareuchaeta norvegica was associated with the Gold (Northern)-Transitional water bodies but not with the Warm (Southern) water body. Species have been shown to be associated with p a r t i c u l a r waters many times i n the l i t e r a t u r e , and from these associations arose the concept of i n d i c a t o r species. However, very l i t t l e of the .work on in d i c a t o r species has attempted: to explain why an organism i s associated with one water and not ano-ther . Bary (1963) stated that zooplankton-water body associations were due, not to va r i a t i o n s i n the temperature and s a l i n i t y o f the water bodies, but to v a r i a t i o n s i n the other properties of the waters. A species such as Pareuchaeta norvegica survived i n i t s native water body because i t was tolerant of the properties of that water. Converse-l y , i t was not associated with the other water bodies because i t was in t o l e r a n t of the properties of that water. The e a r l i e r work of Wilson and Armstrong had shown that v a r i a t i o n s d i d occur i n the q u a l i t y of these waters, and the l a t e r work of Johnston confirmed t h i s . Bary's contribution was to hypothesize that these v a r i a t i o n s were s u f f i c i e n t l y great, and the tolerances of zooplankton s u f f i c i e n t l y s m a l l , for the species to bbe li m i t e d to c e r t a i n waters. Several c r i t i c i s m s may be made of Bary's work (1963). Many of the species he examined were at the northern-most or southern-5 most boundaries of t h e i r geographic ranges; at these boundaries temperature may have been l i m i t i n g . Bary believed that t h i s was not the v a r i a b l e l i m i t i n g zooplankton to t h e i r native water bodies, because,.over the year, the species experienced f l u c t u a t i o n s i n tem-perature and s a l i n i t y which were greater than the v a r i a t i o n s between water bodies. As the native water body varied seasonally i n tempera-ture a n d . s a l i n i t y , the. zooplankton associated with these waters must have had a wide temperature a n d . s a l i n i t y tolerance over the year. However, G i l f i l l a n (1970) showed that the temperature and s a l i n i t y tolerances of the zooplankter Euphausia p a c i f i c a ..varied through the year, with the r e s u l t that the tolerances over the year were greater than the tolerances i n any one month. An a l t e r n a t i v e explanation of Bary's data.is that although the zooplankton species he examined were able to t o l e r a t e changes in. temperature and s a l i n i t y during the year, t h i s a b i l i t y to t o l e r a t e changes.was not the same at a l l times of the year. • Because of t h i s , temperature and s a l i n i t y v a r i a t i o n s , between water bodies could have been l i m i t i n g , e i t h e r because the v a r i a t i o n s were l e t h a l to the species, or because the species avoided the surface layer.and remained deeper i n the water column. Another, c r i t i c i s m o f Bary's work was that he examined only one depth i n the water column and, by this., f a i l e d to describe ade-quately the dimensions o f the water bodies; the events occurring i n the zone o f mixing between water bodies, and the v e r t i c a l d i s t r i b u t i o n of the species within the water bodies. Therefore, while h i s data 6. are open to the i n t e r p r e t a t i o n that species are associated with c e r t a i n water bodies because of t h e i r tolerances to the properties of these waters, the data are inc o n c l u s i v e . A l s o , as h i s studies were not conducted well within the geographic range of most, of the species he studied, he f a i l e d to give a good evidence that a species i s a f f e c t e d by v a r i a t i o n s i n the properties or q u a l i t y of the water within i t s range. The purpose of t h i s study i s to te s t Bary's. hypothesis by i n v e s t i g a t i n g whether or not t h e c a l a n o i d copepod Pareuchaeta elongata i s affected by temporal and s p a t i a l v a r i a t i o n s i n the .properties of water bodies. This species i s an i d e a l study organism f o r many re a -sons. , Lewis and Ramnarine (1969) showed that the egg c l u s t e r was s e n s i t i v e to v a r i a t i o n s i n water q u a l i t y . These c l u s t e r s were reared i n t h e i r native water, and experiments conducted once a month over a 12-month period indicated that there were temporal v a r i a t i o n s i n the su r v i v a l of the eggs. This suggested that there were temporal v a r i a -tions i n the q u a l i t y of sea water. Survival could be enhanced at c e r t a i n times of the year by the addit i o n of trace elements or the synthetic chelator EDTA to the sea water. Unlike Euphausia p a c i f i c a , which G i l f i l l a n (1970) showed to be s e n s i t i v e to water q u a l i t y , P ar euchacta e1on gat a breeds a l l year round. It i s possible to c o l l e c t a l l the developmental stages.each month, and to observe changes i n t h e i r d i s t r i b u t i o n . Although P_.• elongata has been captured i n many areas i n the open and coastal North P a c i f i c , i t has generally been captured, i n very low numbers; 7 conversely, the species occurred i n large numbers i n the S t r a i t of Georgia. This suggested that P_. elongata survives best i n water bodies such as those associated with the S t r a i t of Georgia, and i s less able to survive i n water bodies with a closer geographic and oceanographic connection with the open waters of the'.Pacific Ocean. , ( i i ) The d i s t r i b u t i o n and biology of P. elongata Very l i t t l e i s known about the biology of P. elongata. Most of the f i e l d work has consisted.of s t a t i n g i t s occurrence i n various areas, and most of the descriptions have been i n oceanographic rather than geographic terms. Few studies have described the v e r t i c a l d i s -t r i b u t i o n of the.species and the temperature and s a l i n i t y of the water i n which the species was found. The species has been described by various authors as Pareuchaeta  elongata, P_. japoriica,- Eiichaeta elongata, and E_. japoriica. A l i t e r a -ture search was made to determine the basis f o r the generic and species names, and, from t h i s , i t i s decided that the name Pareuchaeta elongata i s c o r r e c t . The r e s u l t s of t h i s l i t e r a t u r e s s e a r c h are reported i n the appendix. P_. elongata has been captured from the Bering Sea, the Sea of . Okhotsk (Brosky 1950), the Sea of Japan (Marukawa, 1921), the Izu region of Japan (Tanaka and Omori 1968), the subarctic P a c i f i c Ocean, with smaller numbers i n the t r a n s i t i o n zone between the subarctic and subtropical North P a c i f i c Ocean (Morris 1970), the Alaskan Peninsula 8 (Davis 1949), the Queen Charlotte Island region (Cameron 1957), the S t r a i t , of Georgia (Campbell 1929, 1934) and Howe Sound (Pandyan 1971) which l i e s east of the s t r a i t , and the San Diego region (Esterly 1913) . The l i f e h i s t o r y of P_. elongata consists of an egg (retained i n a c l u s t e r of 8 to 24 eggs; Lewis and Ramnarine 1969), s i x naupliar stages, and s i x copepodite stages. The f i r s t two naupliar stages are nonfeeding, and the remaining four are herbivorous. The copepo-di t e s are p r i m a r i l y carnivorous, with the exception of the adult male, which is.herbivorous (Pandyan 1971). The morphology of the develop-mental stages has been described-by Campbell (1934). • This thesis presents the r e s u l t s o f four s t u d i e s . These are: 1) Two physical oceanography s t u d i e s . The f i r s t consisted of three survey cruises of a number of stations i n the waters of the west coast of Vancouver Island the B r i t i s h Columbia mainland, the con-necting passages, and the P a c i f i c Ocean. The second was a two-year study at Juan de Fuca S t r a i t , Haro S t r a i t , Boundary Passage, G.S.-l (in the S t r a i t , of Georgia), and Indian Arm. 2) The study of the temperature-salinity associations of the developmental stages of P_. elongata as determined by the three survey c r u i s e s . 3) A 1-year laboratory study of the responses.of P. elongata egg c l u s t e r s c o l l e c t e d from G.S.-l and Indian Arm to various natural sea waters, and f i v e shorter studies using egg c l u s t e r s c o l l e c t e d from other areas. 9 4) A study of the temporal f l u c t u a t i o n s i n the d i s t r i b u t i o n o f the developmental stages of P. elongata at G.S.-l and Indian Arm, and an evaluation of t h i s i n terms of the laboratory data and the temperature-salinity data. In order to maintain c l a r i t y and to better i l l u s t r a t e trends, the four sections are presented separately with an i n t r o d u c t i o n , a materials and methods s e c t i o n , a r e s u l t s section^and a discussion or summary. 10 CHAPTER I (!) PHYSICAL OCEANOGRAPHY OF THE STUDY AREA INTRODUCTION A p r e r e q u i s i t e for a successful study o f the temperature-s a l i n i t y associations of an organism,is the.examination of a com-prehensive range of waters with d i f f e r e n t temperatures and s a l i n i t i e s . The area c o n s i s t i n g of the i n l e t s , and the insid e passage between1 Vancouver Island and the B r i t i s h Columbia mainland, and the P a c i f i c Ocean i s id e a l f o r such a study. The waters within t h i s area possess d i s t i n c t temperature-salinity c h a r a c t e r i s t i c s and are, on t h i s b a s i s , d i v i s i b l e into a number of groups and domains (Pickard 1961, 1963; Dodimead et _ a l . 1963; Herlinveaux and Giovando-(1969). This area i s also i d e a l because there.is a continual exchange of water between the inshore and offshore environments, so that a study conducted over a 1-year period should reveal whether or not a species i s l i m i t e d to a - p a r t i c u l a r water. This would be indicated i f the species were asso-ciated.with one water, .and disappeared as t h i s water was transported i n t o another area. Within the study area, the dominant process by which oceanic water i s transported to the inshore environment and fresh water to the offshore environment i s estuarine c i r c u l a t i o n . Estuarine c i r c u -l a t i o n consists of a 3-layered system with a surface layer of fresh and l o w - s a l i n i t y water moving out towards the ocean, and:a deeper, high-11 s a l i n i t y layer moving inshore. Between'the surface and.deep l a y e r s , i s an intermediate layer where the deeper, h i g h - s a l i n i t y water i s mixed upwards into the l o w e r - s a l i n i t y water and c a r r i e d seaward. The lower l i m i t of the h a l o c l i n e represents the point of no net transfer ( T u l l y 1958). A second process by .which .subsurface P a c i f i c Ocean water i s tr a n s f e r r e d to the inshore.environment i s upwelling. Upwelled water i s moved inshore, generally i n the summer, by estuarine c i r c u l a t i o n and t i d a l currents (Tully 1958; T u l l y and Barber 1960; Lane 1962, 1963). Materials and Methods (i) Survey Cruises The three survey cruises, were conducted i n May and J u l y 1970, and i n February 1971, where 22, 26 and 18 stations r e s p e c t i v e l y were examined; Figure 1 shows the positi o n s of the s t a t i o n s . Not a l l the stations were occupied during each cr u i s e e i t h e r due to the design of the cruise or to the weather. Table 1 l i s t s the stations occupied during each c r u i s e ; the depth of the water column, and the greatest depth to which plankton and water samples were made., The data, i n -cluding the co-ordinates of the stations and the time of sampling, are reported i n the I n s t i t u t e of Oceanography Data Reports (1971', 1972). Measurements of temperature and the c o l l e c t i o n of water sam-ples f o r s a l i n i t y analysis were made by using NIO b o t t l e s equipped with reversing thermometers. A surface sample was c o l l e c t e d with a bucket. 12 Figure 1. The study area and the p o s i t i o n of the stations occupied during the three survey c r u i s e s # , the two year s t u d y ® , and two short cruises i n the P a c i f i c Ocean A. 13 TABLE 1. The depth of the water column, the depth of the deepest sample, and"the month of sampling f o r the stations occupied during the three survey c r u i s e s . Station Depth of Depth of Months Water Column Deepest Sampled (meters) , Sample (meters) Howe Sound (How) 248 225 M J F Georgia 6 (Geo 6) 132 100 J Malaspina S t r a i t (Mai) 402 340 M J F Georgia 10 (Geo 10) 143 100 J Georgia 11 (Geo 11) 358 325 M J F J e r v i s Inlet (Je) 677 600 M J F Pendrell Sound (Pe) 431 400 M J F Bute Inlet (Bu) 658 600 M J F Nodales Channel (Nod) 333 275 M J Loughborough Inlet (Lo) 256 220 M J F Johnstone S t r a i t (Jo) 483 450 M J F Knight Inlet (Knight) 527 475 J F Kingcome Inlet (Kin) 475 450 M J F Seymour Inlet (Se) 490 450 M J Belize Inlet (Be) 388 375 M J Smith Inlet (Sm) 358 340 M J F Queen Charlotte Strait(QCOStr)373 340 M J Queen Sound (QC snd„) 298 250 M J F Kashutl Inlet (KAS). 256 200 M J F Muchulat Inlet (MUC) 358 340 M J F Alberni Inlet (ALB) 311 275 M J F Pac 1 1,902 1,000 M J Pac 2 1,390 1,000 M J F Pac 3 1,792 1,000 M J F . Pac 3-1 227 150 M J F Pac 4 274 250 M J F Pac 5 2,578 1,000 F M = May; J = J u l y ; F = February Temperature was read at sea with an accuracy of ±0. 0 1 C. Samples f o r s a l i n i t y analysis were drawn from the NIO b o t t l e s , and the s a l i n i t y was estimated in.the laboratory by using the Model 601 MK3 Auto-Lab Inductively Coupled Salinometer (Extended Range Model). For s a l i n i t i e s above 28%o, the salinometer has a reported accuracy of ±0.003 % o ( I n s t i t u t e of Oceanography Data Report, 1970). A bathythermograph was used before.the b o t t l e cast at a l l the stations occupied during the three survey c r u i s e s , and at a l l the f i v e stations occupied during the second year of sampling (October 1970 to October 1971). of the 2-year study. A l s o , a d d i t i o n a l samples were drawn from the water b o t t l e s , and the dissolved oxygen concentra-t i o n was measured, at sea, by using the Winkler method as modified by C a r r i t t and Carpenter (1966). ( i i ) The 2-Year Study Five stations were studied from October 1969 to October 1971 i n c l u s i v e , with each s t a t i o n being occupied once a month. . These s t a -tions were i n Juan de Fuca S t r a i t , Haro S t r a i t , Boundary Passage, the S t r a i t of Georgia (G.S.-l), and Indian Arm; Figure 1 shows the p o s i -tions of the s t a t i o n s . The data are reported i n the I n s t i t u t e of Oceanography Data Reports (1970, 1971,and 1972). The methods used at each s t a t i o n are as described above f o r the survey c r u i s e s . The s t a t i o n (48° 23'N, 124° 21'W) i n Juan de Fuca S t r a i t was located i n the coastal seaways domain (Herlinveaux and Giovando 1969), i n a trough approximately 230 m deep communicating with Juan de Fuca 15 canyon which runs across the continental s h e l f . The physical oceanography of t h i s s t r a i t has been described by Herlinveaux and T u l l y ,(1961). The s t a t i o n i n Haro S t r a i t ( 4 8° 29*N, 123° 9*W) was located i n a narrow depression approximately 300 m deep. The Boun-dary Passage s t a t i o n (48° 50'N, 122° 59'W) was located at the junc-t i o n of Boundary Passage with the S t r a i t of Georgia, and was over a f l a t p l a i n approximately 220 m deep. Both the Haro S t r a i t s t a t i o n and the Boundary Passage s t a t i o n were located within the southern homogeneous domain (Herlinveaux and Giovando 1969). The s t a t i o n i n the S t r a i t of Georgia (49° 17'N, 123° 51*W) was located i n the center of a Y-shaped trough; the water column was approximately 420 m deep. The physical oceanography of the S t r a i t of Georgia has been described by.Waldichuk (1957). The Indian Arm s t a -t i o n ( 4 9° 24'N, 122° 53'W) was located i n the middle of the i n l e t ; the water column was approximately 220 m deep. The physical oceano-graphy of t h i s i n l e t has previously been described by Gilmartin (1962)i Results (i) Survey Cruises Although the temperature and s a l i n i t y of the upper 150 m of water at the stations were d i f f e r e n t during the three times they, were studied, the deep waters were s i m i l a r i n these c h a r a c t e r i s t i c s . Second-l y , the r e l a t i v e abundance of the developmental stages of Pareuchaeta  elongata among the stations was s i m i l a r during the three c r u i s e s . 16 Because of these observations, the r e s u l t s of only one survey cruise are presented. The July 1970 survey cruise was chosen f o r represen-t a t i o n because i t was the most extensive. The stations were divided into s i x groups on the basis of the temperature-salinity c h a r a c t e r i s t i c s of t h e i r subsurface waters. The c l a s s i f i c a t i o n s of Pickard (1961, 1963) for the i n l e t s , Herlinveaux and Giovando (1969) for the waters of the insi d e passage, and Dodimead e_t a l . ., (1963) f o r the sub-arctic P a c i f i c Ocean were r e f e r r e d t o , and with s l i g h t m o d i f i c a t i o n s , used. The groups.are: (i) l o w - s a l i n i t y 'southern' waters, ( i i ) southern waters, ( i i i ) intermediate and nor-thern waters, (iv) west coast i n l e t s , (v) coastal seaway waters, and (vi) sub-arctic P a c i f i c Ocean waters. Figure 2 shows the temperature-salinity curves f o r the s i x groups of stations studied during the J u l y 1970 survey c r u i s e . In the summer, surface waters are generally warmer and lower i n s a l i n i t y than deep water; therefore, the upper l e f t portion of each curve represents the near-surface water, and the lower r i g h t portion represents the deep water. A l l the temperature-salinity data c o l l e c t e d from 10-m to the deepest water sample were used i n drawing the curves; tempera-t u r e - s a l i n i t y points where horizontal plankton samples were c o l l e c t e d are indicated by symbols on each curve. The - temperature-salinity curves confirm the differences i n the deep water c h a r a c t e r i s t i c s as discussed by Pickard (1961, 1963), Herlinveaux and Giovando (1969), and Dodimead et al.,. (1963). There was a gradient of s a l i n i t y and temperature from tne warm, l o w - s a l i n i t y . 17 Figure 2. The temperature-salinity curves for the s i x groups of stations studied during the J u l y 1970 c r u i s e (with the exclusion of the 0-meter data). (a) low s a l i n i t y 'southern' waters, (b-1,2) southern waters, (c) i n -termediate and northern waters, (d) west coast i n l e t s waters, (e) coastal seaway waters, (f) sub-arctic P a c i f i c Ocean waters (abbreviations as i n Table 1). The missing 10-m (*) data for the southern i n l e t s are: Inlet Temperature S a l i n i t y °C %. Howe 13.6 27.0 Mai 15.2 26.8 Geo 6 12.7 28.2 Geo 10 15.7 26.9 Geo 11 15.9 27.1 Je 15.0 26.3 Pe 13.7 28.1 Bu 9.5, 28.5 17i 18 southern waters through to the c o l d , h i g h - s a l i n i t y west coast i n l e t waters. The coastal seaway waters were higher i n s a l i n i t y and cooler i n d i c a t i n g less d i l u t i o n of oceanic water by the warm, l o w - s a l i n i t y surfacewaters from the i n l e t s and the inner s t r a i t s . ( i i ) The 2-Year Study Figure 3 shows the fl u c t u a t i o n s i n temperature, s a l i n i t y , and dissolved oxygen concentration which occurred during the 2-year study period at Juan.de Fuca S t r a i t , H a r o . S t r a i t , Boundary Passagej the S t r a i t of Georgia (G.S.-l), and Indian Arm. The data f o r the period November 1971 to February 1972 f o r Indian Arm.and G.S.-l are from Mr. G. Gardner (pers. comm.). Broken l i n e s on the figures i n d i c a t e uncertain data p o i n t s . The sampling depths are indicated on each graph;, h o r i z o n t a l plankton samples were c o l l e c t e d from the same depths with the exclusion o f 0 and 20 meters. Temperatures of the surface waters at a l l f i v e stations were lowest i n the winter and ear l y s p r i n g , and highest i n the l a t e summer and autumn. The lowest s a l i n i t i e s occurred from the l a t e spring to the l a t e summer associated with the increased discharge of r i v e r s such as the Fraser (Water Survey of Canada 1971, unpublished data f or 1971). A second period of low s a l i n i t y occurred i n the l a t e winter; and was associated with the period i n which d i r e c t p r e c i p i t a t i o n was greatest. The dissolved oxygen concentrations of the near-surface waters were high i n the ear l y spring and winter, and low from the l a t e summer to October or November. 19 The deep water i n Juan de Fuca S t r a i t was coldest and most s a l i n e from A p r i l to October or November. This was because upwelled subsurface P a c i f i c Ocean water was present i n the s t r a i t "at t h i s time. During the la t e summer, when upwelling ceased, t h i s oceanic water was gradually, mixed into the overlying warmer, l e s s - s a l i n e waters. This mixing continued through the autumn and winter, at which time the deep waters reached t h e i r lowest s a l i n i t i e s and highest tempera-tures.- S i m i l a r l y , the dissolved oxygen concentrations were low from the spring to the l a t e summer when the undiluted, low-oxygen P a c i f i c Ocean subsurface water was present i n the- s t r a i t , and increased through the autumn and winter as t h i s water was mixed with the o v e r l y i n g , higher-oxygen water. The deep water i n Haro S t r a i t was most s a l i n e from the spring to the la t e autumn. In' 1970, the deep water reached i t s maximum s a l i n i -ty and lowest temperature in ' September although, i n Juan de Fuca S t r a i t , the maximum s a l i n i t y and minimum temperature were reached i n J u l y . From t h i s i t i s estimated that the deep water i n Juan de Fuca S t r a i t takes one to two months to reach Haro S t r a i t . The dissolved oxygen concentration of the deep water i n Haro S t r a i t was lowest i n the la t e summer and ea r l y autumn, when the low-oxygen subsurface P a c i f i c Ocean water was mixed into the waters of the San Juan Archipelago. Values were higher during the rest of the year, being greatest i n the winter when intensive mixing of the water column occurred as evidenced by the water being almost completely isothermal and i s o h a l i n e . 20 Figure 3. The temperature,, s a l i n i t y , and dissolved oxygen concentrations' o f the water at (i) Juan de Fuca S t r a i t , ( i i ) Harp S t r a i t , ( i i i ) Boundary Passage, (iv) G.S.-l i n the S t r a i t of Georgia, and (v) Indian Arm during the study per i o d . Dashed l i n e s i n d i c a t e uncertain or missing dataim p o i n t s . The depths at which samples were c o l l e c t e d are i n d i -cated by dots. O U> x a> D> — 3 3 *p O -o O c: > Q. CD o > GO —I 23 > © © © o © o O 09 0> & N> O O O 21 The deep water of Boundary Passage was highest i n s a l i n i t y from the l a t e spring to the lat e autumn. The temperature of the deep water was lowest i n the winter. The dissolved oxygen concen-tra t i o n s were low from the lat e spring to the late autumn, presumably owing to the low-oxygen P a c i f i c Ocean subsurface water being mixed into the waters of Boundary Passage. Values were high during the winter and ear l y spring when there was intensive mixing of the water. The temperature and s a l i n i t y of the deep water at G.S.-l i n the S t r a i t of Georgia, ,were lowest i n the early spring and highest i n the lat e autumn. Beginning i n the l a t e summer, the bottom water of the S t r a i t of Georgia was replaced by the warmer, h i g h e r - s a l i n i t y water which was formed i n the San Juan Archipelago. This water was formed from the mixing of subsurface Juan de Fuca S t r a i t water, and surface water from areas such as the S t r a i t of Georgia and Puget Sound. The replacement of the bottom water of the S t r a i t of Georgia continued u n t i l October or November, a f t e r which the 'new* water was gradually eroded away and mixed in t o the overlying c o l d e r , l e s s - s a l i n e water. The dissolved oxygen concentration of the deep water at G.S.-l was lowest i n the, late.autumn when the low-oxygen water from the San Juan Archipelago replaced the bottom water. In the winter and spring the values increased as the higher-oxygen water formed i n the San Juan Archipelago intruded into the S t r a i t of Georgia at intermediate depths, and eroded away and mixed into the low-oxygen water. 22 In Indian Arm, the deep, water was most s a l i n e from the l a t e autumn to the early spring when the water was replaced by an i n f l u x of more s a l i n e water. This 'new' water was only s l i g h t l y eroded away and mixed in t o the o v e r l y i n g , l e s s - s a l i n e water during the summer. The deep water, was. r e l a t i v e l y isothermal through the year with changes occurring at the time of deep water replacement. The dissolved oxygen concentration was. highest when the deep water was ' replaced by the higher-oxygen water formed i n the v i c i n i t y of the s i l l at the mouth of the i n l e t . Oxygen values decreased through the l a t e summer and early autumn. Summary (1) The three survey cruises of a number of i n l e t s of the B r i t i s h Columbia mainland and the west coast.of Vancouver Island, the connecting passages, and the P a c i f i c Ocean examined a wide range of waters with d i s t i n c t temperature-salinity c h a r a c t e r i s t i c s . These stations could be subdivided.into s i x groups on the basis of the tem-perature-salinity, c h a r a c t e r i s t i c s of the subsurface waters. (2) The survey c r u i s e s , because they covered an extensive range of waters with d i s t i n c t temperature-salinity c h a r a c t e r i s t i c s , were i d e a l for determining the temperature-salinity associations of' Pareuchaeta elongata, and determining whether or not the species was r e s t r i c t e d to various waters. 23 (3) The 2-year study at Juan de Fuca S t r a i t , Haro S t r a i t , Boundary Passage, G.S.-l (in the S t r a i t of Georgia), and Indian Arm observed the tr a n s f e r of subsurface P a c i f i c Ocean water .inshore, and the t r a n s f e r of fresh and low s a l i n i t y water to the offshore environ-ment. (4) The 2-year study,, while covering a less extensive range of waters than the three survey c r u i s e s , was i d e a l for showing whe-ther or not temporal v a r i a t i o n s i n the d i s t r i b u t i o n of P\ elongata i n an area were associated.with changes i n the water of that area. 24 CHAPTER II • P. ELONGATA TEMPERATURE-SALINITY ASSOCIATIONS AS DETERMINED BY THE THREE SURVEY CRUISES INTRODUCTION Pandyan (1971) showed t h a t , i n Howe Sound, the naupliar and f i r s t copepodite stages o f P. elongata were found i n the deep water, while the l a t e r stages were found higher up i n the water column. Secondly, she indicated that the t h i r d to s i x t h copepodite stages were found nearer the surface at night than during the day, although they were always found throughout a large portion of the water column. This suggests that these stages exhibit d i e l v e r t i c a l migration, a l -though the v e r t i c a l migration i s less pronounced than that of zob-plankton such as Euphausia p a c i f i c a , which are found at more d i s c r e t e depths during the day and nig h t . In Howe Sound, the v e r t i c a l d i s t r i b u t i o n of P_. elongata ap-peared to be a function of the stage of development of the organism, and the variables a f f e c t i n g d i e l migration. What was not known f o r Howe Sound or.for any other area, was the r o l e of temperature, s a l i n i t y and the other properties of sea waters i n determining the d i s t r i b u t i o n of P_. elongata. The purpose of the three survey cruises was to inves-t i g a t e the q u a l i t a t i v e and quan t i t a t i v e d i s t r i b u t i o n of the develop-mental stages of P_. elongata i n a number of groups of waters with, d i s t i n c t temperature-salinity c h a r a c t e r i s t i c s . In p a r t i c u l a r , the following were investigated: 25 (1) Is P_. elongata capable of surviving across the range of waters which constitute the oceanic and coastal environments? (2) Is P_. elongata capable of reproducing across the range of waters which constitute the oceanic and.coastal environments? (3) Is the v e r t i c a l . d i s t r i b u t i o n of P_. elongata throughout i t s range a function of temperature and s a l i n i t y , or i s the v e r t i c a l d i s t r i b u t i o n s i m i l a r both i n the oceanic and coastal environment? (4) What other environmental variables might account f o r populations o f P., elongata being r e l a t i v e l y small i n the P a c i f i c Ocean, and r e l a t i v e l y large i n areas such as the S t r a i t of Georgia? Materials and Methods (i) F i e l d Procedures Figure 1 shows the p o s i t i o n s of the stations occupied during the three survey c r u i s e s , and Table 1 shows the stations occupied dur-ing each cruise,' and the maximum depth of plankton and water sampling. The techniques employed at each s t a t i o n were the same. Horizontal plankton tows were made, and the temperature, s a l i n i t y , and dissolved oxygen concentration of the water were measured at a number of depths. Plankton samples were made at the same depths as the water samples, with the exclusion of 0 and 20 meters. Discrete horizontal plankton samples were c o l l e c t e d by using the opening arid c l o s i n g Clarke-Bumpus samplers equipped with a number 2 mesh (approximate pore size-360 u ) . The samplers had a mouth diame-ter of 12-cm, and were each mounted with a flowmeter. The samplers 26 had e a r l i e r been c a l i b r a t e d thereby allowing 'quantitative' samples to be c o l l e c t e d . Two plankton tows were made at each s t a t i o n , with si x samplers being used for the f i r s t tow, and a vari a b l e number of up to s i x during the second tow. A l l samples were preserved i n a 10% formalin-sea-water s o l u t i o n buffered with borax. ( i i ) Treatment of the P. elongata F i e l d Data The data c o l l e c t e d during the three survey cruises were ex-amined i n two ways. There were: 2 (1) The t o t a l number of animals at each stage i n a 1-m column of water was estimated f o r each s t a t i o n . This was accomplished by determining the concentration of animals caught at each depth, c a l c u -l a t i n g the mean between two successive depths, and then mu l t i p l y i n g this.value by the distance between the two sampling depths. This was done for a l l sample, depths, and the values summed to give the t o t a l f o r the water column. (2) A second method was to draw the standard temperature-sa-l i n i t y - p l a n k t o n graphs to show the occurrences of P. elongata with water types. The most common method has been to use various sized symbols to represent the numbers or the concentrations of animals caught at various temperature-salinity values (Bary 1963). There were several disadvantages to using t h i s technique i n t h i s study, and so i t was modified s l i g h t l y . The f i r s t disadvantage was that unless a l l the temperature-salinity values were shown on the graph, zero-values f o r captures d i d not appear. A second problem occurred because few samples were taken i n water i n which the temperature and s a l i n i t y changes with 27 depth were great ( i . e . the upper 30-m), and many samples were taken . at depths i n which the temperature and s a l i n i t y varied only s l i g h t l y . It was d i f f i c u l t to present a l l the datan; points on the temperature-s a l i n i t y - p l a n k t o n graphs for those.areas i n which temperature and s a l i n i t y varied only s l i g h t l y . , A l s o , i t was f e l t that presenting the data i n t h i s fashion would place a bias on i n t e r p r e t i n g the r e s u l t s ; i f the animals, were uniformly d i s t r i b u t e d throughout the water column, the graph would have a tendency to suggest that they were more concen-trated i n the r e l a t i v e l y homogeneous zone simply because more, symbols appeared there. In order to circumvent these problems, the mean concentration of organisms i n temperature-salinity areas (0.25 C° X 0.25%») on the temperature-salinity-plankton graph were c a l c u l a t e d . The study s t a -tions had e a r l i e r (Chapter I) been divided into s i x groups on the basis of the s i m i l a r i t i e s of the temperature-salinity c h a r a c t e r i s t i c s of t h e i r subsurface waters. For each group, the temperature-salinity graph (Figure 2) was divided into rectangles 0.25 C° X 0.25%* A l l the plankton data were examined, and each sample was assigned to i t s p a r t i c u l a r temperature-salinity rectangle on a master sheet. When a l l the data for each stage had been entered onto the master sheet, the mean value f or each rectangle was c a l c u l a t e d . On the f i n a l graph, the temperature-salinity rectangles f or which there were plankton sam-ples were drawn, and the mean concentration of organisms f o r each rectangle was written i n s i d e . By r e f e r r i n g back to the temperature-28 s a l i n i t y - c u r v e s (Figure 2) f o r the s i x groups of s t a t i o n s , one can determine how many sample points were used to c a l c u l a t e the mean. Results (i) The Abundance of P. elongata i n the Six Groups of Waters Tables 2, 3, and 4 show, f o r each s t a t i o n , the estimated number of P. elongata at each developmental stage (the s i x naupliar stages are combined), and the estimated mean concentration of animals between 10 m and the deepest horizontal plankton sample. For the purposes of comparison, the calculations for Indian Arm, G.S.-l (in the S t r a i t of Georgia), Boundary Passage, Haro S t r a i t , and Juan de Fuca S t r a i t are included i n the t a b l e s . Although the number at each s t a t i o n varied from one cruise to the next, the r e l a t i v e abundance of P. elongata within the s i x groups of stations was s i m i l a r during the. three time periods studied. Second-l y , there was no consistent pattern for the p a r t i c u l a r stages to be more numerous during one cruise than during another. Complete populations of P. elongata, c o n s i s t i n g of a l l the developmental stages, were associated with the l o w - s a l i n i t y .'southern' waters, although Seymour and B e l i z e Inlets had r e l a t i v e l y small popu-lat i o n s i n comparison with Indian '.Arm, and i n comparison with the populations i n adjacent i n l e t s such as Smith and Kingcome. : Complete populations of P_. elongata were also associated with southern waters, 29 TABLE 2. The estimated number of the developmental stages of P. elongata in- a column (1-m^) of water between 10 meters and the deepest plankton sample.* (1) l o w - s a l i n i t y 'southern' waters; (2~) southern waters, (3) intermediate and northern waters, (4) west coast i n l e t waters, (5) coastal seaway waters, and (6) sub-arctic P a c i f i c Ocean waters. May 1970 Cruise Station and Type* Maximum Sample Depth . (m) Egg N c - i C-2 C-3. C-4 C-5 C-6 * * T o t a l ** Total Depth Seymour (1) 475 3 75 55:'7 42 3 22 23 13' 235 0.49 Belize (1) 240 4 25 40 67 3 5 0 8 148 0.61 Howe (2) 225 10 268 103 103 88 98 84 23 767 3.41 Mai. (2) 340 44 586 375 639 246 . 112 88 103 2149 6.32 J e r v i s (2) 600 25 613 1006 1589 472 385 120 109 4294 7.16 Geo-11 (2) 325 50 89 127 478 299 156 53 141 1343 4.13 Pendrell. (2) 400 18 815 670 1202 518 60 24 159 3448 8.62 Bute (2) 600 105 870 737 1475 755 263 447 642 5189 8.65 Nodales (2) 275 0 0 0 0 0 0 0 0 0 0.00 Lough. (2) 220 0 5 28 27 48 39 18 27 192 0.87 John.(3) 450 • 0 0 49 0 0 47 . 0 0 96 0.21 King.(3) 400 23 152 201 237 138 . 213 326 86 1354 3.39 Smith (3) 325 36 774 764 697 271 253 175 61 2995 9.22 Kashutl (4) 200 13 49 ' 43 137 71 9 30 .:30 369 1.85 Much.- (4) 340 83 425 413 722 309 133 41 159 2202 6.48 A l b . (4) , 275 23 1158 745 1006 481 68 63 124 3645 13.25 Q.C. S t r . (5) 340 0 0 0 0 0 ' 7 0 0 7 0.02 Q.C. Snd.(5) 250 0 0 0 44 0 0 0 0 44 0.18 Pac 4 (5) 250 0 13 0 13 23 6 14 15 84 0.34 Pac 1***(6) 750 0 : 0 0 7 28 7 0 0 42 0.05 Pac 2***(6) 1000 0 12 181 92 54 23 30 4 396 0.40 Pac 3***(6) 1000 0 78 205 117 130 45 45 0 620 0.62 Ind (1) 200 18 1423 530 286 175 32 11 51 2508 12.54 G.S.-l (2) 390 23 630 588 678 349 198 159 109 2711 6.95 Bound. (2) 200 0 0 0 2 2 1 0 0 5 0.03 Haro (3) 250 0 0 0 0 0 0 0 0 0 0.00 J.F. S t r . (5) 215 0 10 0 4 66 55 24 0 159 0.74 ** excluding the egg c l u s t e r *** shallowest sample was at 25 meters 30 TABLE 3. The estimated number of the developmental stages of P_. elongata i n a 1-m column of water between 10 meters and the deepest plankton sample* (1) l o w - s a l i n i t y 'southern' waters, (2) southern waters, (3) intermediate and northern waters, (4) west coast i n l e t waters, (5) coastal seaway waters, and (6) sub-arctic P a c i f i c Ocean waters. July. 1970 Cruise Station and Maximum Egg N C-l C-2 - C-3 C-4 C-5 C-6 Tot a l Total Type* Sample ** Depth** Depth (mY Seymour (1) 450 0 85 59 74 43 24 16 15 316 0. 70 Beliz e (1) 275 3 47 72 77 30 53 36 3 318 1. 16 Howe (2) 225 14 242 99 97 122 190 44 .86 880 3. 91 Geo-6 (2) 100 0 0 1 29 35 0 0 0 65 0. 65 Mai. (2) 340 35 1018 682 459 354 132 37 82 2764 8. 13 . J e r v i s (2) 600 5 582 1004 964 396 390 98 93 3527 5. 88 Geo-10 (2) 100 0 0 0 12 11 91 229 22 365 3. 65 Geo-il (2) 325 34 366 271 151 191 316 309 142 1746 5. 37 Pendrell (2) 400 17 604 1203 1360 566 61 64 23 3881 9. 70 Bute (2) 600 38 564 723 1042 1000 72 0 53 3454 5. 76 Nodales (2) 255 0 0 0 2 2 2 0 0 6 0. 02 Lough.(2) 220 0 99 52 48 32 6 27 6 270 1. 23 John.(3) 450 0 0 0 0 0 0 0 0 0 0. 00 Knight (3) 475 13 80 88 144 72 140 1076 157 1757 3. 70 King. (3) 450 27 341 160 187 175 91 212 98 1264 2. 81 Smith (3) 340 16 370 178 123 98 226 194 86 1275 3. 75 Kashutl (4) 200 39 468 349 578 836 460 1339 122 3152 15. 76 Much. (4) 340 14 466 346 336 273 363 193 52 2029 5. 70 A l b . (4) 275 10 884 1175 758 315 458 309 55 3954 14. 38 Q.C. Str.(5> 3,40 0 0 0 0 0 0 8 0 8 0. 02 Q.C. Snd. (5) 250 3 0 0 3 13 14 16 3 46 0. 18 Pac 3-1 (5) 150 ' 0 0 0 51 29 14 •6 3 103 0. 69 Pac 4 (5) 250 0 0 5 12 38 18 5 0 78 0. 31 Pac 1***(6) 1000 0 9 9 86 90 18 15 2 229 0. 23 Pac 2***(6) 1000 0 26 22 173 100 43 20 39 422 0. 42 Pac 3***(6) 250 1 0 0 129 , 68 18 4 6 225 0. 90 Ind (1) 200 8 163 148 148 120 76 160 109 870 4. 35 G.S.-l (2) 390 25 626 535 476 402 132 50 92 . 2313 5. 35 Bound. (2) 200 3 0 0 0 0 4 15 8 35 0. 18 Haro (3) 250 0 8 0 0 9 27 29 0 73 0. 29 J.F. S t r . (5) 215 . 0 1 . 0 16 76 72 17 0 . 192 0. 89 ** excluding the egg c l u s t e r *** shallowest sample was at 25 meters. Pac 3 i s the r e s u l t of only one tow as the second malfunctioned. 31 TABLE 4. The estimated number of the developmental stages of P. elongata i n a 1-m^  column.of water between 10 meters and the deepest plankton sample* (1) l o w - s a l i n i t y 'southern' waters, (2) southern waters, (3) intermediate and northern waters, (4) west coast, i n l e t waters, (5) coastal 5^fseaway waters, and (6) sub-arctic P a c i f i c Ocean waters. February 1971 Cruise Station and Type* Maximum Sample Depth (m) ' Egg N C-l C-2 C-3 C-4 C-5 C-6 Total ** Total Depth** Howe (2) 200 3 26 10 7 30 9 37 14 133 0.67 Mai. (2) 340 17' 229 59 82 28 36 60 55 549 1.61 J e r v i s (2) 0 4 0 26 19 16 8 3 76 0.51 Geo-11 (2) 325 17 86 47 103 40 25 119 91 511 1.57 Pendrell (2) 375 44 239 110 64 54 111 113 94 785 2.09 Bute (2) 600 94 828 830 674 548 139 40 220 3279 5.47 Lough. (2) 220 7 368 169 65 32 0 13 40 687 3.12 John.(3) 450 0 53 16 7 0 4 7 0 87 0.19 Knight (3) 475 15 466 386 672 89 7 42 75 1737 3.65 King. (3) 450 3 234 265 176 39 11 9 26 760 1.69 Smith (3) 330 106 176 51 128 5 11 0 126 497 1.51 Kashutl (4) 200 27 137 107 291 115 207 982 263 2104 10.52 Much. (4) 340 11 209 116 251 26 21 270 165 1058 3.11 Alb. (4) 275 46 338 191 333 70 139 590 223 1884 6.85 Q.C. Str.(5) 340 0 21 18 16 7 14 0 0 76 0;22 Pac 4 (5) 225 0 8 0 15 23 5, 10 0 61 0.27 Pac 3***(6) 1000 0 27 38 91 10 1 0 1 166 0.17 Pac 5***(6) 1000 0 0 112 56 0 0 0 0 168 0.17 Ind. (1) 200 8 348 225 75 5 0 0 33 611 3.06 G.S.-I (2) 390 48 338 128 177 148 88 101 203 1183 3.03 Bound. (2) 200 0 0 2 3 6 3 0 3 17 0.09 Haro (3) 250 0 0 0 0 0 5 8 0 13 . 0.05 J.F. -Str. (5) 220 0 0 5 4 4 16 17 10 56 0.25 Excluding egg c l u s t e r Shallowest sample was at 25 meters One tow only as the second malfunctioned. 32 intermediate and northern waters, and west coast i n l e t waters with four exceptions; these were Georgia 6, Georgia 10, Nodales Channel, and Johnstone S t r a i t . . Georgia 6 and Georgia 10 were located i n shallow areas adjacent to deeper areas (Howe Sound and Georgia 11, respectively) with the purpose of comparing the d i s t r i b u t i o n of P. elongata i n deep and shallow areas. .. The naupliar and f i r s t copepodite stages were absent from the two shallow areas, while they were present i n the two adjacent deep areas. This absence from the. shallow areas.could be due to the f a c t that these stages were.not transported, by curren t s , from the adjacent deep areas.to the more shallow banks. A second p o s s i b i l i t y i s that these stages could not survive i n the waters associated with these shallow areas. Nodales Channel and Johnstone S t r a i t form part of the northern homogeneous domain.(Herlinveaux and Giovando,,, 1969) and, dur-ing the three times studied, had only r e l a t i v e l y small populations of P. elongata. S i m i l a r l y , Haro S t r a i t and Boundary Passage, which form part of the southern homogeneous domain.(Herlinveaux and Giovando 1969), had small populations of -F_. elongata; t h i s was c o n s i s t e n t l y observed during the 2-year study period. The largest estimated popula-2 t i o n at Haro S t r a i t , i n a 1-m column of water, was 74 organisms and, at Boundary Passage, was 122 organisms. However, because a l l the developmental stages have been captured i n the two homogeneous domains, the species i s probably capable of completing i t s development i n these waters. . 33 R e l a t i v e l y small populations of P. elongata were associated with the northern coastal seaway waters and Juan de Fuca S t r a i t . These low numbers were consistent during the 2-year study p e r i o d , with the 2 largest estimated population i n a 1-m column of water of Juan de Fuca S t r a i t being 232 organisms. As a l l the developmental stages have been captured i n coastal seaway; waters, the species i s probably capable of completing i t s development i n these waters. Complete populations of P. elongata were generally asso-ciated with the waters of the eastern sub-arctic P a c i f i c Ocean,.although the concentration of animals was low. A l l the developmental stages have been captured i n these waters, which indicates that P_. elongata i s capable of completing i t s l i f e cycle i n sub-arctic P a c i f i c Ocean water. Loughborough Inlet had high dissolved oxygen concentrations (5 ml/1) throughout the water column i n May 1970. These values were comparable to those for Johnstone S t r a i t and Nodales Channel, which suggests that the i n l e t had been flushed at some e a r l i e r i n t e r v a l . • As the s a l i n i t y of the deep water was intermediate to the h i g h - s a l i n i t y water of Johnstone S t r a i t and the l o w e r - s a l i n i t y water of Nodales Channel, t h i s 'new' water probably originated from Johnstone S t r a i t . In May 1970, the population of P_. elongata was r e l a t i v e l y small and was comparable i n s i z e to those associated with the homogeneous domains. In J u l y 1970, the population was l a r g e r , and reached i t s largest s i z e i n February.1971. Associated with t h i s : was a decrease i n the dissolved oxygen concentration of the deep water, which suggests that the deep water, which had been brought i n t o the i n l e t during the spring i n f l u x . (1970), remained i n the i n l e t with l i t t l e replacement. 34 ( i i ) The temperature-salinity associations of the developmental  stages of P. elongata (July 1970). Figure 4 shows the temperature-salinity associations o f the egg, the combined (six) naupliar stages, and the s i x copepodite stages of P_. elongata. These graphs, with the exception of that f o r the southern waters, were drawn on the same scale.as the temperature-salini-ty curves (Figure 2) f o r the s i x groups of waters. On these curves,, the points at which plankton samples were taken are indicated by symbols. Generally,, the egg c l u s t e r was associated with the deep water of the various s t a t i o n s , although occasional egg c l u s t e r s were found higher up i n the water column. The temperature-salinity associations of the naupliar stages were s i m i l a r to that of the egg c l u s t e r , i n that the strongest associations were with the deep water. In the southern waters group, a few n a u p l i i were captured i n near-surface waters (30'Jm). During the 2-year f i e l d study, n a u p l i i were usually found below 100 m, although occasional samples c o l l e c t e d as shallow as 10 or 30 m had a small number of n a u p l i i . T h i s , along with the observation that egg c l u s t e r s were occas i o n a l l y .found i n near-surface water suggests t h a t , although egg c l u s t e r s normally hatched i n deep waters, they were capable of hatching i n near-surface waters. Plankton samples were c o l l e c t e d as deep as 1,000 m i n the P a c i f i c Ocean. There, the n a u p l i i were associated with P a c i f i c Ocean subsurface water and were most abundant between 500 and 750 meters. 35 Figure 4. The temperature-salinity associations of the egg c l u s t e r , nauplius, and the s i x copepodite stages of P_. elongata i n (a) l o w - s a l i n i t y 'southern' waters, (b) southern waters, (c) intermediate and northern waters, .(d) west coast i n l e t waters, (e) coastal seaway waters, and (f) the sub-arctic P a c i f i c Ocean. The value i n s i d e each temperature-salinity rectangle i s the mean concentration of specimens (numbers/m ) associated with that rectangle. The data are from the J u l y 1970 survey c r u i s e . 35 i egg clusters CD CD CHI m CD 29 3 '0 0 30 3.1 en CD CD 32 S % 0 35 CD CD CD CD rrrr CD ED CD CD CD CD CD CO 5 t n hO>l0 03lfl?>l S 7 3 /oc 33 d. CD CD CD CD S % o CD CD CD CD CD CD CD CD 35 ij 21 LL CD co co ca 1 0 I 0 iB.Oil 3< naupli b. CD 2 7 S T ED CO CD CO 0 0 l i t S i t 1 0 (Ml 0 1.17 J i t I193| 0 0 3 0S %° 3.1 CD CD CD 3.3 3 4 e. CD CD CD CD CD CCD CD CD CD . 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Jrf_ CO CO CO E E ED JiL o ° - « i o » i CD CD s 7 3,3 b / 0° 3,4 F5H CO CD ED CD 35vi S 2 9 3,0 ED ED EH) ED iB.til 0 JB.1t C-4 lo n ~ b, iiisJ CD CD s 7 2t8 0 0 29 CD CD CD -Fbn 7-CD CD S % 0 30 3.1 CD CD m 33 CD CD ESI CD CD CD CD 33 34 CD 10.10 1 1 » 4.14 1-26 m S % o 3,3 CD CD CD G5) CD CD PszP CD 35vfi S 'oo 2.9 30 a. C-5 G5D m I o I » lull cn CD 29 3 0 '» i 10-O 9-o 8-7-8-CD ~!-\ I • I • 1^ ] •sEa cc S % o 3.3 1.4 35 e. CD CD CD CD E E dm EH) s %« lb. ^ /oo 28 29 1H 12' 11 O10-CD CD u o i-<J 8 CD CD CD CD CD FED S %o 3.3 3 J CD CD CD CD S % /oo 3 3 3.4 CD CD CD ESI CD CD CD 2 13 2*5 0.13 o.Ji 0 012 2.1 S 0.1 7 0 07 0 2« 0.10 1.2 < 0.1 S O.'J 0J7 O.od 0.1 z CD 35 vi i i S %o m m CD CD IQI.OII » I pTj [ B 1 B lOOi C-6 b. CD CD CD CD CD CD CD 3 , 0S %° 3.1 CD CD 10 I? l o i f e. CD CD CD CD CD CDJ CD US) CD CD CD s0/ CD S 0 / CD CD CD CD CD CD CD R Y"|_ IJ~R L ED CD 36 The temperature-salinity association of the f i r s t copepodite was s i m i l a r to that o f the naupliar stages i n that they both tended to be associated with deep water. The second copepodite was less r e s t r i c t e d to deep water, being found higher up i n the water column. The temperature-salinity associations of the t h i r d to the s i x t h copepodite were s i m i l a r . These stages were found throughout the water column although they occurred i n higher concentrations i n the near-surface waters. No apparent d i f f e r e n c e was noted i n the d i s t r i -bution of males and females (which can be distinguished beginning with the fourth copepodite), and so the sexes were not p l o t t e d separately. Although i t i s not weld indicated by the graphs, i t was ob-served that the t h i r d to sixth copepodites were found nearer to the surface i n those stations occupied at n i g h t , than those stations occu-pied during the day. For example, the p a r t i c u l a r l y high value for.the. 3 f i f t h copepodite (65.18 animals/m ) was from a sample c o l l e c t e d i n Knight Inlet at 0010-0025 PDT, J u l y 24, 1970 at 10 m depth. There was an obvious discrepancy between the d i s t r i b u t i o n of the adult female and the egg c l u s t e r . Although adult females were found throughout the water column, the egg clusters were generally r e -s t r i c t e d to the deep water. As egg c l u s t e r s were always captured with at least as many females, females bearing egg c l u s t e r s must have been associated with the deep water. Females without egg c l u s t e r s must have been associated both with deep and near-surface water. 37 Discussion The r e s u l t s of the three survey cruises i n d i c a t e that P_. elongata.was r e s t r i c t e d neither to the oceanic nor to the n e r i t i c water within the study area. Throughout this area, the v e r t i c a l d i s t r i b u -t i o n remained s i m i l a r with the egg, nauplius, and e a r l y copepodite stages being associated with the deep water of a l l s i x groups of waters studied, and the l a t e r stages being found i n deep and near-surface waters. As the s i x groups of waters had d i f f e r e n t temperature-s a l i n i t y c h a r a c t e r i s t i c s , the v e r t i c a l d i s t r i b u t i o n of the species throughout the study area could not be associated with temperature and s a l i n i t y , per S £ . However, there may be temperatures and s a l i n i -t i e s of the surface Raters (0 to 20 meters), which the species avoids. As the species i s capable of breeding i n a l l the waters studied, v a r i a -bles other than water q u a l i t y may account for the differences i n the r e l a t i v e abundances of the species within the study area. Although there are few estimates a v a i l a b l e f o r the primary, pro-duction i n the areas studied, the a v a i l a b l e data i n d i c a t e that there i s a good c o r r e l a t i o n between the t o t a l primary production of some areas, and the r e l a t i v e abundance of P_. elongata i n those areas. Low concen-tr a t i o n s of P_. elongata were associated with the eastern P a c i f i c Ocean sub-arctic waters. However, t h i s area i s characterized by low primary 2 production , (43 to 78 gC/m year; Anderson 1964). The S t r a i t of Georgia, had higher concentrations of P_. elongata, and higher primary production 38 2 (120 gC/m year; Parsons .et a l . , 1970). Indian Arm had, on the average, higher concentrations of P_. elongata than the S t r a i t of Georgia, and 2 higher primary production (609 gC/m ..year; Gilmartin 1964). The coastal seaways domains have low concentrations of P. elongata probably because the waters i n these areas are continuous with surface and subsurface P a c i f i c Ocean water which also has low concentrations of P_. elongata. As the subsurface water i n Juan de Fuca S t r a i t and Queen Charlotte S t r a i t moves further inshore, i t mixes with the l o w - s a l i n i t y waters from the i n l e t s and the S t r a i t of Georgia i n the regions of turbulent mixing i n the two homogeneous d o m a i n s H e r e a l s o , the populations of P. elongata.are small. One of the reasons f o r t h i s i s that the two waters which contribute to the resultant water both have comparatively small populations of P_. elongata. The sub-surface P a c i f i c Ocean water has small populations of P_. elongata pro-bably because of the low production of the oceanic environment. The surface waters from the i n l e t s and the S t r a i t of Georgia have low popu-la t i o n s because of the c h a r a c t e r i s t i c s 'of the species' d i e l v e r t i c a l migration and the estuarine c i r c u l a t i o n of these areas. In the B r i t i s h Columbia i n l e t s and the S t r a i t of Georgia, the surface layer u s u a l l y extends only as deep as 20 m (Pickard 1961, 1963; Waldichuk 1957). P.. elongata has only been found to be associated with this layer from the t h i r d to the s i x t h copepodite, and then only during the night*during t h i s time they are c a r r i e d seaward. However, during the day, these stages are associated with the subsurface layer and so are c a r r i e d back towards the head of the i n l e t or back in t o the S t r a i t 39 of Georgia. Because of t h i s pattern of d i e l v e r t i c a l migration i n r e l a t i o n to the estuarine c i r c u l a t i o n of these areas, P. elongata i s 'conserved' within the inlets, and the S t r a i t of Georgia. This conser-vation mechanism has previously been proposed f o r the plankton i n i n l e t s (LeBrasseur 1955), and estuaries : (Rogers 1940). Therefore, because of t h i s conservation mechanism, areas such as Haro S t r a i t , Boundary Passage, Nodales Channel, and Johnstone S t r a i t receive a r e l a -t i v e l y small, number of immigrants from the i n l e t s and the S t r a i t of Georgia. In order f o r a population to increase i n s i z e i n an area through reproduction, the residence time of the-population i n the area must be longer than the time required to complete the l i f e c y c l e . In .the i n l e t s , the bottom water i s replaced at i n t e r v a l s of one year or greater (Pickard 1961, 1963), and i t i s probably only r a r e l y that the major portion of the i n l e t water i s replaced by new water. It i s e s t i -mated that P_. elongata requires a minimum of s i x to eight months to com-plete i t s l i f e cycle (pers. obser.)., Because of the long residence time of the deep water i n the i n l e t s r e l a t i v e to the time required f o r P. elongata to complete i t s l i f e c y c l e , i t i s possible f o r the popula-t i o n to increase through reproduction. Whether or not a population of P_. elongata w i l l increase i n s i z e by reproduction i n an i n l e t or the S t r a i t of Georgia w i l l depend upon several v a r i a b l e s . Considering only the replacement of the deep water, two variables, are the rate of replacement and the o r i g i n of the deep water. The west coast, northern and intermediate i n l e t s , and Seymour, B e l i z e , and Loughborough Inlets a l l open almost d i r e c t l y onto 40 the P a c i f i c Ocean or to the waters i n the northern homogeneous domain. These l a t t e r areas have r e l a t i v e l y small populations of P_. elongata so that an i n t r u s i o n of water from these regions i n t o an i n l e t might d i l u t e the r e l a t i v e l y large resident population. Whether i t does should depend on the rate of i n f l u x ; i f i t i s so rapid that the species cannot r e t a i n i t s v e r t i c a l d i s t r i b u t i o n within the i n l e t , and i s car-r i e d out with the older water, then there w i l l be a reduction i n the s i z e of the population. Such an event may have occurred i n Loughborough Inlet i n the spring of 1970. However, i f the rate of i n t r u s i o n i s low, and P_. elongata can r e t a i n i t s v e r t i c a l p o s i t i o n i n the water column, then the population should not be appreciably reduced. The southern i n l e t s , with deep s i l l s which open onto the S t r a i t of Georgia, are less l i k e l y to have t h e i r populations reduced by an i n f l u x of new water, since t h i s water originates i n t h e : S t r a i t of Georgia. This l a t t e r area generally has comparatively large populations of P_. elongata a l l year around. . The waters i n the areas o f turbulent mixing have a very short residence time, with water passing through areas such as the San Juan Archipelago i n one or two months. The currents.in t h i s area are turbu-lent currents,.and P. elongata i s probably transported.through these areas at much the same rate as the water i n which i t l i v e s . Because i t takes only one or two months for the species to pass through such an area, while i t requires a minimum of s i x to eight months to complete i t s l i f e c y c l e , i t i s highly u n l i k e l y that populations of P_. elongata w i l l dncrease s i g n i f i c a n t l y i n numbers i n these turbulent areas 41 through reproduction. The l o s s . o f the l a t e r developmental stages from the i n l e t s , the S t r a i t of Georgia, and the P a c i f i c Ocean may-be more important i n determining the siz e o f the populations of P_. elongata i n the regions of turbulent mixing i n the homogeneous domains. Conclusions (1) Breeding populations of P_. elongata are associated with a l l s i x groups of waters studied, i . e . l o w - s a l i n i t y 'southern' waters, southern waters, intermediate and northern waters, west coast i n l e t waters, coastal seaways waters, and sub-arctic P a c i f i c Ocean waters. (2) The v e r t i c a l d i s t r i b u t i o n of the developmental stages throughout the study area i s independent of the temperature and s a l i n i -ty of the subsurface water, but dependent upon the stage of development of the organism, and p o s s i b l y upon the factors which a f f e c t d i e l v e r t i c a l migration. (3) Populations , of P_. elongata i n . the P a c i f i c Ocean are probably small because of the low production of t h i s environment. (4) Populations of P_. elongata i n the coastal seaways are pro-bably small because t h i s area i s simply .xaii^J&ej^qp 0 f the oceanic environment. (5) The homogeneous domains are characterized by small popula-tions of P_. elongata. The populations are small, because (i) the two waters which contribute to the formation of the water i n the homogeneous 42 domains both contain small populations of P. elongata, and ( i i ) the short residence time of the water i n the homogeneous domains r e l a t i v e to the time required for P_. elongata to complete i t s l i f e cycle prevents a s i g n i f i c a n t increase i n the s i z e of the population through breeding. (6) The r e l a t i v e l y large si z e of the populations of P. elongata associated with the i n l e t s and the S t r a i t of Georgia i s probably due-to several f a c t o r s . Three of these are (i) the high primary production of these areas, ( i i ) the long residence time of the deep water r e l a t i v e to the time required f o r P. elongata to complete i t s l i f e c y c l e , and ( i i i ) the v e r t i c a l d i s t r i b u t i o n of the developmental stages i n r e l a t i o n to the c h a r a c t e r i s t i c s of the estuarine c i r c u l a t i o n i n these areas. 43 CHAPTER III ..i j ' THE LABORATORY STUDY-AN EXAMINATION OF THE HATCHING SUCCESS OF P., ELONGATA EGG CLUSTERS IN VARIOUS NATURAL SEAWATERS INTRODUCTION It was shown i n the preceding section that breeding populations of P. elongata are r e s t r i c t e d neither to the oceanic nor to the n e r i t i c water within the study area. This implies that the species e i t h e r has a wide range of tolerances f o r temperature, s a l i n i t y , and the other properties of the waters of i t s range, or else i s able to adapt to i t s environment. P h y s i o l o g i c a l variations within a species i n d i f f e r e n t parts o f i t s range have been demonstrated.for responses to temperature (Moore 1949, 1950; Stauber 1950; Loosanoff and Nemejko 1951; Vernberg 1962; G i l f i l l a n 1970), to s a l i n i t y (Prosser .1955, G u i l l a r d and Ryther 1962; G i l f i l l a n 1970), and to the.'other' properties of sea-water ( G i l f i l l a n 1970). Although P_. elongata has been shown to be r e s t r i c t e d neither to oceanic nor to n e r i t i c water within the study area t h i s does not imply that v a r i a t i o n s i n temperature, s a l i n i t y , and the.other properties of the water within the species' range do not af f e c t the organisms. Subpopulations of the species may possess a narrow range of tolerances for temperature, s a l i n i t y , and other properties of sea waters. However, i f the species can adapt to i t s environment, then i t w i l l have a wider range than would be i n f e r r e d from determining the tolerances of a sub-population c o l l e c t e d from one area. 44 This chapter presents - the r e s u l t s of two i n v e s t i g a t i o n s : (1) A study was conducted to determine whether, or not sea waters with s i m i l a r s a l i n i t i e s and temperatures have d i f f e r e n t other p r o p e r t i e s . The properties which were measured were the concentrations of dissolved z i n c , copper, n i c k e l , and manganese. Lewis and Ramnarine (1969) indicated that the s u r v i v a l of P. elongata egg cl u s t e r s c o l l e c t e d from G.S.-l (in the S t r a i t of Georgia) was affected by the addition of trace elements to the sea water. (2) A study was conducted to.determine whether or not P_. elongata egg c l u s t e r s c o l l e c t e d from d i f f e r e n t areas and at d i f f e r e n t times, from waters of s i m i l a r temperatures and s a l i n i t i e s , were d i s t i n c t i n t h e i r a b i l i t y to survive i n various natural sea waters of s i m i l a r s a l i n i t y . Experiments were also conducted to determine whether or not P_. elongata egg cl u s t e r s c o l l e c t e d from various areas with large d i f f e r -ences i n s a l i n i t y were d i s t i n c t i n t h e i r a b i l i t y to survive i n waters with large differences i n s a l i n i t y . The egg c l u s t e r was tested because t h i s stage i s frequently the most s e n s i t i v e stage i n the l i f e h i s t o r y of an organism. It was thought that t e s t i n g t h i s stage would have a greater p r o b a b i l i t y of i n d i c a t i n g differences between waters than t e s t i n g one of the more hardy stages. Materials and Methods Water for experiments was c o l l e c t e d with a 96-L f i b r e g l a s s and l u c i t e water sampler. The water was.passed through two thicknesses of 45 a number-20 mesh net (approximate pore size-64u), and placed i n 5-gallon Nalgene carboys. A portion of the water was further f i l t e r e d through a 0.45u-millipore f i l t e r f o r dissolved trace element a n a l y s i s . This was done only for the water c o l l e c t e d from Indian Arm, G.S.-l and Juan de Fuca S t r a i t . In the laboratory, a l l sea water was stored i n a non-illuminated, cold-room at 8°C.- Water c o l l e c t e d from the P a c i f i c Ocean was stored at 4°C . Egg c l u s t e r s were c o l l e c t e d with a 1-m r i n g net. (approximate pore size-700u). The plankton sample was placed i n p l a s t i c trays,, along with water c o l l e c t e d by the water sampler. . Egg c l u s t e r s and egg-c l u s t e r bearing females were examined, and .young, undamaged c l u s t e r s (and females) were transferred with, a large bore pipette to a cooled 4-L isotherm containing sea water. • In the laboratory, the egg,clusters were sorted under a bino-cular microscope, and only young egg c l u s t e r s were set aside f o r use i n experiments. Young egg c l u s t e r s are a uniform blue In.colour,, while i n older egg c l u s t e r s , the i n d i v i d u a l eggs are p o l a r i z e d , with one pole being blue and the other white. Egg c l u s t e r s were i n d i v i d u a l l y reared i n 1,000-ml Nalgene Erlenmeyerr f l a s k s . These f l a s k s were rins e d three times with a t o t a l of 400 ml of sea water, and then 600 ml of sea water was added. The number of eggs i n a c l u s t e r were counted-, and the egg c l u s t e r added to a f l a s k . The mouth of the fla s k was then covered with a piece of Parafilm (American Can Company, Marathon Products) to reduce evaporation. 46 Flasks were maintained i n the dark at 8°C i n a Psycrotherm incubator (New Brunswick S c i e n t i f i c Company), and were h o r i z o n t a l l y rotated at 40 rpm. In supplementary experiments, f l a s k s were maintained i n the dark i n a cold-room; f l a s k s maintained i n the cold-room were not r o -tated. Every three days, the contents of each f l a s k was,placed i n a large fingerbowl, the number of organisms at each stage were counted, and dead organisms were removed. Each f l a s k was again rin s e d with a t o t a l of 400.-.ml of sea water, and 600 ml of sea water was added. The remaining l i v i n g organisms were replaced, and the f l a s k was returned to the incubating chamber. Eggs were reared through to the f i r s t copepodite. However, only the hatching success of the egg was.used because (i) most of the-mortality between the egg and the f i r s t copepodite occurred i n the egg and the f i r s t two naupliar stages (Lewis and Ramnarine 1969), ( i i ) 90% of the eggs hatch d i r e c t l y into the second nauplius (Borgmann 1971), and ( i i i ) the mor t a l i t y of the hatched f i r s t and second nauplius was low, being less than 5% ( W h i t f i e l d , pers. comm.; pers. obser.). Tests Of the f i v e stations studied over the 2-year p e r i o d , only Indian Arm and G.S.-l had l a r g e , breeding populations o f P. elongata; therefore, the laboratory work was l a r g e l y r e s t r i c t e d to these two populations. The s p e c i f i c procedures were: (1) Egg c l u s t e r s were c o l l e c t e d from Indian Arm and G.S.-l 47 once a month, from March 1971 to February 1972. These egg c l u s t e r s were tested i n three waters, i . e . (i) Indian Arm 200-m water, ( i i ) G.S.-l 350-m water, and ( i i i ) Juan de Fuca 200-m water u n t i l October 1971. A f t e r t h i s time, tests were made using only Indian Arm and G.S.-l water. Five r e p l i c a t e s were used for each t e s t , and a l l tests were run i n the Pyscrotherm incubator. (2) Egg cl u s t e r s from Indian Arm were c o l l e c t e d and tested i n a second serie s of Indian Arm 200-m water, and Juan de Fuca 200-m water ( A p r i l 1971). A t h i r d water was made by d i l u t i n g the Juan de Fuca water with d i s t i l l e d water, so that i t s s a l i n i t y was the same as the Indian Arm 200-m water. Five r e p l i c a t e s were used f o r each t e s t , and these te s t s were run i n an 8°C cold-room. (3) Egg c l u s t e r s were.collected from Pac^6 (Figure 1) i n May 1971, and tested i n Pac-6 750-m water, Juan de Fuca 200-m water, G.S.-l 350-m waterj and Indian Arm 200-m water; the s a l i n i t i e s of these waters were 34.4%o, 33.8%^ 30.9%^ and 27 . 8 V r e s p e c t i v e l y . Five r e p l i c a t e s were, made for each t e s t , except f o r Indian Arm where only 3 r e p l i c a t e s were made. A l l tests were run i n a 4°C cold-room. (4) Egg c l u s t e r s were c o l l e c t e d from.Pac-8. (Figure 1), i n J u l y 1971, and tested i n Pac-8 750-m water, Juan de Fuca 200-m water, G.S.-l 350-m water, and Indian. Arm 200-m water; the s a l i n i t i e s of these waters were 34.2%c, 33.9%*, 30.9%*, and 2 7 . 8 % » r e s p e c t i v e l y . Five r e p l i c a t e s were used f or each t e s t , and the test s were run i n a 4°C cold-room. (5) Egg clusters were c o l l e c t e d from Bute Inlet i n June 1971, and tested i n Bute 600-m water ( s a l i n i t y - 31.1%*) and G.S.-l 350-m 48 water ( s a l i n i t y - 30.8%,).. Nine r e p l i c a t e s were used f o r each t e s t , and the tests were run i n an 8°C cold-room. (6) Egg cl u s t e r s were c o l l e c t e d from Seymour I n l e t , i n August 1971, and tested i n Seymour 450-m water ( s a l i n i t y - 28.9%°) and Indian Arm 200-m water ( s a l i n i t y - 27.8%^); f i v e r e p l i c a t e s were used for each t e s t . Egg clu s t e r s were also c o l l e c t e d from Indian Arm and tested i'n the two waters using four r e p l i c a t e s f o r each t e s t . The test s were run i n an 8°C cold-room. (7) Egg cl u s t e r s were c o l l e c t e d from Alberni I n l e t , i n September 1971, and reared i n Alberni 250-m water ( s a l i n i t y - 32.8%^ and i n Juan de Fuca 200-m water ( s a l i n i t y - 33.9%o). Five r e p l i c a t e s were used f or each t e s t , and the tests were run i n an 8°C cold-room. (8) Egg clusters were c o l l e c t e d from Indian Arm and G.S.-l, and reared i n G.S.-l 20-m water ( s a l i n i t y - 29.6%.) i n January 1972. Five r e p l i c a t e s were used f o r each t e s t , and the tests were run i n the Psycrotherm incubator. Results (i) Variations i i i the Concentrations of Dissolved Zinc, Manganese, Copper and Nickel Figure 5 shows the concentrations of the four measured trace elements during the study period.at the three s t a t i o n s . These values are higher than values previously determined from other s t u d i e s , and some contamination may have been introduced e i t h e r during the c o l l e c t i n g or the f i l t e r i n g of the water (E. G r i l l , pers. comm.). • The data were 49 Figure 5. The concentrations.of dissolved.zinc,.manganese, copper, and n i c k e l i n Juan de Fuca 200-m water (——-r—), G.S.-l 350-m water (_____),, and Indian Arm 200-m water ( • » » . • . ) . The data for dissolved ni c k e l , are incomplete as analyses were not made every month. 49 i 50' interpreted by assuming that they were q u a l i t a t i v e l y c o r r e c t . Figure 5 shows the fl u c t u a t i o n s i n the concentrations of dissolved zinc i n Indian Arm 200-m water, G.S.-l . 350-m water, and Juan de Fuca 200-m water during the period of the laboratory study. Concentrations were generally greatest i n Indian Arm water, interme-diate i n Juan de Fuca water, and lowest i n G.S.-l 350-m water. There-f o r e ; the concentration of dissolved zinc was not d i r e c t l y r e l a t e d to the s a l i n i t y of the water. Secondly, while the concentrations of dissolved zinc at the three stations fluctuated with time, there was no apparent association with changes i n the deep water as measured by temperature and s a l i n i t y (Figure 3). Figure 5 shows the fluc t u a t i o n s in.the concentrations of d i s -solved manganese, copper, and n i c k e l at,the three s t a t i o n s . Concentra-tions were generally highest at Indian Arm, and lowest at G.S.-l. Again, there was no apparent r e l a t i o n s h i p between fl u c t u a t i o n s i n the concen-t r a t i o n of an element and changes i n the temperature and s a l i n i t y of the deep water. While the concentrations of the four elements at each s t a t i o n varied with time, there was l i t t l e s i m i l a r i t y i i i t h e i r f l u c t u a -t i o n s . This implies that d i f f e r e n t processes regulate the concentration of each element, rather than.one process regulating a l l f o u r . These processes were probably chemical a n d ' b i o l o g i c a l , and other physical processes not adequately described by temperature and s a l i n i t y measure-ments . 51 ( i i ) Fluctuations i n the Survival of Indian Arm and G.S.-l Egg Clusters i n Indian Arm, G.S.-l, and Juan de Fuca deep Waters Figure 6a shows the f l u c t u a t i o n s i n the percentage hatching of G.S.-l egg c l u s t e r s i n the three waters. With f i v e r e p l i c a t e s , one standard deviation was 10 to 30%, and the standard error was 5 to 15%. Although there were large differences i n the s a l i n i t i e s of the three waters, s u r v i v a l was generally goodr/\usually being above 60%. Survival of G.S.-l egg c l u s t e r s i n Indian Arm water was s i g -n i f i c a n t l y c o r r e l a t e d with the concentration of dissolved copper (r =..8; p = .004), and i n G.S.-l water with the concentration of dissolved manganese (r = -.68; p = .04). Survival did not appear to be associated with changes i n the temperature and s a l i n i t y of the deep water, although s u r v i v a l was lowest i n Indian Arm water i n December, January, and February, when the deep water was.replaced.(Figure 3). Figure 6b shows the f l u c t u a t i o n s i n the percentage hatching of Indian Arm egg c l u s t e r s i n the three waters. These f l u c t u a t i o n s were d i s t i n c t from those of G.S.-l egg c l u s t e r s . Survival was generally highest i n Indian Arm water, and lowest i n Juan de Fuca water. Table 5 presents the r e s u l t s of the experiments using Juan de Fuca water, diluted.Juan de Fuca water, and Indian Arm water as a r e a r i n g medium for Indian Arm egg c l u s t e r s . These r e s u l t s suggest that the high s a l i n i t y of the Juan de Fuca water was probably the causal factor in preventing the hatching of Indian Arm egg c l u s t e r s . The 52 Figure 6. The mean percentage hatching of (a) G.S.-l egg c l u s t e r s , and (b) Indian Arm egg cl u s t e r s i n Juan de Fuca 200-m water ( . - - ) , G.S.-l 350-m water ( , ) , and Indian Arm 200-m water ( . ) . PERCENTAGE HATCHING PERCENTAGE HATCHING 53 TABLE 5. Results and the analysis of variance of the s u r v i v a l of Indian Arm egg clu s t e r s i n Indian Arm 200-m water, Juan de Fuca 200-m water, and d i l u t e d Juan de Fuca 200-m water. Percentage Survival Indian Arm Juan de Fuca Diluted Juan de Water Water Fuca Water 200-m 200-m 200-m Replicate 1 61.5 59.0 78.5 Replicate 2 61.5 5.2 100 Replicate 3 64.7 30.7 61.5 Replicate. 4 62.5 5.2 69.2 Replicate 5 71.4 64.2 68.4 Mean Survival 64.3 32.8 75.5 Sum of Degrees of Mean sum of F - r a t i o Squares Freedom Squares Category, means 0.489 2 0.245 Within means , 0.416 12 0.035 7.00 Total 0.905 14 A s i g n i f i c a n t difference i n the means at the 99% confidence l e v e l . 54 actual factor may. have been associated with the a b i l i t y of the eggs to osmoregulate i n h i g h - s a l i n i t y water. Secondly, s u r v i v a l i n the d i l u t e d Juan de Fuca water was higher than i n Indian Arm water i n d i c a t i n g that there were differences i n the properties of these two waters. The s u r v i v a l of Indian Arm egg cl u s t e r s i n Indian Arm water and Juan de Fuca water i n the cold-room was higher than i n the duplicate serie s run i n the\ Psycrotherm incubator. This was noted several times during the.study when duplicate series were run; the reason for these differences i s not known. Survival of Indian Arm egg'clusters i n the three waters was not s i g n i f i c a n t l y c o r r e l a t e d with the concentration of dissolved z i n c , manganese, copper, or n i c k e l . S i m i l a r l y , changes i n s u r v i v a l did not appear to be associated with changes i n the temperature and s a l i n i t y of the deep water (Figure 3). The smallest f l u c t u a t i o n s i n s u r v i v a l of Indian Arm egg cl u s t e r s i n Indian Arm and G.S.-l waters occurred from September 1971 to February 1972, and i t was during t h i s period that the deep water of these two areas was replaced. An analysis of variance was made by using the method outl i n e d i n Steel and T o r r i e (1960) f o r f a c t o r i a l experiments with three v a r i a -b l e s . The data analyzed were the s u r v i v a l of Indian Arm and G.S.-l egg c l u s t e r s i n Indian Arm 200-m water and G.S.-l 350-m water. Sur-v i v a l i n Juan de Fuca 200-m water was excluded because i t was believed that the f a i l u r e of Indian Arm egg clusters to hatch i n t h i s water was probably due to an osmotic stress imposed on the eggs by the r e l a t i v e l y 55 high s a l i n i t y of the water. Since the purpose of t h i s s e r i e s of tests was to examine differences i n water other than s a l i n i t y , i t was decided to exclude the Juan de Fiica data from t h i s a n a l y s i s . Table 6 presents the r e s u l t s of the analysis of variance. Over the 12-month p e r i o d , there was a s t a t i s t i c a l l y s i g n i f i c a n t d i f f erence i n the properties of Indian Arm and G.S.-l waters, and i n the su r v i v a l of Indian Arm and G.S.-l egg c l u s t e r s . Survival of the egg clu s t e r s i n the two waters varied over the 12-month p e r i o d , as did the proper-t i e s of the waters from these two areas. There was no s i g n i f i c a n t i n t e r a c t i o n over the 12-month period. The data were further analyzed to determine the source of v a r i a t i o n . Three analyses of variance were made, t e s t i n g (i) the sur-v i v a l of Indian Arm egg clu s t e r s i n the two waters over the 12-month pe r i o d , ( i i ) the s u r v i v a l of G.S.-l egg clu s t e r s i n the two waters over the 12-month p e r i o d , and ( i i i ) the s u r v i v a l of G.S.-l egg clu s t e r s i n Indian Arm, G.S.-l and Juan de Fuca water over the 8-month test p e r i o d . The analysis was made by using the method described i n Dixon and Massey (1957) for two variables :£of c l a s s i f i c a t i o n and repeated measurements. Table 7 shows the r e s u l t s f o r Indian Arm egg c l u s t e r s ; there was a s i g n i f i c a n t difference i n the response of the egg cl u s t e r s to the two waters t e s t e d , and a s i g n i f i c a n t d i f f e r e n c e i n the response over the 12-month period. Conversely, there was no s i g n i f i c a n t d i f f e r -ence i n the response of G.S.-l egg clu s t e r s to the two waters tested 56 TABLE 6. Results of the analysis of variance of the percentage hatching of Indian.Arm and G.S.-l egg cl u s t e r s i n Indian Arm 200-m water and G.S.-l 350-m water (March 1971-February 1972). Source df SS MS F r a t i o P r o b a b i l i t y Blocks 4 0.399 0.099 2,475 > .05 A (Popular tion) 1" 0.510 0.510 12.750 < .005 B (Water) 1 . 0.323 0.323 8.075 < .005 C (Time) 11 0.739 0.067 1.675 > .05 AB • 1 0.491 0.491 12.275 < .005 AC 11 1.401 0.127 3.175 < .005 BC 11 0.870 0.079 1.975 < .05 ABC 11 0.410 0.037 0.925 • > .05 Error 188 7.650 0.040 57 TABLE 7. Analysis of variance of (a) the s u r v i v a l of Indian Arm egg c l u s t e r s i n Indian Arm 200-m water and G.S.-l 200-m water (12 months), (b) the su r v i v a l of G.S.-l egg clu s t e r s i n G.S.-l 350-m water and.Indian Arm 200-m water (12 months), (c) the s u r v i v a l of G.S.-l egg c l u s -ters i n Indian Arm 200-m water, G.S.-l 350-m water, and Juan de Fuca 200-m water, (8 months). Sum of Degrees of Mean Sum of F - r a t i o p Squares Freedom Squares Row means 0. .322 1 0. 322 5. .919 < 0. 025 Column means 1. .'465 11 0. 132 2. ,430 < 0. 025 Interaction 1. .122 11 0. 102 1. .873 > 0. 05 Subtotal 2. .909 23 0. 126 Within groups 5. .226 96 0. 054 Total 8. .135 119 Row means 0, .004 1 0. 004 0. .144 > 0. 05 Column means 0. .331 11 0. 030 0. .984 > 0. 05 Interaction 0. .466 11 0. 042 1. .382 > 0. 05 Subtotal 0. .801 23 0. 035 Within groups 2. .938 96 0. 031 Total 3, .739 119 C) Row means 0, .327 2 0. 164 4. ,810 < 0. 001 Column means 0. .247 7 • 0. 035 1, .035 > 0. 05 Interaction 0, . 708 14 0. 051 1. .481 > 0. 05 Subtotal 1. .283 23 0. 037 Within groups 3. .280 96 0. 034 Total 4. .5.62 119 58 (Table 7b), nor i n the responses over the 12-month peri o d . Therefore whether or not there are s i g n i f i c a n t differences i n the ' q u a l i t y ' of the Indian Arm or G.S.-l water tested depends on whether or not Indian Arm or G.S.-l egg clusters are used as a bioassay. Table 7c shows the r e s u l t s of the analysis of G.S.-l egg c l u s t e r s i n the three waters. In t h i s case there were s i g n i f i c a n t differences i n the response to the three waters, although there were no s i g n i f i c a n t temporal v a r i a t i o n s . Over the8-month test p e r i o d , Juan de Fuca water was a le s s s a t i s f a c -tory r e a r i n g medium for G.S.-l egg c l u s t e r s (and Indian Arm egg c l u s -ters) than G.S;-1 water, g i v i n g a mean s u r v i v a l of 57.9% vs. '65.6%. ( i i i ) . Survival of P a c i f i c Ocean Egg Clusters i n Four Natural Sea  Waters of D i f f e r e n t S a l i n i t i e s Table 8 presents the r e s u l t s of the Pac-6 experiments. S u r v i -v a l was good i n a l l four waters, although i t was lower i n Indian Arm water (43.8%). This indicates that Pac-6 egg c l u s t e r s were tolerant of large v a r i a t i o n s i n s a l i n i t y , and of the other properties associated with these waters. It also suggests that the populations o f P_. elongata i n the P a c i f i c Ocean are.not r e l a t i v e l y small because the properties of the water are unfavourable for the s u r v i v a l of the species. Because the.station was close to the coast (50 m i l e s ) , i t i s p o s s i b l e that a s i g n i f i c a n t percentage of P_. elongata originated from the n e r i t i c en-vironment. This could account f o r the tolerance f o r low s a l i n i t i e s . Table 9 presents the r e s u l t s of the.Pac-8 experiments. Sur-v i v a l was highest in Pac-8 water, higher i n Juan de Fuca waterj high 59 TABLE 8. Results and the analysis of variance of the hatching success of Pac-6 egg clu s t e r s i n four d i f f e r e n t sea waters. Percentage Hatching Pac-6 750-m J.F. 200-m G.S.-l 350-m. Ind. Arm 200-m Water Water Water Water Replicate'1 89.4 52.9 82.3 20.0 Replicate 2 31.8 76.1 47.3 50.0 Replicate 3 83.3 65.4 75.0 65.2 Replicate 4 23.5 94.4 31.1 Replicate 5 57.1 83:3 55.5 Mean Survival 57.0 74.4 58.3 43.8 Sum of Degrees of Mean Sum of F-r a t i o Squares Freedom Squares Category means 0.175 3 0.058 . 1.137 Within means 0.724 14 0.051 Total 0.899 17 No s i g n i f i c a n t difference at the 95% confidence l e v e l . 60 TABLE 9. Results and the analysis of variance of the s u r v i v a l of Pac-8. Egg c l u s t e r s i n four d i f f e r e n t sea waters. Percentage Hatching Pac-8 750-m J.F. 200-m G.S.-l 350-m Ind, . Arm 200-m Water 'Water Water Water Replicate 1 63.6 90.0 9.5 0 Replicate 2. 88.8 65.0 47.8 40.0 Replicate 3 85.7 65i0 57.1 36.8 Replicate 4 85.0 66.6 56.5 42.1 Replicate 5 70.0 76.1 38.0 0 Mean s u r v i v a l 78.6 72.5 41.8 23.8 Sum of Degrees of Mean Sum of F--r a t i o Squares Freedom Squares Category means : 1.005 3 0.335 12.41 Within means 0.437 16 0.027 Total 1.442 19 A s i g n i f i c a n t d i f f e r e n c e i n the means at the 99.95%c-confi:denee: Tevel. 61 i n G.S.-l water, and low i n Indian Arm water. There was a s t a t i s t i -c a l l y s i g n i f i c a n t difference i n the means at the 99.95% confidence l e v e l . However, i t i s questionable whether t h i s d i f f e r e n c e was due to differences i n the s a l i n i t y of the four waters which exerted an osmotic stress on the eggs, or due.to the other properties of the waters. The s a l i n i t y f a c t o r , per se, was probably more important, just as t h i s f a c t o r was more, important i n causing the low s u r v i v a l of Indian Arm eggs i n Juan de Fuca deep water. Pac-8 egg c l u s t e r s may have been less t o l e r a n t . o f l o w - s a l i n i t y water than Pac-6 egg c l u s t e r s because the P. elongata i n the former region were more i s o l a t e d from the n e r i t i c environment (80 miles from the c o a s t ) , and had fewer immi-grants from the coastal r e g i o n . Correspondingly, there may have been a larger percentage of the P. elongata population which had spent several generations i n the.oceanic environment. (iv) Bute, A l b e r n i , and Seymour Experiments Table 10 presents the r e s u l t s of the series t e s t i n g Bute.egg clusters i n Bute water and G.S.-l water; there.were no s i g n i f i c a n t d i f -ferences i n the s u r v i v a l i n the two waters. Table 11 presents the r e -s u l t s of the series t e s t i n g Alberni egg c l u s t e r s i n A l b e r n i water and Juan de Fuca water; again there were no s t a t i s t i c a l l y s i g n i f i c a n t differences i n the r e s u l t s . Table 12 presents the r e s u l t s of the se r i e s t e s t i n g Seymour and Indian Arm egg c l u s t e r s i n waters from the two areas. Indian Arm egg c l u s t e r s survived equally well i n the two 62 TABLE 10. Results and the analysis of variance of the s u r v i v a l of Bute Inlet egg c l u s t e r s i n Bute Inlet water-and G.S.-l. water. PresentagetHatching Bute 600-m G.S.-l 350-m Water Water Replicate 1 60.0 66.6 Replicate 2 88.8 53.3 Replicate 3 37.5 76.9 Replicate 4 90.9 76.9 Replicate 5 43.7 76.9 Replicate 6 76.4 52.9 Replicate 7 58.8 81.2 Replicate 8 86.6 66.6 Replicate 9 66:6 75.0 Mean Survival 67.7 69.2 Sum of Degrees of Mean Sum of F-r a t i o Squares Freedom: ''': Squares Category means 0.001 1 0.001 0.042 Within means 0.338 16 0.024 Total 0.039 17 No s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e i n the means at the 95% confidence l e v e l . 63 TABLE 11. Results and the analysis of variance of the s u r v i v a l of Alberni egg c l u s t e r s i n Alberni water and Juan de Fuca water i Percentage Hatching Alberni 250-m Water Juan de Fuca 200-m Water Replicate 1 Replicate 2 Replicate 3 Replicate 4 Replicate 5 75.0 83.3 100 93.7 60.0 64.7 82.3 72.2 94.1 73.3 Mean Survival 70.4 77.3 Sum of Degrees of Mean Sum of F - r a t i o Squares Freedom Squares Category means 0.012 1 0.012 0.090 Within means 1.063 8 0.132 Total i:075 No s i g n i f i c a n t d i f f e r e n c e i n the means at the 95% confidence l e v e l . 64 TABLE 12. Results and the analysis of variance of the hatching success of Seymour egg c l u s t e r s and Indian Arm egg clus t e r s i n water c o l l e c t e d from the two i n l e t s . Percentage Hatching Seymour egg c l . Indian Arm egg c l . Seymour '450-m Ind. Arm 200-m Seymour 450-m Ind. Arm 200-m Replicate 1 84.2 Replicate 2 78:9 Replicate 3 63.1 Replicate 4 5.2 Replicate 5 72.2 61.9 55.5 50.0 0 28.5 94.4 80.9 71.4 35.2 61.1 95.0 57.8 78.9 Mean s u r v i v a l 60.7 39 .2 70.7 73.2 Sum of Squares Degrees of Freedom Mean Sum of Squares F - r a t i o Category mean 0.329 Within means 0.942 Total 1.271 3 14 17 0.109 0.067 1.626 No s i g n i f i c a n t difference i n the means at the 95% confidence l e v e l . 65 waters. Seymour egg clu s t e r s had lower s u r v i v a l i n Seymour water than.Indian Arm egg c l u s t e r s , and very low s u r v i v a l i n Indian Arm water. This suggests that there were differences i n the egg clu s t e r s from the two areas, and that f o r Seymour egg c l u s t e r s , the two waters were q u a l i t a t i v e l y d i f f e r e n t . However, there were no s t a t i s t i c a l l y s i g n i f i c a n t differences i n the results.-(v) G.S.-l 20-m Water Table 13 presentsthe r e s u l t s of the series t e s t i n g G.S.-l and Indian Arm egg clu s t e r s i n G.S.-l 20-m water. Survival o f these egg,; clus t e r s i n G.S.-l 350-m water and Indian Arm 200-m water i s shown on Figure 6. Survival of Indian Arm egg clusters i n G.S.-l 20-m water was s l i g h t l y higher than i n G.S.-l 350-m water while the reverse was true f o r G.S.-l egg c l u s t e r s . There i s , from t h i s experiment, no e v i -dence to suggest that egg cl u s t e r s are incapable o f developing i n the near-surface water. This supports the hypothesis that one of the rea-sons n a u p l i i are usually found only i n deep water i s that the females, which carry the egg clu s t e r s u n t i l the n a u p l i i hatch, normally remain i n deep water. Summary The analysis of the concentrations of dissolved z i n c , manganese, copper, and n i c k e l i n Indian Arm 200-m water, G.S.-l '350-m water, and Juan de Fuca 200-m water, indicated that the values associated with 66 TABLE 13. Results 'of the s u r v i v a l o f Indian Arm and G.S.-l egg clu s t e r s i n G.S.-l near surface (20-m) and deep (350-m) water. ' P ef c en t- age M a t c M ng Indian Arm egg clu s t e r s G.S.-l egg clu s t e r s G.S.-l 20-m G.S.-l 350-m G.S.-l 20-m G.S.-l 350m Replicate 1 50.0 50.0 50.0 76.9 Replieate2/2 50.0 54.5 28.5 90.9 Replicate 3 71.4 12.5 76.9 92.3 Replicate 4 58.3 75.0 45.4 54.5 Replicate 5 72.7 26.6 64.2 53.8 Mean s u r v i v a l 60.4 43.7 53.0 73.6 67 each water were not a.function o f s a l i n i t y . G.S.-l deep water general-l y had the lowest concentrations of dissolved trace elements, and yet was intermediate i n s a l i n i t y to the deep waters of Juan de Fuca S t r a i t and Indian Arm. There were,,;at each of the three s t a t i o n s , temporal v a r i a t i o n s i n the concentrations of the four measured trace elements. While the s a l i n i t y of the water also v a r i e d , there was no apparent r e l a t i o n s h i p between the fl u c t u a t i o n s i n the s a l i n i t y • (and temperature) of the waters, and fl u c t u a t i o n s i n the concentrations of the dissolved trace elements. This suggests that unmeasured b i o l o g i c a l and chemical processes, and physical processes not adequately described by measure-ments o f temperature and s a l i n i t y , were a f f e c t i n g the concentrations of these trace elements. Therefore, within each of the three areas studied, measurements of temperature and s a l i n i t y by themselves would not give a good i n d i c a t i o n of the concentrations of the trace elements which would be associated with that water. The laboratory data indicated that the s u r v i v a l o f G.S.-l egg clu s t e r s i n G.S.-l water was s i g n i f i c a n t l y correlated with the concen-t r a t i o n of dissolved manganese, and i n Indian Arm water with the con-centration of dissolved copper. There were no other s i g n i f i c a n t c o r r e -l a t i o n s between the su r v i v a l of egg clusters i n a water and the concen-t r a t i o n s of the dissolved trace elements. The laboratory data also indicated that P_. elongata egg c l u s -ters c o l l e c t e d from d i f f e r e n t areas may exhibit d i f f e r e n t responses to a serie s :of sea waters (when tested at the same temperature). The 68 f a c t o r to which the egg responds may be the s a l i n i t y of the.water or i t s other-properties. For example, i t was shown that both Indian Arm eggs and Pac-8 eggs reacted d i f f e r e n t l y to a s e r i e s of waters which had large differences i n s a l i n i t y (28 to 34%^. These differences i n r e -sponse were probably due to the egg responding to the s a l i n i t y of.the test waters per se, rather than to t h e i r other p r o p e r t i e s . It was also shown that egg c l u s t e r s may react d i f f e r e n t l y to a s e r i e s of waters with s i m i l a r s a l i n i t i e s . It was shown that Indian Arm egg clusters reacted d i f f e r e n t l y to Indian Arm and G.S.-l- deep.waters, that G.S.-l egg clusters reacted d i f f e r e n t l y to' Juan de Fuca deep water than to Indian Arm and G.S.-l deep waters, and i t was suggested that Seymour Inlet egg c l u s t e r s may react d i f f e r e n t l y to Indian Arm and Seymour deep waters. As the s a l i n i t i e s o f these waters were s i m i l a r , the egg c l u s t e r may have been r e a c t i n g to differences i n other proper-t i e s of these waters. Many of the tests indicated that egg c l u s t e r s did not react d i f f e r e n t l y to sea waters with s i m i l a r s a l i n i t i e s . ' G.S.-l egg c l u s t e r s had s i m i l a r responses to Indian Arm and G.S.-l water, Alberni Inlet egg c l u s t e r s had s i m i l a r s u r v i v a l i n Alberni and Juan de Fuca deep waters, Bute Inlet egg clusters had s i m i l a r s u r v i v a l i n Bute and.G.S.-l deep waters, Indian Arm egg c l u s t e r s had s i m i l a r s u r v i v a l i n Indian Arm and Seymour deep waters, and Pac-6 egg clusters had s i m i l a r sur-v i v a l i n Pac-6, Juan de Fuca, G.S.-l, and Indian Arm deep waters. This study has therefore shown that sea waters with s i m i l a r s a l i n i t i e s may vary i n q u a l i t y . Whether these differences are 69 b i o l o g i c a l l y detectable depends l a r g e l y upon the t e s t organism which i s used as a bioassay. Secondly, F_. elongata egg c l u s t e r s c o l l e c t e d from d i f f e r e n t areas may be d i s t i n c t i n t h e i r response to s a l i n i t y , and i n t h e i r response to the other properties of sea waters. Whether or not P_. elongata l i v i n g i n areas such as Indian Arm and G.S.-l are s i g n i f i c a n t l y affected by v a r i a t i o n s i n water q u a l i t y w i l l be discussed i n the f i n a l section of t h i s t h e s i s . . There are no data to suggest that areas such as Juan de Fuca S t r a i t and the eastern sub-arctic P a c i f i c Ocean, which c o n s i s t e n t l y had r e l a t i v e l y small populations of P_. elongata, have waters whose properties are unfavourable f o r the s u r v i v a l of the egg ( c o l l e c t e d from or near these areas).. This supports the r e s u l t s of the survey cruises (section 3 ) , which indicated that the r e l a t i v e l y small popula-tions i n these areas were probably associated with low primary produc-t i o n . 70 CHAPTER IV ... AN EVALUATION OF THE ROLE OF THE VARIATION IN WATER QUALITY IN THE DISTRIBUTION OF P. ELONGATA AT INDIAN ARM AND G.S.-l INTRODUCTION The data i n Chapter II indicated that P_. elongata was capable of breeding both i n the oceanic and the n e r i t i c waters examined by the three survey c r u i s e s . This suggests that the species i s probably not l i m i t e d i n these areas'by v a r i a t i o n s i n the q u a l i t y of natural sea waters. However, the laboratory data (Chapter III) indicated, that within areas such as Indian Arm, the s u r v i v a l of egg c l u s t e r s i n t h e i r home water va r i e d over a 12-month peri o d . As the abundance of the species i s , i n p a r t , dependent upon the s u r v i v a l of the egg c l u s t e r s , l o c a l v a r i a t i o n s i n water q u a l i t y may a f f e c t the abundance of l o c a l populations. G i l f i l l a n (1970) showed that the zooplankter Euphausia p a c i f i c a . was s e n s i t i v e to v a r i a t i o n s i n water q u a l i t y . However, he indicated that v a r i a t i o n s i n water q u a l i t y were probably not a major l i m i t i n g factor i n the d i s t r i b u t i o n of the species. Wilson (1951) and Wilson and Armstrong (1952, 1954, 1958, 1961) showed, by using sea urchin larvae c o l l e c t e d near Eddystone, that there were varia t i o n s i n the q u a l i t y of sea waters. While they attempted to determine the sources of the v a r i a t i o n within the t e s t waters, they did not attempt to evaluate the s i g n i f i c a n c e of t h i s v a r i a t i o n i n the ecology of sea urchins near Eddystone. Sea water c o l l e c t e d from Eddystone gave poor s u r v i v a l over the 12-year study period (1948 to 71 1960) and yet there was no apparent decline i n the s i z e of the adult sea urchin population. Smith (1972) estimated that echinoderm popu-la t i o n s turnover at a range of 0.1 to 1.6 per year. An a p p l i c a t i o n of t h i s estimate to the sea urchin population hear Eddystone indicates t h a t , over the 12-year study p e r i o d , the population was replaced 1.2 to 9.2 times. As the s i z e of the population did not diminish, v a r i a -tions i n the q u a l i t y o f sea water (or l a r v a l q u a l i t y ) at Eddystone as determined i n the laboratory must have had a minor r o l e i n a f f e c t -ing the l o c a l abundance of sea urchins. This section investigates whether or not v a r i a t i o n s i n water q u a l i t y were a s i g n i f i c a n t f a c t o r i n determining the abundance of P_. elongata i n G.S.-l and Indian Arm. As temperature and s a l i n i t y have been used to describe water bodies, fluctuations i n the tempera-ture and s a l i n i t y of the water i n an area may be i n d i c a t i v e of changes i n the ' q u a l i t y ' of the water. I f the species i s affected by v a r i a t i o n s i n the q u a l i t y of sea.water, then there, might be some r e l a t i o n s h i p be-tween fl u c t u a t i o n s i n the species': d i s t r i b u t i o n and f l u c t u a t i o n s . i n the temperature and s a l i n i t y of the water. This does not imply that temperature and s a l i n i t y act d i r e c t l y on the species, but r a t h e r , that these measurements may be i n d i c a t i v e of some f l u c t u a t i n g environ-mental v a r i a b l e (water quality) that i s less e a s i l y measured. This chapter also attempts to determine what other variables might be important.in regulating the abundance of P. elongata i n G.S.-l and Indian Arm. It was shown, i n Chapter I I I , that there were no s i g -n i f i c a n t differences i n the s u r v i v a l of G.S.-l egg c l u s t e r s i n G.S.-l 350-m water over the 12-month study p e r i o d . However, the f i e l d data 72 ind i c a t e d that there were pronounced f l u c t u a t i o n s i n the number of n a u p l i i i n the water. This suggests that variables other than water q u a l i t y may be more important i n regulating the abundance of n a u p l i i at t h i s s t a t i o n . Materials and Methods The methods f o r the c o l l e c t i o n of the f i e l d data have been described e a r l i e r (Chapters I and I I ) , as have been the techniques fo r estimating the abundance and v e r t i c a l d i s t r i b u t i o n of the develop-mental stages (Chapter I I ) . The f i e l d data were examined i n the f o l -lowing ways: (1) The v e r t i c a l d i s t r i b u t i o n of the developmental stages were examined,.arid were su b j e c t i v e l y compared with the changes i n the temperature and s a l i n i t y of the water. (2) The v a r i a t i o n i n the abundance of the developmental stages were examined over the 29-morith study period to determine whether or not the species was more abundant; at some times than others. (3) The c o r r e l a t i o n c o e f f i c i e n t between the number of n a u p l i i i n the water and (i) the s u r v i v a l o f the egg i n i t s home water as determined i n the laboratory, and ( i i ) the number of eggs i n the water, was c a l c u l a t e d . The estimate of the number of eggs was obtained by 2 mult i p l y i n g the number of egg c l u s t e r s i n a 1-m column of water (Clarke-Bumpus sampler data) by the mean number of eggs per c l u s t e r (laboratory data) . 73 (4) The mean percentage mortality of the developmental stages was calculated by estimating the mean concentration of each stage over the 29-month study p e r i o d , and comparing these estimates with the mean number expected.. The mean number expected was calculated by estimating the proportion of the population each stage should represent simply on the basis of the time spent i n that stage r e l a t i v e to the t o t a l time of the l i f e c y c l e . The data f o r the development, time of the egg and the s i x naupliar stages are from Borgmann (1971). The f i r s t and second copepodites require three to four weeks to complete development (Ramnarine, pers. comm.; pers. obser.), and an estimate of three to four weeks can be used for the other three copepodite stages. The average time spent i n each of these stages i s shown i n Table 14. The laboratory studies I n d i c a t e that the adult male and female can survive for at le a s t three months (Ramnarine, pers. comm.; pers. obser.). From these data, the mortality between stages, and the cumulative mortality from the egg to the adult can be ca l c u l a t e d . The number of n a u p l i i and successive stages expected were also r e c a l c u l a t e d with the assumption that 30.5% o f the G.S.-l eggs and 38.5% of the Indian Arm eggs f a i l e d to hatch owingc'to t h e i r i n t e r a c t i o n with t h e i r home water. This e s t i -mated mean mortality was obtained from the laboratory study • (Chapter I I I ) . The r e c a l c u l a t i o n of these data allows the cumulative mortality from the egg to the adult to be estimated with an allowance being made for the mortality due to the i n t e r a c t i o n between the egg and the water. These, calculated m o r t a l i t i e s are therefore due to other environmental stresses such as food l i m i t a t i o n and predation. 74 TABLE 14. . NThe estimated mean time spent i n each of the. develop-mental stages of P. elongata, the percent of the t o t a l spent i n each stage, and the time spent i n each stage r e l a t i v e to the time spent i n the egg and f i r s t nauplius. Stage , Time (days) % of Total Relative to egg + N-l Egg + N-l 7 2.9 1 N-2 to N-6 19 7.,9 2.7 C-l., 25 10.4 3.6 C-2 25 10.. 4 3.6 C-3 25 10.4 3.6 C-4 25 10.4 3.6 C-5 25 10.4 3.6 C-6 90 37.3 Total 241 75 (5) The s t a b i l i t y of the measured b i o l o g i c a l , chemical, and p h y s i c a l variables was estimated. Leigh (1971) states that "a system i s stable i f i t returns to equilibrium when disturbed; the s t a b l e r the system, the more quickly equilibrium i s restored." Patten (1961, 1962), while not formally d e f i n i n g s t a b i l i t y , obtained a q u a n t i t a t i v e value for the s t a b i l i t y of the system where S t a b i l i t y = n=l E j = l: det P. 3 n=l E cs/x). j=l 3' s. i s the standard deviation f o r the i v a r i a b l e and x i s the mean j » of the v a r i a b l e , and P. = i d dd n d i which i s the matrix of t r a n s i t i o n p r o b a b i l i t i e s f o r the jt n of m v a r i a b l e s . For a s e r i e s o f measurements, P ^ = p r o b a b i l i t y of an increase followed by a,decrease. P ^ = p r o b a b i l i t y of an increase followed by aniincrease P^j = p r o b a b i l i t y of a decrease followed by a decrease P ^ = p r o b a b i l i t y of a decrease followed by an increase and Det P. = (P., P.. - P.. P..). j i d d i i i dd' The b i o l o g i c a l data used i n the analysis were the ;?;,"abundance of the developmental stages of P_. elongata at Indian Arm and G.S.-l over the 29-month study period. The physical data were the temperature 0 and 76 s a l i n i t y of the water at a number of depths. These were 0, 10, 75, 100, 150, and 200:.m at Indian Arm and G.S.-l, and 250 and 350>:m at G.S.-l. The chemical data were the concentrations of dissolved z i n c , manganese, copper, and n i c k e l i n Indian Arm 200-m water and G.S.-l 350-m water. The analysis was made by using the .IBM) l:l'30p.comp,uter. Results (i) The v e r t i c a l d i s t r i b u t i o n . o f the nauplius and the t h i r d copepodite  at Indian Arm and G.S.-l from October 1970 to October 1971 As the v e r t i c a l d i s t r i b u t i o n s of the developmental stages were s i m i l a r over the study p e r i o d , only the data f o r the second year of the study (October 1970 to October 1971) are presented. This year was chosen because of the greater changes which occurred i n the temperature and s a l i n i t y of the deep water than i n the preceding year. Only the v e r t i c a l d i s t r i b u t i o n of the nauplius and the t h i r d copepodite are presented as t h i s i s s u f f i c i e n t to i l l u s t r a t e the trends. Figure shows the v e r t i c a l d i s t r i b u t i o n of the nauplius at G.S.-l and Indian Arm. At each s t a t i o n , the n a u p l i i were found deep and were seldom above 100 meters. Over the years.,, the v e r t i c a l d i s -t r i b u t i o n was e s s e n t i a l l y .the same (although the abundance v a r i e d ) , and was not affected by changes i n the temperature and s a l i n i t y of the deep water (Figure 3). Although the deep water at both stations was replaced, the v e r t i c a l d i s t r i b u t i o n of the nauplius remained unchanged. The t h i r d copepodite was found through a large portion of the water column, although i t was found nearer to the surface at G.S.-l 77 Figure 7. The v e r t i c a l d i s t r i b u t i o n of the nauplius and the t h i r d copepodite at Indian Arm (a) and at G.S.-l (b). Broken l i n e s i n d i c a t e an uncertain datum poin t , (ns) indicates that no sample was c o l l e c t e d from that depth. 00 77ji < 78 than at Indian Arm. However, the former s t a t i o n .was always occupied during the day, and the l a t t e r was always occupied during the n i g h t . As the t h i r d copepodite may be found nearer to the surface at night than during the day (Pandyan 1971; pers. obser.), these differences may be accounted f o r by considering the time of sampling. The v e r t i -cal d i s t r i b u t i o n of the t h i r d copepodite was not affected by changes i n the temperature and s a l i n i t y (and other properties) o f the water. Nor was the v e r t i c a l d i s t r i b u t i o n altered at the time of deep water replacement at both stations (Figure 3). ( i i ) Temporal v a r i a t i o n i n the abundance of the developmental stages  of P. elongata at G.S.-1 and Indian Arm. Figure $ presents the data showing the temporal v a r i a t i o n s i n the t o t a l number of P_. elongata (excluding the egg) at G.S.-l and Indian Arm during the study p e r i o d . The species was abundant^ during the s p r i n g , summer, and autumn, was low i n numbers i n the winter, and was p o s s i b l y less abundant i n 1971 than i n 1970. There i s no evidence that the deep water replacement at e i t h e r G.S.-1 or Indian Arm r e s u l t e d i n a marked reduction i n the number of P_. elongata. The 'new' deep water at G.S.-l was formed i n the San Juan . Archipelago, and t h i s l a t t e r area i s characterized by r e l a t i v e l y small populations of P. elongata.. The 'new' deep water at Indian Arm was formed from surface and near-surface waters i n the v i c i n i t y of the shallow s i l l (26 m) at the mouth of the i n l e t , and t h i s area i s probably also characterized by r e l a t i v e l y , small populations of elongata. 79 The f a i l u r e of the populations to be reduced at either G.S.-l or Indian Arm at the time of deep water replacement supports the. hypothesis t h a t , within these areas, deep water replacement occurs at a slow enough rate for the species to r e t a i n i t s . v e r t i c a l p o s i t i o n i n the water c o l -umn, and so reduces the tendency for the species to be l o s t from the area with the older deep water. Na u p l i i and the f i r s t four copepodite-stages were most abundant during the s p r i n g , summer, and early autumn, and.were less abundant dur-ing the la t e autumn and the winter. There was no apparent seasonal trend i n the abundance of the f i f t h and s i x t h copepodites at.G.S.-l. At Indian Arm, these stages were less abundant i n the spring and early summer; The number of egg cl u s t e r s varied throughout the year, and were more numerous at G.S.-l during the spr i n g . Egg c l u s t e r s were p o s s i b l y more numerous at Indian Arm during the late summer and autumn. The number of eggs per c l u s t e r varied through the year, with c l u s t e r s containing the fewest eggs i n the winter and the most during the summer. Increases i n the number of eggs per c l u s t e r occurred at the same time at Indian Arm and G.S^-l. However, Indian Arm egg clu s t e r s tended to have fewer eggs than G.S.-l egg c l u s t e r s . ( i i i ) C o r r e l a t i o n between the number of n a u p l i i and (i) the s u r v i v a l  of the egg, and ( i i ) the number of eggs i n the water The number of n a u p l i i at G.S.-l was not s i g n i f i c a n t l y c o r r e l a -ted with the s u r v i v a l of G.S.-l eggs i n G.S.-l 350-m water (r = .25; 80 Figure 8. The estimated number of the developmental stages of P. elongata in. the water column at G.S.-l (10-390m) ( _ _ _ _ ) , and at Indian Arm (10-200m) ( ) . The estimate of the t o t a l number, of P_. elongata includes only the naupliar and copepodite stages. The data for the mean number, of eggs per c l u s t e r were c a l c u -lated from the laboratory data. NUMBERS MEAN NUMBER. m \ \ V \ o \ \ \ v >// MOB 81 p>.l) but was s i g n i f i c a n t l y correlated with the number o f eggs (r = .76; p<.005). S i m i l a r l y , the number of n a u p l i i at Indian Arm was not s i g n i f i c a n t l y c o r r e l a t e d with the su r v i v a l of Indian Arm eggs i n Indian Arm 200-m water (r = -.17; p >.l) but was s i g n i f i c a n t l y correlated with thenumber of eggs (r =.79; p<^005). This indicates that the number of n a u p l i i at G.S.-l and at Indian Arm were not s i g -n i f i c a n t l y affected by the i n t e r a c t i o n between the egg and the native water (as measured i n the lab o r a t o r y ) , but were affected, by processes which a f f e c t egg production. This may be because v a r i a t i o n s - i n the su r v i v a l of eggs during the study period were very much smaller than the v a r i a t i o n s i n the numbers of eggs produced during the study pe r i o d . (iv) The estimated mean m o r t a l i t i e s of the developmental stages of  P. elongata at G.S.-l and Indian Arm Table 15 shows, f o r G.S.-l and Indian Arm, (i) the mean number of the developmental stages, ( i i ) the estimated mean mor t a l i t y between stages, ( i i i ) the estimated mean cumulative mortality from the egg to the a d u l t , and (iv) the estimated mean cumulative m o r t a l i t y from the egg to the adult excluding the estimated mortality of the egg due to i t s i n t e r a c t i o n with the water. High mortality between stages occurred at G.S.-l, between the egg and the f i r s t nauplius and the second to si x t h nauplius (68.5%), between the second and t h i r d copepodites (52.4%), and the f i f t h and s i x t h copepodites (76.3%). No v a l i d estimate was made f o r the m o r t a i l i t y between the f i r s t and second copepodites, and 82 TABLE 15. The mean number of the developmental stages during the 29-month study period i n a 1-m^  column of water at G.S.-l (10-390m) and at Indian Arm (10-200m), ( i i ) the.estimated mean mortality between successive stages, ( i i i ) '/the estimated mean cumulative mortality from the egg to the a d u l t , and (i v ) ' „ the estimated mean cumulative mortality from.the egg to the adult excluding the poss i b l e mortality due to the i n t e r a c t i o n between the egg and the water. Percentage M o r t a l i t y Stage Mean Number Between Cumulative Cumulative Stages ( i i i ) (iv) G.S.-l Egg + N-l N-2 to N-6 C-l C-2 C-3 C-4 C-5 C-6 408 357 308 363 173 129 140 120 68.5 33.1 x 52.4 25.5 x 76.3 68.5 78.9 x 88.2 90.4 x 97.8 53.2 68:7 x 82.4 86.9 x 96.7 Indi an Arm Egg + N-l N-2 to N-6 C-l C-2 C-3 C-4 C-5 C-6 292 385 213 155 80 55 78 88 51.1 58.1 27.3 48.4 31.3 x 68.8 51.1 79.5 85.1 92.3 94.7 x 97.7 20. 66. 75. 87. 91 x 96.2 ,2 .5 .6 ;5 .4 83 the fourth and f i f t h copepodites.' The cumulative m o r t a l i t y from the egg to the adult was 97.8% with only 2.2% of the eggs maturing to the adult stage. I f the mortality of the egg due to i t s i n t e r a c t i o n with the water i s removed from t h i s estimate, 3.3% of the eggs which are successful i n hatching reach the adult stage. Table 15 also shows the c a l c u l a t i o n f o r Indian Arm. High estimated mortality between stages occurred between the egg and the f i r s t nauplius and the second to the s i x t h nauplius (58.1%), the • second and t h i r d copepodites (48.4%), and the f i f t h and s i x t h copepo-dites (68.8%). No v a l i d estimate was made f o r the m o r t a l i t y between the fourth and f i f t h copepodites, p o s s i b l y because a longer time i s spent i n the f i f t h copepodite than estimated. The cumulative mor-t a l i t y from the egg to the adult stage was 97.7% with only 2.3% of the eggs reaching the adult. This was s i m i l a r to the estimate f o r the cumulative mortality from the egg to the adult at G.S.-l. I f the mo r t a l i t y of the egg due to the i n t e r a c t i o n with the water i s removed from t h i s estimate, 3.8% of the eggs which are successful i n hatching reach the adult stage. (v) S t a b i l i t y Analysis Tables 16 and 17 present the determinants, the mean v a r i a b i l i -t i e s , and the s t a b i l i t y indices for the b i o l o g i c a l , chemical, and phy-s i c a l variables measured at G.S.-l and Indian Arm. The physical v a r i a -bles were generally characterized by negative determinants and negative 84 TABLE 16. T h e analysis of s t a b i l i t y of the b i o l o g i c a l , chemical, and physical variables measured at G.S.-l Variable Determinant Mean S t a b i l i t y V a r i a b i l i t y Index Egg clusters -0.03 0077.3' 0.04 Nau p l i i 0.04 0.69 0.06 C-l 0.34 0.63 . 0.54 C-2 0.12 0.58 0.21 C-3 0.23 0.60 0.38 C-4 0.11 0.70 0.16 C-5 0.23. 0.61 0.38 C-6 0:26 0.38 0.63 Total b i o l o g i c a l 0.24* Copper -0017 0.37 -0046 Nickel . 6.27 0.26 1.04 Manganese 0.60 0.5.8 1.03 Zinc 0.25 0.61 0.41 Total chemical 0.52* Temperature 0-m -0.35 0.40 -0.88 : S a l i n i t y • " -0.15 0.14 -1.07 Temperature 10-m -0.38 0.25 -1.52 S a l i n i t y " 0:00 0.06 0.00 Temperature 75-m -0.15 0.09 • -1.67 S a l i n i t y " 0.08 o;oi 8.00 Temperature 150-m -0.14 0.07 -2.00 S a l i n i t y " -0.03' 0.01 -3.00 Temperature 200-m -0.28 0.05 -5.60 S a l i n i t y " -0:31 0.004 -77.50 Temperature 250-m -0.12 0.04 -3.00 S a l i n i t y " -0.46 0.003 -153.53 Temperature 350-m -0.07 0.03 -2.33 : S a l i n i t y " -0.58 0.003 -193.33 Total physical -2.53* *0btained by d i v i d i n g the sum of the determinants by the sum of the mean v a r i a b i l i t i e s (Patten 1963). An examination of Patten's analysis of s t a b i l i t y i s presented i n the appendix. 85 TABLE 17. The analysis of the s t a b i l i t y of the b i o l o g i c a l , chemical, and physical variables measured at Indian Arm Variable Determinant Mean S t a b i l i t y V a r i a b i l i t y Index Egg Clusters 0.41 0.69 0.59 Nau p l i i 0.12 0.72 0.17 C-l 0.16 0.77 0.21 C-2 S01I7 0.99 -0.17 C-3 0.12 1.17 0.10 C-4 0.28 1.20 • 0.23 C-5 0.20 0.84 0.24 C-6 0.04 0.63 0.06 Total b i o l o g i c a l 0.17* Copper 0.60 0.51 1.17 Nickel 0.40 0.41 0.98 Manganese 0.50. 0.57 0.88 Zinc 0.60 0.64 0.94 Total chemical 0.99* Temperature 0-m -0.18 • 0.43 -0.42 S a l i n i t y " 0.60 0.47 1.28 Temperature 10-m -0.55 0.18 -3.06 S a l i n i t y " -0.31 0.04 -7.75 Temperature 75-m -0.26 0.09 -2.89 S a l i n i t y " -0.48 0.01 -48.00 Temperature 150-m -0.18 0.07 -2.57 S a l i n i t y " -0.10 0.01 -10.00 Temperature 200-m, 0.14 0.08 1.75 S a l i n i t y " -0.21 0.01 -21.00 Total physical -1.10* *0btained by d i v i d i n g the sum of the determinants by the sum of the mean- v a r i a b i l i t i e s • (Patten 1963). 86 s t a b i l i t y i n d i c e s . Conversely, the b i o l o g i c a l variables were charac-t e r i z e d by p o s i t i v e determinants and p o s i t i v e s t a b i l i t y indices (with the exception of the number of egg clusters at G.S.-l, and the number of second copepodites at Indian Arm). The o v e r a l l s t a b i l i t y of the measured b i o l o g i c a l system was greater than that of the measured p h y s i -c a l system, suggesting that the b i o l o g i c a l system was r e l a t i v e l y i n -s e n s i t i v e to the physical system. Patten (1961, 1962) also measured a higher s t a b i l i t y of the b i o l o g i c a l system over that of the physical system. The chemical variables were (with the exception of copper i n G.S.-l 350-m water) j, characterized by p o s i t i v e determinants and p o s i -t i v e s t a b i l i t y indices}• The o v e r a l l s t a b i l i t y index was higher than that for the physical system, again suggesting that the measured chemi-c a l system was r e l a t i v e l y i n s e n s i t i v e to the measured physical system. Conclusions There was no i n d i c a t i o n that v a r i a t i o n s i n the temperature and s a l i n i t y of the deep water, and v a r i a t i o n s i n water q u a l i t y were important i n determining the abundance of P_. elongata at Indian Arm and G.S.-l. At both s t a t i o n s , the number of n a u p l i i i n the water was s i g n i f i c a n t l y c o r r e l a t e d with the number of eggs present i n the water, but not with the s u r v i v a l of the eggs due to t h e i r i n t e r a c t i o n with the water. The estimated mean mortality from the egg to the adult stage was 97.8% at G.S.-l and 97.7% at Indian Arm. I f the mor t a l i t y of the : y87 egg due to the i n t e r a c t i o n between the egg arid the water i s removed from these estimates, the mortality from the egg to the adult becomes 96.7% at G.S.-l and 96.2% at Indian Arm. This indicates that there is. a large mortality (or loss) of the developmental stages a f t e r the nauplius hatches, and again suggests that the i n t e r a c t i o n between the egg and the water has only a minor r o l e i n determining the abundance of P. elorigata at Indian Arm and G.S.-l. The v e r t i c a l d i s t r i b u t i o n of the nauplius and the t h i r d cope-podite at Indian Arm and G.S.-l was s i m i l a r throughout the study period. This would not be expected i f (i) v a r i a t i o n s i n the temperature and s a l i n i t y of the deep water were associated with v a r i a t i o n s i n the q u a l i t y of the water, and ( i i ) these v a r i a t i o n s i n the q u a l i t y of the water affected the developmental stages. While the v e r t i c a l d i s t r i b u t i o n of the developmental stages was.similar throughout the study p e r i o d , there were pronounced f l u c t u a -tions i n t h e i r abundance. The species was most abundant during the s p r i n g , summer, and e a r l y autumn. This i s the period i n which primary production i s highest both at. Indian Arm (Gilmartin 1964) and at,G.S.-l (Parsons et a l . 1970). This r e l a t i o n s h i p between increases i n the number of P_. elongata and increases i n primary production suggest that environ-mental variables associated with primary production may be important i n r e g u l a t i n g the abundance of the species i n these two areas. These variables may be associated with the a v a i l a b i l i t y of prey organisms and predation. 88 Many zooplankton breed at those times of the year when primary production i s greatest. The increase i n the primary production of the surface water i n the S t r a i t of Georgia, i s also associated with an increase i n secondary production (Parsons et al.1970). This increase i n secondary production.may provide more prey organisms f o r the c a r n i -vorous copepodite stages of P_. elongata. Secondly, there may-be a reduction, of the predation pressure on the n a u p l i i and the copeppdites, which are, i n the main, found below the surface l a y e r , where the high-est primary and secondary production occurs. In the autumn and winter, there i s a reduction i n the primary and secondary production i n the surface water (Parsons _£f a l . 1970) , and/ these times the developmental stages may be food l i m i t e d . 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Metal ions i n b i o l o g i c a l systems. B i o l . Rev. 28_: 381-415. Wilson, D.P. (1951). A b i o l o g i c a l d i f f erence between natural sea waters. J . mar. bio'l. Ass. U.K. 30;: 1-20. Wilson, D.P. and F.A.J. Armstrong (1952). Further experiments on b i o -l o g i c a l differences between natural sea waters. J . mar. b i o l . Ass.- U.K. 3_1_: 335-349. Wilson, D.P. and F.A.J. Armstrong (1954). B i o l o g i c a l differences be-tween sea waters; experiments i n 1953: J . mar. b i o l . Ass. U.K. 3_3_: 347-360. Wilson, D.P. and F.A.J. Armstrong (1958). B i o l o g i c a l differences be-tween sea waters: experiments i n 1954 and 1955. J . mar. b i o l . Ass., U.K. 37: 331-348. Wilson,.,D.P. and F.A.J. Armstrong (1961). B i o l o g i c a l differences be-tween- sea waters: experiments i n 1960. J . mar. b i o l . Ass. U.K. 41_: 663-681. Woodhouse, C.D. (1971). A study of the e c o l o g i c a l r e l a t i o n s h i p s and. taxonomic status of two species o f the genus Calanus (Crustacea: Copepoda). Ph.D. T h e s i s . Zool., Univ. B r i t . C o l . 175 p. 99 APPENDIX THE GENERIC.NAME AND SPECIES NAME. OF THE STUDY ORGANISM It was apparent, from the l i t e r a t u r e that there i s some d i s -agreement over the generic and species name of the study organism. It i s the purpose of th i s appendix to present an unbiased p i c t u r e of the arguments for.and against each name, and then to give the reasons why the f i n a l name was chosen. However, only d e t a i l e d laboratory studies can determine whether or not the genus Pareuchaeta i s v a l i d , and whe-ther or not the species elongata and japonica are so g e n e t i c a l l y d i s -t i n c t as to constitute separate species. (1) Genus Euchaeta or Pareuchaeta? The f i r s t genus of the family Euchaetidae, Euchaeta marina (Prestandrea), was established by P h i l l i p p i i n 1882 (Scott 1909). In the following years, the genera V a l d i v e l l a , Pseudeuchaeta, and Pareuchaeta have been added to the family (Brodsky 1950). There are at least e i g h t y - f i v e species, within the famil y , of which one belongs to the genus Pseudeuchaeta, eight to the genus V a l d i v e l l a , nineteen to the genus Euchaeta, and f i f t y - s e v e n to the genus Pareuchaeta. The genus Pareuchaeta was established by Scott' (1909) who used, as d i s t i n g u i s h i n g c h a r a c t e r i s t i c s , the armature of the second max i l l a i n the adult female, and the structure of the f i f t h leg i n the male. In Euchaeta, some of the spines on the apex of the second maxilla are equipped with long spinules; i n Pareuchaeta, the spines are equipped with short spinules. In the adult male Euchaeta, the 100 t h i r d segment of the exopodite of the l e f t f i f t h l eg i s long and spinfprm; i n Pareuchaeta, i,£ i s short and rudimentary. Scott (1909) i d e n t i f i e d twelve species of the genus Pareuchaeta and seven of the genus Euchaeta by using these two c h a r a c t e r i s t i c s . Sars (1925, i n Sewell .1929) agreed with the establishment of the genus Pareuchaeta, and added a t h i r d d i s t i n g u i s h i n g c h a r a c t e r i s -t i c based on the structure of the accessory setae of the f u r e a l rami. In Euchaeta, these setae are more.strongly developed than the other f u r c a l setae; i n Pareuchaeta, these setae are quite slender, and form a 'knee-joint' a short distance pasit t h e i r point o f o r i g i n . • Brodsky (1950) and Tanaka (1958) also accepted t h e . v a l i d i t y of the genus Pareuchaeta although each used only two of the three, d i s t i n g -uishing c h a r a c t e r i s t i c s . Brodsky (1950)- used the structure of the l e f t f i f t h leg i n the male, and the caudal rami. Tanaka (1958) used the structure of the l e f t f i f t h leg in.the male, and the second m a x i l l a . While the above used only two of.the three d i s t i n g u i s h i n g c h a r a c t e r i s -tics,- they gave no i n d i c a t i o n that they considered the t h i r d i n v a l i d . Veervoot (1963) did not accept the v a l i d i t y of the species Pareuchaeta. He found that i t was equally possible to divide the t h i r t e e n Euchaeta-Pareuchaeta species he examined into five-groups which would probably not deserve any more than a sub-generic rank. However, three of his groups contain only Euchaeta species, and the remaining two contain only Pareuchaeta species (according to the above' who recognize the genus Pareuchaeta). In e f f e c t , Veervoot used c e r t a i n 101 c h a r a c t e r i s t i c s to divide the species into two groups which could be further subdivided. Sewell (1929) also found i t possible to further subdivide the genus Euchaeta (into two groups), and the genus Pareuchaeta (into four groups). Secondly, he acknowledged that there was at least one species of those.he examined which wasji intermediate i n character to Euchaeta and Pareuchaeta, but he believed that t h i s species was a connecting l i n k between the two genera. It i s probable that there are several such intermediates and, that with a thorough study of the morphology of the family Euchaetidae, t h e i r r o l e i n the phylogeny of the family w i l l be better understood. Veervoot examined t h i r t e e n of the known seventy-six species of Euchaeta and Pareuchaeta and concluded that the separation of the species into two genera was not j u s t i f i e d . Conversely, Scott (1909), Sewell (1929), Brodsky (1950), and Tanaka and Omori (1968) examined f i f t y - n i n e of the known seventy-six species and concluded that the separation was v a l i d . As the l a t t e r group have examined a more repre-sentative sample of the family Euchaetidae, i t was decided to accept t h e i r c l a s s i f i c a t i o n of Euchaetidae.. Therefore, the genus Pareuchaeta i s accepted as being v a l i d . Brodsky (1950) and Tanaka and Omori (1968) have both placed the study organism i n the genus Pareuchaeta. The structure of the second maxilla (Campbell 1934), the male f i f t h leg (Campbell 1934), and the caudal f u r c i (pers. obser.) indic a t e that the study organism belongs to.the genus Pareuchaeta, and that i t i s not.an intermediate form. 102 (2) Species japonica or elongata? In 1913, E s t e r l y i d e n t i f i e d a new species, Euchaeta elongata, from the San Diego region. The specimen, an adult female 4.13 mm i n length, was characterized by the blunt p r o j e c t i o n on the side of the l a s t t h o r a c i c segment, the. asymmetric genital protuberance, and the structure of the f i r s t and second pa i r s of f e e t . In 1921, Marukawa described a new species from the Sea of Japan, using the same.identifying c h a r a c t e r i s t i c s as E s t e r l y (1913). However, the adult females was l a r g e r , being 8 mm i n length. Marukawa named the species japonica. It i s apparent, from the l i t e r a t u r e , that the species name japonica has been accepted by c e r t a i n authors over that of elongata, and yet none of the reasons given are s a t i s f a c t o r y . Wailes (1929) i d e n t i f i e d E_. japonica from the S t r a i t of Georgia, but was apparently unaware of E s t e r l y1s o r i g i n a l d e s c r i p t i o n of elongata. Campbell (1929) captured E_. japonica from Deep Cove, Rocky Bay, Sherington, and Seaside Park. She noted that her specimens d i f f e r e d t s l i g h t l y i n the structure of the second foot from Marukawa's d e s c r i p t i o n s , and that Vancouver Island region specimens were only 5 to .6.3 mm i n length. While she assigned the species name japonica to her specimens, she was aware of E s t e r l y ' s d e s c r i p t i o n arid concluded (Esterly (1913) seems to have described the same species (as Marukawa)." In a l a t e r paper (1934), Campbell was less c e r t a i n as to whether or not elongata' and japonica were, i n f a c t , two forms of the same species. 103 Brodsky (1959) noted the occurrence of a species which he c a l l e d P.• japonica i n the Sea of Ohkotsk, and the Sea of Japan, the Bering Sea, and the northwest P a c i f i c Ocean. He was aware of E s t e r l y ' s d e s c r i p t i o n and stated " t h i s species (japonica) i s i d e n t i c a l to P_. elongata of E s t e r l y . " Tanaka and Omori (1968) noted the occurence of P_. elongata from the. Izu^region of Japan, and state that E s t e r l y ' s elongata and Marukawa's japonica are synonomous. Morris (1970) c o l l e c t e d E_.' elongata from the sub-arctic P a c i f i c Ocean, and agrees that elongata and japonica are synonomous.species (pers. comm.). Davis (1949) captured specimens of E . j a p o n i c a from o f f the mouth of Juan de Fuca S t r a i t and from the Portland Canal. He concluded that these specimens were d i s t i n c t from E s t e r l y ' s elongata because of q u a l i t a t i v e differences i n the species. His specimens were 5.4 to 6.4 mm i n length i n comparison to 4.13 mm of Esterly's;elongata. There were also q u a l i t a t i v e d ifferences i n the f r o n t a l p a p i l l a , and the con-c a v i t y of the border of the exopod of the f i r s t l e g . The v a l i d i t y of Davis' arguments (1949) are hard to accept. F i r s t , he believes that h i s specimen's and E s t e r l y ' s are d i s t i n c t spe-ci e s because they d i f f e r i n s i z e . However, h i s specimens were i n t e r -mediate i n s i z e to Marukawa' s j aponica and E s t e r l y ' s elongata, and so were s i m i l a r to neither holotypes. It i s well documented i n the l i t e r a t u r e that a species can mature to d i f f e r e n t s i z e s . Species l i v i n g i n the same area may, f o r example, exhibit d i f f e r e n t sizes at maturity. Campbell (1929) 104 measured adult female E.. japonica as being 5.0 to-6.3 mm i n length, Fulton (1968) measured adult females as being 6.3 to 6.5 mm i n length, arid Pandyan (1971) measured adult females as being 4.4 to 5.99 mm i n length. These specimens were a l l captured from the S t r a i t of Georgia or i t s surrounding waters. A species may exhibit d i f f e r e n t sizes at maturity i n d i f f e r e n t parts of i t s range (Deevy 1966; McLaren 1965). McLaren (1963, 1965) showed that Pseudocalanus minutus l i v i n g i n d i f f e r e n t areas attained sizes at maturity which could be correlated with the temperature of the water i n which the species was l i v i n g and with possible physiolo-g i c a l differences within the species. Davis (1949) accepted the differences i n the structure of the second foot between his specimens and Marukawa's, but did not accept the differences i n the structure of the f i r s t foot and.the f r o n t a l p a p i l l a between his specimens .and E s t e r l y ' s . In both cases, the d i f -ferences were q u a l i t a t i v e rather than q u a n t i t a t i v e . There i s ample evidence i n the l i t e r a t u r e of morphological v a r i a t i o n within a species i n d i f f e r e n t parts of i t s range.' Brinton (1962) observed morphological v a r i a t i o n s within two species of Euphausiids i n d i f f e r e n t parts of t h e i r range. Morphological v a r i a t i o n within a species does not mean, a p r i o r i , that the variants are d i s t i n c t species-only extensive studies can resolve t h i s . In the case of elongata-japonica, t h i s kind of study has not been done, and so there i s no v a l i d reason for con-s i d e r i n g the species d i s t i n c t . As Esterley's (1913) d e s c r i p t i o n was 105 the o r i g i n a l , h i s species name i s accepted. It i s concluded that the study organism should be c a l l e d Pareuchaeta elongata. 106 AN EXAMINATION OF PATTEN'S ANALYSIS OF STABILITY Patten's (1961, 1962) analysis of s t a b i l i t y i s of i n t e r e s t as i t attempts to qua n t i t i z e f l u c t u a t i o n s i n the variables of an ecosystem. Several c r i t i c i s m s can be made of Patten's a n a l y s i s . The major c r i t i c i s m stems from the fa c t that ' s t a b i l i t y ' can be defined i n several ways, and so be applied to quite d i f f e r e n t systems. For the purposes of t h i s d i s c u s s i o n , they w i l l be c a l l e d s t a t i s t i c a l l y stable and p h y s i c a l l y stable systems. A system i n which the measured v a r i a b l e does not fluc t u a t e with time i s a s t a t i c system. A s t a t i s t i c a l l y stable system i s one i n which the measured v a r i a b l e remains, i n theory, constant with time^ but, due to sampling e r r o r , fluctuates i n a random d i r e c t i o n about the mean value. For example, an experiment could be conducted i n which the same coin was tossed one hundred times and the number of 'heads' recorded. This could be repeated several times, and the data p l o t t e d with the number of 'heads' recorded at the end of each experiment on the Y-axis, and the experiment number on the X-axis. The data would be described by the l i n e y=50, and the actual data points would be scattered randomly about that l i n e . This system i s stable i n that the v a r i a b l e 'number of heads' remains s t a t i s t i c a l l y constant with time, and the data fluctuates i n a random d i r e c t i o n about the mean value. Conversely, a system i n which the measured v a r i a b l e fluctuates i n a predictable and c y c l i c d i r e c t i o n about the mean with time i s p h y s i c a l l y s t a b l e . For example, the swing of a pendulum i s 107 a p h y s i c a l l y stable system. Therefore, to state that a system i s stable i s ambiguous unless the type of s t a b i l i t y i s described. There i s a tendency among ecologists to consider a p h y s i c a l l y stable system as being e c o l o g i c a l l y i n s t a b l e , and a statistically stable system as being ecologicallyiV stable. For example, Dunbar (1960), i n discussing the s t a b i l i t y of the marine environment, based h i s arguments on the premise that " o s c i l l a t i o n s are bad f o r any system and that v i o l e n t o s c i l l a t i o n s are often l e t h a l . " In t h i s paper, he discussed the variables which dampen o s c i l l a t i o n s ( i e increase the trend towards a s t a t i c or s t a t i s t i c a l l y stable system) , and increase the e c o l o g i c a l s t a b i l i t y of that ecosystem. Patten (1961, 1962) f a i l e d to describe what he meant be ' s t a b i l i t y ' . From his 1961 paper, i t i s suggested that he considered a p h y s i c a l l y stable system to be e c o l o g i c a l l y i n s t a b l e , and a system which fluctuates less abouttthe mean over the same time i n t e r v a l to have a greater e c o l o g i c a l s t a b i l i t y . However, Patten f a i l e d to recognize that the system with the highest e c o l o g i c a l s t a b i l i t y i s a s t a t i s t i c a l l y stable system and, because of t h i s , made several errors i n deriving h i s index. Patten (1961) derived the s t a b i l i t y index e m p i r i c a l l y , and the assumption of which he based the index i s i n c o r r e c t . Patten stated " i f a l l the variables of an ecosystem were random v a r i a b l e s , randomly sampled), thenieach v a r i a b l e might be regarded as most stable i f and when the probablity f o r an increase i n value when low 108 and f o r a decrease i n value when high were unity." This i s i n c o r r e c t . In a s t a t i s t i c a l l y (and e c o l o g i c a l l y ) stable system, the probability of a low value followed by a high i s 0.5, and the probablity of a low value followed by another 1'pw i s 0.5. S i m i l a r l y , the probability of a high value followed by another high i s 0.5, and the probability of a high value followed by a low i s 0.5. Patten (1961) derived a s t a b i l i t y measure, 0 , for the determinant of P, where P= pi d pi i Pdd pi d (as on page 75) When o>Q:itthe\-system, according to Patten, i s s t a b l e . The greatest e c o l o g i c a l s t a b i l i t y i s when a=l, i e , P^<j=P(_i=-'-» a n^ P i i= Pd d=^ * Thus, a system i n which an increase i s followed by a decrease, and then by an increas e , e t c , i s s t a b l e . However, t h i s i s a p h y s i c a l l y stable system i n which fl u c t u a t i o n s i n d i r e c t i o n about the mean are c y c l i c and p r e d i c a t b l e . The system does not possess s t a t i s t i c a l s t a b l i t y and i s therefore e c o l o g i c a l l y i n s t a b l e . When a=0, the system, according to Patten, has n u l l s t a b i l i t y . This value i s applicable to three systems. In a s t a t i c system, P ^ ^ P _ j i= p. .=p, =0. In a s t a t i s t i c a l l y stable system, p. =p , .=p. .=p, =0.5. * i i dd i d dx IX dd Patten p r e d i c t s that both these systems have n u l l s t a b i l i t y , and are less stable than the above system i n which the variables f l u c t u a t e 109 i n a les s random manner. This i s incorrect,;) as the greatest e c o l o g i c a l s t a b i l i t y occurs when the measured v a r i a b l e remains constant with time, or else fluctuates i n a random manner. A n u l l s t a b l i t y i s also obtained i f the measured v a r i a b l e increases £(por decreases) continuously with time, i e , p^=1.0, and p^=p^^=p^=g0.%>Tlius', Patten s s t a b i l i t y index f a i l s to d i s t i n g u i s h between a system i n which the v a r i a b l e i s constant,-, or varies i n a random manner, and between a system i n which the var i a b l e increases (or decreases) continuously with time. It i s also obvious that a vari a b l e which does not approach an equilibrium value i s ins t a b l e (both s t a t i s t i c a l l y and p h y s i c a l l y ) , arid does not possess a n u l l s t a b i l i t y . When a<0, the system, according to Patten, i s i n s t a b l e . The greatest i n s t a b i l i t y occurs when p^=p^->^,< arid P - j ^ P ^ i " ^ » a n c* This type of system i s a p h y s i c a l l y stable system i n which the va r i a b l e fluctuates i n a c y c l i c and predicatable d i r e c t i o n with time. A c r i t i c a l examination of Patten's analysis indicates that there i s no difference i n the s t a b i l i t y of a system when a= 1,^ -and a=-l f o r , i n both systems, the fl u c t u a t i o n s are c y c l i c and are predic.tajjies'^ i n d i r e c t i o n , rather than being random. A second l i m i t a t i o n to Patten's anaylsis i s that i t i s s e n s i t i v e to sampling frequency. Figure 9 shows a system i n which an environmental v a r i a b l e fluctuates i n a c y c l i c manner with time, i e the system i s p h y s i c a l l y stable^Cbut e c o l o g i c a l l y i n s t a b l e ) . 110 Figure 9. A hypothetical system i n which the measured variab has p h y s i c a l s t a b i l i t y . 11CM T i m e i n Depending on when the va r i a b l e i s measured, at least three d i f f e r e n t values of a can be obtained. ( i ) i f measurements are made only at!t=l,5,9, e t c , or t=2,6,10, e t c , or t=3 , 7 , l l , e t c , then a=0:. According to the a n a l y s i s , and with the a v a i l a b l e data, the system has n u l l s t a b i l i t y . ( i i ) i f measurements are made only at t= 1,3,5,7,etc, then a=l as P^(_=:P(_:j=-'-» a nd P i i= pd d=^ " According to the a n a l y s i s , the system i s stable ^ e c o l o g i c a l l y ) / . ( i i i ) i f many measurements are made during each c y c l e , then as the sampling frequency increases, a->-l, as P^-^P^d "*"-'-» a n d P i d=P d i^0. According to the a n a l y s i s , the system i n i n s t a b l e e c o l o g i c a l l y . These problems could be avoided by choosing the sampling such that i t coincided with several stages i n the phases of a variaable which v a r i e d c y c l i c a l l y . Secondly, i t might be better to consider only the absolute value of a. A stable system would be one i n which a=0, and a less stable system would be one i n which |a|>0. Those systems i n which variables increased or decreased with time • would have to be excluded from the analysis i n i t s present form. Patten (1962) 'improved' the s t a b i l i t y index by d i v i d i n g a by the mean v a r i a b i l i t y . Small mean v a r i a b i l i t i e s tend to increase the magnitude of the s t a b i l i t y index, and large mean v a r i a b i l i t i e s decrease the magnitude of the s t a b i l i t y index. However, i t i s u n l i k e l y that an e c o l o g i c a l l y i n s t a b l e system with a small mean v a r i a b i l i t y i s a c t u a l l y less stable than an e c o l o g i c a l l y i n s t a b l e system with a large mean v a r i a b i l i t y . Therefore, i f Patten's approach to s t a b i l i t y analysis i s to be re t a i n e d , i t i s 112 probably best to consider only |c|. The data i n Tables 16 and 17 were re-examined, and the mean values of \a\ f o r the b i o l o g i c a l , chemical, and p h y s i c a l variables determined. These were; B i o l o g i c a l Chemical Phy s i c a l The b i o l o g i c a l system has a higher e c o l o g i c a l s t a b i l i t y than e i t h e r the p h y s i c a l or chemical system.However, the chemical system i s les s stable e c o l o g i c a l l y than the p h y s i c a l system while, i n the previous a n a l y s i s , i t was more s t a b l e . Patten's s t a b i l i t y measure therefore might be modified to give a better index of s t a b i l i t y than i t i t s present form. However, th i s index, l i k e any index, has l i m i t e d use i n describing ecosystem processes. A b e t t e r approach would be to make use of some of the mathematical techniques used by p h y s i c i s t s , ime.tejtiologists, ^ arid astronomers i n time lag studies tqT'describe the dynamics of the i n t e r a c t i o n s between the v a r i a b l e s within a system. G.S.-l 0.1Z> 0.32J 0.22 Indian Arm 0.53 0.30 

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