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A morphological and biochemical comparison of articially and naturally-reared salmonids Ludwig, Bryan William 1980

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A MORPHOLOGICAL AND BIOCHEMICAL COMPARISON OF ARTIFICIALLY AND NATURALLY-REARED SALMONIDS B . S c , The U n i v e r s i t y of B r i t i s h Columbia, 1977 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n ' THE FACULTY OF GRADUATE STUDIES (Department of Zoology) We accept t h i s t h e s i s as conforming to the re q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA May 1980 by BRYAN WILLIAM LUDWIG Bryan W i l l i a m Ludwig, 1980 I n 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 t h e r e q u i r e m e n t s f o r an a d v a n c e d d e g r e e a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e 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 a g r e e 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 c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by t h e Head o f my D e p a r t m e n t o r by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f 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 n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . D e p a r t m e n t o f The U n i v e r s i t y o f B r i t i s h C o l u m b i a 2075 W e s b r o o k P l a c e V a n c o u v e r , C a n a d a V6T 1W5 „.*. Itffxc mo D E - 6 B P 75-51 1 E i i ABSTRACT Wild salmonids are u s u a l l y s u p e r i o r to hatchery salmonids i n marine s u r v i v a l . In t h i s study, comparisons were made between w i l d and a r t i f i c i a l l y - r e a r e d coho salmon (Oncorhynchus k i s u t c h ) and steelhead t r o u t (Salmo g a i r d n e r i ) to i d e n t i f y morphological and biochemical d i f f e r e n c e s and the causes of these d i f f e r e n c e s . Coho salmon were obtained from three types of r e a r i n g f a c i l i t i e s : a hatchery production-channel, a semi-natural rearing-channel ( p o o l - r i f f l e sequence w i t h i n s e c t d r i f t ) both at the Qualicum r i v e r , and Burrows ponds at the Capilano r i v e r . Coho were fed an Oregon Moist P e l l e t d i e t . Steelhead t r o u t , fed a S i l v e r Cup d i e t , were reared i n lak e net-pens (O'Connor l a k e ) . Wild f i s h were captured from the same watersheds i n which the c u l t u r e d f i s h were reared. For Qualicum coho, comparisons were made at various periods i n the l i f e h i s t o r y . Coho smolts, reared i n the production-channel (11.8 cm, 17.5 g) and Burrows ponds (12.4 cm, 18.4 g) were longer and heavier than w i l d coho from the Qualicum r i v e r (10.1 cm, 11.6 g) and Capilano r i v e r (11.1 cm, 14.6 g). Rearing-channel smolts (10.0 cm, 11.8 g) were s i m i l a r i n s i z e to w i l d coho from the Qualicum r i v e r . C o n d i t i o n f a c t o r s were higher i n w i l d coho. Production-channel and Burrows pond smolts were lower i n moisture (76.3%, 77.3% r e s p e c t i v e l y ) but higher i n l i p i d (4.4%, 3.8%) than t h e i r w i l d counterparts (79.1%, 79.7% moisture; 3.0%, 2.0% l i p i d ) . There were few d i f f e r e n c e s i n ash or p r o t e i n (% wet t i s s u e ) . W ild coho were higher i n ash and p r o t e i n and lower i n l i p i d " ( % dry t i s s u e ) but there were few d i f f e r e n c e s when the data were expressed as a percent of the l i p i d - f r e e dry t i s s u e . Therefore, d i f f e r e n c e s i n proximate composition were confined to i i i moisture and l i p i d . P h o s p h o l i p i d content was s i m i l a r i n w i l d and c u l t u r e d coho averaging 12.9 mg/g wet t i s s u e . In coho, the greatest d i f f e r e n c e s i n f a t t y a c i d composition were i n n e u t r a l l i p i d (NL). Production-channel and rearing-channel smolts were higher i n monounsaturates (58.2, 55.5% r e s p e c t i v e l y ) and u)6 f a t t y a c i d s (9.0, 7.5%) but were lower i n u3 f a t t y a c i d s (12.7, 14.9%) than the w i l d coho (43.9% monounsaturates, 5.7% u)6 and 28.4% co3 f a t t y a cids) . D i f f e r e n c e s i n p o l a r l i p i d (PL) f a t t y a c i d s were s l i g h t . In w i l d coho, the NL content of 18:2w6 (3.8%) was 0.6 times that of the production and rearing-channel coho w h i l e the 22:6w3 content (14.8%) was 2.2 times that of the production and rearing-channel coho. In steelhead, pen-reared and w i l d smolts d i d not d i f f e r i n le n g t h (18.5 cm), weight (62.4 g), c o n d i t i o n f a c t o r (4.62), moisture (76.4%), ash (2.6%), p r o t e i n (16.8%) and ph o s p h o l i p i d (9.2 mg/g wet t i s s u e ) . The values given are averages f o r pen-reared and w i l d smolts. Pen-reared smolts (2.9%) were s i g n i f i c a n t l y lower i n l i p i d than the w i l d steelhead smolts (4.2%). F a t t y a c i d content of pen-reared and w i l d steelhead d i f f e r e d i n both n e u t r a l and p o l a r l i p i d . Pen-reared smolts had an co6 content of 29.2% NL and 10.0% PL and an 0)3 content of 13.2% NL and 51.2% PL. The w i l d smolts were lower i n w6 f a t t y acids (4.9% NL, 3.5% PL) but were higher i n w3 f a t t y a c i d s (39.6% NL, 55.2% PL). The content of 22:6w3 (21.3%) i n n e u t r a l l i p i d of w i l d smolts was 2.7 times l a r g e r than that of the pen-reared smolts. The high l i p i d content i n c u l t u r e d coho was a t t r i b u t e d to t h e i r high r a t i o n l e v e l and the higher l i p i d content i n Oregon Moist P e l l e t (18.3% i v dry •mWttoeV?) than i n aquatic i n s e c t s (12.4% dry t i s s u e ) ( P h i l l i p s et a l . 1954). The higher l i p i d content i n w i l d smolts may be a r e s u l t of t h e i r o l d e r age at smolting (2-3 y e a r s ) , although a d e f i n i t i v e explanation i s not yet a v a i l a b l e . D i f f e r e n c e s i n f a t t y a c i d composition were due to the d i e t . Oregon Moist P e l l e t was much higher i n monounsaturates (58.9%) than aquatic i n s e c t s ( P l e c o p t e r a , T r i c h o p t e r a , Ephemeroptera, Chironomidae) (40.7%). S i l v e r Cup was much higher i n w6 f a t t y a c i d s (19.3%) than the aquatic i n s e c t s (6.8%). V TABLE OF CONTENTS Page ABSTRACT. i i TABLE OF CONTENTS v LIST OF TABLES v i i i LIST OF FIGURES i x LIST OF APPENDIX TABLES x i ACKNOWLEDGMENTS x i i INTRODUCTION 1 Review of F i s h L i p i d Metabolism 2 MATERIALS AND METHODS. . 6 I. Study Areas 6 A. Qualicum River 6 B. Capilano R i v e r 6 C. Keogh R i v e r 6 I I . Rearing Conditions 6 A. Qualicum Coho Salmon. 6 1. Production-channel 7 2. Rearing-channel 7 B. Capilano Coho Salmon. 8 C. Keogh Steelhead Trout. 8 I I I . F i e l d Sampling 9 A. Qualicum R i v e r 9 1. Production- and Rearing-channel Coho 9 2. Qualicum R i v e r Coho 9 3. F i e l d Processing of Qualicum Coho 10 4. Aquatic Insects 10 B. Capilano R i v e r 11 C. Keogh River 11 IV. Proximate A n a l y s i s 11 A. F i s h Tissue 11 B. Hatchery D i e t s 13 C. Aquatic Insects 14 V. Ph o s p h o l i p i d A n a l y s i s 14 VI. F a t t y A c i d A n a l y s i s 14 A. Methods • 14 B. C a l c u l a t i o n s . 15 VI I . Data Handling and S t a t i s t i c a l A n a l y s i s 17 V I I I . F i s h Health 17 RESULTS 19 I. Length, Weight, and Condition, Factor 19 A. Coho Salmon from the Qualicum R i v e r . . . . . . . 19 v i TABLE OF CONTENTS (cont'd) Page B. Coho Salmon from the Capilano R i v e r . . . 20 C. Steelhead Trout from the Keogh R i v e r . . . 20 I I . Proximate Composition 20 A. Coho Salmon from the Qualicum R i v e r 20 1. Presmolts and Smolts 20 2. Fry and P a r r 21 B. Coho Salmon from the Capilano R i v e r . 22 C. Steelhead Trout from the Keogh R i v e r . . 22 D. Seasonal Changes i n Qualicum Coho... 22 E. Aquatic Insects and Hatchery D i e t s 23 I I I . P h o s p h o l i p i d Content 24 IV. F a t t y A c i d Composition 24 A. I n d i v i d u a l F a t t y A c i d Composition 24 1. F i s h 24 i . Coho Smolts from the Qualicum R i v e r . . . . 24 i i . Steelhead Smolts from the Keogh R i v e r . . 26 2. Aquatic Insects and Hatchery D i e t s 26 3. Comparison of the D i e t and the F i s h Composition 27 B. F a t t y A c i d Class Composition 27 1. F i s h 28 i . Coho Smolts from the Qualicum R i v e r . . . . 28 i i . Steelhead Smolts from the Keogh R i v e r . . 28 2. Aquatic Insects and Hatchery D i e t s 29 3. Comparison of the Diet and the F i s h Composition 29 V. Age of the Smolts 30 DISCUSSION 31 I. I n f l u e n c e of Rearing Conditions on Morphology and Biochemistry 31 A. Length, Weight, and Condition. F a c t o r . . 31 B. Proximate Composition 32 1. Comparisons of N a t u r a l l y and A r t i f i c i a l l y -reared F i s h 32 2. Seasonal Changes 36 C. P h o s p h o l i p i d Content 37 D. F a t t y A c i d Content 38 I I . Impact of Smolt S i z e and Biochemical Composition on Marine S u r v i v a l 40 A. Smolt S i z e 40 B. Proximate Composition... 41 C. F a t t y A c i d Content 41 1. E s s e n t i a l F a t t y Acids i n F i s h — 42 2. F a t t y A c i d Content and Membrane and L i p i d Function •• 43 v i i TABLE OF CONTENTS (cont'd) Page 3. Docosahexaenoic A c i d (22:6w3) 44 4. F a t t y A c i d Requirements i n Fresh and S a l t Water.. 45 I I I . Concluding Remarks.... 46 BIBLIOGRAPHY 48 v i i i LIST OF TABLES Page Table 1 Rearing c o n d i t i o n s i n the Qualicum, Capilano, and Keogh r i v e r study areas 55 Table 2 Fork l e n g t h , wet weight and c o n d i t i o n f a c t o r of coho salmon and steelhead t r o u t 57 Table 3 Whole body proximate composition (% wet t i s s u e ) and phos p h o l i p i d content of coho salmon and steelhead t r o u t 59 Table 4 Whole body proximate composition (% dry t i s s u e ) of coho salmon and steelhead t r o u t 61 Table 5 Proximate composition of some aquatic i n s e c t s (% wet t i s s u e ) and hatchery d i e t s (% wet t i s s u e and % dry t i s s u e ) 63 Table 6 F a t t y a c i d composition of coho smolts reared n a t u r a l l y i n the Qualicum r i v e r 65 Table 7 F a t t y a c i d composition of coho smolts reared i n a production-channel 67 Table 8 F a t t y a c i d composition of coho smolts reared i n a rearing-channel 69 Table 9 F a t t y a c i d composition of steelhead smolts reared n a t u r a l l y i n the Keogh r i v e r 71 Table 10 F a t t y a c i d composition of steelhead smolts reared i n net-pens 73 Table 11 F a t t y a c i d composition of some aquatic i n s e c t s and hatchery d i e t s 75 Table 12 F a t t y a c i d c l a s s composition (%) of some aquatic i n s e c t s and hatchery d i e t s 77 i x LIST OF FIGURES Page Figure 1 Map of the study areas showing the Keogh, Qualicum and Capilano r i v e r s . 79 Figure 2 Map of the Qualicum r i v e r system.... 81 Figure 3 Map of the Keogh r i v e r system........ 83 Figure 4 Map of the Capilano r i v e r system.... 85 Figure 5 Fork lengths of Qualicum coho salmon 87 Figure 6 . Wet weights of Qualicum coho salmon 89 Figure 7 C o n d i t i o n f a c t o r s of Qualicum coho salmon 91 Figure 8 Seasonal v a r i a t i o n s i n moisture content of Qualicum coho salmon 93 Figure 9 Seasonal v a r i a t i o n s i n ash content of Qualicum coho salmon 95 Figure 10 Seasonal v a r i a t i o n s i n p r o t e i n content of Qualicum coho salmon. 97 Figure 11 Seasonal v a r i a t i o n s i n l i p i d content of Qualicum coho salmon 99 Figure 12 Saturated f a t t y a c i d s i n coho salmon from the Qualicum r i v e r 101 Figure 13 Monounsaturated f a t t y a c i d s i n coho salmon from the Qualicum r i v e r . . . 103 Figure 14 Polyunsaturated f a t t y a c i d s . i n coho salmon from the Qualicum r i v e r 105 Figure 15 F a t t y a c i d s of the co6 s e r i e s i n coho salmon from the Qualicum r i v e r 107 Figure 16 F a t t y a c i d s of the CJ3 s e r i e s i n coho salmon from the Qualicum r i v e r 109 X LIST OF FIGURES (cont'd) Page Figure 17 Ratio of u6/co3 f a t t y a c i d s i n coho salmon from the Qualicum r i v e r , and steelhead t r o u t from the Keogh r i v e r . I l l Figure 18 Saturated f a t t y a c i d s i n steelhead t r o u t from the Keogh r i v e r . 113 Figure 19 Monounsaturated f a t t y a c i d s i n steelhead t r o u t from the Keogh r i v e r 115 Figure 20 Polyunsaturated f a t t y a c i d s i n steelhead t r o u t from the Keogh r i v e r . 117 Figure 21 F a t t y a c i d s of the w6 s e r i e s i n steelhead t r o u t from the Keogh r i v e r . 119 Figure 22 F a t t y a c i d s of the u3 s e r i e s i n steelhead t r o u t from the Keogh r i v e r 121 x i LIST OF APPENDIX TABLES Page Appendix t a b l e 1 Proximate composition (% dry t i s s u e ) of n a t u r a l l y - r e a r e d coho salmon from the Qualicum r i v e r . 123 Appendix t a b l e 2 Proximate composition (•% dry t i s s u e ) of production-channel coho salmon from the Qualicum r i v e r 125 Appendix t a b l e 3 Proximate composition (% dry t i s s u e ) of rearing-channel coho salmon from the Qualicum r i v e r . 127 Appendix t a b l e 4 Whole body proximate composition (% l i p i d - f r e e dry t i s s u e ) of coho salmon and steelhead t r o u t 129 x i i ACKNOWLEDGMENTS Many persons have provided a s s i s t a n c e i n the development of t h i s t h e s i s . I am g r a t e f u l to Dr. W. S. Hoar f o r h i s generous support and prompt and c o n s t r u c t i v e c r i t i c i s m of e a r l i e r d r a f t s of t h i s t h e s i s . Drs. E. M. Donaldson, D. A. Higgs, T. G. Northcote, and A. F. Tautz a l s o provided u s e f u l comments on an e a r l i e r d r a f t . With pleasure I acknowledge the t e c h n i c a l a i d s u p p l i e d by M. Skwarok, B. Dosanjh, H. Mahood, D. MacDonald, and the s t a f f at the West Vancouver Laboratory. This study would not have been p o s s i b l e without the generosity of Dr. H. Mundie, D. Harvie, P. Slaney, and E. Stone i n a l l o w i n g access to t h e i r r e a r i n g f a c i l i t i e s and p r o v i d i n g f i e l d a s s i s t a n c e . Laboratory f a c i l i t i e s (West Vancouver Laboratory) were provided by Dr. E. M. Donaldson. I g r a t e f u l l y acknowledge the a s s i s t a n c e of H. M. Dye, and M. Young i n the pr e p a r a t i o n of f i g u r e s and t a b l e s . F i n a n c i a l support was generously s u p p l i e d by the B r i t i s h Columbia F i s h and W i l d l i f e Branch; West Vancouver Laboratory, Department of F i s h e r i e s and Oceans; and g r a n t s - i n - a i d of research to Dr. W. S. Hoar. With g r a t i t u d e , I dedicate t h i s t h e s i s to my w i f e Carol f o r she endured more than I . 1 INTRODUCTION B r i t i s h Columbia i s c u r r e n t l y i n the midst of a salmonid enhancement program, the goal of which i s to double present l e v e l s of salmonid stocks. Much of the emphasis of t h i s program w i l l be placed on a r t i f i c i a l r e a r i n g of salmonids. H i s t o r i c a l l y , the q u a l i t y of the hatchery product has been poor. Over the pe r i o d 1937-1954, ocean s u r v i v a l of coho salmon from Minter creek, Washington, averaged 3.5% w h i l e the w i l d coho s u r v i v a l was 7.5% (Gonsolus 1978). More recent data suggest that the q u a l i t y of the hatchery product has not yet improved. A summary of A t l a n t i c salmon re l e a s e s (1963-1969) f o r northern Europe, U.S.S.R., and North America revealed that the marine s u r v i v a l of w i l d f i s h was 2.5 times that of the hatchery f i s h (Heland et a l . 1972). L o c a l l y , r e turns of hatchery coho to the Quinsam r i v e r , Vancouver I s l a n d , i n 1978 averaged 5.4% w h i l e the w i l d coho returns were 9.8% (D. MacQuarrie, personal communication). The reasons f o r poor marine s u r v i v a l i n c u l t u r e d salmonids are u n c e r t a i n . Biochemical composition i s one of s e v e r a l f a c t o r s i n f l u e n c i n g marine s u r v i v a l . U n fortunately, the optimal biochemical composition f o r c u l t u r e d salmon has not been i d e n t i f i e d . A composition s i m i l a r to w i l d salmonids may be d e s i r a b l e i n c u l t u r e d salmon; however, few d e t a i l e d comparisons of w i l d and c u l t u r e d P a c i f i c salmon have been made. In t h i s study, l e n g t h , weight, c o n d i t i o n f a c t o r , proximate composition, p h o s p h o l i p i d and f a t t y a c i d content of w i l d and hatchery coho salmon and steelhead t r o u t were compared. The o b j e c t i v e s of the p r o j e c t were to i d e n t i f y the morphological and biochemical d i f f e r e n c e s i n w i l d and hatchery salmonids, the source of these d i f f e r e n c e s i n the r e a r i n g e n v i r o n -ment, and to speculate on the i n f l u e n c e of the morphological and biochemical 2 d i f f e r e n c e s on marine s u r v i v a l . To determine when d i f f e r e n c e s occurred, comparisons of coho salmon were made throughout the freshwater p o r t i o n of the l i f e h i s t o r y . Since the d i e t a f f e c t s the biochemical composition of f i s h , a comparison of two hatchery d i e t s and some aquatic i n s e c t s was made. Proximate composition i n c l u d e s four main t i s s u e components: moisture, ash, p r o t e i n , and l i p i d . Only gross measurements were made f o r ash and p r o t e i n content. The e f f e c t s of these two c o n s t i t u e n t s on salmonid marine s u r v i v a l are considered i n the d i s c u s s i o n s e c t i o n . Since much of t h i s study i s concerned w i t h crude l i p i d and i t s components, f i s h l i p i d metabolism i s reviewed. Review of F i s h L i p i d Metabolism L i p i d metabolism i n f i s h i s poorly understood but i s thought to be s i m i l a r to mammals. D e t a i l s on mammalian l i p i d metabolism are based on reviews by B e l l et. al_. (1976) and Harper et a l . (1979). Where recognized, d i f f e r e n c e s between f i s h and mammalian l i p i d metabolism are noted. In mammals, most of the l i p i d s are absorbed from the i n t e s t i n e as g monoacyglycerols and f a t t y a c i d s . The d i g e s t i v e enzymes are s p e c i f i c f o r the a p o s i t i o n on the a c y l g l y c e r o l s . The absorbed l i p i d i s then synthesized to t r i a c l y g l y c e r o l s and rel e a s e d to the lymph system as chylomicrons. In f i s h , a p o r t i o n of the l i p i d may be completely hydrolyzed to f r e e f a t t y a c i d s before ab s o r p t i o n (Cowey and Sargent 1979). F i s h may a l s o d i f f e r i n the method of l i p i d a b sorption. Robinson and Mead (1973) proposed that i n f i s h , f a t t y acids were absorbed by i n t e s t i n a l c e l l s , synthesized to t r i a c y l g l y c e r o l s , and rel e a s e d to the lamina p r o p r i a . Free f a t t y a c i d s 3 were then absorbed from the lamina p r o p r i a , transported to the l i v e r v i a the p o r t a l blood, and synthesized to t r i a c y l g l y c e r o l s . The d i f f e r e n c e i n the absorbtion route between .. , . f i s h and mammals i s assumed to be r e l a t e d to the l a c k of a w e l l developed l a c t e a l system i n f i s h . Absorp-t i o n of f a t t y acids d i r e c t l y from the i n t e s t i n e to the blood, or the mammalian system of t r a n s p o r t of t r i a c y l g l y c e r o l s by the lymph system to the blood have not been discounted i n f i s h (Cowey and Sargent 1979). A f t e r a b s o r p t i o n , f a t t y a c i d s can be: transported to storage depots, u t i l i z e d f o r energy, converted to d i f f e r e n t f a t t y a c i d s by chain e l o n g a t i o n and d e s a t u r a t i o n , or incorporated i n phospholipid (Lee and Sinnhuber 1972). The r e g u l a t i o n of these pathways i s l a r g e l y unknown. In salmonids, l i p i d i s stored i n red and white muscle, and mesenteric storage depots ( B i l i n s k i 1969; L i n e_t ad. 1977) . Less a c t i v e species of f i s h such as cod u t i l i z e the l i v e r as the primary l i p i d storage depot ( B i l i n s k i 1974). L i p i d depots i n white muscle are e x t r a c e l l u l a r w h i l e i n red muscle the depots are i n t r a c e l l u l a r and e x t r a c e l l u l a r (Cowey and Sargent 1979). Red muscle i s p r i m a r i l y f o r low-speed, sustained swimming, and u t i l i z e s aerobic metabolism of f a t as an energy source. White muscle i s used f o r short burst or high-speed swimming and draws energy mainly from anaerobic metabolism of glycogen ( B i l i n s k i 1974). L i p i d s are r e l e a s e d from depots i n t o the blood i n the form of n o n - e s t e r i f i e d f a t t y a c i d s . In f i s h , there i s a p o s s i b i l i t y that muscle f a t reserves can be u t i l i z e d d i r e c t l y , without p a r t i c i p a t i o n of the blood stream (Cowey and Sargent 1979). Fat r e l e a s e from storage depots i s i n h i b i t e d by i n c r e a s i n g d i e t a r y energy i n t a k e . High concentrations of adenosine diphosphate i n the t i s s u e s , or hormones such as epinephrine, 4 growth hormone, and t h y r o i d hormone, s t i m u l a t e f a t m o b i l i z a t i o n . C a s t l e d i n e and Buckley (1979) i n v e s t i g a t e d the question of m o b i l i z a t i o n of n e u t r a l l i p i d f a t t y a c i d s f o r use i n p h o s p h o l i p i d . U n f o r t u n a t e l y , t h e i r experiments were i n c o n c l u s i v e as i n two of the eight cases there was some evidence of m o b i l i z a t i o n . As w i l l be discussed l a t e r , the question of m o b i l i z a t i o n of f a t t y a c i d s between l i p i d depots i s important f o r determin-i n g the s i g n i f i c a n c e of f a t t y a c i d d i f f e r e n c e s i n w i l d and hatchery f i s h . F a t t y a c i d s are o x i d i z e d by beta o x i d a t i o n , as i n mammals. Oxidation takes place i n mitochondria and r e q u i r e s c a r n i t i n e f o r t r a n s f e r of f a t t y a c i d s across the inner m i t o c h o n d r i a l membrane ( D r i e d z i c and Hochachka 1978). Red muscle has a greater c a p a c i t y to o x i d i z e f a t t y a c i d s than white muscle ( B i l i n s k i 1969). In coho salmon, f a t t y a c i d s are synthesized p r i m a r i l y by the l i v e r ( L i n _et a l . 1977) . An e x t r a m i t o c h o n d r i a l system f o r de novo synthesis of p a l m i t a t e from a c e t y l Co-A has been found i n many t i s s u e s . As w e l l , there are systems f o r chain e l o n g a t i o n and d e s a t u r a t i o n i n both mitochondria and microsomes. F i s h are not able to synthesize f a t t y a c i d s of the u3 ( l i n o l e n i c ) or CJ6 ( l i n o l e i c ) s e r i e s . The system f o r f a t t y a c i d nomenclature i s explained w i t h an example: 18:2co6 where 18 i s the t o t a l number of carbons i n the chain, 2 i s the t o t a l number of double bonds, and w6 i s the number of carbons, counting from the methyl end, to the p o s i t i o n of the f i r s t double bond. F a t t y a c i d s of the w3 and co6 s e r i e s , once gained from the d i e t , can be a l t e r e d by chain elongation and d e s a t u r a t i o n . The end p o i n t f o r e l o n g a t i o n and d e s a t u r a t i o n of to3 f a t t y a c i d s i n f i s h i s 22:6w3, w h i l e f o r a)6 f a t t y a c i d s , the end p o i n t i s 22:5OJ6. Thus, a greater degree of u n s a t u r a t i o n i s gained from the ix>3 c o n f i g u r a t i o n . 5 Fa t t y a c i d s of the w3, u)6, and u9 s e r i e s compete f o r enzyme s i t e s f o r e l o n g a t i o n and d e s a t u r a t i o n . The to3 f a t t y a c i d s have the greatest a f f i n i t y f o r enzyme s i t e s , and the u)9 f a t t y a c i d s the l e a s t (Lee and Sinnhuber 1972). L i t t l e i s known on the c o n t r o l of f a t t y a c i d s y n t h e s i s , although again, d i e t has some i n f l u e n c e . F a t t y a c i d s y n t h e s i s i s i n h i b i t e d when the d i e t a r y i n t a k e of l i p i d i s high or when energy i n t a k e i s r e s t r i c t e d . 6 MATERIALS AND METHODS I. Study Areas A. Qualicum River This r i v e r i s l o c a t e d on the east s i d e of Vancouver I s l a n d ( F i g . 1,2). Ri v e r f l o w i s c o n t r o l l e d by a gate at the o u t l e t of Home l a k e . The p h y s i c a l features of the r i v e r and d e t a i l s on flow c o n t r o l have been described by L i s t e r and Walker (1966). F i s h production i n the r i v e r i s augmented by a hatchery f a c i l i t y which i n c l u d e s a production-channel and an experimental rearing-channel f o r coho. B. Capilano R i v e r Located i n North Vancouver, B. C , t h i s 29 km long r i v e r drains i n t o Burrard I n l e t . A dam l o c a t e d 6 km from the mouth of the r i v e r marks the upper l i m i t of f i s h access. A hatchery f a c i l i t y i s l o c a t e d 0.5 km downstream from the dam. C. Keogh R i v e r This 30 km r i v e r d r a i n s i n t o Queen C h a r l o t t e S t r a i t ( F i g . 1,3). The p h y s i c a l features of the r i v e r have been described by Ward and Slaney (1979). The r i v e r supports a n a t u r a l run of steelhead. As w e l l , steelhead are r a i s e d i n net-pens l o c a t e d on O'Connor l a k e . I I . Rearing Conditions A. Qualicum Coho Salmon Coho salmon were r a i s e d i n a production-channel and a rearing-channel by employees of the Department of F i s h e r i e s and Oceans. Egg sources f o r these salmon were a d u l t coho that had returned to the r i v e r system i n the f a l l of 1977. Adult coho not trapped by a counting fence at the hatchery 7 were allowed to spawn n a t u r a l l y i n the r i v e r . Coho eggs were incubated i n Heath t r a y s u n t i l hatching. These f r y were then used to stock the production and the .rearing-channels. 1. Production-channel Coho salmon were reared i n a g r a v e l bottom channel l o c a t e d 1.2 km from the r i v e r mouth ( F i g . 2). Coho f r y were r a i s e d f o r three months ( A p r i l to J u l y , 1978) i n a concrete pond and then moved to the production-channel (750,000 f r y ) . Coho remained i n the channel u n t i l smolting ( l a t e May). F i s h were fed d a i l y w i t h Oregon Moist P e l l e t . During the winter (December to A p r i l ) feeding frequency was reduced depending on f i s h a c t i v i t y . 2. Rearing-channel The rearing-channel was l o c a t e d 4.5 km from the r i v e r mouth ( F i g . 2). The channel was constructed w i t h pools and r i f f l e s designed to mimic the p h y s i c a l f e a t u r e s of a n a t u r a l stream. Plywood f l o a t s were anchored i n the pools to provide cover f o r the coho. The channel was completely covered by n e t t i n g to reduce b i r d p r e d a t i o n . P h y s i c a l features of the channel are f u r t h e r described by Mundie and Mounce (1978). Coho f r y were introduced i n t o the channel i n l a t e A p r i l , 1978 and remained i n the f a c i l i t y u n t i l smolting i n June, 1979. F i s h were fed Oregon Moist P e l l e t every other day. P e l l e t s were introduced to the tops of the pools and allowed to d r i f t throughout the p o o l . I t was hoped that on days when p e l l e t s were not o f f e r e d , the f i s h would feed on i n v e r t e b r a t e d r i f t and benthos produced i n the channel r i f f l e s . P e l l e t s were fed l e s s f r e q u e n t l y during the winter depending on f i s h a c t i v i t y . F i s h movement up and down the channel was r e s t r i c t e d by aluminum fences to i n s u r e e f f i c i e n t usage of the channel. 8 B. Capilano Coho Salmon Coho were reared i n Burrows ponds by employees of the Department of F i s h e r i e s and Oceans. Eggs were taken from ad u l t coho that had returned to the r i v e r i n the f a l l of 1977. Eggs were incubated i n Heath t r a y s . Coho were moved to the Burrows ponds as f r y arid reared u n t i l smolting (June, 1979) on a d i e t of Oregon Moist P e l l e t . C. Keogh Steelhead Trout Steelhead were r a i s e d i n net-pens by employees of the F i s h and W i l d l i f e Branch. Nets were hung from f l o a t s and anchored to the bottom of O'Connor la k e ( F i g . 3). Net mesh s i z e v a r i e d from 0.6 to 1.0 cm depending on f i s h s i z e . Eggs were taken from a d u l t s trapped at the mouth of the Keogh r i v e r (March, 1978) and incubated i n wooden troughs. Parr were t r a n s f e r r e d to the pens by August, 1978. F i s h were fed d a i l y w i t h S i l v e r Cup, a dry d i e t . F i s h a l s o had the opportunity to feed on zooplankton produced i n the l a k e , although no measure of the amount of zooplankton eaten was a v a i l a b l e . Smolts were r e l e a s e d at the mouth of the r i v e r (May, 1979) a f t e r t r a n s p o r t by tank t r u c k . Rearing c o n d i t i o n s i n the three study areas are f u r t h e r described i n Table 1. Rearing areas were s i m i l a r i n mean annual water temperature but d i f f e r e d i n water v e l o c i t y and f i s h d e n s i t y . Burrows ponds had the lowest water v e l o c i t y but the highest f i s h d e n s i t y . . Water temperatures were not measured i n the Qualicum r i v e r . The rearing-channel water temperature would be a c l o s e estimate of the water temperature at the three sample s t a t i o n s i n the Qualicum r i v e r . 9 I I I . F i e l d Sampling A. Qualicum R i v e r 1. Production and Rearing-channel Coho Coho were sampled as f r y ( A p r i l , 1978), parr (August, 1978; January, 1979), presmolts ( A p r i l , 1979), and smolts (May, 1979). Fry were f i s h that had r e c e n t l y emerged from the g r a v e l . Parr demonstrated prominent bars of dark pigment (parr marks) extending above and below the l a t e r a l l i n e and were p h y s i o l o g i c a l l y adapted f o r l i f e i n f r e s h water. Presmolts had begun the parr-smolt transformation (some s i l v e r c o l o r a t i o n ) but s t i l l showed prominent p a r r marks. Smolts demonstrated the t y p i c a l s i l v e r c o l o r a t i o n (guanine d e p o s i t i o n ) w i t h dark f i n t i p s and were p h y s i o l o g i c a l l y adapted f o r l i f e i n sea water. Each sample c o n s i s t e d of f i s h taken from po i n t s along the e n t i r e lengths of the r e s p e c t i v e channels. F i s h were captured w i t h a dip net, transported l i v e to the l a b o r a t o r y at the main hatchery, and h e l d there u n t i l weighing. Sample s i z e v a r i e d w i t h the weight of the f i s h . 2. Qualicum R i v e r Coho Coho were c o l l e c t e d monthly over the p e r i o d May, 1978 to May, 1979. Several sample s t a t i o n s were u t i l i z e d . S t a t i o n number 1, l o c a t e d 7.8 km from the r i v e r mouth ( F i g . 2), was dominated by a l a r g e l o g jam which created 1.0 m to 3.0 m deep pools. Extensive cover was provided by logs and cutbanks. S t a t i o n number 2 was l o c a t e d 3.8 km from the r i v e r mouth ( F i g . 2). This s t a t i o n c o n s i s t e d of a s i n g l e l o g , running p a r a l l e l to the r i v e r bank, c r e a t i n g a 0.5 m deep pool . S t a t i o n number 3 was l o c a t e d i n the main r i v e r adjacent to the r e a r i n g channel ( F i g . 2). I t c o n s i s t e d of a 100.0 m long s t r e t c h of cutbanks and overhanging v e g e t a t i o n along both 10 sides of the r i v e r . Samples f o r the months of May to September, 1978 were c o l l e c t e d from s t a t i o n 1 and 2. S t a t i o n 2 was not u t i l i z e d a f t e r October, 1978 due to an increase i n r i v e r flow. The October, 1978 to January, 1979 samples were made up of f i s h caught p r i m a r i l y a t s t a t i o n 1. Samples f o r the months of February to A p r i l , 1979 were c o l l e c t e d at s t a t i o n s 1 and 3. F i s h were caught using a pole seine and s c i s s o r s net, when p o s s i b l e . A f t e r December, 1978 f i s h began u t i l i z i n g heavy cover under l o g d e b r i s and cutbanks. Nets were not s u i t a b l e i n t h i s type of h a b i t a t and sampling was completed by e l e c t r o s h o c k i n g . Smolts were c o l l e c t e d by anchoring a fyke net and l i v e box to the counting fence at the main hatchery (1.2 km from the r i v e r mouth). The net was f i s h e d f o r 24 hours May 31, 1979. F i s h were transported l i v e to the l a b o r a t o r y at the hatchery f o r weighing. 3. F i e l d Processing of Qualicum Coho I n d i v i d u a l weights and f o r k lengths were recorded a f t e r r o l l i n g the f i s h on an absorbant c l o t h . Pooled samples of f i s h were then placed i n p l a s t i c bags, i n f l a t e d w i t h n i t r o g e n gas, and sealed. Samples were shipped on dry i c e to the f i s h e r i e s l a b o r a t o r y , West Vancouver, B. C , where they were st o r e d at -27°C. Scales were taken from n a t u r a l l y - r e a r e d smolts f o r aging. 4. Aquatic Insects Insects were c o l l e c t e d from the rearing-channel using a Surber sampler (212 ym mesh). Samples were c o l l e c t e d i n A p r i l and June, 1979 from r i f f l e areas midway along the length of the channel. The P l e c o p t e r a sample was c o l l e c t e d from the Qualicum r i v e r i n a r i f f l e area adjacent to s t a t i o n 1. Samples were placed i n p l a s t i c bags, f i l l e d w i t h n i t r o g e n gas, and shipped 11 on dry i c e to the f i s h e r i e s l a b o r a t o r y i n West Vancouver. The samples were stored at -27°C u n t i l a n a l y s i s . B. Capilano R i v e r Hatchery coho smolts were c o l l e c t e d June 5, 1979 j u s t p r i o r to t h e i r r e l e a s e from the hatchery. The sample was c o l l e c t e d a f t e r the f i s h had been confined i n t o a small area of the pond. Wild smolts were caught June 1, 1979 as they migrated downstream. A fyke net and l i v e box was suspended i n the r i v e r adjacent to the hatchery, and f i s h e d f o r 72 hours. F i s h were weighed and measured at the Capilano hatchery and placed i n p l a s t i c bags i n f l a t e d w i t h n i t r o g e n gas. The f i s h were transported, on i c e , to the f i s h e r i e s l a b o r a t o r y i n West Vancouver, B. C. and stored at -27°C u n t i l a n a l y s i s . Scales were taken f o r aging. C. Keogh R i v e r Hatchery steelhead smolts were c o l l e c t e d May 10, 1979 j u s t p r i o r to t h e i r r e l e a s e from the net pens. Wild steelhead smolts were captured May 16 by a sampling fence l o c a t e d 200 m from the mouth of the r i v e r . F i s h were weighed and measured and then shipped frozen to the l a b o r a t o r y i n West Vancouver, B. C. There the samples were stored at -27°C u n t i l a n a l y s i s . Scales were c o l l e c t e d f o r aging. IV. Proximate A n a l y s i s A. F i s h Tissue A minimum of 30 g of f i s h t i s s u e was r e q u i r e d f o r proximate a n a l y s i s . Depending on the i n d i v i d u a l f i s h weights, 2-60 f i s h were pooled f o r a n a l y s i s . A n a l y s i s i n a l l cases was on the whole body. 12 F i s h were homogenized i n a Waring blender and weighed f r a c t i o n s removed f o r t o t a l n i t r o g e n , moisture, ash, and l i p i d determinations. Samples f o r t o t a l n i t r o g e n were wrapped i n weighing paper (nitrogen free) and stored at -27°C u n t i l enough samples had accumulated to permit e f f i c i e n t use of the autoanalyser. T o t a l n i t r o g e n was analysed using the A.O.A.C. method f o r crude p r o t e i n , as modified f o r a Technicon autoanalyser (A.O.A.C. 1975). Samples were digested and analysed using the Technicon I n d u s t r i a l Method number 369-75 A/A and 334-74 w/B, r e s p e c t i v e l y . T o t a l n i t r o g e n was m u l t i p l i e d by 6.25 to give crude p r o t e i n content. Samples f o r moisture determination were d r i e d f o r 24 hours at 105°C i n a g r a v i t y oven. Samples f o r ash determination were combusted f o r two hours at 600°C i n a muffle furnace. L i p i d s were e x t r a c t e d using a m o d i f i c a t i o n of the method of B l i g h and Dyer (1959). Samples taken during the p e r i o d May, 1978 to March, 1979 were e x t r a c t e d i n the f o l l o w i n g manner: A 20 g sample of homogenized t i s s u e was blended i n an omnimixer w i t h 10 ml of chloroform and 20 ml of methanol f o r two minutes. Ten ml of chloroform were added and blended a f u r t h e r 30 s. F i n a l l y , 9 ml of d i s t i l l e d water were added and blended f o r 30 s. The homogenate was f i l t e r e d through Whatman Number 1 f i l t e r paper, on a Buchner f u n n e l . The residue was washed w i t h a s o l u t i o n of 20 ml chloroform, 20 ml methanol and 9 ml d i s t i l l e d water, and f i l t e r e d again. This f i l t r a t e was then added to the o r i g i n a l . The f i l t r a t e was poured i n t o a volumetric f l a s k and allowed to separate i n t o two l a y e r s . The c a l c u l a t i o n of percent crude l i p i d was based on a 3 ml a l i q u o t of the chloroform l a y e r that was taken to dryness. In March, 1979,it was noted that t h i s m o d i f i c a t i o n was l e a v i n g 10-20% of the l i p i d i n the f i s h t i s s u e . The B l i g h and Dyer method was again 13 modified i n the f o l l o w i n g manner. A 20 g sample of homogenated t i s s u e was blended w i t h 30 ml chloroform and 60 ml of methanol i n an omnimixer fo r two minutes. T h i r t y ml of chloroform were added and blended f o r 30 s. Then, 25 ml of d i s t i l l e d water were added and blended f o r 30 s (B. Dosanjh, personal communication). The homogenate was f i l t e r e d through Whatman Number 1 f i l t e r paper on a Buchner f u n n e l , and the percent crude l i p i d determination c a r r i e d out as p r e v i o u s l y described. This m o d i f i c a t i o n performed w e l l when compared to the f i r s t B l i g h and Dyer method and the method of Folch et^ a l . (1957), and was used on a l l of the remaining samples. A c o r r e c t i o n f a c t o r , c a l c u l a t e d by comparing the two m o d i f i c a t i o n s of the B l i g h and Dyer method was a p p l i e d to samples analysed from May, 1978 to March, 1979. L i p i d s were stored i n the f o l l o w i n g manner. Bu t y l a t e d hydroxy-toluene was added to the l i p i d chloroform mixture (0.1% of the weight of l i p i d ) and then c e n t r i f u g e d f o r f i v e minutes at 5000 RPM i n a r e f r i g e r a t e d c e n t r i f u g e (-5°C). The l i p i d chloroform mixture was then poured i n t o s c i n t i l l a t i o n v i a l s and capped w i t h n i t r o g e n gas. The v i a l s were placed i n p l a s t i c bags, i n f l a t e d w i t h n i t r o g e n gas, and stored at -45°C. In a l l cases, l i p i d s were e x t r a c t e d from the f i s h and placed i n storage no more than one day a f t e r f i e l d sampling. B. Hatchery D i e t s D i e t s were analysed using procedures s i m i l a r to the f i s h samples. The B l i g h and Dyer method was used to e x t r a c t l i p i d , w i t h the appropriate m o d i f i c a t i o n s made to a l l o w f o r the lower moisture content i n hatchery d i e t s . V a r i a b i l i t y between d i e t batches was not a f a c t o r i n t h i s study. The d i e t batches sampled were fed to the f i s h f o r at l e a s t seven months p r i o r to smolting. 14 C. Aquatic Insects Only crude l i p i d was determined on aquatic i n s e c t s due to the small amount of t i s s u e a v a i l a b l e . Samples were washed through a 600 ym mesh screen and then q u i c k l y sorted i n t o i n s e c t types. The i n s e c t types u t i l i z e d were Ephemeroptera (146 animals), Chironomidae (337 ani m a l s ) , T r i c h o p t e r a (45 animals), and P l e c o p t e r a (4 animals). L i p i d s were ex t r a c t e d using the method of Fo l c h e_t a l . (1957) and stored i n the same manner as f i s h l i p i d . V. P h o s p h o l i p i d A n a l y s i s L i p i d s e x t r a c t e d from Qualicum coho presmolts and smolts, Capilano coho smolts, and Keogh steelhead smolts were analysed f o r phospholipid content using the method of Raheja et a l . (1973). Phosphatidyl c h o l i n e d i s t e a r o l y l (Serdary Research Laboratory, London, Ontario) was used as the phospholipid standard. Absorbance was measured at 710 nm w i t h a G i l f o r d 2400 spectr o -photometer equipped w i t h a red f i l t e r . P h o s p h o l i p i d content was expressed as a percent of the crude l i p i d , and as mg phospholipid/g wet t i s s u e . VI. F a t t y A c i d A n a l y s i s A. Methods F a t t y a c i d analyses were conducted on Qualicum coho smolts, Keogh steelhead smolts (four samples), hatchery d i e t s (one sample), and aquatic i n s e c t s (one sample). F i s h crude l i p i d ' w a s separated i n t o n e u t r a l and p o l a r l i p i d f r a c t i o n s using s i l i c i c a c i d column chromatography. S i l i c i c a c i d ( S i l i c a r CC-7) was sup p l i e d by M a l l i n c k r o d t Inc. Glass b a r r e l columns, 30 cm x 1 cm (l.D.) (Bio-Rad L a b o r a t o r i e s , M i s s i s s a u g a , Ontario) were used. N e u t r a l l i p i d s 15 were separated using ten column volumes of chloroform, w h i l e p o l a r l i p i d s were separated using ten column volumes of methanol. N e u t r a l and p o l a r l i p i d f r a c t i o n s were checked f o r cross-contamination using the method of Raheja et^ a l . (1973) f o r phospholipids and the method of Foster and Dunn (1973) f o r t r i g l y c e r i d e s . T r i o l e i n (Serdary Research Laboratory, London, Ontario) was used as the t r i g l y c e r i d e standard. F a t t y a c i d methyl e s t e r s of both n e u t r a l and p o l a r l i p i d f r a c t i o n s were prepared w i t h sodium methoxide as described by C h r i s t i e (1973). F a t t y a c i d methyl e s t e r s of hatchery d i e t s and aquatic i n s e c t s were prepared d i r e c t l y from whole l i p i d w i t h sodium methoxide. F a t t y a c i d methyl e s t e r s were separated and q u a n t i f i e d using a Hewlett Packard model 5830A gas chromatograph equipped w i t h a flame i o n i z a -t i o n d e tector. A 3.2 m x 1.8 mm s t a i n l e s s s t e e l column packed w i t h 10% Sp 2330 on 100/120 chromosorb W. was used. The c a r r i e r gas was n i t r o g e n (25 ml/min). A l l runs were isothermal w i t h an oven temperature of 175°C. The i n j e c t i o n port temperature was 220°C and the detector temperature was 270°C. Peak areas were c a l c u l a t e d a u t o m a t i c a l l y w i t h a Hewlett Packard model 18850A microprocessor. F a t t y a c i d methyl e s t e r s were i d e n t i f i e d by comparing the r e l a t i v e r e t e n t i o n times w i t h f a t t y a c i d methyl e s t e r standards supplied by Serdary Research Laboratory, London, Ontario. Compounds f o r which standards were not a v a i l a b l e were i d e n t i f i e d by semilog p l o t s of carbon number versus r e l a t i v e r e t e n t i o n time, or by s e p a r a t i o n f a c t o r s (Ackman, 1963). B. C a l c u l a t i o n s The content of i n d i v i d u a l f a t t y a c i d s was expressed i n two ways: as a percent of the f a t t y a c i d s which chromatographed, and as mg f a t t y a cid/g 16 wet t i s s u e . To make t h i s second c a l c u l a t i o n , two assumptions were r e q u i r e d : 1) that a l l of the n e u t r a l l i p i d f r a c t i o n c o n s i s t e d of t r i g l y c e r -i d e , and 2) that a l l of the p o l a r l i p i d f r a c t i o n c o n s i s t e d of p h o s p h o l i p i d . N e u t r a l l i p i d f r a c t i o n s were analysed f o r t r i g l y c e r i d e using the method of Foster and Dunn (1973) and the p o l a r l i p i d f r a c t i o n s were analysed f o r phos p h o l i p i d using the method of Raheja et a l . (1973). Not a l l of the weight of a pho s p h o l i p i d or t r i g l y c e r i d e molecule i s f a t t y a c i d . C o r r e c t i o n f a c t o r s as c a l c u l a t e d by C h r i s t i e (1973) were used to convert the weight of the t o t a l molecule to the weight of f a t t y acids present i n the molecule. The conversion f a c t o r s were 1.326 (based on phosphatidyl c h o l i n e d i o l e o y l ) f o r p h o s p h o l i p i d , and 0.996 (based on t r i o l e i n ) f o r t r i g l y c e r i d e . Thus, to c a l c u l a t e the weight of f a t t y acid/g wet t i s s u e the f o l l o w i n g c a l c u l a t i o n s were used: 1 % crude l i p i d p h o s p h olipid as a % of crude l i p i d 1.326 * 100 X 100 fo r the p o l a r l i p i d f r a c t i o n , and 1 % crude l i p i d . _ phospholipid as a % of crude l i p i d . 0.996 X 100 X U 100 ; f o r f a t t y a c i d s from the n e u t r a l l i p i d f r a c t i o n . The weight of f a t t y acid/g wet t i s s u e , i n the whole l i p i d was c a l c u l a t e d by t o t a l l i n g the weights f o r a l l of the va r i o u s f a t t y a c i d s i n the n e u t r a l and p o l a r f r a c t i o n s . By d i v i d i n g the weight of f a t t y acid/g wet t i s s u e of each of the va r i o u s types of whole l i p i d f a t t y a c i d s by the t o t a l weight of f a t t y a cids/g wet t i s s u e , the content of the va r i o u s types of f a t t y a c i d i n whole l i p i d could be expressed as a percent. The f a t t y a c i d composition was condensed i n t o s e v e r a l groupings. Saturates were those f a t t y a c i d s without double bonds. Monounsaturates were 17 those f a t t y a c i d s having one double bond. Polyunsaturated f a t t y a c i d s were those f a t t y acids having more than one double bond. F a t t y a c i d s w i t h more than one double bond, but w i t h the f i r s t double bond, at carbon 6 or carbon 3 (counting from the methyl end) were termed u)6 arid w3 f a t t y a c i d s r e s p e c t i v e l y . F a t t y a c i d s which were l i s t e d as unknown were not included i n these groupings. V I I . Data Handling and S t a t i s t i c a l A n a l y s i s C o n d i t i o n f a c t o r , used as a measure of the r e l a t i o n s h i p between weight and l e n g t h : was c a l c u l a t e d as: 3 25 wet weight g / ( f o r k length cm) * x 1000 (Vanstone and Markert 1968). Computer programs, developed at the U n i v e r s i t y of B. C. Computing Centre, and the U n i v e r s i t y of B. C. Bio s c i e n c e s Data Centre were used f o r data a n a l y s i s . Data were subjected to a n a l y s i s of variance (program ANVAR), and then Scheffe's t e s t , to detect d i f f e r e n c e s between means. There were s e v e r a l cases where, according to B a r t l e t t ' s t e s t , the assumption of homogeneity of vari a n c e was v i o l a t e d . K r u s k a l W a l l i s t e s t and T - t e s t , when a p p l i e d to these cases r e s u l t e d i n the same co n c l u s i o n as the a n a l y s i s of variance. Therefore, i t was assumed that the a n a l y s i s of variance was robust and the heterogeneity of variance was ignored. V I I I . F i s h Health Qualicum coho p a r r , from the production-channel and rearing-channel, and n a t u r a l smolts were inspected by the D i a g n o s t i c S e r v i c e , P a c i f i c B i o l o g i c a l S t a t i o n , Nanaimo, B. C. No b a c t e r i a l or v i r a l diseases were encountered i n w i l d smolts nor were the smolts h e a v i l y p a r a s i t i z e d . W ild smolts had l e s s adipose t i s s u e than that normally found i n c u l t u r e d smolts. 18 There were some signs of s t r e s s i n c l u d i n g clubbing and edema of g i l l l a m e l l a e , and eye c a t a r a c t s . These symptoms were most l i k e l y a r e s u l t of the capture and ho l d i n g methods. No b a c t e r i a l diseases were encountered i n rearing-channel or production-channel coho p a r r . In the rearing-channel p a r r , 27% of the f i s h sampled contained e i t h e r Myxidium (myxosporidian p a r a s i t e ) or Cryptobia ( b i f l a g e l l a t e d protozoan). In the production-channel coho the incidence of these two p a r a s i t e s was 6.0%. The prognosis of i n f e c t e d f i s h i s unknown (G. Hoskins, personal communication). 19 RESULTS I. Length, Weight, and C o n d i t i o n Factor A. Coho Salmon from the Qualicum River Production-channel presmolts were s i g n i f i c a n t l y l a r g e r than r e a r i n g -channel or w i l d presmolts both i n le n g t h and weight (Table 2). Rearing-channel and w i l d presmolts a l s o d i f f e r e d i n s i z e w i t h the rearing-channel presmolts s i g n i f i c a n t l y l a r g e r . Production-channel smolts had the l a r g e s t l e n g t h and weight. There were only s l i g h t d i f f e r e n c e s i n s i z e between rearing-channel and n a t u r a l l y -reared smolts. Wild presmolts and smolts had higher c o n d i t i o n f a c t o r s than production-channel coho (Table 2). Rearing-channel smolts had the highest c o n d i t i o n f a c t o r followed by w i l d and then production-channel smolts. Qualicum coho le n g t h s , weights, and c o n d i t i o n f a c t o r s were measured at three-month i n t e r v a l s over the p e r i o d May, 1978 to May, 1979. Production-channel coho maintained the l a r g e s t length and weight during t h i s p e r i o d ( F i g . 5,6). Wild coho remained the smallest i n le n g t h and weight w i t h the rearing-channel coho intermediate i n s i z e . D i f f e r e n c e s i n s i z e apparent at the l a t e f r y stage tended to increase as the f i s h grew to the smolt stage. In a l l f i s h groups, c o n d i t i o n f a c t o r s decreased between May, 1978 and May, 1979 ( F i g . 7). There was no c o n s i s t e n t r e l a t i o n s h i p between the three groups of f i s h during the e n t i r e p e r i o d . However, as the f i s h approached the smolt stage, the c o n d i t i o n f a c t o r of production-channel and w i l d coho d e c l i n e d sharply w h i l e that of the rearing-channel coho increased. 20 B. Coho Salmon from the Capilano R i v e r Hatchery smolts were s i g n i f i c a n t l y longer than the w i l d coho i n f o r k l e n g t h (Table 2). There were, however, no d i f f e r e n c e s i n wet weight. Consequently, the hatchery smolts had a lower c o n d i t i o n f a c t o r . Wild Capilano smolts were s l i g h t l y l a r g e r than the Qualicum smolts i n l e n g t h and weight. This i s no doubt a r e s u l t of the greater number of two-year-old smolts i n the Capilano system. Capilano smolts were much slimmer than the Qualicum smolts as i n d i c a t e d by the lower c o n d i t i o n f a c t o r . C. Steelhead Trout from the Keogh River Wild and pen-reared steelhead were s i m i l a r i n l e n g t h , weight, and c o n d i t i o n f a c t o r (Table 2). I I . Proximate Composition Proximate composition has been expressed as a percent of the wet t i s s u e , the dry t i s s u e , and the l i p i d - f r e e dry t i s s u e . Expressing the data only as a percent of wet t i s s u e or dry t i s s u e would tend to mask d i f f e r e n c e s i n ash and p r o t e i n i f the f i s h v a r i e d i n moisture or l i p i d . Since the f i s h i n t h i s study d i f f e r e d i n moisture and l i p i d , a l l three methods of expressing the data were used. Phos p h o l i p i d and f a t t y a c i d content were only expressed as a percent of the wet t i s s u e , s i n c e d i f f e r e n c e s i n moisture content i n coho and steelhead smolts were not l i k e l y to mask the very l a r g e d i f f e r e n c e s i n l i p i d . A. Coho Salmon from the Qualicum River 1. Presmolts and Smolts When expressed as a percent of the wet t i s s u e , w i l d presmolts were s i g n i f i c a n t l y higher i n moisture but lower i n p r o t e i n and l i p i d than the production-channel presmolts (Table 3). There were no d i f f e r e n c e s i n ash 21 content. Wild smolts a l s o had higher moisture and lower l i p i d than production-channel smolts; d i f f e r e n c e s i n p r o t e i n , however, were s l i g h t . Rearing-channel and w i l d smolts were s i m i l a r i n moisture and l i p i d . P r o t e i n i n the rearing-channel smolts was s i g n i f i c a n t l y lower than e i t h e r the production-channel or w i l d smolts. Ash content i n the three groups of smolts was s i m i l a r . When expressed as a percent of the dry t i s s u e , s e v e r a l other d i f f e r -ences i n composition were evident (Table 4). Wild presmolts and smolts were s i g n i f i c a n t l y higher than the production-channel coho i n ash and p r o t e i n , w h i l e l i p i d was again s i g n i f i c a n t l y lower. Rearing-channel presmolts and smolts remained intermediate i n dry t i s s u e composition. When expressed as a percent of the l i p i d - f r e e dry t i s s u e , few s i g n i f i c a n t d i f f e r e n c e s i n ash or p r o t e i n were noted between n a t u r a l l y and a r t i f i c i a l l y - r e a r e d coho (Appendix t a b l e 4). Thus i t appears that the d i f f e r e n c e s i n ash and p r o t e i n (% dry t i s s u e ) were merely p r o p o r t i o n a l d i f f e r e n c e s r e s u l t i n g from the lower l i p i d content i n w i l d coho. Therefore, d i f f e r e n c e s i n proximate composition were confined to moisture and l i p i d . 2. Fry and Par r Wild f r y and parr were higher i n moisture and lower i n l i p i d and p r o t e i n than production-channel f r y ( F i g . 8-11). These d i f f e r e n c e s were maintained and i n some cases p r o g r e s s i v e l y increased to the smolt stage. There were no d i f f e r e n c e s i n ash content. Over the p e r i o d May, 1978 to January, 1979 the composition of the rearing-channel coho was more l i k e that of the production-channel coho than the w i l d coho. A f t e r January, however, the composition of the rearing-channel coho approached that of the 22 w i l d coho. The p a t t e r n was the same when the data were expressed as a percent of dry t i s s u e except that ash and p r o t e i n remained higher i n w i l d coho than production-channel coho (Appendix t a b l e s 1-3). B. Coho Salmon from the Capilano R i v e r Wild smolts had a higher moisture content (% wet t i s s u e ) but lower l i p i d than hatchery smolts (Table 3). There were no d i f f e r e n c e s i n ash or p r o t e i n . The composition of the dry t i s s u e of w i l d smolts was higher than the hatchery smolts i n ash and p r o t e i n but lower i n l i p i d (Table 4 ) . As i n the Qualicum coho, there were no d i f f e r e n c e s i n ash and p r o t e i n when expressed as a percent of the l i p i d - f r e e dry t i s s u e (Appendix t a b l e 4). D i f f e r e n c e s between w i l d and hatchery coho were thus confined to moisture and l i p i d . C. Steelhead Trout from the Keogh R i v e r The composition of the steelhead smolts d i d not f i t the p a t t e r n observed i n w i l d and hatchery coho. The only d i f f e r e n c e s Were i n l i p i d content, but i t was the w i l d smolts w i t h the highest l i p i d content (Table 3-4, Appendix t a b l e 4). D. Seasonal Changes i n Qualicum Coho Monthly v a r i a t i o n s i n proximate composition f o r w i l d Qualicum coho are summarized i n F i g . 8-11. Seasonal changes were not s t r i k i n g . There was a gradual d e c l i n e i n moisture over the p e r i o d May to November, 1978 w i t h an i n c r e a s e to A p r i l , 1979. Ash content increased g r a d u a l l y from 1.5% i n May, 1978 to 2.5% i n May, 1979. There was l i t t l e change i n p r o t e i n or l i p i d over w i n t e r ; however, there were major a l t e r a t i o n s i n proximate composition at the f r y and smolt stages of the l i f e h i s t o r y . At the f r y stage, p r o t e i n increased sharply during the p e r i o d May to 23 August, 1978, w h i l e l i p i d decreased. Expressing the data as a percent of the l i p i d - f r e e dry t i s s u e revealed a constant p r o t e i n content of 84.1 to 85.9% (May-August, 1978). Thus, the increase i n p r o t e i n (% wet t i s s u e ) i s a p r o p o r t i o n a l one only, r e s u l t i n g from changes i n l i p i d content. Comparing presmolts and smolts, moisture d e c l i n e d and l i p i d increased i n a l l three f i s h groups. P r o t e i n increased between w i l d and production-channel presmolts and smolts (% wet t i s s u e ) although again the changes i n p r o t e i n are l i k e l y p r o p o r t i o n a l as there was l i t t l e change i n p r o t e i n on a dry t i s s u e b a s i s (Table 4). In summary, the greatest seasonal v a r i a t i o n s i n proximate composition are i n moisture and l i p i d . E. Aquatic Insects and Hatchery D i e t s Due to the small amount of i n s e c t t i s s u e a v a i l a b l e f o r proximate composition, only the l i p i d content could be determined. P l e c o p t e r a , Chironomidae and T r i c h o p t e r a were s i m i l a r i n l i p i d content (Table 5). The l i p i d content i n Ephemeroptera was approximately double that of the other i n s e c t groups. S i l v e r Cup, a dry d i e t , had a much lower moisture content than Oregon Moist P e l l e t (Table 5). On a dry weight b a s i s the hatchery d i e t s were s i m i l a r i n ash and p r o t e i n content. L i p i d content itt S i l v e r Cup (12.98%) was lower than i n Oregon Moist P e l l e t (18.31%). Expressed on a wet weight b a s i s , the l i p i d content i n the hatchery d i e t s was much higher than the l i p i d content i n aquatic i n s e c t s . 24 I I I . P h o s p h o l i p i d Content P h o s p h o l i p i d content was expressed as a percentage of the crude l i p i d and as mg phospholipid/g wet t i s s u e . As." the crude l i p i d content i n f i s h t i s s u e i n c r e a s e d , the percentage makeup of ph o s p h o l i p i d decreased (Table 3). Thus w i l d coho smolts from the Qualicum and Capilano r i v e r s had s i g n i f i c a n t l y higher percentage contents of phospholipid than hatchery smolts. Pen-reared steelhead from the Keogh r i v e r had a s i g n i f i c a n t l y higher percentage content of p h o s p h o l i p i d than the w i l d steelhead smolts. With one exception, the weight of phospholipid/g wet t i s s u e was s i m i l a r i n hatchery and w i l d coho, and pen-reared and w i l d steelhead. Steelhead as a group had l e s s p h o s p h o l i p i d than the coho. Changes i n ph o s p h o l i p i d content during smolting were s l i g h t . IV. F a t t y A c i d Composition A. I n d i v i d u a l F a t t y A c i d Composition 1. F i s h I n d i v i d u a l f a t t y a c i d s were expressed as a percentage of the t o t a l amount of f a t t y a c i d s , and as a weight of f a t t y a c id/g wet t i s s u e . G e n e r a l l y , the same f a t t y a c i d s were present i n a l l of the f i s h samples; however, there were s u b s t a n t i a l d i f f e r e n c e s i n the amounts of the various f a t t y a c i d s . i . Coho Smolts from the Qualicum R i v e r On a percentage b a s i s , production-channel and rearing-channel smolts were much higher i n 20:lu)9 and 22:1OJ9 (Table 6-8). Wild smolts had only t r a c e amounts of 22:1OJ9. The oi6 f a t t y a c i d s were stored p r i m a r i l y i n the form of 18:2u6 and 20:4w6. The content of 18:2co6 was always higher i n n e u t r a l l i p i d , w h i l e the content of 20:4w6 was higher i n p o l a r l i p i d . 25 The 18:2w6 content was highest i n the production-channel n e u t r a l and whole l i p i d w i t h only s l i g h t d i f f e r e n c e s .in p o l a r content. On the other hand, w i l d smolts were highest i n 20:4oi6 content, i n n e u t r a l and p o l a r l i p i d . F a t t y a c i d s of the u)3 s e r i e s were stored i n the form of 18:3o>3, 20:5CJ3, 22:5a)3, and 22:6w3. F a t t y a c i d s of the u)3 s e r i e s were u s u a l l y higher i n p o l a r l i p i d than n e u t r a l l i p i d . The content of 18:3co3, 20:5w3, and 22:5w3 was highest i n w i l d smolts. Production and rearing-channel smolts were s i m i l a r i n 18:3u)3, 20:5OJ3, and 22:6a>3 content. Considerable d i f f e r e n c e s were found i n the content of 22:6a>3, the form i n which most of the w3 f a t t y a c i d s were stored. The 22:6w3 content i n w i l d smolt n e u t r a l l i p i d was 2.2 times that of the production .or rearing-channel smolts. However, i n p o l a r l i p i d , the production-channel smolts had the highest 22:6w3 content, w i t h s i m i l a r amounts i n the rearing-channel and w i l d smolts. F a t t y a c i d content was a l s o expressed as a weight/g wet t i s s u e . This c a l c u l a t i o n assumed that n e u t r a l l i p i d c o n s i s t e d e n t i r e l y of t r i a c y l g l y c e r o l and that p o l a r l i p i d c o n s i s t e d e n t i r e l y of phospholipid. The a c t u a l t r i a c y l g l y c e r o l content i n n e u t r a l l i p i d was 85% w h i l e the phospholipid content of p o l a r l i p i d was 90%. The weight of 20:lco9 and 22:lw9 was much higher i n production and rearing-channel coho, w i t h the greatest d i f f e r ^ -ences o c c u r r i n g i n n e u t r a l and whole l i p i d (Table 6-8). Concerning the w6 f a t t y a c i d s , 18:2oo6 was highest i n production channel n e u t r a l and whole l i p i d w i t h l i t t l e d i f f e r e n c e i n the p o l a r l i p i d content. The 20:4u>6 content was highest i n w i l d smolts n e u t r a l , p o l a r and whole l i p i d . In the w3 f a t t y a c i d s , the 18:3o>3 content of n e u t r a l and p o l a r l i p i d was highest i n w i l d smolts. A l l three groups of f i s h were s i m i l a r i n 20:5w3 and 22:5o)3 w i t h the exception of lower 22:5o)3 i n n e u t r a l l i p i d of rearing-channel coho. 26 Production-channel and w i l d smolts were s i m i l a r i n 22:6u3 content of n e u t r a l l i p i d , w h i l e the content i n n e u t r a l l i p i d of rearing-channel coho was h a l f that of the other two groups. The content of 22:6w3 i n w i l d smolt p o l a r l i p i d was s l i g h t l y lower than the other two groups, i i . Steelhead Smolts from the Keogh R i v e r As i n the coho smolts, there was more 18:2w6 i n n e u t r a l l i p i d and more 20:4oi6- and 22:6aBin p o l a r l i p i d (Table 9,10). There were n o t i c e a b l e d i f f e r e n c e s i n u)6 f a t t y a c i d content of pen-reared and w i l d smolts. The percentage content of 18:2o)6 i n pen-reared smolts was nine times that of the w i l d smolts. There were l a r g e d i f f e r e n c e s i n 18:2u)6 on a weight b a s i s as w e l l . D i f f e r e n c e s i n 20:4w6 were not as s t r i k i n g as i n 18:2w6. The 18:3co3 percentage content of pen-reared smolts was twice that of w i l d smolts. In c o n t r a s t the 20:5w3 and 22:5w3 content i n w i l d smolt n e u t r a l and p o l a r l i p i d was higher than the pen-reared smolts. The n e u t r a l l i p i d content of 22:6w3 was much higher i n w i l d smolts, both on a percent and a weight b a s i s ; however, the p o l a r l i p i d content was s i m i l a r . 2. Aquatic Insects and Hatchery D i e t s Ephemeroptera and T r i c h o p t e r a were s i m i l a r ' i n f a t t y a c i d content (Table 11). P l e c o p t e r a d i f f e r e d from these two groups i n having a lower content of 16:lw7 but a higher content of 18:1OJ9 and 18:3CJ3. Chironomidae were much higher i n 18:2co6 content but lower i n 18:3co3 content. In a l l of the i n s e c t groups, the u)6 f a t t y a c i d s were stored p r i m a r i l y i n the form of 18:2w6 w h i l e the to 3 f a t t y a c i d s were stored as 18:3(JO3 and 20:5w3. The 22:6w3 content was very low. The two hatchery d i e t s were very d i f f e r e n t i n f a t t y a c i d content (Table 11). The S i l v e r Cup d i e t was higher i n 16:0, 18:2OJ6, 18:3w3, and 27 22:6o>3 but much lower i n 16:lu)7, 20:lo)9, and 22:lo)9. F a t t y a c i d s of the 0)6 s e r i e s were i n the form of 18:2u>6 wh i l e the o>3 f a t t y a c i d s were i n the form of 20:5o)3 and 22:6o)3. There was very l i t t l e 18:3o>3 i n Oregon Moist P e l l e t . In comparison w i t h the aquatic i n s e c t s , the hatchery d i e t s were lower i n 18:3u)3 but higher i n 20:lo>9, 22:lu)9, and 22:6oi3. S i l v e r Cup was much higher than the i n s e c t groups i n 18:2o>6. 3. Comparison-of ,.the-Diet'.'..and• the F i s h Composition As noted i n the previous s e c t i o n , the hatchery d i e t s were c h a r a c t e r i s -t i c a l l y d i f f e r e n t i n s e v e r a l f a t t y a c i d s . These d i f f e r e n c e s were a l s o evident i n the f a t t y a c i d composition of the hatchery f i s h . Oregon Moist P e l l e t was very high i n 20:lo)9 and 22:lo>9. Production and rearing-channel coho, fed Oregon Moist P e l l e t , had h i g h contents of these two f a t t y a c i d s . The high 18:2o)6 i n S i l v e r Cup was r e f l e c t e d by the 18:2oi6 content i n pen-reared steelhead. Rearing-channel coho had the opportunity to feed on aquatic i n s e c t s as w e l l as Oregon Moist P e l l e t . U nfortunately, there were no d i s t i n c t i v e f eatures i n the f a t t y a c i d composition of the aquatic i n s e c t s , thus, the i n f l u e n c e of these i n s e c t s on the composition of r e a r i n g -channel coho could not be evaluated. B. F a t t y A c i d Class Composition I n d i v i d u a l f a t t y a c i d s were c l a s s i f i e d according to t h e i r degree and type of u n s a t u r a t i o n as s a t u r a t e d , monounsaturated, polyunsaturated, o)6, and 0)3 f a t t y a c i d s . 28 1. F i s h i . Coho Smolts from the Qualicum River The g r e a t e s t d i f f e r e n c e s i n f a t t y a c i d c l a s s composition were found i n n e u t r a l and whole l i p i d . When the composition was c a l c u l a t e d as a percent-age, the w i l d smolts were higher than the production-channel smolts i n sa t u r a t e d , polyunsaturated, and u>3 f a t t y a c i d s , but lower i n 0)6 and monounsaturated f a t t y a c i d s ( F i g . 12-16). Expressed as a weight/g wet t i s s u e , the saturated, monounsaturated, polyunsaturated, and o)6 f a t t y a c i d s were lower i n w i l d smolts. Production-channel smolts had the highest u6 and polyunsaturated f a t t y a c i d content. The n e u t r a l and whole l i p i d content of rearing-channel smolts was i n most cases intermediate i n f a t t y a c i d c l a s s composition. P o l a r l i p i d f r a c t i o n s were s i m i l a r i n composition w i t h the exception of s l i g h t l y higher percentage o>6 f a t t y a c i d content i n w i l d smolts. The r a t i o of co6/w3 f a t t y a c i d s was s i g n i f i c a n t l y higher i n production-channel n e u t r a l and whole l i p i d ( F i g . 17). In p o l a r l i p i d , the r a t i o was s i g n i f i c a n t l y higher i n the w i l d smolts. i i . Steelhead Smolts from the Keogh River Expressed as a percent, the monounsaturated, polyunsaturated, and u>3 f a t t y a c i d content of n e u t r a l and whole l i p i d i n w i l d smolts was s i g n i f i -c a n t l y higher than that of the pen-reared smolts. Wild smolts were lower i n saturated and w6 f a t t y a c i d s ( F i g . 18-22). There were d i f f e r e n c e s i n the p o l a r l i p i d content as w e l l , w i t h the w i l d smolts higher than the pen-reared smolts i n monounsaturated and co3 f a t t y a c i d s , but lower i n polyun-saturated and w6 f a t t y a c i d s . On a weight b a s i s , w i l d smolt n e u t r a l and whole l i p i d f r a c t i o n s were higher i n s a t u r a t e d , monounsaturated, u)3, and polyunsaturated f a t t y a c i d s 29 but much lower i n 0)6 f a t t y a c i d s . The p o l a r l i p i d f r a c t i o n of w i l d smolts was much lower i n o>6 f a t t y a c i d s than the pen-reared smolts. The r a t i o of o)6/o>3 f a t t y a c i d s was s i g n i f i c a n t l y higher i n pen-reared smolts f o r a l l of the l i p i d f r a c t i o n s ( F i g . 17). 2. Aquatic Insects and Hatchery D i e t s Ephemeroptera, P l e c o p t e r a , and T r i c h o p t e r a were s i m i l a r i n f a t t y a c i d c l a s s composition (Table 12). Chironomidae was higher i n oi6 but lower i n 0)3 f a t t y a c i d s than the other i n s e c t groups, and thus, the r a t i o of oi6/o)3 f a t t y a c i d s f o r Chironomidae was much higher. The Oregon Moist P e l l e t d i e t was higher than the S i l v e r Cup d i e t i n monounsaturated f a t t y a c i d s but lower i n saturated, polyunsaturated, 0)6, and o)3 f a t t y a c i d s (Table 12). Neither hatchery d i e t was p a r t i c u l a r l y s i m i l a r to the i n s e c t groups. The most outstanding d i f f e r e n c e s were i n the monounsaturated and 0)6 f a t t y a c i d s . Oregon Moist P e l l e t was much higher than the aquatic i n s e c t s i n monounsaturates w h i l e S i l v e r Cup was higher i n o>6 f a t t y a c i d s . 3 . Comparison of the Diet and the F i s h Composition Hatchery d i e t s were d i s t i n c t i v e l y d i f f e r e n t i n t h e i r content of monounsaturated (Oregon Moist P e l l e t ) and o)6 ( S i l v e r Cup) f a t t y a c i d s . D i f f e r e n c e s were a l s o observed i n the f i s h fed these d i e t s . Rearing-channel and production-channel coho when fed Oregon Moist P e l l e t were high i n monounsaturated f a t t y a c i d content. Pen-reared steelhead, fed S i l v e r Cup, were high i n o>6 f a t t y a c i d s . As w i t h the composition of i n d i v i d u a l f a t t y a c i d s , there were no d i s t i n c t i v e f eatures i n the f a t t y a c i d c l a s s composition of aquatic i n s e c t s which would a l l o w t h e i r i n f l u e n c e i n r e a r i n g -channel coho to be evaluated. 30 V. Age of the Smolts Hatchery coho from the Qualicum and Capilano r i v e r s , and w i l d coho from the Qualicum r i v e r smolted at the age of 1+ years. Wild coho smolts from the Capilano r i v e r v a r i e d i n age from 1+ to 2+, w i t h 73% of the f i s h smolting at age 1+. Keogh r i v e r steelhead, reared i n net pens, smolted at the age of one year. Wild steelhead smolts ranged i n age from three to four years. Data c o l l e c t e d by the F i s h and W i l d l i f e Branch suggest that 75% of the w i l d steelhead smolts are age three (P. Slaney, personal communication). 31 DISCUSSION Having i d e n t i f i e d the morphological and biochemical d i f f e r e n c e s i n w i l d and hatchery salmonids, p a r t I of the d i s c u s s i o n w i l l consider the e f f e c t of r e a r i n g c o n d i t i o n s on f i s h morphology and biochemistry. The impact of these morphological and biochemical d i f f e r e n c e s on marine s u r v i v a l w i l l be considered i n part I I . I. I nfluence of Rearing Conditions on Morphology and Biochemistry A. Length, Weight, and C o n d i t i o n Factor Hatchery coho were longer and heavier than the w i l d coho (Table 2 ) . D i f f e r e n c e s i n length and weight were evident at the f r y stage and maintained throughout the freshwater p o r t i o n of the l i f e h i s t o r y . A r t i f i -c i a l r e a r i n g of coho (Vanstone and Markert 1968) , pink salmon ( B a i l e y e_t a l . 1976), and h e r r i n g ( B a l b o n t i n j i t a l . 1973) r e s u l t e d i n f i s h that were l a r g e r i n length and weight than the w i l d f i s h . At l e a s t f o r the coho and pink salmon, the f i s h were of s i m i l a r age and genetic background. E v i d e n t l y , the abundant food supply and favourable r e a r i n g c o n d i t i o n s r e s u l t e d i n high growth r a t e s f o r hatchery-reared f i s h . The s i z e s i m i l a r i t y of w i l d and rearing-channel coho appears to be a r e f l e c t i o n of the semi-n a t u r a l c o n d i t i o n s i n the rearing-channel. Some of the sampling methods used i n t h i s study were probably s i z e s e l e c t i v e . Dip nets used f o r sampling rearing-channel, production-channel, and Burrows pond coho would tend to s e l e c t f o r smaller f i s h w h i l e e l e c t r o s h o c k i n g used f o r sampling w i l d coho would tend to s e l e c t f o r l a r g e r f i s h . Thus, the d i f f e r e n c e s i n s i z e between w i l d and c u l t u r e d coho are l i k e l y to be s l i g h t l y underestimated. Pen-reared steelhead were very 32 uniform i n s i z e , t h e r e f o r e , s i z e s e l e c t i o n would not be a problem. Wild coho and steelhead smolts were c o l l e c t e d w i t h fyke nets or downstream t r a p s . These methods would not be s i z e s e l e c t i v e . The growth r a t e of w i l d Qualicum coho from presmolt to smolt was e x c e p t i o n a l at 1.92% body weight per day ( F i g . 6). This growth r a t e f o r w i l d coho i s not without precedent as Vanstone and Markert (1968) recorded a growth r a t e of 4.4% body weight per day f o r coho smolts. Both of the above growth r a t e s occurred subsequent to a winter p e r i o d of low water temperatures and decreased food a v a i l a b i l i t y . In the l a b o r a t o r y , salmon, p r e v i o u s l y fed a reduced r a t i o n , have a l s o demonstrated a very high growth r a t e upon resumption of normal feeding ( G r i f f i o e n and Narver. 1974). Co n d i t i o n f a c t o r s were lower i n c u l t u r e d than i n w i l d coho. Con d i t i o n f a c t o r , at l e a s t f o r some f i s h , i s a measure of body shape and body energy reserves such that f i s h w i t h a s t o u t e r shape and/or increased energy reserves have higher c o n d i t i o n f a c t o r s ( B l a x t e r 1975). However, i n t h i s study c o n d i t i o n f a c t o r was not a r e l i a b l e measure of body energy reserves as w i l d coho had the highest c o n d i t i o n f a c t o r but the lowest l i p i d content. Although the higher c o n d i t i o n f a c t o r i n w i l d coho may represent d i f f e r e n c e s i n f i s h shape, any f a c t o r which increases f i s h weight to a greater extent than f i s h l ength w i l l i ncrease the c o n d i t i o n f a c t o r . Therefore, the greater moisture content i n w i l d coho could a l s o account f o r t h e i r higher c o n d i t i o n f a c t o r . B. Proximate Composition 1. Comparisons of N a t u r a l l y a n d • A r t i f i c i a l l y - r e a r e d ' F i s h In 'this study, n a t u r a l l y - r e a r e d smolts were higher i n moisture and lower i n l i p i d than the a r t i f i c i a l l y - r e a r e d smolts (Table 3). On a dry 33 t i s s u e b a s i s , w i l d coho were higher than the c u l t u r e d coho i n ash and p r o t e i n (Table 4 ) , although few d i f f e r e n c e s were apparent on a l i p i d - f r e e dry t i s s u e b a s i s . Proximate compositions of w i l d and c u l t u r e d f i s h have been compared f o r rainbow t r o u t (Papoutsoglou and Papaparaskeva-Papoutsoglou 1978), brook t r o u t ( P h i l l i p s et a l . 1957), salmon (Wood et a l . 1957), and p l a i c e (Cowey and Sargent 1972). In a l l of these s t u d i e s , w i l d f i s h were higher i n p r o t e i n and ash and lower i n l i p i d (% dry t i s s u e ) than the c u l t u r e d f i s h . However, when the data of Papoutsoglou and Papaparaskeva-Papoutsoglou (1978), P h i l l i p s et a l . (1957) and Cowey and Sargent (1972) were expressed as a percent of the l i p i d - f r e e dry t i s s u e , d i f f e r e n c e s i n p r o t e i n and ash between w i l d and c u l t u r e d f i s h were very much reduced. The data from Wood e_t a l . (1957) could not be converted to a l i p i d - f r e e dry t i s s u e b a s i s s i n c e salmon moisture contents were not given. Thus i t appears that the major d i f f e r e n c e s i n proximate composition between w i l d and c u l t u r e d f i s h are confined to moisture and l i p i d . Most of the s t u d i e s comparing proximate composition i n w i l d and c u l t u r e d f i s h have been made on a s i n g l e l i f e h i s t o r y stage. This study compared the f i s h throughout the freshwater p o r t i o n of the l i f e h i s t o r y r e v e a l i n g that d i f f e r e n c e s i n proximate composition were evident at a very e a r l y age ( F i g . 8-11). The higher moisture content i n w i l d coho i s explained by the i n v e r s e r e l a t i o n s h i p between body l i p i d and moisture (Love 1970). Thus, the higher moisture i n w i l d than c u l t u r e d coho was a r e s u l t of the low l i p i d content i n w i l d coho. Body l i p i d i s i n f l u e n c e by many f a c t o r s i n c l u d i n g water temperature ( B r e t t et a l . 1969), r a t i o n l e v e l ( B r e t t et a l . 1969), and d i e t composition 34 (Ogino at a l . 1976). The i n f l u e n c e of water temperature depends on the r a t i o n l e v e l at which the f i s h are being fed. At a r a t i o n l e v e l of 3% of the dry body weight per day, i n c r e a s i n g the water temperature from 5 to 10°C r e s u l t e d i n a 30% decrease i n sockeye body l i p i d ( B r e t t et a l . 1969). However, at the maximum d i e t a r y food i n t a k e , i n c r e a s i n g water temperature from 5 to 10°C r e s u l t e d i n only a 7% decrease i n l i p i d . Ration l e v e l i s p o s i t i v e l y c o r r e l a t e d w i t h body l i p i d ( B r e t t at a l . 1969) as i s the l i p i d content of the d i e t (Ogino et al. 1976). Increasing the r a t i o n l e v e l or d i e t a r y l i p i d content w i l l i ncrease the body l i p i d . In the present study, water temperature, r a t i o n l e v e l , and d i e t composition f o r w i l d and c u l t u r e d f i s h d i f f e r e d i n the f o l l o w i n g manner. Where measured, the mean annual water temperature f o r n a t u r a l l y and a r t i f i c i a l l y - r e a r e d f i s h was- s i m i l a r (Table 1). Ration l e v e l s , although not measured f o r w i l d f i s h are l i k e l y to be lower than f o r c u l t u r e d f i s h . Cultured f i s h are fed to excess at a l l times of the year. When food i s p l e n t i f u l , w i l d f i s h may a l s o feed to s a t i a t i o n ; however, on an annual b a s i s , the r a t i o n s i z e f o r hatchery f i s h would l i k e l y be higher. Wild and hatchery f i s h d i e t s d i f f e r e d i n composition. Aquatic i n s e c t s (Ephemerop-t e r a , P l e c o p t e r a , Chironomidae, Trichoptera) were much lower than the hatchery d i e t s i n l i p i d (% wet weight). The r e l a t i v e c o n t r i b u t i o n of these i n s e c t groups to the coho d i e t was not measured; however, st u d i e s by Mundie (1969), Mundie and Mounce (1978), and E l l i o t (1973) suggest that the aquatic i n s e c t d i e t of both stream and rearing-channel salmonids i s made up, p r i m a r i l y of Chironomidae and Ephemeroptera. P h i l l i p s eit a l . (1954) measured the proximate composition of some n a t u r a l f i s h foods i n c l u d i n g P l e c o p t e r a , D i p t e r a , and Ephemeroptera. On a wet weight b a s i s , i n s e c t 35 l i p i d (2.2%), ash (1.7%), and p r o t e i n (11.5%) contents were much lower than i n Oregon Moist P e l l e t or S i l v e r Cup. However, when the analyses of P h i l l i p s et a l . (1954) were expressed on a dry weight b a s i s by t h i s author, the i n s e c t ash (9.6%) was s l i g h t l y lower than the hatchery d i e t s , the l i p i d (12.4%) was s i m i l a r to S i l v e r Cup but lower than the Oregon Moist P e l l e t d i e t , and the p r o t e i n (66.8%) was higher than both of the hatchery d i e t s . Thus, d i f f e r e n c e s i n composition between aquatic i n s e c t s , as analysed by P h i l l i p s e_t aJ-. (1954), and the hatchery d i e t s used i n t h i s study were p r i m a r i l y i n p r o t e i n and l i p i d . In summary, the major d i f f e r e n c e s i n the r e a r i n g c o n d i t i o n s of w i l d and hatchery f i s h i n t h i s study were i n r a t i o n l e v e l s , and d i e t composition. Rearing f a c i l i t i e s a l s o d i f f e r e d i n f i s h d e nsity and water.current v e l o c i t y . U n f o r t u n a t e l y , l i t t l e i s known on the i n f l u e n c e of f i s h r e a r i n g d e n s i t y or water current v e l o c i t y on proximate composition; thus, they w i l l not be considered f u r t h e r . The greater l i p i d content i n c u l t u r e d coho can be explained by r e a r i n g c o n d i t i o n d i f f e r e n c e s . The higher r a t i o n l e v e l s and l i p i d content of the d i e t of production-channel and Burrows pond coho would tend to produce f i s h w i t h a higher body l i p i d . That the rearing-channel coho, fed Oregon Moist P e l l e t at h a l f the frequency of the production-channel coho, had a body l i p i d intermediate between production-channel and w i l d coho (% dry t i s s u e ) lends f u r t h e r support to the i n f l u e n c e of r a t i o n l e v e l s and d i e t composition on body l i p i d . The greater l i p i d content i n w i l d steelhead than pen-reared steelhead can be p a r t i a l l y explained by the lower l i p i d content i n the S i l v e r Cup d i e t than Oregon Moist P e l l e t . Furthermore, f a t accumulation increases w i t h age 36 i n saury, mackerel, e e l , anchovy, and sardine as young f i s h devote more of t h e i r energy i n t a k e to growth than do o l d e r f i s h (Shul'man 1974). ,S:hul'man (1974) notes that o l d e r f i s h are u s u a l l y l a r g e r i n s i z e , thus i t i s not c l e a r i f the increase i n l i p i d i s due to age or s i z e . The w i l d steelhead were two and three years o l d e r than the pen-reared steelhead but d i d not d i f f e r i n s i z e . Although age d i f f e r e n c e s might be the reason f o r the higher l i p i d i n w i l d steelhead, a d e f i n i t i v e explanation i s not yet a v a i l a b l e . 2. Seasonal Changes Proximate composition was measured f o r Qualicum coho over the f r e s h -water p o r t i o n of the l i f e h i s t o r y . During t h i s p e r i o d , ash (% wet t i s s u e ) increased g r a d u a l l y ( F i g . 9). Ash c o n s i s t s of i n o r g a n i c ions such as phosphorus, calcium, and sodium. Phosphorus and calcium make up the greatest p o r t i o n (85%) of the m i n e r a l content of f i s h ash (D. Higgs, personal communication). This d i v e r s e composition makes a change i n ash content d i f f i c u l t to i n t e r p r e t . One would suspect, f o r the f r y stage, that the increase i n ash content was at l e a s t p a r t i a l l y due to o s s i f i c a t i o n . Coho demonstrated l i t t l e growth or u t i l i z a t i o n of body energy sto r e s over winter ( F i g . 10,11). Foda (1974) a l s o observed constant p r o t e i n and l i p i d i n A t l a n t i c salmon during w i n t e r . Thus the low winter feeding r a t e combined w i t h low water temperature was enough to meet metabolic demand and l i t t l e e l s e . There were two time periods demonstrating s i g n i f i c a n t changes i n proximate composition. The f i r s t of these was during the e a r l y f r y stage when w i l d coho f r y l i p i d decreased sharply w h i l e c u l t u r e d f r y increased i n l i p i d . I t appears that w i l d coho are u t i l i z i n g a l l a v a i l a b l e energy sto r e s 37 f o r growth and metabolic needs w h i l e c u l t u r e d coho, fed a l a r g e r r a t i o n , are able to s t o r e l i p i d . The other time p e r i o d i n which proximate composi-t i o n was a l t e r e d was during s m o l t i f i c a t i o n . In t h i s study, l i p i d content decreased from February to A p r i l f o r two of the three Qualicum coho groups, but then increased from A p r i l to May ( F i g . 11). Moisture d e c l i n e d sharply f o r a l l three groups. Changes i n proximate composition during smolting vary w i t h the f i s h species. Foda (1974) observed a d e c l i n e i n l i p i d and moisture but an increase i n p r o t e i n f o r hatchery A t l a n t i c salmon. Andersen and Narver (1975) noted a d e c l i n e i n w i l d coho l i p i d from February to A p r i l and then an increase to May. In w i l d masu salmon, the l i p i d content increased from March to A p r i l and then d e c l i n e d to May (Ota and Yamada 1974a). In hatchery steelhead, l i p i d d e c l i n e d f o r smaller smolts, w h i l e both p r o t e i n and l i p i d d e c l i n e d i n l a r g e r smolts ( F e s s l e r and Wagner 1969). In chinook salmon no changes i n proximate composition were observed during smolting (Woo e_t a l . 1978) . The most frequent observation was a decrease i n body l i p i d during smolting. Hoar (1976) discussed s e v e r a l explanations f o r the decreasing l i p i d content during smolting, i n c l u d i n g : adaptation to a hyperosmotic env i r o n -ment, increased metabolism, and increased growth w i t h a channeling of energy i n t o p r o t e i n . L i p i d content during smolting w i l l a l s o be i n f l u e n c e d by d i e t a r y energy i n t a k e . I f energy i n t a k e i s lower than metabolic demand, l i p i d s t o r e s w i l l d e c l i n e . C. Ph o s p h o l i p i d Content As the crude content i n f i s h t i s s u e increased, the pho s p h o l i p i d content (%) decreased (Table 3 ). The w i l d coho were higher than the hatchery coho i n pho s p h o l i p i d (percent of crude l i p i d ) . Oh' a wet t i s s u e 38 b a s i s ; however, ph o s p h o l i p i d content was s i m i l a r i n w i l d and hatchery f i s h . Thus, the d i f f e r e n c e s i n p h o s p h o l i p i d content (%) were due to v a r i a t i o n s i n some other component of the crude l i p i d such as t r i a c y l g l y c e r o l . On a wet t i s s u e b a s i s , phospholipids were a l s o found to be s i m i l a r i n w i l d and hatchery p l a i c e (Owen et a l . 1972). However, Cowey et a l . (1974) noted a higher p h o s p h o l i p i d content i n c u l t u r e d p l a i c e , w h i l e Ota and Yamada (1974b) observed a lower p h o s p h o l i p i d content i n c u l t u r e d masu salmon. Phospholipids e x i s t p r i m a r i l y as s t r u c t u r a l components of b i o l o g i c a l membranes and are not thought to be stored i n s i g n i f i c a n t amounts (Shul'man 1974). Thus, differences.between hatchery and w i l d f i s h are s u r p r i s i n g . The p o s s i b i l i t y of a s t o r e of p h o s p h o l i p i d f o r as yet unknown purposes remains to be explored. D. F a t t y A c i d Content In both coho and steelhead, p o l a r l i p i d s were much higher than n e u t r a l l i p i d s i n polyunsaturated and o>3 f a t t y a c i d s . F i s h o i l s , s p e c i f i c a l l y f i s h p h o s p h o l i p i d s , are known to be r i c h i n polyunsaturated f a t t y a c i d s (Lee and Sinnhuber 1972) . The high content of these f a t t y a c i d s i n ph o s p h o l i p i d i s p r i m a r i l y due to the content of 22:6o)3. Although polyunsaturated f a t t y acids are higher i n ph o s p h o l i p i d than t r i a c y l g l y c e r o l , the p o s i t i o n of the f a t t y a c i d s i n these l i p i d s i s s i m i l a r . Brockerhoff et a l . (1963) found that 0)3 f a t t y a c i d s were p r e f e r e n t i a l l y bound i n the (3 p o s i t i o n f o r both p h o s p h o l i p i d and t r i a c y l g l y c e r o l . The r e s u l t a n t (3-monoacylglycerol was a s t a b l e s t r u c t u r e and a means to preserve the polyunsaturated f a t t y a c i d s from o x i d a t i o n . However, as noted i n the review of l i p i d metabolism, at l e a s t some of the t r i a c y l g l y c e r o l s are completely digested to f a t t y a c i d before absorption by f i s h . The high content of polyunsaturated f a t t y a c i d s 39 i n p h o s p h olipid i s no doubt r e l a t e d to the s t r u c t u r a l r o l e of phospholipids i n b i o l o g i c a l membranes. Most of the o)6 f a t t y a c i d s were i n the .form of 18:2o>6 w h i l e the o>3 f a t t y a c i d s e x i s t e d as 20:5o)3 and 22;6o>3. This was e s p e c i a l l y evident i n the pen-reared steelhead where the content of 18:2o>6 was very much higher than 20:4o)6. As discussed i n the review of l i p i d metabolism, the l a c k of chain e l o n g a t i o n i n pen-reared co6 f a t t y a c i d s may be a r e s u l t of competition w i t h 0)3 f a t t y a c i d s f o r enzyme s i t e s . In coho, the greatest d i f f e r e n c e s i n f a t t y a c i d content were i n the n e u t r a l l i p i d f r a c t i o n s . W i l d smolts were higher i n co3 f a t t y a c i d s but lower i n o>6 f a t t y a c i d s . Production and rearing-channel coho were ch a r a c t e r -i z e d by higher amounts of 18:2CJ6, 20:lo)9, and 22:loi9, w h i l e on a percent b a s i s , the w i l d smolts were higher i n 22:6u>3 content. In steelhead, d i f f e r e n c e s were apparent i n both n e u t r a l and p o l a r l i p i d . Pen-reared smolts Were much higher i n 18:2o>6 w h i l e w i l d smolts were higher i n oi3 f a t t y a c i d s . The content of 22:6cu3 was much greater i n w i l d smolt n e u t r a l l i p i d . R e l i a b l e comparisons of f a t t y a c i d content i n w i l d and hatchery salmonids have been made only f o r masu salmon (Ota and Yamada 1974b). The r e s u l t s were s i m i l a r to t h i s study w i t h the c u l t u r e d masu higher i n 0)6 f a t t y a c i d s and the w i l d masu higher i n o)3 f a t t y a c i d s . Comparisons f o r other species of salmonids are sadly l a c k i n g . F a t t y a c i d content i s s t r o n g l y i n f l u e n c e d by d i e t . The greater o>3 f a t t y a c i d content i n w i l d coho was a r e f l e c t i o n of the 0)3 f a t t y a c i d content i n aquatic i n s e c t s (Table 12).. The Oregon Moist P e l l e t d i e t was very high i n 20:lo)9 and 22:lo)9. The o i l source f o r t h i s d i e t i s l i k e l y a marine type as marine f i s h such as h e r r i n g are known to be h i g h i n 20:loi9 40 and 22:1CJ9 (16.1%, 19.8%,. r e s p e c t i v e l y ) (Cowey and Sargent 1972). The S i l v e r Cup d i e t was very high i n CJ6 f a t t y a c i d s . The o i l source f o r t h i s d i e t i s l i k e l y to be, at l e a s t p a r t i a l l y , a vegetable source as vegetable o i l s are high i n o>6 f a t t y a c i d s (N.R.C. 1973). The i n f l u e n c e of these d i e t s on the f a t t y a c i d content of the f i s h was much more evident i n n e u t r a l l i p i d than p o l a r l i p i d . This i m p l i e s that the f a t t y a c i d content of the p o l a r l i p i d i s t i g h t l y r egulated. .Differences i n f a t t y a c i d content between d i e t s must be very l a r g e before a s i g n i f i c a n t impact w i l l be observed i n p o l a r l i p i d . However, co3 f a t t y a c i d s are an exception. F a t t y a c i d s of the u>3 type a r e . p r e f e r e n t i a l l y bound i n p o l a r l i p i d . This was e s p e c i a l l y evident f o r 22:6a>3 where the content i n the f i s h was much higher than i n the d i e t . Thus d i f f e r e n c e s i n biochemical composition between w i l d and c u l t u r e d salmonids are a r e s u l t of d i f f e r e n c e s i n r a t i o n l e v e l and d i e t composition. By a l t e r i n g r a t i o n s i z e and the f a t t y a c i d content of d i e t s fed to c u l t u r e d f i s h , the l i p i d content of w i l d f i s h can be matched. I I . Impact of Smolt S i z e and Biochemical Composition  on Marine S u r v i v a l A. Smolt S i z e G e n e r a l l y , i n c r e a s i n g smolt s i z e improves marine s u r v i v a l (Johnson 1970; Hager and Nobel 1976). However, r e l e a s i n g l a r g e r smolts a l s o increases the number of precocious male r e t u r n s , r e s u l t i n g i n decreased numbers of r e t u r n i n g a d u l t s ( B i l t o n 1978). According to B i l t o n the i n f l u e n c e of s i z e a l s o depends on time of r e l e a s e . I f coho smolts were rele a s e d i n m i d - A p r i l , the smaller smolts (8-10 g) gave the best r e t u r n s . 41 I f smolts were re l e a s e d i n e a r l y June, i t was the l a r g e r smolts (19 g) g i v i n g the best r e t u r n s . In t h i s study, coho smolts were re l e a s e d i n l a t e May, thus favouring the production-channel coho. B. Proximate Composition The i n f l u e n c e of proximate composition on marine s u r v i v a l has not been w e l l i n v e s t i g a t e d . Returns of chinook salmon were improved where smolts were re l e a s e d w i t h high body p r o t e i n and l i p i d (Burrows 1969). Peterson (1972) increased A t l a n t i c salmon marine s u r v i v a l by feeding a d i e t c o n t a i n -ing 16% marine o i l . I t was not evident from t h i s study i f the higher s u r v i v a l was a r e s u l t of increased body l i p i d or u)3 f a t t y a c i d s . As noted e a r l i e r , marine o i l s are high i n o>3 f a t t y a c i d s . Thus, although higher body p r o t e i n would seem to improve marine s u r v i v a l , the impact of l i p i d i s not c l e a r . Is i t the l i p i d content per se or the f a t t y a c i d content of the l i p i d that i n f l u e n c e s marine s u r v i v a l ? I t does seem c l e a r that the w i l d - t y p e proximate composition would be d e s i r a b l e i n c u l t u r e d f i s h to increase t h e i r marine s u r v i v a l . Wood et a l . (1960) re l e a s e d hatchery coho salmon i n t o a stream a f t e r having reared the f i s h f o r between three and twelve months. Coho reared i n the hatchery f o r three to s i x months r e q u i r e d only three months to r e v e r t to the wild- t y p e proximate composition of low body l i p i d . F i s h r e l e a s e d i n t o the stream a f t e r nine to twelve months of hatchery r e a r i n g d i d not make the conversion to the wi l d - t y p e composition before smolting at fourteen months and s u f f e r e d poor ocean s u r v i v a l s . C. F a t t y A c i d Content There have been no experiments designed s p e c i f i c a l l y to i n v e s t i g a t e the i n f l u e n c e of f a t t y a c i d content on marine s u r v i v a l . Much research has 42 been devoted toward d e f i n i n g e s s e n t i a l f a t t y a c i d requirements and t h e i r f u n c t i o n s i n f i s h . 1. E s s e n t i a l F a t t y Acids i n F i s h The subject of e s s e n t i a l f a t t y a c i d s i n f i s h was r e c e n t l y reviewed by C a s t e l l (1979). Fat t y a c i d s of the o>3 s e r i e s are e s s e n t i a l f o r favourable salmonid growth and food conversion. For rainbow t r o u t , the e s s e n t i a l f a t t y a c i d requirement i s met by 1.0% 18:3o)3 (percent of dry d i e t ) . For coho salmon, the requirement i s somewhat higher at 1.0-2.5%. In rainbow t r o u t , long chain u3 f a t t y a c i d s have more e s s e n t i a l f a t t y a c i d a c t i v i t y than 18:3oi3. F a t t y a c i d s of the u>6 s e r i e s are not a b s o l u t e l y r e q u i r e d f o r growth. When combined w i t h high o>3 f a t t y a c i d s , CJ6 f a t t y a c i d s l e s s than 1.0% (percent of dry d i e t ) are b e n e f i c i a l f o r t r o u t growth (Yu and Sinnhuber 1976). In c r e a s i n g the OJ6 f a t t y , a c i d content i n the d i e t from 1.0 to 2.5% decreased growth r a t e s (Yu and Sinnhuber 1976). In coho salmon, co6 f a t t y acids above 1.0% i n the d i e t w i l l i n h i b i t growth (Yu and Sinnhuber 1979). At l e a s t f o r coho salmon, the decrease i n growth r a t e may be a r e s u l t of the i n h i b i t i o n by co6 f a t t y a c i d s of chain e l o n g a t i o n of o>3 f a t t y a c i d s ( T i n s l e y et a l . 1971). Warm water f i s h such as carp d i f f e r from salmonids i n t h e i r f a t t y a c i d requirements. Carp r e q u i r e both w3 (1.0%) and o>6 (1.0%) f a t t y a c i d s f o r favourable growth ( C a s t e l l 1979). To compare the e s s e n t i a l f a t t y a c i d l e v e l s i n hatchery d i e t s to the d i e t a r y requirements suggested above, we must convert the percent content of f a t t y a c i d s i n the d i e t a r y o i l to a percentage of the dry weight of the d i e t . Thus, we s h a l l assume that 75% of the weight of the o i l i s made up 43 of f a t t y a c i d s . This i s a conservative estimate based on l i p i d c l a s s to f a t t y a c i d weight conversion f a c t o r s c a l c u l a t e d by C h r i s t i e (1973). For Oregon Moist P e l l e t , the content of oi3 and o>6 f a t t y a c i d s (percent of the dry weight) was 2.2% and 0.7% r e s p e c t i v e l y . For S i l v e r Cup, the content of o)3 f a t t y a c i d s was 2.6%, and 1.9% f o r the 0)6 f a t t y a c i d s . The d i e t a r y 0)3 f a t t y a c i d requirements f o r salmonids would be met by both of these d i e t s . Based on the work of Yu and Sinnhuber (1976, 1979) , the 0)6 f a t t y a c i d content of the hatchery d i e t s , as fed i n t h i s study would not r e s u l t i n a depression of f i s h growth. The S i l v e r Cup d i e t would l i k e l y depress growth i f fed to coho salmon s i n c e coho cannot t o l e r a t e as high a d i e t a r y 0)6 f a t t y a c i d content as rainbow t r o u t . 2. F a t t y A c i d Content and Membrane and L i p i d Function F a t t y a c i d s are important s t r u c t u r a l components of b i o l o g i c a l membranes. I t was observed some years ago that the i o d i n e number f o r l i p i d e x t r a c t e d from g o l d f i s h increased as water temperature decreased (Hoar and C o t t l e 1952). The i o d i n e number i s a measure of the degree of s a t u r a t i o n i n l i p i d f a t t y a c i d s such that the higher the i o d i n e number the more unsaturated the f a t t y a c i d s . I n c r e a s i n g the u n s a t u r a t i o n of the f a t t y a c i d s would lower t h e i r melting p o i n t and r e t a i n the f l u i d i t y of the membrane. Hazel (1979a) i d e n t i f i e d the s p e c i f i c f a t t y a c i d s that were, a l t e r e d i n phospholipids from rainbow t r o u t l i v e r as water temperature decreased. The i n c r e a s i n g unsatur-a t i o n was p r i m a r i l y a r e s u l t of o>3 f a t t y a c i d s (22:6o)3). In c a t f i s h whole l i p i d , both 0)3 and 0)6 f a t t y a c i d s were i n v o l v e d i n temperature adaptation (Andrews and Stickney 1972). F a t t y a c i d u n s a t u r a t i o n i s not the only a l t e r a t i o n made to membrane s t r u c t u r e w i t h water temperature changes. Wodtke (1978) noted a decrease 44 i n the molar r a t i o of c h o l e s t e r o l and phospholipid i n l i v e r m i t o c h o n d r i a l membranes from carp, reared at low water temperatures. The decreased c h o l e s t e r o l / p h o s p h o l i p i d r a t i o increased the s u s c e p t i b i l i t y of phospholipids to f l u i d i t y c o n t r o l by f a t t y a c i d s . Further support f o r the importance of o>3 f a t t y a c i d s i n membrane s t r u c t u r e has come from the work of C a s t e l l et a l . (1972). Rainbow t r o u t mitochondria were suspended i n a 0.25 M sucrose s o l u t i o n . Mitochondria from f i s h fed a l i n o l e n i c a c i d (18:3o>3) d i e t had the lowest s w e l l i n g r a t e . A l i n o l e i c a c i d (18:2ai6) d i e t a l s o reduced the s w e l l i n g r a t e over the f a t - f r e e d i e t , but was not as e f f e c t i v e as the l i n o l e n i c a c i d d i e t . N e u t r a l l i p i d a l s o e x h i b i t s changes i n f a t t y a c i d content w i t h temperature. Monounsaturated (20:lo)9), 0)3 (22:6w3) and. o)6 (20:4oi6) f a t t y a c i d s increased i n content at low water temperatures (Hazel 1979b). Presumably, the change i n u n s a t u r a t i o n f o r n e u t r a l l i p i d a l t e r s the s t a t e of the l i p i d ensuring i t s a v a i l a b i l i t y f o r use as an energy s t o r e . Thus, 0)3 f a t t y a c i d s are important f o r temperature adaptation i n both n e u t r a l and pol a r l i p i d . 3. Docosahexaenoic A c i d (22: 6o)3) Docosahexaenoic a c i d has a s p e c i a l r o l e i n f i s h l i p i d . I t i s the most unsaturated f a t t y a c i d found i n f i s h l i p i d and thus i s of great importance i n temperature adaption. As w e l l , f i s h eggs are high i n 22:6oi3 content (Nakagawa and Tsuchiya 1978; Schauer and Simpson 1978). In carp, i f the 22:6o>3 content of the egg was decreased below 10.0% the h a t c h a b i l i t y of the eggs was reduced (Shimma et a l . 1977). Rainbow t r o u t s a c - f r y s e l e c t i v e l y r e t a i n e d 22:6oi3 i n the t i s s u e s , a t t e s t i n g to the s t r u c t u r a l r o l e played by t h i s f a t t y a c i d (Hayes et a l . 1973). Several authors have speculated that 45 22:6w3 has a r e g u l a t o r y r o l e on body l i p i d content; however, c o n c l u s i v e evidence i s not yet a v a i l a b l e (Owen et a l , 1972; Schauer and Simpson 1978). 4. F a t t y A c i d Requirements i n Fresh and S a l t Water The e s s e n t i a l f a t t y a c i d requirements of salmonids have been measured only i n the freshwater environment. In A t l a n t i c salmon, the groups that grew best i n f r e s h water were not n e c e s s a r i l y those that d i d best i n s a l t water (Gunnes and Gjedrom 1978; R e f s t i e and Steine 1978; R e f s t i e , personal communication). Thus, at l e a s t f o r growth, the requirements i n s a l t water were d i s t i n c t i v e . F a t t y a c i d s of the u>3 s e r i e s are much higher i n marine f i s h ( C a s t e l l 1979). Ayu c o l l e c t e d i n the sea were higher i n o>3 f a t t y a c i d s than those c o l l e c t e d from a lake (Ota and Takagi 1977). In salmonids, the r e s u l t was the same. As j u v e n i l e masu smolts migrated from f r e s h water to s a l t water the o)6/u)3 r a t i o decreased (Ota 1976). I t i s not c l e a r whether the high o>3 f a t t y a c i d content i n marine f i s h i s a d i e t a r y response, or a p h y s i o l o g i c a l requirement f o r the sa l t w a t e r environment. The work of L a l l and Bishop (1975) suggests i t i s at l e a s t p a r t l y a p h y s i o l o g i c a l requirement. These authors noted a higher m o r t a l i t y i n s a l t water than f r e s h water f o r rainbow t r o u t fed an o>6 f a t t y a c i d d i e t . Thus, the requirement f o r u)3 f a t t y a c i d s i n s a l t water i s l i k e l y to be grea t e r than i n f r e s h water. The high content of 22:lo>9 (17.8%) i n Oregon Moist P e l l e t fed f i s h r e q u i r e s f u r t h e r comment. Takagi (1978) reported that r a t s fed d i e t s high i n 22:1 demonstrated a decreased growth r a t e and c a r d i a c damage. This f a t t y a c i d i s l e g a l l y r e s t r i c t e d to l e s s than 5.0% of the d i e t a r y f a t i n d i e t s f o r human consumption (Takagi 1978), a l e v e l much lower than that present i n Oregon Moist P e l l e t . The i n f l u e n c e of t h i s f a t t y a c i d on the 46 marine s u r v i v a l of Oregon Moist P e l l e t fed f i s h i s unknown. That marine f i s h such as h e r r i n g (Cowey and Sargent 1972) are high i n 22:1 content suggests a b a s i c d i f f e r e n c e i n f i s h and mammal l i p i d metabolism. I I I . Concluding Remarks As compared to the w i l d coho, production-channel coho were ch a r a c t e r -i z e d by high body l i p i d and low moisture. F a t t y a c i d content d i f f e r e d mostly i n the n e u t r a l l i p i d f r a c t i o n . Production-channel coho, on a percent b a s i s , were higher i n o>6 f a t t y a c i d s and lower i n o>3 f a t t y a c i d s , than the w i l d coho. Rearing-channel coho were intermediate i n proximate composition and o>6 f a t t y a c i d content but were s i m i l a r to the production-channel coho i n the u3 f a t t y a c i d content of n e u t r a l l i p i d . W i ld coho had 2.2 times the 22:6o)3 content ( n e u t r a l l i p i d ) of the production-channel and rearing-channel coho. Pen-reared steelhead were s i m i l a r to the w i l d steelhead i n p r o t e i n and ash content but were lower i n l i p i d content. The f a t t y a c i d content of both n e u t r a l and p o l a r l i p i d d i f f e r e d i n w i l d and pen-reared steelhead. Pen-reared steelhead were much higher i n o>6 f a t t y a c i d s but lower i n 0)3 f a t t y a c i d s , than the w i l d steelhead. The content of 22:6o)3 i n w i l d steelhead n e u t r a l l i p i d was almost 2.7 times that of the pen-reared steelhead. There i s no doubt that e s s e n t i a l f a t t y a c i d d e f i c i e n t f i s h w i l l s u f f e r poor marine s u r v i v a l ; however, none of the f i s h i n t h i s study are d e f i c i e n t i n f a t t y a c i d s . I:; have suggested that oi3 f a t t y a c i d s , s p e c i f i c a l l y 22:6o)3 are more important f o r temperature adaptation than the o)6 f a t t y a c i d s . As w e l l , the requirement f o r oi3 f a t t y a c i d s i s probably higher i n the sea. Thus a higher OJ3 content i s l i k e l y to improve marine 47 s u r v i v a l . U n f o r t u n a t e l y , I cannot yet s t a t e whether the d i f f e r e n c e s i n proximate composition and f a t t y acid.content i n the w i l d and hatchery f i s h i n t h i s study are l a r g e enough to i n f l u e n c e the marine s u r v i v a l of hatchery f i s h . The s p e c i f i c biochemical requirements f o r salmonids, m i g r a t i n g to the sea, are unknown. C e r t a i n l y , u n t i l these requirements are i d e n t i f i e d , the best approach would be to match the biochemical composition of w i l d salmonids. Therefore, i t would be appropriate to suggest a d d i t i o n a l areas of research. The optimal f a t t y a c i d content f o r sea-going salmonids must be i d e n t i f i e d as i t i s l i k e l y that f r e s h water and s a l t water requirements d i f f e r . 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Genetic and environmental sources of v a r i a t i o n i n length and weight of A t l a n t i c salmon i n the freshwater phase. Aquaculture 14: 221-234. 53 Robinson, J . S., and J . F. Mead. 1973. L i p i d absorption and d e p o s i t i o n i n rainbow t r o u t (Salmo g a i r d n e r i ) . Can. J . Biochem. 51: 1050-1058. Schauer, P. S., and K. L. Simpson. 197.8. L i p i d metabolism and f a t t y a c i d composition of w i l d and c u l t u r e d A t l a n t i c s i l v e r s i d e s (Menidia  menidia). (unpublished data). Shimma, Y., R. Suzuki, M. Yamaguchi, and T. Akiyama. 1977. On the l i p i d s of a d u l t carps r a i s e d on f r e s h meal and SCP feeds, and h a t c h a b i l i t i e s of t h e i r eggs. B u l l . Freshwater F i s h . Res. Lab. 27: 35-48. Shul'man. G. E. 1974. L i f e c y c l e s of f i s h . Physiology and biochemistry. John Wiley and Sons, New York, Toronto. Takagi, T. 1978. Progress i n the s t u d i e s on Docosenoic. a c i d s . F i s h . Mar. Serv. T r a n s l a t i o n S e r i e s No. 4328, 1978. T i n s l e y , I . J . , J . B. Saddler, H. M. Kreuger, and R. R. Lowry. 1971. I n t e r a c t i o n s i n the metabolism of polyunsaturated f a t t y a c i d s i n coho salmon (Oncorhynchus k i s u t c h ) . I n t . J . Biochem. 2: 345-348. Vanstone, W. E., and J . R. Markert. 1968. Some morphological and biochemi-c a l changes i n coho salmon, Oncorhynchus k i s u t c h , during parr-smolt transformation. J . F i s h . Res. Board Can. 25: 2403-2418. Ward, B. R., and P. A. Slaney. 1979. E v a l u a t i o n of instream enhancement s t r u c t u r e s f o r the production of j u v e n i l e steelhead t r o u t and coho salmon i n the Keogh r i v e r ; Progress 1977 and 1978. B. C. F i s h and W i l d l i f e Br., F i s h . Tech. C i r c . 45, 47 p. Wodtke, E. 1978. L i p i d adaptation i n l i v e r m i t o c h o n d r i a l membranes of carp acclimated to d i f f e r e n t environmental temperatures. Biochimica. et Bio p h y s i c a . Acta 529: 280-291. Woo, N. Y. S., H. A. Bern, and R. S. Ni s h i o k a . 1978. Changes i n body composition a s s o c i a t e d w i t h s m o l t i f i c a t i o n and premature t r a n s f e r to seawater i n coho salmon (Oncorhynchus k i s u t c h ) and ki n g salmon (0. tshawytscha). J . F i s h . B i o l . 13: 421-428. Wood, E. M. , W. Y. Yasutake, J . E. Halver, and A. N. Woodall. 1960. Chemical and h i s t o l o g i c a l s t u d i e s of w i l d and hatchery salmon i n f r e s h water. Trans. Am. F i s h . Soc. 89: 301-307. Wood, E. M., W. T. Yasutake, A. N. Woodall, and J . E. Halver. 1957. The n u t r i t i o n of salmonid f i s h e s . I . Chemical and h i s t o l o g i c a l s t u d i e s of w i l d and domestic f i s h . J . Nutr. 61: 465-478. Yu, T. C , and R. 0. Sinnhuber. 1976. Growth response of rainbow t r o u t (Salmo g a i r d n e r i ) to d i e t a r y 0)3 and w6 f a t t y a c i d s . Aquaculture 8: 309-317. 54 Yu, T. C , and R. 0. Sinnhuber. 1979. E f f e c t of d i e t a r y <D3 and w6 f a t t y a c i d s on growth and food conversion e f f i c i e n c y of coho salmon (Oncorhynchus k i s u t c h ) . Aquaculture 16: 31-38. 55 Table 1. Rearing c o n d i t i o n s i n the Qualicum, Capilano, and Keogh r i v e r study areas. Q u a l i c u m r i v e r C a p i l a n o r i v e r K e o g h r i v e r P r o d u c t i o n - R e a r i n g - N a t u r a l B u r r o w s c h a n n e l c h a n n e l p o n d N a t u r a l Pen N a t u r a l L e n g t h ( m ) W i d t h ( m ) W a t e r d e p t h ( m ) M e a n a n n u a l w a t e r t e m p e r a t u r e Cc) 2 7 5 3 9 6 4.6 1 . 0 p o o l 0 . 9 r i f f l e 0 . 1 5 8 . 6 8.7 4 6 2 . 4 0 . 9 7 . 5 4 . 6 3 . 3 4 . 6 1 0 . 1 O 8 . 8 W a t e r f l o w ( m / m i n ) 3 4 2 4 425 1 . 7 W a t e r v e l o c i t y ( m / m i n ) 4 . 2 p o o l 5 . 8 r i f f l e 3 4 . 8 0 . 8 N u m b e r o f f i s h r e l e a s e d 6 1 5 , 2 4 2 63,000 7 5 , 0 0 0 3 , 0 0 0 T o t a l w e i g h t o f f i s h a t r e l e a s e ( k g ) 1 2 , 4 0 3 . 0 743.4 1 3 8 3 . 8 1 9 2 . 3 F i s h D e n s i t y 3 « a t r e l e a s e ( k g / m ' 5 . 6 1.9 1 3 . 9 2 . 8 57 Table 2. Fork l e n g t h , wet weight and c o n d i t i o n f a c t o r of coho salmon and steelhead t r o u t . Values are means w i t h 95% confidence l i m i t s . Groups w i t h the same s u p e r s c r i p t form a homogeneous subset (ANOVA, Scheffe's t e s t , p_<0.05). Groups from d i f f e r e n t l i f e h i s t o r y stages and r i v e r systems are analysed s e p a r a t e l y . 58 Rearing method No. of f i s h sampled Fork length (mm) Wet weight (g) C o n d i t i o n f a c t o r Sampling date 1979 Qualicum coho Natural 61 69.8 + 2.5 a 3.74 + 0.43 a 6.44 + 0.21 a A p r i l 2 presmolt Production -channel 40 101.4 +2.7 b 11.47 + l . l l b 5.97 + 0.13 b A p r i 1 9" R e a r i n g -channel 50 88.4 +1.9 C 7.35 + 0.46 c 6.08 + 0.11 b A p r i l 9 Qualicum coho Natural 38 101.2 + 4.0 a 11.63 + 1.14 a 6.05 + 0.15 a May 31 smolt P r o d u c t i o n -channel 30 117.7 +2.9 b 17.46 + 1.45 b 5.61 + 0.25 b May 14 Rea r i n g -channel 40 99.6 + 2.3 a 11.80 + 0.81 a 6.70 + 0.15 C May 17 Capilano coho Natural 31 110.6 + 7.0 a 14.60 + 3.00 a 5.36 + 0.14 a June 1 smolt Hatchery 20 123.8 +4.3 b 18.45 + 1.97 a 5.11 + 0.16 b June 5 Keogh steelhead Natural 20 182.8 + 9 . f l a 60.7 +10.16 b 4.64 + 0.30 a May 16 smol t Pen 20 187.6 +9.0 a 64.1 + 7.73 b 4.59 + 0.19 a May 10 59 Table 3. Whole body proximate composition (% wet t i s s u e ) and phospholipid content of coho salmon and steelhead t r o u t . Values are means w i t h 95% confidence l i m i t s . Groups w i t h the same s u p e r s c r i p t form a homogeneous subset (ANOVA, Scheffe's t e s t , pj<0.05). Groups from d i f f e r e n t l i f e h i s t o r y stages and r i v e r systems are analysed s e p a r a t e l y . Proximate composition {% wet tissue) Phospholipid content Rearing method No. fish per sample X of Phospholipid (mg) No. samples Moisture Ash Protein Lipid crude lipid g wet tissue Qualicum coho Natural 6 10 81.6 + 0.6* 2.79 • 0-43* 13.9 + 0.5* 1.78 • 0.37* 65.0 • 4.5* 11.6 1 2.3* presmolt Production -channel 10 4 b 77.5 • 1.0 2.48 • 0.18* b 14.7 • 0.5 b 4.27 • 0.60 31.2 + 3.7b 13.0 +1.2* Rearing -channel .... 10 5 79.4 • 0.4° 2.63 • 0.22* b 14.8 + 0.3 2.78 • 0.25C 42.9 • 3.5° 11.8 +0.8* O O Qualicum coho Natural 10 4 79.1 • 1.1* 2.58 • 0.21* 16.2 + 0.6* 3.02 • 0.60* 41.7 • 8.0* 11.8 +0.5* smolt Production -channel 10 3 76.3 • 0.56 2.53 • 0.2l" 15.6 • 0.3* b 4.41 • 0.41 28.1 • 2.4b 12.2 +0.4* Rearing -channel 10 4 79.1 + 0.3* 2.51 • 0.12* 14.5 + O . ^ 3.20 • 0.19* 42.3 • 1.7* 13.5 +0.6 Capilano coho Natural 11 2-4 79.7 • 0.3* 254 • 0.20* 16.2 • 0.5* 2.05 • 0.16* 68.5 • 4.2* 13.8 +0.7* smolt Hatchery 10 2 77.3 • O.SP 2.53 • 0.30* 16.1 • 0.3* 3.81 • 0.62b 36.9 • 6.5 13.4 • 1.0* Keogh steelhead Natural 10 2 76.2 • 1.0* 2.49 • 0.27* 16.5 • 0.4* 4.19 • 0.84* 22.8 • 4.4* 9.0 • 0.6* smolt Pen 10 2 76.6 + 0.7* 2.71 • 0.36* 17.0 • O.i b 2.93 • 0.16 31.9 • 1.65 9.3 +0.2* 61 Table 4. Whole body proximate composition (% dry t i s s u e ) of coho salmon and steelhead t r o u t . Values are means w i t h 95% confidence l i m i t s . Groups w i t h the same s u p e r s c r i p t form a homogeneous subset (ANOVA, Scheffe's t e s t , p_<0.05). Groups from d i f f e r e n t l i f e h i s t o r y stages and r i v e r systems are analysed separately. 62 Rearing No. f i s h Proximate composition (% dry tissue) method No. samples per sample Ash Protein Lipid Qualicum coho Natural 6 10 15.23 + 2.673 75.37 + a 2.16 9.67 + 1.773 presmolt Production -channel 10 4 b 11.02 +0.61 65.38 + b 3.30 b 18.78 + 2.03 Rearing -channel 10 5 b 12.76 + 0.99 72.00 + a 1.80 c 13.45 + 0.97 Qualicum coho Natural 10 4 12.42 + 1.24* 77. ,73 + a 4.40 14.25 + 2.053 smolt Production -channel 10 3 b 10.72 + 0.97 65. .90 + b 1.67 b 18.59 + 1.41 Rearing -channel 10 4 s,b 11.99 + 0.52 69. ,25 + b 1.22 15.28 + 0.81 3 Capilano coho smolt Natural Hatchery 11 10 2-4 2 12.54 + 1.09* b 11.14 + 1.13 79.92 + 71.47 + a 1.75 b 3.93 10.08 + 0.77 3 b 16.73 + 2.39 Keogh steelhead smolt Natural Pen 10 10 2 2 10.55 + 1.61 * 12.00 + 2.02* 69. 71. ,44 + .23 + a 4.13 a 4.15 17.43 + 2.98 3 b 12.31 + 0.95 63 Table 5. Proximate composition of some aquatic i n s e c t s (% wet t i s s u e ) and hatchery d i e t s (% wet t i s s u e and % dry t i s s u e ) . P r o x i m a t e c o m p o s i t i o n (%) M o i s t u r e A s h P r o t e i n L i p i d E p h e m e r o p t e r a - - - 6 . 0 0 o A q u a t i c P l e c o p t e r a - - - 3 . 3 0 • i n s e c t s C h i r o n o m i d a e T r i c h o p t e r a ; 2 . 4 4 2 . 7 4 H a t c h e r y O r e g o n M o i s t P e l l e t 3 0 . 3 8 . 8 8 ( 1 2 . 7 4 ) 3 4 . 1 ( 4 8 . 9 ) ••' 1 2 . 7 6 ( 1 8 . 3 1 ) d i e t s S i l v e r Cup 6 . 3 1 1 . 2 7 ( 1 2 . 0 3 ) 4 5 . 2 ( 4 8 . 2 ) 1 2 . 1 6 ( 1 2 . 9 8 ) ( ) c o n t a i n t h e c o m p o s i t i o n e x p r e s s e d as a % o f t h e d r y t i s s u e 65 Table 6. F a t t y a c i d composition of coho smolts reared n a t u r a l l y i n the Qualicum r i v e r . Values are means f o r four samples w i t h each sample c o n s i s t i n g of four f i s h . "Trace" i n d i c a t e s _<0.05%, £0.005 mg/g. 66 Fatty Fatty acid composition (2) Fatty acid (ng/g wet tissue) acid Neutral Polar Whole Neutral Polar Uhole type li p i d l i p i d l i p i d l i p i d lipid l i p i d 14:0 2.4 0.4 1.7 0.38 0.03 0.41 14:1 1.0 0.1 0.6 0.14 trace 0.14 15:0 0.5 0.3 0.4 0.07 0.03 0.10 15:1 trace trace trace trace trace trace 16:0 13.1 18.2 15.2 2.01 1.66 3.67 16:lu>7 7.4 2.8 5.8 1.14 ^  0.26 1.40 17:0 0.8 0.9 0.9 0.13 0.08 0.21 unknown 0.1 - 0.1 0.02 - 0.02 17:1 0.6 0.2 0.5 0.10 0.02 0.12 18:0 5-1 5.7 5.3 0.76 0.52 1.28 18:lu>9 1 29.5 13.4 24.0 4.57 1.22 5.79 18:2u6 3.8 1.6 2.9 0.55 0.15 0.70 18:3u>6 0.1 trace trace 0 . 0 1 trace 0.01 18:3o)3 2.5 1.4 2.1 0.37 0.13 0.50 20:la)9 1.2 0.2 0.8 0.18 0.02 0.20 18:4u3 1.1 0.3 0.8 0.18 0.03 0.21 20:2u6 0.1 0.1 0.1 0.02 trace 0.02 20:3oi6 trace 0.1 0.1 0.01 0.01 0.02 20:4u6 1.5 3.8 2.4 0.22 0.35 0.57 22:lw9 trace - trace 0 . 0 1 - 0.01 20:4u>3 1.0 0.4 0.8 0.15 0.03 0.18 20:5u>3 5.5 7.8 6.6 0.87 0.71 1.58 22:3u>6 0.1 - trace 0 . 0 1 - 0.01 22:4u>6 0.1 0.1 0.1 0.01 0.01 0.02 24:lu9 4.1 trace 1.4 0.32 trace 0.33 22:4u3 - 1.8 0.7 - 0.16 0.16 22:5a>3 3.5 3.0 3.4 0.54 0.27 0.81 22:6OJ3 14.8 37.1 23.5 2.28 3.38 5.66 67 Table 7. F a t t y a c i d composition of coho smolts reared i n a produc t i o n -channel. Values are means f o r four samples w i t h each sample c o n s i s t i n g of three f i s h . "Trace" i n d i c a t e s _<0.05%, j<0.005 mg/g. 68 Fatty Fatty a c i d composition (%) Fatty a c i d (mg/g wet ti s s u e ) acid Neutral Polar Whole Neutral Polar Whole type l i p i d l i p i d l i p i d l i p i d l i p i d l i p i d 14:0 4.0 1.1 3.4 1.34 0.10 1.44 14:1 0.2 - 0.1 0.05 - 0.05 15:0 0.2 0.2 0.2 0.08 0.02 0.10 15:1 0.1 trace 0.1 0.03 trace 0.03 16:0 12.1 19.3 13.7 4.04 1.78 5.80 16:lu7 9.0 2.9 7.7 2.99 0.26 3.25 17:0 - 0.6 0.2 0.05 0.05 0.10 unknown 0.5 - 0.3 0.11 - 0.11 17:1 0.7 0.2 0.6 0.24 0.01 0.25 18:0 2.5 3.9 2.8 0.84 0.36 1.20 18:1<D9 25.2 11.2 22.2 8.41 . 1.03 9.44 unknown trace - trace t r a c e - trace 18:2(j6 7.4 1.7 6.2 2.46 0.16 2.62 13:3<D6 0.5 - 0.4 0.16 - 0.16 18:3u3 0.6 0.2 0.5 0.18 0.02 0.20 20:lo)9 9.8 1.6 8.0 3.27 0.15 3.42 18:4u)3 0.9 0.1 0.8 0.31 0.01 0.32 20:2u6 0.1 0.1 0.1 0.03 trace 0.03 20:3u6 trace 0.1 0.1 0.02 0.01 0.03 20:4bi6 0.3 1.9 0.6 0.10 0.18 0.28 22:lo)9 9.5 0.4 7.5 3.16 0.03 3.19 20:4u3 - trace trace - trace trace 20:5(o3 3.2 6.9 4.0 1.08 0.64 1.72 22:3(D6 0.6 trace 0.5 0.22 trace 0.22. 22:4d)6 0.1 trace 0.1 0.03 trace 0.03 24:lu>9 3.8 1.0 3.1 1.23 0.08 1.31 unknown - 0.8 0.2 • - 0.07 0.08 22:4w3 - 0.6 0.1 - 0.06 0.06 unknown 0.7 - 0.5 0.23 - 0.23 22:5ID3 1.5 2.1 1.6 0.49 0.19 0.68 22:6u)3 6.5 43.1 14.5 2.19 3.96 6.15 69 Table 8. F a t t y a c i d composition of coho smolts reared i n a rearing-channel. Values are means f o r four samples w i t h each sample c o n s i s t i n g of four f i s h . "Trace" i n d i c a t e s £0.05%, £0.005 mg/g. 70 Fatty Fatty acid composition (%) Fatty acid (tng/g wet tissue) acid Neutral Polar Whole Neutral Polar Whole type lipid lipid lipid lipid lipid lipid 14:0 4.7 1.5 3.6 0.90 0.15 1.05 14:1 0.3 - 0.2 0.06 - 0.06 15:0 0.3 0.2 0.3 0.06 0.02 0.08 15:1 0.1 trace 0.1 0.03 trace 0.03 16:0 12.6 18.5 14.7 2.39 1.94 4.33 16:l(o7 10.6 3.8 8.2 2.01 0.40 2.41 17:0 - 0.6 0.2 - 0.05 0.05 unknown 0.5 - 0.3 0.09 - 0.09 17:1 0.8 0.2 0.6 0.15 0.02 0.17 18:0 2.5 4.3 3.2 0.48 0.45 0.93 18:lu>9 22.5 12.7 19.1 4.27 1.33 5.60 unknown 0.2 - 0.1 0.04 - 0.04 18:2o6 6.2 2.3 4.8 1.16 0.24 1.41 18:3u6 0.6 trace 0.4 0.12 trace 0.12 18:30)3 1.0 0.4 0.7 0.18 0.04 0.22 20:lw9 9.7 2.1 7.1 1.86 0.22 2.09 18:4u3 1.8 0.4 1.3 0.34 0.04 0.38 20:2a)6 0.1 0.1 0.1 0.02 0.01 0.03 20:3o6 trace 0.2 0.1 0.01 0.02 0.03 20:4u)6 0.3 2.0 0.9 0.06 0.20 0.26 22:1(D9 11.3 1.0 7.8 2.17 0.11 2.28 20:4a)3 - 0.1 trace - 0.01 0.01 20:5Q)3 4.1 7.5 5.3 0.78 0.78 1.56 22:3u3 trace 0.1 trace trace 0.01 0.01 22:4a 6 0.3 0.1 0.2 0.05 0.02 0.07 unknown 1.2 - 0.8 0.23 - 0.23 22:4(o3 - 1.1 0.4 - 0.12 0.12 unknown - 0.4 0.2 - 0.04 0.04 22:5u3 1.2 2.2 1.6 0.23 0.23 0.46 22:6a)3 6.7 37.7 17.8 1.29 3.94 5.23 ! 71 Table 9. F a t t y a c i d composition of steelhead smolts reared n a t u r a l l y i n the Keogh r i v e r . Values are means f o r four samples w i t h each sample c o n s i s t i n g of two f i s h . "Trace" i n d i c a t e s <0.05%, <0.005 mg/g. Fatty a c i d type 72 F a t t y a c i d c o m p o s i t i o n (%) Neutral l i p i d Polar l i p i d Whole l i p i d F a t t y a c i d (mg/g wet t i s s u e ) Neutral l i p i d Polar l i p i d Whole l i p i d 14:0 1.4 0.5 1.2 0.47 0.03 0.50 14:1 0.1 0.2 0.1 0.03 0.01 0.04 15:0 0.2 0.3 0.3 0.09 0.02 0.11 15:1 trace trace trace 0.01 trace 0.01 16:0 10.8 17.5 12.1 3.69 1.21 4.90 16:lu7 6.4 2.0 5.6 2.14 0.14 2.28 17:0 0.5 0.9 0.6 0.20 0.04 0.24 17:1 1.0 0.4 0.8 0.32 0.03 0.35 18:0 4.4 6.2 4.8 1.50 0.43 1.93 18:lu9 27.4 12.6 24.9 9.25 0.88 10.13 18:2u6 2.4 0.6 2.0 0.78 0.04 0.82 18:3u>3 1.1 0.3 1.0 0.38 0.02 0.40 20:lu9 1.8 0.4 . 1.6 0.61 0.03 0.64 18:4w3 0.7 trace 0.6 0.22 trace 0.22 20:2w6 0.2 0.1 0.2 0.06 trace 0.06 20:3u>6 0.1 trace 0.1 0.04 trace 0.04 20:4ID6 1.7 2.6 1.9 0.58 0.18 0.76 22:la)9 0.2 - 0.2 0.07 - 0.07 20:4(D3 2.2 0.6 2.0 0.76 0.04 0.80 20:5(D3 8.2 5.7 7.8 2.77 0.40 3.17 22:3o)6 - trace trace - trace trace 22:4(D6 0.5 0.1 0.5 0.18 0.01 0.19 unknown 1.0 - . 0.8 0.32 - 0.32 22:4a)3 - 0.8 0.1 - 0.06 0.06 22:5(D3 6.0 2.8 5.4 2.00 0.20 2.20 22:6(D3 21.3 45.0 25.5 7.22 3.12 10.34 73 Table 10. Fa t t y a c i d composition of steelhead smolts reared i n net-pens. Values are means f o r four samples w i t h each sample c o n s i s t i n g of two f i s h . "Trace" i n d i c a t e s £0.05%, £0.005 mg/g. \ Fatty acid type 74 Fatty acid composition (%) Fatty acid (mg/g wet tissue) Neutral l i p i d Polar li p i d Whole lip i d Neutral l i p i d Polar l i p i d Whole li p i d 14:0 14:1 unknown 15:0 15:1 16:0 16:lu7 17:0 17:1 18:0 18:la)9 18:2a>6 18:3u6 18:303 20:lu9 18:4u)3 20:2b)6 20:3(D6 20:4u6 22:lu)9 20:4o)3 20:5u3 22:3o)6 22:4a)6 unknown 22:4o)3 unknown 22:5a)3 22:6(D3 2.1 0.2 0.1 0.4 trace 13.2 3.8 0.6 0.4 4.2 27.0 25.8 0.2 2.4 2.7 0.4 1.4 0.7 0.8 1.3 0.4 1.7 trace 0.2 1.2 0.6 7.8 0.6 trace trace 0.2 trace 18.7 1.4 0.6 0.1 5.2 10.2 5.5 0.7 0.4 0.1 0.6 0.6 3.1 0.2 4.4 trace 0.2 1.9 0.1 0.9 43.8 1.7 0.1 trace 0.3 trace 14.7 3.2 0.6 0.3 4.5 22.8 20.6 0.1 2.0 2.2 0.3 1.2 0.7 1.4 1.0 0.3 2.4 trace 0.2 0.9 0.5 trace 0.7 17.2 0.40 0.04 trace 0.07 0.01 2.58 0.74 0.11 0.08 0.81 5.27 5.03 0.03 0.47 0.53 0.07 0.28 0.14 0.16 0.25 0.07 0.33 0.01 0.04 0.23 0.12 1.52 0.04 trace trace 0.01 trace 1.28 0.10 0.04 0.01 0.36 0.70 0.38 0.05 0.03 trace 0.04 0.04 0.22 0.02 0.31 trace 0.01 0.13 trace 0.06 3.01 0.44 0.04 trace 0.08 0.01 3.86 0.84 0.15 0.09 1.17 5.97 5.41 0.03 0.51 0.56 0.07 0.32 0.18 0.38 0.25 0.09 0.64 0.01 0.05 0.23 0.13 trace 0.18 4.53 75 Table 11. F a t t y a c i d composition of some aquatic i n s e c t s and hatchery d i e t s . "Trace" i n d i c a t e s <0.05%. 76 Fatty a c i d composition (%) Aquatic i n s e c t s Hatchery d i e t s F atty Oregon a c i d Ephemei- Ple c - Chirono- T r i c h - moist S i l \ type optera optera midae optera p e l l e t Cup 14:0 3.6 1.2 5.4 6.2 4.3 3.3 14:1 0.6 1.2 2.8 3.8 0.1 0.1 unknown 0.2 0.1 - 0.2 - -15:0 0.4 tr a c e 0.6 0.1 0.2 0.4 15:1 0.1 - t r a c e - 0.3 0.1 16:0 26.2 17.0 19.9 22.4 13.5 17.9 16:lu7 14.7 9.3 14.3 12.2 9.8 4.4 17:0 - 0.8 - - - . 1.2 unknown tr a c e - t r a c e - - -17:1 1.0 1.0 0.8 1.1 0.9 0.7 18:0 2.2 3.8 3.7 2.2 2.0 4.7 18:la.9 20.4 32.4 23.3 22.3 16.8 17.0 unknown 0.2 - - - • 0.7 0.3 18:2u6 3.82 2.6 11.5 5.1 4.3 17.6 18:3u6 - - • ' 0.1 - - . 18:3(1)3 11.9 18.8 2.0 11.9 t r a c e 2.9 20:1(1)9 - - 1.4 - 12.5 2.3 18:4ID3 1.5 1.1 0.4 1.7 1.4 1.1 20:2u6 - - - - 0.1 0.2 20:3u6 - - - - - t r a c e 20:4u>6 0.7 1.0 2.0 0.6 tr a c e 1.1 22:lu.9 - - - - 17.8 2.1 20:4u3 0.1 0.1 0.2 - - 0.4 20:5a.3 11.7 8.7 9.7 7.6 7.1 6.4 22:4u6 - - - - 0.7 0.4 unknown 0.6 1.0 1.4 2.6 - _ 22:4u3 - - - - 1.5 1-3 22:5<i>3 - t r a c e - - 0.6 1.0 22:6u)3 0.2 - 0.6 - 5.4 13.3 77 Table 12. F a t t y a c i d c l a s s composition (%) of some aquatic i n s e c t s and hatchery d i e t s . Aquatic insects Fatty acid class composition Ephemeroptera Plecoptera Chironomidae Saturated 3 2 . 4 2 2 . 8 2 9 . 6 Monounsaturated 3 6 . 8 4 3 . 9 4 2 . 6 Polyunsaturated 2 9 . 9 3 2 . 3 2 6 . 5 w6 4 . 5 3 . 6 1 3 . 6 o)3 2 5 . 4 2 8 . 7 1 2 . 9 o)6/w3 0 . 1 8 0 . 1 3 1.05 Hatchery diets Oregon S i lver Moist Pel let Cup 3 0 . 9 2 0 . 0 2 7 . 5 3 9 . 4 5 8 . 2 2 6 . 7 2 6 . 9 21 .1 4 5 . 7 5 . 7 5.1 1 9 . 3 2 1 . 2 1 6 . 0 2 6 . 4 0 . 2 7 0 . 3 2 0 . 7 3 F i g . 1. Map of the study areas showing the Keogh, Qualicum and Capilano r i v e r s . 81 F i g . 2. Map of the Qualicum r i v e r system. 83 F i g . 3. Map of the Keogh r i v e r system. 84 Q U E E N CHARLOTTE STRAIT KEOGH SCALE 2 . 4 RIVER V k m O'CONNOR LAKE STEELHEAD PENS 85 F i g . 4. Map of the Capilano r i v e r system. 86 87 F i g . 5. Fork lengths of Qualicum coho salmon. Values are means w i t h 95% confidence l i m i t s . 88 89 F i g . 6. Wet weights of Qualicum coho salmon. Values are means w i t h 95% confidence l i m i t s . 20 90 91 F i g . 7. C o n d i t i o n f a c t o r s of Qualicum coho salmon. Values are means w i t h 95% confidence l i m i t s . 9 2 8.0 NATURAL I B fl PRODUCTION - CHANNEL o--o REARING - CHANNEL 7.0 cm O »— U < z o O 6.0| u 5.01 JL JULY SEPT NOV 1978 JAN MAR 1979 MAY 93 F i g . 8. Seasonal v a r i a t i o n s i n moisture content of Qualicum coho salmon. Values are means w i t h 95% confidence l i m i t s . 1 I I I I I 1 — MAY JULY SEPT NOV JAN MAR MAY 1978 1979 95 F i g . 9. Seasonal v a r i a t i o n s i n ash content of Qualicum coho salmon. Values are means w i t h 95% confidence l i m i t s . 96 MAY JULY SEPT 1978 NOV JAN MAR MAY 1979 97 F i g . 10. Seasonal v a r i a t i o n s i n p r o t e i n content of Qualicum coho salmon. Values are means w i t h 95% confidence l i m i t s . 98 1 • 1 I L. I I MAY JULY SEPT NOV JAN MAR MAY 1978 1979 99 F i g . 11. Seasonal v a r i a t i o n s i n l i p i d content of Qualicum coho salmon. Values are means w i t h 95% confidence l i m i t s . The sample taken on December 5, 1978 f o r the w i l d coho seems to be i n c o n s i s t e n t w i t h the other r e s u l t s . 100 NATURAL •-— PRODUCTION-CHANNEL o-.-o REARING-CHANNEL MAY JULY SEPT 1978 NOV JAN MAR 1979 MAY 101 F i g . 12. Saturated f a t t y a c i d s i n coho salmon from the Qualicum r i v e r . V e r t i c a l l i n e s represent one-half of the 95% confidence l i m i t s . Groups w i t h the same s u p e r s c r i p t form a homogeneous subset (AN0VA, Scheffe's t e s t , p<0.05). 28.01 26.0H 24.0-^ a 2 22.0H 20.0 4 18.0 I I PRODUCTION-CHANNEL [Til REARING-CHANNEL NATURAL J L 1 • • • • • • • • o u 12.0 < ~ M.O 3 O < OC z> t— < to cn \ E NEUTRAL POLAR WHOLE NEUTRAL POLAR WHOLE LIPID 103 F i g . 13. Monounsaturated f a t t y a c i d s i n coho salmon from the Qualicum r i v e r . V e r t i c a l l i n e s represent one-half of the 95% confidence l i m i t s . Groups w i t h the same s u p e r s c r i p t form a homogeneous subset (AN0VA, Scheffe's t e s t , p<0.05). PI PRODUCTION-CHANNEL t o Q t— »— < < OC < t o Z r> O z o 70.On y 58.0H < 46.0H 34.0-^  22.0-L E3 REARING-CHANNEL NATURAL 10.0 1 NEUTRAL POLAR I • • • • • • • • • • • • • • o • • • L WHOLE I X 1 X ' Innk'.'l 1 L.18.0 < • a • • • • • • • • • • a o o o • o • • • • • • o • I L O 9 24.0 ^ 12.0 V6.0 NEUTRAL POLAR WHOLE 3 < OC 3 t o Z I D o z o - o cn E LIPID 105 F i g . 14. Polyunsaturated f a t t y a c i d s i n coho salmon from the Qualicum r i v e r . V e r t i c a l l i n e s represent one-half of the 95% confidence l i m i t s . Groups w i t h the same s u p e r s c r i p t form a homogeneous subset (ANOVA, Scheffe's t e s t , p<_0.05). 66.CH 58. OH g 50.0-a,b J L 42.0-9. 34.04 26-0-18.0-1 a w . . IM I I • a • • • NEUTRAL a 1 D • • • • • • • Q O • • • • • • • • a a a • • • • • • • • • o • a • • • a • • • o • • • • a • • • • • • • • • • • • • • POLAR 1 f~ l PRODUCTION-CHANNEL 1 1 1 • • [ • a • • • • • • • • • I o I la a I • • l a • REARING-CHANNEL NATURAL ab • • • a a a a • • • a a a.b I TTTT • • • • a • • o • • • • • • • • • • • a • • • • 7tt 18.0 g 9 14.0 r 6 . 0 > _ ~ * o 10.0 £ CO wn < an U) < to Z 3 o o E WHOLE NEUTRAL POLAR LIPID WHOLE 107 F i g . 15. F a t t y a c i d s of the CJ6 s e r i e s i n coho salmon from the Qualicum r i v e r . V e r t i c a l l i n e s represent one-half of the 95% confidence l i m i t s . Groups w i t h the same s u p e r s c r i p t form a homogeneous subset (ANOVA, Scheffe's t e s t , p<0.05). I I PRODUCTION - CHANNEL H REARING - CHANNEL >N NATURAL 12.CH g < >-< •o 3 8.0-4.0-0 a.b b 1 " 1 a J L D • • • b b a , w • jr. t r n n o t v . 1 NEUTRAL POLAR WHOLE NEUTRAL POLAR • • • • i • c H6.0 r-4.0 12.0 WHOLE CO o < >-»— < o 3 0) 3 —' S o • - 00 e LIPID 109 F i g . 16. F a t t y acids of the o>3 s e r i e s i n coho salmon from the Qualicum r i v e r . V e r t i c a l l i n e s represent one-half of the 95% confidence l i m i t s . Groups w i t h the same s u p e r s c r i p t form a homogeneous subset (ANOVA, Scheffe's t e s t , p_<0.05). 6 O . O 1 50.0H CO o ^ 40.0-1 t— < CO 3 30.0H 20.0-10.0-a I a a I- ^ ~ • • a • ^ L»fi-I I • « PRODUCTION - CHANNEL [01 REARING-CHANNEL NATURAL NEUTRAL POLAR WHOLE a a a a T T,J i_ a |TT- I • • r • • 1 » • a a • • • • • • :| • o a • • • , » • • • • D n o • • !« • • • 0 > • NEUTRAL POLAR LIPID CO M2.0 9 < 8.0 L4.0 CO 3 WHOLE 3 >- 0) cn cn E I l l F i g . 17. Ratio of u>6/u>3 f a t t y a c i d s i n coho salmon from the Qualicum r i v e r , and steelhead t r o u t from the Keogh r i v e r . V e r t i c a l l i n e s represent one-half of the 95% confidence l i m i t s . Groups w i t h the same s u p e r s c r i p t form a homogeneous subset (ANOVA, Scheffe's t e s t , p<0.05). 2.4-1 2.0H </> o 1.6-< 1.2-< U-ro 3 0.8-X «o • 3 0.44 C] PRODUCTION-CHANNEL REARING-CHANNEL NATURAL i3 SM. 1 b a • a • D • b 4-NEUTRAL POLAR WHOLE COHO SALMON LIPID • PEN-REARED ± 3 NATURAL to 1 a NEUTRAL POLAR WHOLE STEELHEAD TROUT LIPID 113 F i g . 18. Saturated f a t t y a c i d s i n steelhead t r o u t from the Keogh r i v e r . V e r t i c a l l i n e s represent one-half of the 95% confidence l i m i t s . Groups w i t h the same s u p e r s c r i p t form a homogeneous subset (ANOVA, Scheffe's t e s t , p<0.05). CU P E N - R E A R E D N A T U R A L 27.(H 2 3 . 0-i 19.0H 1 5 . 0 1 a " 1 a j . > • « a J L a a H 2 . 0 NEUTRAL POLAR W H O L E N E U T R A L POLAR W H O L E LIPID 115 F i g . 19. Monounsaturated f a t t y a c i d s i n steelhead t r o u t from the Keogh r i v e r . V e r t i c a l l i n e s represent one-half of the 95% confidence l i m i t s . Groups w i t h the same s u p e r s c r i p t form a homogeneous subset (ANOVA, Scheffe's t e s t , p<0.05). 42.CH 34.CH 26.0-18.0-10.0-> • < > • < A l a • P E N - R E A R E D NATURAL I n n a 2. • • •; I • • NEUTRAL POLAR T T r20.0 H 6 . 0 M2.0 H8.0 h4.0 W H O L E NEUTRAL POLAR 0 W H O L E LIPID to Q U < < 3 —. L U CO cn < cn z E o z o 117 F i g . 20. Polyunsaturated f a t t y a c i d s i n steelhead t r o u t from the Keogh r i v e r . V e r t i c a l l i n e s represent one-half of the 95% confidence l i m i t s . Groups w i t h the same s u p e r s c r i p t form a homogeneous subset (ANOVA, Scheffe's t e s t , p<0.05). • P E N - R E A R E D g < < a L U < Z) < z > o 64 .(H a 56 .0H 48.0-40.0-• T , N A T U R A L u . a N EU T R A L POLAR W H O L E 1 1-K24.0 h8.0 NEUTRAL POLAR W H O L E 0 L I P I D CO g < < .2 M6.0 Q < to Z Z> >-I O 2 < CO E 119 F i g . 21. F a t t y a c i d s of the o>6 s e r i e s i n steelhead t r o u t from the Keogh r i v e r . V e r t i c a l l i n e s represent one-half of the 95% confidence l i m i t s . Groups w i t h the same s u p e r s c r i p t form a homogeneous subset (ANOVA, Scheffe's t e s t , p<0.05). I I PEN-REARED 32.0-g 24.0H < < UL. o 3 16.0 8.0< r h b e e • • •_2_ a • o • a a b FSI NATURAL l • v • v • v •!•• •••• NEUTRAL POLAR WHOLE NEUTRAL POLAR WHOLE LIPID H8.0 6 . 0 2 . 0 CO < 4 . 0 > < 3 a> o D-«/» a> ^ » c n E 121 F i g . 22. F a t t y a c i d s of the u3 s e r i e s i n steelhead t r o u t from the Keogh r i v e r . V e r t i c a l l i n e s represent one-half of the 95% confidence l i m i t s . Groups w i t h the same s u p e r s c r i p t form a homogeneous subset (ANOVA, Scheffe's t e s t , p<0.05). co 3 FATTY ACIDS ( 1 ) o b z m C —I TO > 1 o 6 Cn CO b _ i _ o I— > TO . . . . . . . . I cr X O z m C —( > ••••••••••••• •'• •••••• ••••••• • • •• • • ••••••••••• • • • • • •••••••••• • **••*•», | • « • • HO" 03 • z > —i a TO > z I TO m > TO ~o o I — > TO H Q T T > • • • • • H Q O • • < • • t • • • • • • • • • • • • » » « -H CT - r " 00 O T" b —r— to o CO 3 FATTY ACIDS ( mg / g wet tissue ) 123 Appendix t a b l e 1. Proximate composition (% dry t i s s u e ) of n a t u r a l l y - r e a r e d coho salmon from the Qualicum r i v e r . Values are means w i t h 95% confidence l i m i t s . 124 P r o x i m a t e c o m p o s i t i o n (% d r y t i s s u e ) S a m p l i n g N o . D a t e S a m p l e s A s h P r o t e i n L i p i d May 8 1 9 7 8 10 8 . 9 4 4- 0 . 9 1 7 4 . 3 4 + 4 , . 3 0 1 4 . 34 + 1 . 9 4 J u n e 13 10 11 . 8 3 + 1 . 4 7 7 6 . 36 + 4 , .81 1 0 . 6 0 + 2 . 1 8 J u l y 18 10 12 . 6 5 + 1 . 1 4 7 8 . 56 + 2 , . 2 7 7 . 45 + 1 . 1 7 Aug 15 15 12 . 0 8 + 0 . 5 6 7 7 . 85 + 1, . 9 3 7 . 43 + 0 . 8 4 S e p t 12 15 12 . 9 0 + 0 . 5 9 7 4 . 93 + 1, . 2 9 8 . 41 + 0 . 8 9 O c t 9 10 . 13 . 2 1 + 0 . 8 9 7 4 . 25 + 1. . 8 5 8 . 46 0 . 7 7 Nov 7 9 13 . 4 9 + 1 . 3 0 7 4 . 92 + 2 , .21 8 . 34 + 1 . 3 6 Dec 5 10 13 . 0 5 + 1 . 0 6 7 7 . 08 + 5 . . 1 6 1 4 . 31 + 2 . 3 0 J a n 9 1979 7 13 . 3 7 + 2 .71 7 1 . 8 0 + 5 , . 9 9 8 . 53 + 2 . 2 0 Feb 5 10 13 . 2 2 + 1 . 1 2 7 2 . 72 + 1 , .41 1 1 . 04 + 1 . 4 9 M a r 5 10 13 . 9 2 + 1 . 2 2 7 5 . 15 + 1. .77 7 . 53 4 1 . 2 8 A p r i l 2 6 15 . 2 3 + 2 . 6 7 7 5 . 37 + 2 . . 1 6 9 , 67 + 1 . 7 7 May 31 10 12 . 4 2 + 1 . 2 4 7 7 . 73 + 4 . . 4 0 1 4 . 25 + 2 . 0 5 125 Appendix t a b l e 2. Proximate composition (% dry t i s s u e ) of production-channel coho salmon from the Qualicum r i v e r . Values are means w i t h 95% confidence l i m i t s . 126 P r o x i m a t e c o m p o s i t i o n (% d r y t i s s u e ) S a m p l i n g N o . D a t e S a m p l e s A s h P r o t e i n L i p i d A p r i l 20 1978 10 7 . 4 1 + 0 . 5 8 7 3 . 1 1 + 5 . 8 6 1 7 . 1 3 + 1 . 2 7 Aug 22 15 9 . 6 1 + 0 . 3 2 6 3 . 8 0 + 1 . 6 9 2 1 . 2 1 + 1 . 2 0 J a n 15 1 9 7 9 10 1 0 . 2 9 + 0 . 8 5 6 8 . 1 9 + 3 . 9 1 1 6 . 6 2 + 3 . 1 5 A p r i l 9 10 1 1 . 0 2 + 0 . 6 1 6 5 . 3 8 + 3 . 3 0 1 8 . 7 8 + 2 . 0 3 May 14 10 1 0 . 7 2 + 0 . 9 7 6 5 . 9 0 + 1 . 6 7 1 8 . 5 9 + 1 . 4 1 127 Appendix t a b l e 3. Proximate composition (% dry t i s s u e ) of rearing-channel coho salmon from the Qualicum r i v e r . Values are means w i t h 9 5 % confidence l i m i t s . 128 P r o x i m a t e c o m p o s i t i o n (% d r y t i s s u e ) S a m p l i n g N o . D a t e ; S a m p l e s A s h P r o t e i n L i p i d A p r i l 2 0 1978 10 7 . 0 6 + 0 . 4 9 7 1 . 32 + 1 . 1 9 1 7 . 2 2 + 2 . 0 7 Aug 22 15 1 0 . 3 3 + 0 . 4 3 6 3 . 93 + 1 . 7 5 2 0 . 3 5 + 1 . 5 4 J a n 15 1979 10 1 1 . 3 1 + 1 . 2 9 6 8 . 81 + 1 . 7 0 1 4 . 5 1 + 1 . 5 2 A p r i l 9 10 1 2 . 7 6 + 0 . 9 9 7 2 . 00 + 1 . 8 0 1 3 . 4 5 + 0 . 9 7 May 17 10 1 1 . 9 9 + 0 . 5 2 6 9 . 25 + 1 . 2 2 1 5 . 2 8 + 0 . 8 1 129 Appendix t a b l e 4. Whole body proximate composition (% l i p i d - f r e e dry t i s s u e ) of coho salmon and steelhead t r o u t . Values are means w i t h 95% confidence l i m i t s . Groups w i t h the same s u p e r s c r i p t form a homogeneous subset (ANOVA, Scheffe's t e s t , p<0.05). Groups from d i f f e r e n t l i f e h i s t o r y stages and r i v e r systems are analysed s e p a r a t e l y . R e a r i ng method Q u a l i cum coho p r e s m o l t Q u a l i cum coho smol t C a p i l a n o coho smol t N a t u r a l P r o d u c t i on c h a n n e l R e a r i n g -c h a n n e l N a t u r a l P r o d u c t i on c h a n n e l Rea r i n g -c h a n n e l N a t u r a l H a t c h e r y Keogh s t e e l h e a d smol t N a t u r a l Pen P r o x i m a t e c o m p o s i t i o n (% l i p i d - f r e e d r y t i s s u e ) Ash P r o t e i n 16.83 ± 2.53 a 83.44 ± 2.37a 13.57 ± 0.87b 80.49 ± 2.77a 14.74 ± 1.14a 83.22 ± 1.90a 14.43 ± 1.22a 90.61 ± 3.88a 13.14 ± 1.09a 80.94 + 1.14b 14.16 ± 0.67a 81.98 ± 1.68b 14.07 ± 1.21 a 88.98 ± 2.36a 13.45 ± 1.57a 85.76 ± 3.53 a CO O 12.70 ± 1.55' 13.58 + 1.90' 84.04 ± 2.94' 83.36 ± 2.69' 

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