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Genetic structure in populations of steelhead trout in British Columbia Parkinson, Eric A. 1980

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GENETIC STRUCTURE IN POPULATIONS OF STEELHEAD TROUT IN BRITISH COLUMBIA by ERIC A. PARKINSON B . S C U.B.C. 1973 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF THE FACULTY OF GRADUATE STUDIES (Department of Zoology) We a c c e p t the t h e s i s as c o n f o r m i n g t o the r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA . December 15 1980 MASTER OF SCIENCE i n E r i c A. P a r k i n s o n , 1980 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of "Zoology The University of British Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 i i ABSTRACT Rainbow t r o u t (Salmo g a i r d n e r i ) c o l l e c t e d from 63 l o c a t i o n s i n B r i t i s h Columbia were s t u d i e d u s i n g e l e c t r o p h o r e s i s t o examine g e n e t i c s t r u c t u r i n g of p o p u l a t i o n s . Most c o l l e c t i o n s were from anadromous p o p u l a t i o n s , i n which gene f l o w i s p o s s i b l e between w i d e l y s e p a r a t e d l o c a t i o n s . Repeated s a m p l i n g of a number of l o c a t i o n s p r o v i d e d an e s t i m a t e of the i n t r a p o p u l a t i o n v a r i a b i l i t y of a l l o z y m e f r e q u e n c i e s . A l t h o u g h 20-30 enzyme l o c i were i n i t i a l l y s c r e e n e d f o r a s m a l l number of p o p u l a t i o n s , o n l y f o u r enzyme systems (LDH-4, SOD, MDH-3, IDH-3,4) were c o n s i s t e n t l y v a r i a b l e . The AGP-1 l o c u s was s c o r e d when p o s s i b l e because i t was h i g h l y v a r i a b l e i n two p o p u l a t i o n s . Each of t h e s e systems has been shown t o have a c l e a r g e n e t i c b a s i s by o t h e r w o r k e r s . In a d d i t i o n , the ME and SDH systems were used t o d i s t i n g u i s h c u t t h r o a t and rainbow t r o u t f r y which o f t e n cannot be e a s i l y d i s t i n g u i s h e d m o r p h o l o g i c a l l y . The v a r i a b i l i t y i n a l l o z y m e f r e q u e n c i e s w i t h i n streams was h i g h l y s i g n i f i c a n t f o r each of the f o u r enzyme systems s t u d i e d . T h i s v a r i a b i l i t y was not c l e a r l y a s s o c i a t e d w i t h d i f f e r e n c e s between l o c a t i o n s , year c l a s s e s or l i f e h i s t o r y s t a g e s . G e n e t i c d r i f t , a r e s u l t of the s m a l l numbers of a d u l t s spawning each year can account f o r a l l of the w i t h i n stream v a r i a b i l i t y . A h i e r a r c h i c a l ANOVA was used t o d e t e r m i n e the s i z e of a r e a i n which g e n e t i c s t r u c t u r i n g i s p r e s e n t i n Salmo  g a i r d n e r i . S i g n i f i c a n t d i f f e r e n c e s , i m p l y i n g g e n e t i c s t r u c t u r i n g , were found i n t h r e e out of f o u r systems between streams a d j a c e n t t o each o t h e r a l o n g a l a r g e r i v e r or ocean c o a s t l i n e . W i t h one e x c e p t i o n gene f r e q u e n c i e s averaged over l a r g e r a r e a s were u n i f o r m and s i m i l a r t o p r e v i o u s l y measured f r e q u e n c i e s i n a r e a s of the n o r t h w e s t e r n U n i t e d S t a t e s . The one e x c e p t i o n t o t h i s l a r g e s c a l e u n i f o r m i t y i s a s h a r p d i s c o n t i n u i t y i n LDH-4 and SOD f r e q u e n c i e s i n t r i b u t a r i e s of the F r a s e r R i v e r a t t h e boundary between th e c o a s t a l and i n t e r i o r r e g i o n s . A s i m i l a r d i s c o n t i n u i t y on the Columbia R i v e r i s c o n s i d e r e d t o r e p r e s e n t the boundary between two l a r g e groups of p o p u l a t i o n s i s o l a t e d d u r i n g the l a s t g l a c i a t i o n . E v i d e n c e a g a i n s t t h i s c o n t e n t i o n i n c l u d e s the l a c k of c o i n c i d e n c e of the LDH-4/S0D d i s c o n t i n u i t y i n the more n o r t h e r l y Dean and Skeena r i v e r s , the presence of n o n c o i n c i d e n t d i s c o n t i n u i t y i n AGP-1 and PEP f r e q u e n c i e s i n the F r a s e r and Columbia r i v e r s , r e s p e c t i v e l y , and e v i d e n c e of p h y s i o l o g i c a l e f f e c t s , i m p l y i n g s e l e c t i o n , i n the v a r i a t i o n a t the LDH-4 l o c u s . A s i n g l e non-anadromous p o p u l a t i o n t r a n s p l a n t e d from an i n t e r i o r l a k e t o a c o a s t a l l a k e a p p r o x i m a t e l y 40 y e a r s ago i s f i x e d f o r the SOD(IOO) a l l o z y m e v a r i a n t and shows no o b v i o u s i v change i n the f r e q u e n c y of the LDH-4(100) a l l o z y m e and t h e r e f o r e p r o v i d e s no e v i d e n c e of s e l e c t i o n a c t i n g on t h i s l o c u s . V TABLE OF CONTENTS ABSTRACT i i LIST OF TABLES v i LIST OF FIGURES v i i ACKNOWLEDGEMENTS v i i i INTRODUCTION 1 G e n e r a l L i f e H i s t o r y 10 MATERIALS AND METHODS 12 Sample C o l l e c t i o n 12 Sample P r e p a r a t i o n and E l e c t r o p h o r e s i s 13 Review of Enzyme Systems 15 RESULTS 19 W i t h i n Stream V a r i a b i l i t y 25 V a r i a b i l i t y Between Streams 28 DISCUSSION 52 APPLICATIONS TO STEELHEAD MANAGEMENT 78 LITERATURE CITED 86 LIST OF TABLES T a b l e 1. The B u f f e r Systems, S t a i n i n g S o l u t i o n s And R e f e r e n c e s For I n h e r i t a n c e S t u d i e s For Enzymes Used In T h i s Study 15 Ta b l e 2. V a r i a b i l t i y Between L o c a t i o n s In V a r i o u s S i z e d Streams 26 Tab l e 3. Summary Of The S i g n i f i c a n c e Of V a r i a b i l i t y Between Samples W i t h i n Streams 27 Ta b l e 4. Number Of P a r e n t s E x p e c t e d For P o i n t Samples Of Fr y 31 Ta b l e 5. Summary Of The R e s u l t s Of The O v e r a l l H e i r a r c h i c a l ANOVA 32 Ta b l e 6. C o r r e l a t i o n M a t r i x Of Frequency D i f f e r e n c e s At D i f f e r e n t L o c i 45 Tab l e 7. LDH-4 And SOD A l l o z y m e F r e q u e n c i e s In H e n r i e t t e And Penask Lakes 51 Tab l e 8. Average LDH-4 And SOD A l l o z y m e F r e q u e n c i e s In The S t e i n And N a h a t l a t c h R i v e r s And The C o a s t a l And I n t e r i o r Regions 61 Tab l e 9. A C o m p a r i s i o n Of LDH-4 And SOD A l l o z y m e F r e q u e n c i e s I n B. C. And The N o r t h w e s t e r n U. S. 71 LIST OF FIGURES F i g u r e 1. D i a g r a m a t i c R e p r e s e n t a t i o n Of S t e e l h e a d And C u t t h r o a t T r o u t Phenotypes At The SDH And ME L o c i 20 F i g u r e 2. Map Of Study Area 29 F i g u r e 3. Sources Of V a r i a t i o n In The A l l o z y m e F r e q u e n c i e s Of The Four V a r i a b l e Enzyme Systems 34 F i g u r e 4. Mean LDH-4(76) A l l o z y m e F r e q u e n c i e s 37 F i g u r e 5. Mean SOD(152) A l l o z y m e F r e q u e n c i e s 39 F i g u r e 6. Mean MDH-3(71) A l l o z y m e F r e q u e n c i e s 41 F i g u r e 7. Mean IDH-3,4(72) And IDH-3,4(.48) ' A l l o z y m e F r e q u e n c i e s 43 F i g u r e 8. Dendrogram Of The R e l a t i o n s h i p s Between C o a s t a l P o p u l a t i o n s 46 F i g u r e 9. Examples Of A l l o z y m e Frequency D i f f e r e n c e s At Two L o c i 49 F i g u r e 10. An Example Of Two P o s s i b l e R e l a t i o n s h i p s Between The P a t t e r n Of V a r i a t i o n Of The A l l o z y m e s At Two L o c i 68 F i g u r e 11. Large S c a l e Geographic V a r i a t i o n I n LDH-4 And SOD Gene F r e q u e n c i e s 73 v i i i ACKNOWLEDGEMENTS I would l i k e t o thank my committee members D r s . Don M c P h a i l , Judy Myers, Con Wehrhahn and Henry T s u y u k i f o r t h e i r a d v i c e and a s s i s t a n c e over the' l a s t f i v e y e a r s as w e l l as f o r r e v i e w i n g and e d i t i n g the m a n u s c r i p t . I would a l s o l i k e t o thank Dr. F r e d U t t e r f o r h i s t e c h n i c a l a s s i s t a n c e and D r s . Joe F e l s e n s t e i n and S t a n l e y Nash f o r t h e i r s t a s t i s t i c a l a d v i c e . J e r r y S t e i n b e r g and L l o y d H i l d e b r a n d p r o v i d e d a s s i s t a n c e i n both t h e l a b and the f i e l d and B i n g Sanson and Aenea P a r k i n s o n t y p e d the f i r s t d r a f t . The F i s h and W i l d l i f e Branch of B. C , thro u g h the Salmonid Enhancement Program, p r o v i d e d f i n a n c i a l s u p p o r t f o r t h i s p r o j e c t . F i n a l l y I would l i k e e x p r e s s my s i n c e r e g r a t i t u d e t o Ruth W i t h l e r who was always ready t o p a l a v e r over a p a r t i c u l a r l y ambiguous g e l or t o comment on my l a t e s t s t a t i s t i c a l and d i a l e c t i c a l b l u n d e r s . 1 INTRODUCTION R e c e n t l y i t has become c l e a r t h a t g e n e t i c d i f f e r e n t i a t i o n of p o p u l a t i o n s i s an i m p o r t a n t a s p e c t i n the e c o l o g y of many s p e c i e s of p l a n t s and a n i m a l s ( E n d l e r , 1977). Such d i f f e r e n t i a t i o n i s o f t e n a s s o c i a t e d w i t h o b v i o u s e n v i r o n m e n t a l changes (eg. heavy m e t a l r e s i s t a n c e i n g r a s s e s l i v i n g on and o f f of o l d mine t a i l i n g s ( J a i n and Bradshaw, 1966; A n t o n o v i c s , 1971), or the change i n c o a t c o l o u r of some s m a l l mammals l i v i n g on s o i l s of s h a r p l y c o n t r a s t i n g c o l o u r ( B l a i r , 1 9 5 0 ) ) . In o t h e r s i t u a t i o n s no o b v i o u s e n v i r o n m e n t a l change i s i n v o l v e d and the u n d e r l y i n g causes of d i f f e r e n t i a t i o n a r e e i t h e r d i f f i c u l t t o document or have d e f i e d adequate e x p l a n a t i o n . An example i s the complex p a t t e r n of s h e l l pigment v a r i a t i o n i n s n a i l s (Cepea) which was a t f i r s t thought t o be e n t i r e l y random. A tremendous amount of work over the l a s t 25 y e a r s has i m p l i c a t e d v a r i o u s s e l e c t i v e f o r c e s , but a number of d i s c o n t i n u i t i e s i n the p a t t e r n remain u n e x p l a i n e d ( C l a r k e , 1978; Jones et a l . , 1977). R e s t r i c t i o n of gene f l o w i s a key element i n d i f f e r e n t i a t i o n . T o t a l r e s t r i c t i o n of gene f l o w by g e o g r a p h i c b a r r i e r s appears t o be the b a s i s f o r the f o r m a t i o n of a number of s u b s p e c i e s complexes and i s the c l a s s i c a l e x p l a n a t i o n f o r s p e c i a t i o n (Mayr, 1963) b u t , i n the absence of g e o g r a p h i c 2 b a r r i e r s , i s o l a t i o n may occur because of r e s t r i c t e d movement by i n d i v i d u a l s . E n d l e r (1977) d e f i n e d m i g r a t i o n and d i s p e r s a l as the two t y p e s of movements made by i n d i v i d u a l s . M i g r a t i o n i s d e f i n e d as "the r e l a t i v e l y l o n g d i s t a n c e movements of l a r g e numbers of i n d i v i d u a l s i n a p p r o x i m a t e l y the same d i r e c t i o n a t a p p r o x i m a t e l y the same time and i s u s u a l l y f o l l o w e d by a r e g u l a r r e t u r n m i g r a t i o n " . D e s p i t e the l o n g d i s t a n c e s moved by m i g r a n t s , gene f l o w between p o p u l a t i o n s i s s e v e r e l y r e s t r i c t e d i n many s p e c i e s because i n d i v i d u a l s tend t o r e t u r n t o t h e i r b i r t h p l a c e t o b r e e d . In one example g u i l l e m o t s t y p i c a l l y b r e d w i t h i n a few meters of t h e i r b i r t h p l a c e f o l l o w i n g . a m i g r a t i o n of hundreds of m i l e s (Southern e_t a l . , 1965). D i s p e r s a l , on the o t h e r hand, i n v o l v e s randomly d i r e c t e d movements of i n d i v i d u a l s which u s u a l l y do not r e t u r n . E n d l e r p o i n t s out t h a t d i s p e r s a l i s o f t e n l e s s than mean d i s p e r s a l d i s t a n c e s i n d i c a t e because the d i s t r i b u t i o n of d i s p e r s a l d i s t a n c e s i s l e p t o k u r t i c . Thus, a few i n d i v i d u a l s d i s p e r s i n g l o n g d i s t a n c e s a r e not n e c e s s a r i l y an i n d i c a t i o n of h i g h d i s p e r s a l i n the s p e c i e s as a whole. In a d d i t i o n , post-movement mechanisms such as s o c i a l o s c t r a c i s m or d i f f e r e n c e s i n m i c r o h a b i t a t t o l e r a n c e s may reduce the s u c c e s s of d i s p e r s i n g i n d i v i d u a l s . Gene f l o w , t h e r e f o r e , can be s e v e r e l y r e s t r i c t e d even though t h e r e a r e no o b v i o u s b a r r i e r s t o d i s p e r s a l and the i n d i v i d u a l s i n v o l v e d a r e q u i t e c a p a b l e of. moving the n e c e s s a r y d i s t a n c e s . In anadromous s a l m o n i d s gene f l o w i s p o s s i b l e between 3 p o p u l a t i o n s s e p a r a t e d by almost any ge o g r a p h i c d i s t a n c e . J u v e n i l e s can d i s p e r s e w i t h i n r i v e r systems, and so p r o v i d e gene f l o w between p o p u l a t i o n s i n t r i b u t a r y streams. A d u l t s o f t e n m i g r a t e many hundreds of m i l e s and, a l t h o u g h they u s u a l l y r e t u r n t o t h e i r n a t a l stream, t h e r e a r e many documented i n s t a n c e s of s t r a y i n g t o bo t h nearby and d i s t a n t l o c a t i o n s ( H a r d i n - J o n e s , 1968; Shapavalov and T a f t , 1954; E v e r e s t , 1973). D e s p i t e t h i s apparent o p p o r t u n i t y f o r gene f l o w between p o p u l a t i o n s , g e n e t i c d i f f e r e n t i a t i o n appears t o be common among s a l m o n i d p o p u l a t i o n s s e p a r a t e d by l a r g e g e o g r a p h i c d i s t a n c e s or s t r o n g s e l e c t i v e g r a d i e n t s . Summer s t e e l h e a d s t o c k s from the Washougal, Deschutes and C l e a r w a t e r r i v e r s ( l o w e r , mid and upper Columbia R i v e r t r i b u t a r i e s ) d i s p l a y e d a h i g h r e s i s t a n c e t o a m y x o s p o r i d i a n p a r a s i t e t h a t i s common throughout the Columbia d r a i n a g e . In c o n t r a s t , a s t o c k from the S i l e t z R i v e r on the Oregon c o a s t , where the p a r a s i t e i s not p r e s e n t , l a c k e d r e s i s t a n c e (Buchanan, 1975). The Deschutes and C l e a r w a t e r s t o c k s a l s o r e s i s t e d i n f e c t i o n by two b a c t e r i a l d i s e a s e s a t te m p e r a t u r e s below 68°F whereas the Washougal s t o c k was o n l y r e s i s t a n t t o the same two d i s e a s e s a t te m p e r a t u r e s below about 62°F. T h i s d i f f e r e n c e i s presumably r e l a t e d t o temperature d i f f e r e n c e s between the n a t i v e environments of t h i s s t o c k . One i n s t a n c e of g e n e t i c d i f f e r e n t i a t i o n over a s h o r t d i s t a n c e i s i n s a l m o n i d s p e c i e s i n which the f r y r e a r i n l a k e s w h i l e the a d u l t s spawn i n both i n l e t and o u t l e t streams of the same l a k e . 4 O u t l e t f r y m i g r a t e upstream t o r e a c h the l a k e whereas i n l e t f r y m i g r a t e downstream. A l t h o u g h e n v i r o n m e n t a l f a c t o r s can s t r o n g l y i n f l u e n c e t h i s b e h a v i o r , t h e r e a l s o appears t o be a g e n e t i c component t o the m i g r a t i o n a l d i f f e r e n c e between i n l e t and o u t l e t s t o c k s (Bowler, 1975; c u t t h r o a t t r o u t ; R a l e i g h , 1971; sockeye salmon; N o r t h c o t e , 1969; rainbow t r o u t ) . T h i s g e n e t i c d i v e r g e n c e i s p r o b a b l y m a i n t a i n e d by s t r o n g s e l e c t i o n i n s p i t e of c o n s i d e r a b l e gene f l o w between the two p o p u l a t i o n s . R i d d e l l (1979) r e c e n t l y p r o v i d e d a n o t h e r example of g e n e t i c d i f f e r e n t i a t i o n between two p o p u l a t i o n s w i t h i n a s i n g l e , r i v e r system. A t l a n t i c salmon p a r r from a s t e e p e r , c o l d e r t r i b u t a r y of the M i r a m i c h i R i v e r i n New Brunswick had slimmer b o d i e s and l a r g e r f i n s than p a r r from a low g r a d i e n t , warmer t r i b u t a r y 90 k i l o m e t e r s downstream. In a few ca s e s g e n e t i c d i f f e r e n t i a t i o n has o c c u r r e d d e s p i t e a l a c k of o b v i o u s s e l e c t i v e . f o r c e s or b a r r i e r s t o i n t e r b r e e d i n g . S e a s o n a l s t o c k s commonly occur i n a number of s p e c i e s of anadromous s a l m o n i d s (Saunders, 1967; A t l a n t i c salmon: S m i t h , 1969; s t e e l h e a d t r o u t ) . S e a s o n a l s t o c k s a l l spawn a t the same time of year but e n t e r f r e s h w a t e r a t c o m p l e t e l y d i f f e r e n t t i m e s . T h i s h a b i t i s w e l l d e v e l o p e d i n s t e e l h e a d . Summer s t e e l h e a d (which e n t e r f r e s h w a t e r between May and September) a r e o f t e n p r e s e n t i n the same stream as w i n t e r s t e e l h e a d , (which e n t e r f r e s h w a t e r between November and May). Summer and w i n t e r s t o c k s d i f f e r s i g n i f i c a n t l y i n a number of 5 morphometric c h a r a c t e r i s t i c s . Smith (1969) demonstrated t h a t some of the s e d i f f e r e n c e s a r e under p a r t i a l g e n e t i c c o n t r o l thus i n d i c a t i n g r e s t r i c t i o n i n gene f l o w between summer and w i n t e r p o p u l a t i o n s . In some r i v e r s e a r l y e n t r y t o f r e s h w a t e r appears t o be an a d a p t a t i o n t o the presence of p h y s i c a l o b s t r u c t i o n s i n the stream which a r e i n s u r m o u n t a b l e a t o t h e r t i m e s of the y e a r . In o t h e r r i v e r s , however, t h e r e i s no ob v i o u s reason f o r e n t e r i n g f r e s h w a t e r i n s t e a d of r e m a i n i n g i n the ocean and f e e d i n g and growing f o r an e x t r a s i x t o e i g h t months b e f o r e r e t u r n i n g t o spawn. G e n e t i c d i f f e r e n t i a t i o n w i t h i n a s i n g l e d r a i n a g e has a l s o been demonstrated f o r kokanee salmon (Vernon, 1957), brown t r o u t (Ryman, A l l e n d o r f and S t a h l , 1978), A r c t i c char ( N i l s s o n and F i l i p s s o n , 1972) and l a k e w h i t e f i s h ( K i r k p a t r i c and S e l a n d e r , 1979). D i f f e r e n t i a t i o n i s s l i g h t i n the brown t r o u t and kokanee but approaches the s p e c i e s l e v e l i n the A r c t i c char and l a k e w h i t e f i s h . From the p r e c e e d i n g examples i t appears t h a t g e n e t i c s t r u c t u r i n g i n anadromous sa l m o n i d s can be on a v e r y f i n e s c a l e , s i n c e i n some c a s e s d i f f e r e n t i a t i o n t a k e s p l a c e w i t h i n a s i n g l e r i v e r system. I t i s d i f f i c u l t t o g e n e r a l i z e t o each s p e c i e s as a whole, however, s i n c e o n l y two, or a t most t h r e e p o p u l a t i o n s , can be compared i n each study because of the l o g i s t i c problems i n v o l v e d i n making comparisons of c h a r a c t e r i s t i c s under p a r t i a l p o l y g e n i c c o n t r o l . In c o n t r a s t , a l l o z y m e d a t a can be c o l l e c t e d from a l a r g e number of 6 p o p u l a t i o n s and used t o b u i l d up a more complete p i c t u r e of the g e n e t i c s t r u c t u r i n g w i t h i n a s p e c i e s . A major d i s a d v a n t a g e of a l l o z y m e d a t a i s t h a t the s e l e c t i v e f o r c e s i n v o l v e d are d i f f i c u l t t o measure and i n most c a s e s even the mechanism by which t h e s e f o r c e s a c t cannot be i d e n t i f i e d . A l t h o u g h the p r o b a b l e mechanism t h r o u g h which s e l e c t i v e f o r c e s a c t on m o r p h o l o g i c a l or b e h a v i o r a l c h a r a c t e r i s t i c s i s o f t e n known, the s i z e of the s e l e c t i v e f o r c e s i s a l s o v e r y d i f f i c u l t t o e s t i m a t e . For example, i n the case of f r y emerging i n i n l e t and o u t l e t streams of a l a k e , i t i s easy t o see t h a t f r y p e r s i s t e n t l y swimming i n the wrong - d i r e c t i o n w i l l not c o n t r i b u t e t o the next g e n e r a t i o n . I t i s more d i f f i c u l t , however, t o e s t i m a t e the c o s t of temporary m i s t a k e s or t o account f o r e n v i r o n m e n t a l l y i n d u c e d c o r r e c t i o n s i n f r y w i t h i n c o r r e c t genotypes. Simple o b s e r v a t i o n of a g e n e t i c a l l y c o n t r o l l e d m o r p h o l o g i c a l or b e h a v i o r a l d i f f e r e n c e between two p o p u l a t i o n s i s p r o b a b l y more i n f o r m a t i v e than a s i m i l a r a l l o z y m e f r e q u e n c y d i f f e r e n c e but n e i t h e r i s a b l e t o g i v e a good i n d i c a t i o n of the s e l e c t i v e importance of such a d i f f e r e n c e . E l e c t r o p h o r e c t i c s t u d i e s have p r o v i d e d e v i d e n c e of f i n e s c a l e g e n e t i c d i f f e r e n t i a t i o n of p a r t i a l l y i s o l a t e d p o p u l a t i o n s i n many u n r e l a t e d s p e c i e s . E x t e n s i v e work on D r o s o p h i l a spp. r e v e a l s d i f f e r e n t i a t i o n i n gene f r e q u e n c i e s over d i s t a n c e s as s m a l l as 100 meters (Richmond, 1978). D r o s o p h i l a a r e q u i t e 7 0 c a p a b l e of moving much f a r t h e r than t h i s but a p p a r e n t l y do not do so v e r y o f t e n and/or v e r y s u c c e s s f u l l y . S e m i - i s o l a t e d human p o p u l a t i o n s such t h o s e i n S a r d i n i a n mountain v i l l a g e s (Workman et a l , 1979) or A m e r i n d i a n s (Smouse and Ward, 1978; Workman and Niswander, 1970) a l s o show d i f f e r e n c e s over d i s t a n c e s t h a t a r e much s h o r t e r than the p o t e n t i a l d i s p e r s a l d i s t a n c e s of p r i m i t i v e p e o p l e s . Other examples of f i n e s c a l e g e n e t i c s t r u c t u r i n g can be found i n s n a i l s ( S e l a n d e r and Kaufman, 1975), mussels (Koehn, 1978), newts (Hedgecock, 1978), and the e e l p o u t ( C h r i s t i a n s e n and F r y d e n b e r g , 1974). A number of s a l m o n i d s p e c i e s have been s t u d i e d e l e c t r o p h o r e t i c a l l y but no r e a l l y d e t a i l e d a n a l y s e s of g e n e t i c s t r u c t u r e have been done. Most s t u d i e s a r e based on a r e l a t i v e l y s m a l l number of samples from a l a r g e g e o g r a p h i c a l a r e a . G e n e r a l l y t h e s e s t u d i e s i n d i c a t e t h a t t h e r e can be marked d i f f e r e n c e s between anadromous s a l m o n i d p o p u l a t i o n s s e p a r a t e d by d i s t a n c e s g r e a t e r than 100 m i l e s . Maximum gene f r e q u e n c y d i f f e r e n c e s i n v a r i o u s s p e c i e s a r e .25 ( P i n k salmon, G-6-PDH; A s p i n w a l l , 1974), .18 (Sockeye salmon, LDH; Hodgins et a l , 1969), .53 ( A t l a n t i c salmon, t r a n f e r r i n ; M o l l e r , 1971), .67 (Coho salmon, t r a n s f e r r i n ; U t t e r e_t a l . , 1970) and .71 ( S t e e l h e a d t r o u t , LDH; A l l e n d o r f , 1975). S m a l l e r but s t a s t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e s o c c u r w i t h i n much s m a l l e r a r e a s . For example, the n o r t h w e s t and southwest M i r a m i c h i r i v e r s e n t e r the same e s t u a r y but samples of A t l a n t i c 8 salmon from these two r i v e r s had a .15 d i f f e r e n c e i n the f r e q u e n c y of t r a n s f e r r i n a l l e l e s ( M o l l e r , 1971). Coho salmon samples from two t r i b u t a r i e s of the lower Columbia R i v e r d i f f e r e d by .2 i n the f r e q u e n c y of the t r a n s f e r r i n - c a l l e l e ( U t t e r e t a l , 1970). A l l e n d o r f (1975) r e p o r t s a number of d i f f e r e n t gene f r e q u e n c i e s of v a r i o u s a l l e l e s i n the .1 t o .2 range between s t e e l h e a d samples from r i v e r s e n t e r i n g e i t h e r the ocean or the Columbia R i v e r w i t h i n 100 m i l e s of each o t h e r . The s i g n i f i c a n c e of these f i n e s c a l e d i f f e r e n c e s i s u s u a l l y d e t e r m i n e d by u s i n g the b i n o m i a l s a m p l i n g v a r i a n c e as an e s t i m a t e of the w i t h i n p o p u l a t i o n v a r i a n c e . Repeated s a m p l i n g of p o p u l a t i o n s , which i s n e c e s s a r y t o e s t i m a t e the t r u e w i t h i n p o p u l a t i o n v a r i a n c e , has not been done, and t h e r e f o r e the t r u e s i g n i f i c a n c e of t h e s e f i n e s c a l e d i f f e r e n c e s cannot be d e t e r m i n e d . G e n e t i c s t r u c t u r i n g can be an i m p o r t a n t c o n s i d e r a t i o n i n . the management of s t e e l h e a d . For many y e a r s g e n e t i c d i f f e r e n c e s between anadromous s a l m o n i d p o p u l a t i o n s were c o n s i d e r e d t o be i n s i g n i f i c a n t . A ttempts were made t o manage p o p u l a t i o n s ( i e . s t o c k s ) of f i s h on an i n d i v i d u a l demographic b a s i s but e x t e n s i v e t r a n s p l a n t a t i o n programs were used t o r e p l e n i s h d e p l e t e d s t o c k s . A c c u m u l a t i n g e v i d e n c e of some g e n e t i c d i f f e r e n t i a t i o n and i s o l a t i o n between s t o c k s i n a number of 9 s a l m o n i d s p e c i e s has l e a d t o a g e n e r a l d i s s a t i s f a c t i o n w i t h the p o l i c y of e x t e n s i v e t r a n s p l a n t a t i o n . To c l a r i f y t r a n s p l a n t p o l i c y , more i n f o r m a t i o n i s needed on the s c a l e on which d i f f e r e n t i a t i o n t a k e s p l a c e and on the importance of t h a t d i f f e r e n t i a t i o n . E s t i m a t i n g the s c a l e of d i f f e r e n t i a t i o n , i . e . the g e o g r a p h i c d i s t a n c e s over which g e n e t i c d i f f e r e n t i a t i o n can t a k e p l a c e , i s the f i r s t s t e p i n t r y i n g t o e s t a b l i s h the d i s t a n c e over which t r a n s p l a n t s w i l l have l i t t l e e f f e c t on the p r e s e n t p a t t e r n of g e n e t i c d i f f e r e n t i a t i o n w i t h i n the s p e c i e s . I f t h i s s c a l e i s d e f i n e d u s i n g l o c i w i t h s m a l l s e l e c t i v e c o e f f i c i e n t s , d i f f e r e n t i a t i o n can occur a t most l o c i between p o p u l a t i o n s s e p a r a t e d by g r e a t e r d i s t a n c e s ( g i v e n t h a t s t r a y i n g r a t e s a r e dependent on the d i s t a n c e between p o p u l a t i o n s r a t h e r t h a n , f o r example, s i m i l a r i t y between e n v i r o n m e n t s ) . P o p u l a t i o n s s e p a r a t e d by s m a l l e r d i s t a n c e s c o u l d o n l y d i f f e r e n t i a t e a t l o c i where r e l a t i v e l y s t r o n g s e l e c t i o n was o p e r a t i n g . Once the s c a l e of g e n e t i c d i f f e r e n t i a t i o n i s e s t a b l i s h e d , the s i z e of the s e l e c t i v e advantage of d i f f e r e n t s t o c k s i n d i f f e r e n t environments has t o be measured t o d e t e r m i n e the importance of g e n e t i c s t r u c t u r i n g . G e n e t i c i s o l a t i o n by i t s e l f does not n e c e s s a r i l y imply t h a t e n v i r o n m e n t a l d i f f e r e n c e s a r e 10 l a r g e enough t o produce b i o l o g i c a l l y i m p o r t a n t l o c a l a d a p t a t i o n . The p r i m a r y o b j e c t i v e of t h i s t h e s i s i s t o use a l l o z y m e v a r i a t i o n t o e s t i m a t e the s c a l e of d i f f e r e n t i a t i o n i n s t e e l h e a d t r o u t . G e n e r a l L i f e H i s t o r y Salmo g a i r d n e r i p o p u l a t i o n s a r e u s u a l l y c l a s s i f i e d i n t o two main groups. Non-anadromous p o p u l a t i o n s , g e n e r a l l y termed rainbow t r o u t , occupy many l a k e s and streams throughout the p r o v i n c e , but a r e most common e a s t of the Coast Mountain c r e s t . My study i s m o s t l y concerned w i t h anadromous p o p u l a t i o n s , g e n e r a l l y termed s t e e l h e a d t r o u t , which spawn and r e a r i n almost a l l a c c e s s i b l e c o a s t a l r i v e r s and streams and a r e r e p o r t e d t o m i g r a t e up the F r a s e r R i v e r as f a r as P r i n c e George ( C a r l , Clemens and L i n d s e y , 1967). J u v e n i l e s t e e l h e a d can l i v e i n streams f o r one t o f i v e y e a r s ; however, i n B.C. the m a j o r i t y l i v e from 2 t o 3 y e a r s i n f r e s h w a t e r ( W i t h l e r , 1966; Maher and L a r k i n , 1955; N a r v e r , 1969). Smolts u s u a l l y m i g r a t e downstream between March and June a t a s i z e of 150 t o 210 mm and spend between a few months and f o u r y e a r s i n the sea b e f o r e r e t u r n i n g t o t h e i r n a t a l stream ( P e t e r s o n and Lyons, 1968; W a l l i s , 1968; E v e r e s t , 1973). A f t e r spawning, some a d u l t s s u r v i v e t o r e t u r n t o the sea and, a f t e r spending one or two a d d i t i o n a l summers i n the ocean, r e t u r n t o spawn a g a i n . The r e p o r t e d i n c i d e n c e of r e p e a t spawning i n B r i t i s h Columbia r i v e r s ranges from 4.4 % t o 11 31.3 % ( W i t h l e r 1966) but Jones (1974) r e p o r t e d an i n c i d e n c e of re p e a t spawning of 42% i n P e t e r s b u r g Creek, A l a s k a . T i m i n g of the main a d u l t run i s h i g h l y v a r i a b l e ( W i t h l e r , 1966), but appears t o be under some degree of g e n e t i c c o n t r o l ( E v e r e s t , 1973; Wagner, 1967). F i s h t h a t e n t e r f r e s h w a t e r between June and September i n s e x u a l l y immature c o n d i t i o n a r e termed "summer" s t e e l h e a d . S e x u a l l y m a t u r i n g f i s h e n t e r i n g f r e s h w a t e r between October and May a r e termed " w i n t e r " s t e e l h e a d . 12 MATERIALS AND METHODS Sample C o l l e c t i o n C o l l e c t i o n s were made i n streams i n so u t h w e s t e r n B r i t i s h Columbia on d a t e s d e t a i l e d i n Appendix 1. S t o c k i n g r e c o r d s i n d i c a t e t h a t few t r a n s p l a n t s or r e a r i n g o p e r a t i o n s have o c c u r r e d i n t h e s e streams and t h e p o p u l a t i o n s can t h e r e f o r e be c o n s i d e r e d t o be e s s e n t i a l l y pure n a t i v e s t o c k . Some r i v e r s were sampled r e p e a t e d l y t o t e s t f o r d i f f e r e n c e s i n gene f r e q u e n c i e s between l o c a t i o n s more than one k i l o m e t e r a p a r t , between year c l a s s e s and between l i f e h i s t o r y s t a g e s . A l t h o u g h most samples c o n s i s t e d of f r y or p a r r , some s m o l t , anadromous a d u l t and r e s i d e n t a d u l t samples were a l s o t a k e n . F r y and p a r r were c o l l e c t e d by e l e c t r o s h o c k i n g a s m a l l s e c t i o n of stream ( u s u a l l y l e s s than 100 meters) u n t i l 40-50 i n d i v i d u a l s were c a p t u r e d . In sp a r s e p o p u l a t i o n s 40 i n d i v i d u a l s c o u l d not always be found. F r y and p a r r were e a s i l y d i f f e r e n t i a t e d by s i z e , but p a r r were not aged and p r o b a b l y c o n t a i n e d two or t h r e e age groups. Smolts were c a p t u r e d i n t r a p s or g i l l n e t s and were d i f f e r e n t i a t e d from p a r r by t h e i r s i z e and s l i m , s i l v e r y appearance. A d u l t s were o b t a i n e d from a n g l e r c a t c h e s and h a t c h e r i e s which u t i l i z e d w i l d a d u l t s as brood s t o c k . R e s i d e n t rainbow samples were o b t a i n e d by a n g l i n g and g i l l n e t t i n g . In streams w i t h a c c e s s t o the sea , o n l y f i s h between 220 mm and 400 mm were c o n s i d e r e d r e s i d e n t s . Samples were u s u a l l y f r o z e n 13 on d r y i c e or brought back a l i v e and i m m e d i a t e l y f r o z e n . Some, samples were p r e s e r v e d on i c e f o r up t o 12 hours b e f o r e b e i n g f r o z e n . A n g l e r - c a u g h t a d u l t s and some r e s i d e n t f i s h c o u l d not be r e f r i g e r a t e d f o r up t o 12 hours a f t e r d e a t h . Some l o s s i n a c t i v i t y and s u p e r f l u o u s banding ( e s p e c i a l l y i n IDH) was noted i n p o o r l y p r e s e r v e d f i s h , p a r t i c u l a r l y i n f r y . Sample P r e p a r a t i o n And E l e c t r o p h o r e s i s Groups of f i s h f r o z e n i n a s i n g l e b l o c k were thawed and then each f i s h was r e f r o z e n t o f a c i l i t a t e removal of l i v e r s . T i s s u e e x t r a c t s of l i v e r and muscle were p r e p a r e d by combining a p p r o x i m a t e l y e q u a l amounts of t i s s u e and d i s t i l l e d water i n a 12 x 75 mm t e s t t u b e , f r e e z i n g t h i s m i x t u r e f o r up t o a week and then c e n t r i f u g i n g the samples a t lOOOxg f o r 5 minutes b e f o r e l o a d i n g the g e l . Test tubes were kept immersed i n i c e w a t e r d u r i n g sample p r e p a r a t i o n and g e l l o a d i n g . C e n t r i f u g i n g , homogenizing and r e p e a t e d f r e e z i n g of the sample had no n o t i c e a b l e e f f e c t on the i n t e n s i t y or q u a l i t y of the banding p a t t e r n s of the enzymes used i n t h i s s t u d y . E l e c t r o p h o r e t i c a n a l y s e s were conducted u s i n g equipment and methods d e s c r i b e d by May e t a_l. 1979 and U t t e r e t a l . 1974. Two b u f f e r systems were used: 1) A f t e r Ridgeway e t a_l. , 1970, e l e c t r o d e b u f f e r .06M LiOH, .3M b o r i c a c i d (pH 8.3), g e l b u f f e r 14 .005M c i t r i c a c i d , .03M t r i s (pH 8.3), and 2) a f t e r Shaw and P r a s s a r d , 1970, .155M t r i s , .043M c i t r i c a c i d (pH 7.0) used f u l l s t r e n g t h f o r the e l e c t r o d e b u f f e r and d i l u t e d 1:15 w i t h d i s t i l l e d water f o r the g e l b u f f e r . S t a i n i n g s o l u t i o n s , d e t a i l e d i n Table 1, were adapted from A l l e n d o r f , 1975. A l t h o u g h a number of l o c i were i n i t i a l l y s c r e e n e d o n l y f i v e systems (LDH-4, SOD, MDH-3, AGP-1, IDH-3,4) were r e g u l a r l y s c o r e d f o r each p o p u l a t i o n . In a d d i t i o n , the phenotypes of two enzyme systems, ME and SDH, were used t o s e p a r a t e c u t t h r o a t t r o u t from rainbow t r o u t . A l l of the p o l y m o r p h i c l o c i d e s c r i b e d i n t h i s s tudy have been used by o t h e r workers and i n each case a s i m p l e M e n d e l i a n i n h e r i t a n c e of v a r i a n t s has been documented (see r e f e r e n c e s g i v e n i n T a b l e 1 ) . Complete names and c o r r e s p o n d i n g a b b r e v i a t i o n s are l i s t e d i n T a b l e 1. Review Of Enzyme Systems The LDH system i n s a l m o n i d s c o n s i s t s of a complex of f i v e l o c i ( M o r r i s o n and W r i g h t , 1966; U t t e r , A l l e n d o r f and Hodgins, 1973; B a i l e y , T s u y u k i and W i l s o n , 1976). The most p o l y m o r p h i c of t h e s e l o c i i s LDH-4. I t i s e x p r e s s e d i n most t i s s u e s , . b u t i s the o n l y LDH l o c u s s t r o n g l y e x p r e s s e d i n the l i v e r . The M e n d e l i a n i n h e r i t a n c e of v a r i a n t s a t t h i s l o c u s i n Salmo  g a i r d n e r i was e s t a b l i s h e d by U t t e r e t a l . (1973) and S t i l l i n g (1974, c i t e d by K l a r e t a l . 1979a). The s p a t i a l d i s t r i b u t i o n of a l l o z y m e f r e q u e n c i e s a t t h i s l o c u s was r e p o r t e d by Huzyk and Table 1. De t a i l s of electrophoretic methods and stains f o r the enzyme systems used i n t h i s study in c l u d i n g references documenting the genetic nature of the v a r i a t i o n i n each system.  Buffer Reference f o r Enzyme Locus Tissue System Stain Solution* Inheritance Studies LDH-4 (Lactate Dehydrogenase) Liver 10 mis .5 m PL-Na-lactate 5 mg NAD Allendorf (1973) SOD (Superoxide Dimutase) Liver Stain adjusted to pH 8.5 Cedarbaum and Yoshida (1972) SDH (Sor b i t o l Dehydrogenase) Li v e r 1.5 g. s o r b i t a l 5 mg. NAD ME (Malic Enzyme) Liv e r II 10 mis .5 m Na-Malate 5 mg NADP AGP-1 White (Alpha-glycerophosphate Muscle Dehydrogenase) , II 1.5 g a glycerophosphate 5 mg NAD Allendorf (1975) IDH-3,4 (Is o c i t r a t e Dehydrogenase) MDH-3, 4 (Malate Dehydrogenase) Liver White Muscle II II 50 mg Na - l s o c i t r a t e 5 mg NADP 10 mis .5 m Na-malate 5 mg NAD Allendorf (1975) Ropers et al. (1973) Reintz (1977) Bailey et al. (1970) Allendorf (1975) * a l l s tains contain 5 mg PMS, 15 mg MTT, and are mixed i n 100 mis of Buffer I g e l buffer. 16 T s u y u k i (1974) f o r 14 l o c a t i o n s i n B r i t i s h C olumbia; by A l l e n d o r f (1975) f o r 35 l o c a t i o n s i n Washington and s u r r o u n d i n g s t a t e s , and by N o r t h c o t e e t a_l. (1970) f o r 2 l o c a t i o n s above and below a w a t e r f a l l i n the i n t e r i o r of B r i t i s h Columbia. D i f f e r e n c e s i n the k i n e t i c p r o p e r t i e s of the two v a r i a n t s were found by T s u y u k i and W i l l i s c r o f t (1973). V a r i o u s p h y s i o l o g i c a l and b e h a v i o r a l t r a i t s have been a s s o c i a t e d w i t h one or the o t h e r of the a l l o z y m e s a t t h i s l o c u s by K l a r et a l . (1979a,b) Redding and Schreck (1979) and T s u y u k i and W i l l i s c r o f t (1977). The SOD system i n s t e e l h e a d c o n s i s t s of a s i n g l e v a r i a b l e l o c u s i n Salmo g a i r d n e r i ( U t t e r e t a_l. , 1973). The M e n d e l i a n i n h e r i t a n c e of t h i s v a r i a t i o n was c o n f i r m e d by Cedarbaum and Y o s h i d a (1972) and U t t e r et a l . (1973) and the g e o g r a p h i c a l d i s t r i b u t i o n of a l l o z y m e f r e q u e n c i e s i n 35 l o c a t i o n s i n Washington and s u r r o u n d i n g s t a t e s was r e p o r t e d by A l l e n d o r f ( 1 9 7 5). A w i d e r d i s t r i b u t i o n a l map f o r v a r i a n t s a t b o t h t h i s and the LDH-4 l o c u s i s g i v e n by U t t e r and A l l e n d o r f (1977). MDH o c c u r s i n a c y t o p l a s m i c form and a m i t o c h o n d r i a l form i n Salmo g a i r d n e r i ( C l a y t o n e_t a_l. , 1975; B a i l e y e t a l . (1970). The c y t o p l a s m i c system c o n s i s t s of f o u r l o c i , a d u p l i c a t e d l o c u s e x p r e s s e d p r i m a r i l y i n l i v e r and another d u p l i c a t e d l o c u s e x p r e s s e d p r i m a r i l y i n muscle t i s s u e . At l e a s t one of the muscle l o c i (MDH-3) i s p o l y m o r p h i c but the observ e d phenotypes 17 i n t h i s s t u d y p r o v i d e d no e v i d e n c e f o r (or a g a i n s t ) polymorphism a t the o t h e r l o c u s (MDH-4). C l a y t o n e t a l . (1975) p r o v i d e e v i d e n c e t h a t a l l f o u r a l l e l e s a r e p r e s e n t a t both l o c i i n t h e i r p o p u l a t i o n s . U t t e r et a l . (1973), C l a y t o n e t a l . (1975) and B a i l e y e t a_l. (1970) a l l p r e s e n t e v i d e n c e t h a t these a l l e l e s a r e i n h e r i t e d i n a M e n d e l i a n manner. The ge o g r a p h i c d i s t r i b u t i o n of a l l o z y m e f r e q u e n c i e s a t 35 l o c a t i o n s has been r e p o r t e d by A l l e n d o r f (1975). In the ANOVA a n a l y s i s , the f r e q u e n c i e s of the MDH-3(118) a l l e l e were p o o l e d w i t h t h o s e of the MDH-3Q00) a l l e l e , s i n c e MDH-3(118) was r a r e i n a l l p o p u l a t i o n s . The f r e q u e n c i e s of MDH-3(67) and MDH-3(72) were a l s o p o o l e d because they were not d i s t i n g u i s h e d from each o t h e r i n a l l p o p u l a t i o n s . A l t h o u g h b r e e d i n g s t u d i e s ( U t t e r e t a l . , 1973), c o n f i r m the M e n d e l i a n i n h e r i t a n c e of v a r i a n t s i n the AGP system, the g e n e t i c model f o r t h i s system i s s t i l l u n c l e a r . E a r l i e r r e p o r t s ( U t t e r and Hodgins, 1972) i n d i c a t e d t h a t AGP was encoded by a s i n g l e v a r i a b l e l o c u s (AGP-1) but A l l e n d o r f (1975) d e t e c t e d what appeared t o be a second i n v a r i a n t l o c u s (AGP-2). May et a l . (1979) r e c e n t l y r e p o r t e d t h a t the presence of t h i s second l o c u s may be an a r t i f a c t . A f a s t e r zone of weak a c t i v i t y may i n d i c a t e an a d d i t i o n a l two l o c i , b o t h of which appear t o be v a r i a b l e . These two l o c i were not s c o r e d because they were d e t e c t e d l a t e i n the study and d i s p l a y e d i n c o n s i s t a n t a c t i v i t y . 18 The IDH system i n the l i v e r t i s s u e of Salmo g a i r d n e r i appears t o c o n s i s t of two p o l y m o r p h i c l o c i (lDH-3,4) which share f o u r common a l l e l e s . B r e e d i n g s t u d i e s i n d i c a t e t h a t t h i s v a r i a t i o n i s i n h e r i t e d i n a M e n d e l i a n f a s h i o n ( A l l e n d o r f and U t t e r , 1973; Ropers et a l . , 1973; R e i n i t z , 1977). A l t h o u g h most a u t h o r s agree t h a t t h i s enzyme i s a dimer, R e i n i t z (1977) b e l i e v e s i t t o be a monomer. T h i s c o n f u s i o n does not a f f e c t the c l a s s i f i c a t i o n of i n d i v i d u a l f i s h i n t o g e n o t y p i c groups. Because of s u p e r f l u o u s bands p r e s e n t i n p o o r l y p r e s e r v e d samples and p h e n o t y p i c v a r i a t i o n which has not been r e p o r t e d by o t h e r a u t h o r s , IDH was c o n s i d e r e d t o be the most u n s t a b l e of the f i v e enzymes. Because of t h e s e problems the f r e q u e n c i e s of the f o u r a l l e l e s are r e p o r t e d s e p a r a t e l y i n Appendix 1, but the f r e q u e n c i e s of the two f a s t a l l e l e s and the two slow a l l e l e s were p o o l e d i n the a n a l y s i s . T h i s was done because the e x a c t number of each a l l e l e i n each i n d i v i d u a l c o u l d not always be d e f i n i t e l y d e t e r m i n e d . 19 RESULTS Four enzyme systems (LDH-4, SOD, MDH-3, IDH-3,4) were v a r i a b l e enough t o be used i n the l a r g e s c a l e a n a l y s e s . In a d d i t i o n one l o c u s (AGP-1) was v a r i a b l e a t a c o n s i s t e n t l y low fr e q u e n c y (<.05) over most of the s p e c i e s range but was p r e s e n t i n h i g h f r e q u e n c y i n the C h i l c o t i n and B r i d g e r i v e r s . Another l o c u s , IDH-1,2, was found t o be v a r i a b l e but was not used because i t c o u l d not be c o n s i s t e n t l y r e s o l v e d , was u s u a l l y o n l y s l i g h t l y v a r i a b l e and c o u l d not be f i t t e d t o a g e n e t i c model. The IDH-3,4 system was h i g h l y v a r i a b l e but p a t t e r n s were o f t e n d i f f i c u l t t o i n t e r p r e t , p a r t i c u l a r l y i n p o o r l y p r e s e r v e d samples. A l t h o u g h mating s t u d i e s showed t h e v a r i a n t s t o be i n h e r i t e d i n a s i m p l e M e n d e l i a n f a s h i o n , some p h e n o t y p i c d i f f e r e n c e s i n p a t t e r n s seemed t o be p r e s e n t (see a l s o R e i n i t z , 1977; F i g . 3 ) . T h i s p h e n o t y p i c v a r i a t i o n made p r e c i s e d e t e r m i n a t i o n of genotypes d i f f i c u l t i n about 5 % of t h e f i s h examined. Two of t h e problems i n s a m p l i n g j u v e n i l e Salmo i n B r i t i s h Columbia streams a r e d i s t i n g u i s h i n g c u t t h r o a t t r o u t from s t e e l h e a d t r o u t , and d i s t i n g u i s h i n g anadromous s t e e l h e a d from non-anadromous rainbow t r o u t . A c o m b i n a t i o n of two l o c i (ME, SDH) was used t o d i s t i n g u i s h c u t t h r o a t from rainbow t r o u t ( F i g . 1 ) . Each of the t h r e e d i f f e r e n t SDH phenotypes i n s t e e l h e a d 20 F i g u r e 1. D i a g r a m a t i c r e p r e s e n t a t i o n of s t e e l h e a d and c u t t h r o a t t r o u t phenotypes a t the SDH and ME l o c i . V Steelhead Cutthroat S D H Steelhead Cutthroat M E 22 c o u l d be d i s t i n g u i s h e d from the i n v a r i a n t c u t t h r o a t phenotype. O c c a s i o n a l presumed h e t e r o z y g o t e s were found a t b o t h l o c i but the r e s u l t s of such f i s h were d i s c a r d e d . Mixed samples of 40 p a r r from the Keogh, Bhrom, B e r t r a n d , and Salmon r i v e r s were i d e n t i f i e d m o r p h o l o g i c a l l y and e l e c t r o p h o r e t i c a l l y . In a l l c a s e s m o r p h o l o g i c a l and e l e c t r o p h o r e t i c i d e n t i f i c a t i o n s a g reed. IDH-3,4 a l s o proved a u s e f u l system t o d i s t i n g u i s h t h e s e s p e c i e s because t h e r e was a l a r g e d i f f e r e n c e i n a l l o z y m e f r e q u e n c i e s between the two s p e c i e s . The use of a c o m b i n a t i o n of t h r e e enzyme systems ensured t h a t i n d i v i d u a l s were not m i s a s s i g n e d due t o an e r r o r i n the i n t e r p r e t a t i o n of the p a t t e r n f o r a s i n g l e system. The problem of d i s t i n g u i s h i n g non-anadromous rainbow from anadromous s t e e l h e a d i s more d i f f i c u l t . In many anadromous s a l m o n i d p o p u l a t i o n s some males mature w i t h o u t m i g r a t i n g t o the ocean ( s t e e l h e a d , Schmidt and House, 1979; A t l a n t i c salmon, O s t e r d a h l , 1969; Lee and Power, 1976; R i d d e l l , 1979; brown t r o u t , B o h l i n , 1975; c h i n o o k , R o b e r t s o n , 1957; sockeye, McCart, 1970). In c h i n o o k salmon males can s u r v i v e spawning ( R o b e r t s o n , 1957) and i n A t l a n t i c salmon, and p r o b a b l y i n o t h e r Salmo s p e c i e s , ' males may s u r v i v e and smolt a f t e r spawning ( O s t e r d a h l , 1969). In a l l these s p e c i e s p r e c o c i o u s males have been obse r v e d a t t e n d i n g and sometimes spawning w i t h l a r g e anadromous f e m a l e s . In a d d i t i o n , most s p e c i e s i n c l u d e t o t a l l y non-anadromous p o p u l a t i o n s t h a t o ccur i n l o c a t i o n s where a c c e s s t o the sea i s 23 l i m i t e d or a b s e n t . In sockeye salmon non-anadromous and anadromous p o p u l a t i o n s i n t e r b r e e d e x t e n s i v e l y i n a t l e a s t one l a k e where b o t h occur and, t h e r e f o r e , such p o p u l a t i o n s cannot be g i v e n r a c i a l s t a t u s (McCart, 1970). True non-anadromous rainbow t r o u t p o p u l a t i o n s can t h e r e f o r e o n l y be c o n s i d e r e d t o occur where t h e r e a r e s i g n i f i c a n t numbers of non-anadromous fe m a l e s . Such p o p u l a t i o n s occur s y m p a t r i c a l l y w i t h s t e e l h e a d i n some i n t e r i o r streams and c o a s t a l streams, p a r t i c u l a r l y those a s s o c i a t e d w i t h l a k e s . Neave (1944) b e l i e v e d t h a t the s t e e l h e a d and non-anadromous rainbow i n the Cowichan R i v e r system, Vancouver I s l a n d , r e p r e s e n t e d two d i f f e r e n t r a c e s . The ev i d e n c e f o r t h i s view i s not s t r o n g s i n c e the f a c u l t a t i v e n a t u r e of anadromy i n males of many s a l m o n i d s p e c i e s and the e v i d e n c e f o r i n t e r b r e e d i n g between anadromous and non-anadromous sockeye i n d i c a t e s t h a t anadromy i s a poor c h a r a c t e r i s t i c t o use as a b a s i s f o r r a c i a l d i s t i n c t i o n . I have not t r i e d t o d i s t i n g u i s h rainbow and s t e e l h e a d i n j u v e n i l e samples because i n most streams I b e l i e v e rainbow p o p u l a t i o n s a r e s m a l l e r than s t e e l h e a d p o p u l a t i o n s , and t h a t gene f l o w may ta k e p l a c e between the two p o p u l a t i o n s v i a p r e c o c i o u s males. A l t h o u g h no r e l i a b l e e s t i m a t e s a r e a v a i l a b l e , i n most c o a s t a l streams non-anadromous a d u l t s p r o b a b l y a re l e s s numerous than anadromous a d u l t s . In an e x t e n s i v e survey of streams i n the c o a s t a l r e g i o n , Hartman and G i l l (1968) found few rainbow t r o u t of a s i z e and age t h a t i n d i c a t e d non-24 anadromomy, a l t h o u g h p r e c o c i o u s males were found i n a number of streams. Many o>f the non-anadromous t r o u t i n c o a s t a l streams appear t o be p r e c o c i o u s males. In a sample of 28 rainbow t r o u t g r e a t e r than 220 mm taken from the C h i l l i w a c k R i v e r i n J u l y 1978, 17 were m a t u r i n g males ( e n l a r g e d gonads), 4 were immature males and 5 c o u l d not be sexed. Only two f i s h were f e m a l e s . They were both o n l y s l i g h t l y g r e a t e r than 220 mm and had s m a l l gonads i n d i c a t i n g t h a t they might have s m o l t e d the f o l l o w i n g s p r i n g . In i n t e r i o r s t r e ams, where rainbow p o p u l a t i o n s appear t o be l a r g e r , good e s t i m a t e s of r e l a t i v e p o p u l a t i o n s i z e s are a g a i n u n a v a i l a b l e , but the 4.5:1 male t o female r a t i o among non-anadromous t r o u t i n a n g l e r c a t c h e s ( A n t i f e a u , 1977 MS) i n d i c a t e s t h a t the non-anadromous p o p u l a t i o n i s s t i l l much s m a l l e r than the anadromous p o p u l a t i o n . In two l o c i (LDH-4 and SOD) the o b s e r v e d d i s t r i b u t i o n of genotypes i n each sample were compared w i t h t h o s e e x p e c t e d from the assumption of Hardy-Weinberg e q u i l i b r i u m ( G - t e s t ; S o k a l and R o h l f , 1969). The o t h e r two systems (MDH-3 and IDH-3,4) c o n s i s t e d of p a i r s of l o c i and t h e r e f o r e e x p e c t e d numbers of each genotype c o u l d not be g e n e r a t e d . Only samples i n which the e x p e c t e d number i n the s m a l l e s t c l a s s was g r e a t e r than 5 were t e s t e d ; a t o t a l of 47 samples f o r SOD and 8 samples f o r LDH. The sum of the i n d i v i d u a l G's f o r LDH was not s i g n i f i c a n t ( G j 8 ) = 10.4, ' o e ^ g 0 5 - j = 15.5). The sum of the i n d i v i d u a l G's f o r SOD was s i g n i f i c a n t atoC = .05 ( G ^ - j = 71.7, ( x 2 ^ 0 5 j = 25 64.0) indicating a s i g n i f i c a n t departure from Hardy-Weinberg expectations. There was no consistant excess or deficiency of heterozygotes: 25 populations had an excess, 22 populations a deficiency. Samples of smolts and adults were taken when migrating and, therefore, are made up of a mixture of populations from d i f f e r e n t areas of the same stream. These showed no deviation from Hardy-Weinberg expectations (G ^  = 11.3, ( x 2 ( 7 Q 5 ) = • Of the 7 samples, 3 had an excess of heterozygotes and 4 had a deficiency. Within Stream V a r i a b i l i t y For the purposes of t h i s study, a stream was defined as a continuous area of habitat suitable for juvenile steelhead, and separated from other areas of juvenile habitat by poor juvenile habitat (such as the ocean, a very large r i v e r , or an estuary). Streams could thus be considered to contain a continuous population which may, or may not, be subdivided. In contrast, populations in adjacent streams are separated by long stretches of inappropriate habitat with very low population den s i t i e s . Differences between locations, year classes and l i f e history stages are the three sources of v a r i a t i o n within a stream. Fry samples were c o l l e c t e d from more than one location in a number of streams, including a large stream (Chilliwack), 26 a m i d - s i z e d stream ( C o q u i t l a m ) and a s m a l l stream (Weaver). S i g n i f i c a n t d i f f e r e n c e s o c c u r r e d i n a l l t h r e e s t r e a m s , but i f a l l f o u r l o c i a r e c o n s i d e r e d t h e r e i s no c o n s i s t e n t tendency f o r samples from l a r g e r r i v e r s t o be more heterogenous than s m a l l e r r i v e r s or v i c e v e r s a ( T a b l e 2 ) . Year c l a s s e s were compared by sa m p l i n g f r y a t the same l o c a t i o n i n e i g h t streams TABLE 2. V a r i a b i l i t y between l o c a t i o n s i n streams of d i f f e r e n t s i z e s . WATERSHED MEAN STREAM AREA FLOW LDH SOD MDH IDH TOTAL (sq km) (cu m/s) ** NS * NS * C h i l l i w a c k G 658 37 15.6 3.1 13.7 3.5 35.9 df (4) (4) (4) (8) (20) G /df 1.79 NS NS * NS * C o q u i t l a m G 236 5 3.4 1.4 12.5 9.6 26.9 df (3) (3) (3) (6) (15) G /df NS ** NS 1.79 * Weaver G 41 2 F i x e d 0.1 10.2 0.7 10.9 df (2) (2) (2) (6) G /df 1.82 i n two c o n s e c u t i v e y e a r s . Four l i f e h i s t o r y s t a g e s were c o n s i d e r e d ; f r y ( l e s s than one year o l d ) , p a r r (one year o l d t o the time of m i g r a t i o n t o the o c e a n ) , s m o l t s ( d u r i n g m i g r a t i o n t o t he o c e a n ) , and a d u l t s . Samples of two or more of these l i f e h i s t o r y s t a g e s were taken i n the same year from 12 streams. Most of thes e samples (12 out of 15 degrees of freedom) i n v o l v e d a comparison of t r u e s t e e l h e a d ( a d u l t s or s m o l t s ) w i t h f r e s h w a t e r p o p u l a t i o n s ( p a r r or f r y ) t h a t may have c o n t a i n e d progeny of non-anadromous rainbow t r o u t . A l t h o u g h s i g n i f i c a n t 27 d i f f e r e n c e s between l i f e h i s t o r y s t a g e s were found, a comparison of the C h i - s q u a r e r d e g r e e s of freedom r a t i o i n Ta b l e 3 i n d i c a t e s t h a t these d i f f e r e n c e s a r e s i m i l a r t o those between TABLE 3. Summary of the s i g n i f i c a n c e of v a r i a b i l i t y between samples w i t h i n streams • SOURCE OF VARIABILITY LDH SOD MDH IDH TOTAL NS ** * * ** LIFE HISTORY G 22.6 40.0 25.1 20.3 108.0 STAGE df (15) (13) (15) (10) (53) G/df 2.04 NS * ** * ** YEAR CLASSES G 7.2 15.9 30.3 16.6 70.0 df (8) (8) (8) (8) (32) G/df 2.18 * NS ** NS ** LOCATIONS G 26.7 13.9 49.2 14.4 104.2 df (13) (13) (13) (10) (49) G/df 2.12 ** ** ** NS TOTAL WITHIN G 56.5 69.8 104.6 49.3 df (36) (34) (36) (28) year c l a s s e s and l o c a t i o n s w i t h i n a r i v e r . An o v e r a l l assessment of w i t h i n stream v a r i a b i l i t y i n d i c a t e d t h a t d i f f e r e n c e s w i t h i n streams were h i g h l y s i g n i f i c a n t i n t h r e e out of f o u r l o c i ( T a b l e 3 ) . D i f f e r e n c e s between samples a t the LDH-4 and MDH-3 l o c i were w e l l d i s t r i b u t e d , and the o v e r a l l C h i -square was the r e s u l t of a l a r g e number of s m a l l d i f f e r e n c e s . At the SOD l o c u s , however, most of the w i t h i n stream v a r i a t i o n i s a s s o c i a t e d w i t h t h r e e smolt samples. When thes e t h r e e samples a r e d e l e t e d the c a l c u l a t e d C h i - s q u a r e between a l l samples w i t h i n streams i s 55.9 (df =48, p =.2) as compared t o a 28 v a l u e of 104.6 (df = 51, p =.001) when they a r e i n c l u d e d . I f j u v e n i l e d i s p e r s a l i s l i m i t e d and the d e n s i t y of a d u l t s i s low, some h e t e r o g e n e i t y between j u v e n i l e samples w i t h i n a stream can be e x p e c t e d . T h i s i s so even i f a d u l t d i s p e r s a l upon r e t u r n from the ocean, and a v a r i a b l e age of m a t u r i t y , p r e c l u d e any l o n g term d i f f e r e n t i a t i o n between p o p u l a t i o n s o c c u p y i n g d i f f e r e n t a r e a s or t r i b u t a r i e s of the same stream. The amount of h e t e r o g e n i t y e x p e c t e d between samples i s r e l a t e d t o the average number of a d u l t s whose progeny make up the f r y p o p u l a t i o n a t each p o i n t i n the stream by the e q u a t i o n : Np = 2 / 2 n ( x 2 / ( d f - l ) ) ( C a v a l l i - S f o r z a and Bodmer, 1971) Where n i s the average number of f r y per sample, and Np i s the e x p e c t e d number of p a r e n t s of the sample. The e x p e c t e d numbers of p a r e n t s f o r my f r y samples were c a l c u l a t e d on the b a s i s of the o b s e r v e d C h i - s q u a r e between f r y samples w i t h i n streams and i s g i v e n i n T a b l e 4. V a r i a b i l i t y Between Streams One or more samples were c o l l e c t e d and a n a l y z e d from each of 43 streams i n s o u t h w e s t e r n B r i t i s h Columbia ( F i g . 2 ) . The d a t a were a n a l y z e d u s i n g a 5 l e v e l random e f f e c t , c o m p l e t e l y h e i r a r c h i c a l ANOVA. Gene f r e q u e n c i e s were t r a n s f o r m e d u s i n g the a r c s i n square r o o t t r a n s f o r m a t i o n suggested by S o k a l and R o h l f 29 F i g u r e 2. Map of s t u d y a r e a showing h i e r a r c h i c a l s u b d i v i s i o n . 30 LEGEND 31 TABLE 4. Number of p a r e n t s e x p e c t e d f o r p o i n t samples of f r y c a l c u l a t e d from the h e t e r o g e n e i t y i n the a l l o z y m e f r e q u e n c i e s of 4 enzyme systems. LOCUS G df n Np LDH SOD MDH IDH 33.9 29.8 79.5 31.0 21 21 21 18 80.2 78.6 85.9 135.0 260 373 62 373 (1969). The bottom l e v e l i n t h i s h e i r a r c h y i s samples w i t h i n streams. The second l e v e l i s streams w i t h i n the s m a l l groups o u t l i n e d i n F i g . 2. A s m a l l group of streams i s d e f i n e d as 2 or 3 streams e n t e r i n g the ocean, or a l a r g e r i v e r , a d j a c e n t t o each o t h e r , ( i e . t h e r e are no streams w i t h s i g n i f i c a n t s t e e l h e a d p o p u l a t i o n s between two streams w i t h i n a s m a l l group.) The t h i r d l e v e l i s s m a l l groups of streams w i t h i n a l a r g e r group. A l a r g e group i s a l o o s e l y d e f i n e d term f o r the l a r g e g e o g r a p h i c s u b d i v i s i o n s o u t l i n e d i n the c o a s t a l r e g i o n of F i g . 2. D i v i d i n g l i n e s between l a r g e groups were a s s i g n e d i n a somewhat a r b i t a r y f a s h i o n but were g e n e r a l l y meant t o f o l l o w n a t u r a l f e a t u r e s t h a t may o b s t r u c t gene f l o w between groups. The l a s t two l e v e l s a r e l a r g e groups w i t h i n r e g i o n s and the r e g i o n s t h e m s e l v e s . The two r e g i o n s o u t l i n e d i n F i g . 2 were t r e a t e d as a l e v e l because p r e v i o u s s t u d i e s i n d i c a t e d t h e r e were l a r g e d i f f e r e n c e s i n gene f r e q u e n c i e s between c o a s t a l and i n t e r i o r p o p u l a t i o n s of s t e e l h e a d . The r e s u l t s of the f o u r p a r a l l e l a n a l y s e s (one f o r each l o c u s ) a r e summarized i n T a b l e 32 5. S i n c e the v a r i a n c e component due t o l a r g e groups was l e s s TABLE 5. Summary of the r e s u l t s of the n e s t e d ANOVA's of the a r c s i n t r a n s f o r m e d a l l o z y m e f r e q u e n c i e s f o r f o u r enzyme systems. SOURCE OF VARIATION LDH SOD MDH IDH REGIONS ** ** POOLED N.S. LARGE GROUPS POOLED POOLED POOLED POOLED SMALL GROUPS N.S. N.S. N.S. N.S. STREAMS ** ** * N.S. SAMPLES ** ** ** N.S. ** p<.01 * p<.05 than z e r o f o r a l l f o u r enzymes, the sum of squares due t o v a r i a t i o n between l a r g e groups were p o o l e d i n each case w i t h the s m a l l group sum of s q u a r e s . In the p r e v i o u s a n a l y s e s the v a r i a n c e among samples was found t o be s i g n i f i c a n t f o r 3 out of 4 l o c i (LDH-4, MDH-3 and SOD). The added v a r i a n c e due t o d i f f e r e n c e s among streams was a l s o s i g n i f i c a n t i n the s e same t h r e e l o c i . The added v a r i a n c e due t o p o o l e d groups was not s i g n i f i c a n t i n a l l 4 l o c i . The v a r i a n c e component due t o a r e a s was s i g n i f i c a n t a t the SOD and LDH-4 l o c i . A B a r l e t t ' s t e s t f o r homogeneity of v a r i a n c e i n d i c a t e d t h a t the between sample v a r i a n c e was s i m i l a r f o r the t h r e e heterogeneous l o c i (;x2 = 2.42, df = 2.0). I f IDH was added t o the a n a l y s i s , the C h i -square f o r h e t e r o g e n e i t y of sample v a r i a n c e s was h i g h l y s i g n i f i c a n t ( x 2 = 21.42, df = 3 ) . T h i s s u g g e s t s t h a t the between sample v a r i a n c e f o r IDH was lower than f o r the o t h e r 33 t h r e e l o c i . The o v e r a l l p a t t e r n of v a r i a t i o n f o r a l l f o u r l o c i i s i l l u s t r a t e d i n F i g . 3. To make the c o m p a r i s i o n s more m e a n i n g f u l the y - a x i s i s e x p r e s s e d i n terms of s t a n d a r d d e v i a t i o n s r a t h e r than the r e s p e c t i v e v a r i a n c e s . The mean among v a r i a n c e w i t h i n a l e v e l i s the weighted mean of the v a r i a n c e s of the component of each l e v e l . For example, a v a r i a n c e among streams can be c a l c u l a t e d f o r each group w i t h more than one stream and the mean among v a r i a n c e of streams i s the weighted mean of the v a r i a n c e of a l l such groups. The mean among v a r i a n c e s a re a u s e f u l r e p r e s e n t a t i o n of the v a r i a n c e t h a t can be ex p e c t e d w i t h i n a l e v e l i f the v a r i a n c e components a t lower l e v e l s a r e i g n o r e d . The v a r i a n c e components a r e the r e t r a n s f o r m e d v a l u e s of t h o s e c a l c u l a t e d i n the n e s t e d ANOVA of a r c s i n square r o o t t r a n f o r m e d gene f r e q u e n c i e s and a r e a measure of the added v a r i a n c e due t o the e f f e c t of a s i n g l e l e v e l . These r e t r a n s f o r m e d v a l u e s a re a p p r o x i m a t i o n s c a l c u l a t e d u s i n g the e q u a t i o n : p = ( s i n 8) and i t s d e r i v a t i v e . dp/dG = 2 s i n e cos6 Here p i s the mean gene f r e q u e n c y of the p o p u l a t i o n s used t o c a l c u l a t e the v a r i a n c e component, and 6 i s i t s t r a n s f o r m e d v a l u e . I f 0-2 i s s m a l l then dp/d8 can be assumed t o be l i n e a r i n the r e g i o n of 9 and t h e r e f o r e 34 F i g u r e 3. Sources of v a r i a t i o n i n the a l l o z y m e f r e q u e n c i e s of the f o u r v a r i a b l e enzyme systems . 35 36 * ( d p / d e ) 2 a 2 where a 2 i s the v a r i a n c e i n r a d i a n s and o 2 i s the v a r i a n c e i n o P terms of gene f r e q u e n c i e s . The g e n e r a l t r e n d f o r f r e q u e n c i e s a t a l l f o u r l o c i i s t o be more v a r i a b l e over s m a l l a r e a s and l e s s v a r i a b l e between the l a r g e r a r e a s d e l i n e a t e d by the l a r g e or s m a l l group l e v e l s . T h i s r e s u l t s from the tendency of the d i f f e r e n t gene f r e q u e n c i e s i n a d j a c e n t steams w i t h i n a group t o average out t o a mean v a l u e t h a t i s s i m i l a r t o o t h e r groups w i t h i n a r e g i o n . The major d i f f e r e n c e i n p a t t e r n s between l o c i i s the l a r g e d i f f e r e n c e between the f r e q u e n c i e s i n the c o a s t a l and i n t e r i o r r e g i o n s a t the LDH-4 and SOD l o c i (.931 v s . .471 and .644 v s . .996, r e s p e c t i v e l y ) . These c o n t r a s t w i t h the n e a r l y i d e n t i c a l v a l u e s a t the MDH and IDH l o c i (.870 v s . .862 and .690 v s . .696, r e s p e c t i v e l y ) . The a c t u a l gene f r e q u e n c i e s w i t h i n the v a r i o u s l e v e l s a r e r e p r e s e n t e d g r a p h i c a l l y i n F i g s . 4 t o 7. The v a r i a b i l i t y w i t h i n each l e v e l i s w e l l d i s t r i b u t e d between the components of t h a t l e v e l and the u n i f o r m i t y of gene f r e q u e n c i e s a t h i g h e r l e v e l s i s r e a d i l y a p p a r e n t . For the t h r e e l o c i t h a t were v a r i a b l e a t the w i t h i n stream l e v e l a s i m p l e c o r r e l a t i o n a n a l y s i s was performed t o det e r m i n e i f l a r g e d i f f e r e n c e s a t one l o c u s were a s s o c i a t e d w i t h l a r g e d i f f e r e n c e s a t the o t h e r two l o c i . A l l the c o r r e l a t i o n s were not s i g n i f i c a n t i n d i c a t i n g t h a t such an a s s o c i a t i o n c o u l d not be demonstrated (Table 6 ) . 37 F i g u r e 4. Mean LDH-4(76) a l l o z y m e f r e q u e n c i e s w i t h i n each l e v e l i n the h i e r a r c h i c a l ANOVA a n a l y s i s . P o i n t s j o i n e d by l i n e s i n the sample and stream l e v e l s a r e p o o l e d i n the stream and group l e v e l s r e s p e c t i v e l y . R e g i o n a l means ar e the mean of a l l samples from each r e g i o n . Numbers r e f e r t o r i v e r s l i s t e d i n Appendix 2. INTERIOR REGION GENE FREQUENCY COASTAL REGION Lower Fraser Inner East Coast Outer Valley Coast Van. Island Coast 8e 39 F i g u r e 5. Mean SOD(152) a l l o z y m e f r e q u e n c i e s w i t h i n each l e v e l i n t he h i e r a r c h i c a l ANOVA a n a l y s i s . P o i n t s j o i n e d by l i n e s i n the sample and stream l e v e l s a re p o o l e d i n the stream and group l e v e l s r e s p e c t i v e l y . R e g i o n a l means a r e the mean of a l l samples from each r e g i o n . Numbers r e f e r t o r i v e r s l i s t e d i n Appendix 2. INTERIOR REGION GENE FREQUENCY COASTAL REGION 41 F i g u r e 6. Mean MDH-3(71) a l l o z y m e f r e q u e n c i e s w i t h i n each l e v e l i n the h i e r a r c h i c a l ANOVA a n a l y s i s . P o i n t s j o i n e d by l i n e s i n the sample and stream l e v e l s a r e p o o l e d i n the stream and group l e v e l s r e s p e c t i v e l y . R e g i o n a l means ar e t h e mean of a l l samples from each r e g i o n . Numbers r e f e r t o r i v e r s l i s t e d i n Appendix 2. 42 43 F i g u r e 7. Mean IDH-3,4(72) and IDH-3,4(48) a l l o z y m e f r e q u e n c i e s w i t h i n each l e v e l i n the h i e r a r c h i c a l ANOVA a n a l y s i s . P o i n t s j o i n e d by l i n e s i n the sample and stream l e v e l s a r e p o o l e d i n the stream and group l e v e l s r e s p e c t i v e l y . R e g i o n a l means a r e the mean of a l l samples from each r e g i o n . Numbers r e f e r t o r i v e r s l i s t e d i n Appendix 2. GENE FREQUENCY INTERIOR REGION COASTAL REGION Lower Fraser East Coast Outer O ' - ' 'to < Valley 3 K) w < Inner Coast S 3 " Van. Island 3 '-• ro ( Coast D ro mm-•:•:•:•:•:•:•:•:•:•:•:-:•:•:-:-:•>:•:« i , C 1 =3 1 SMALL GROUPS within regions IT • s T - v ft id & * \ a f T • i co ro cn CO cn co RIVERS within groups • \ / 1 loo 1 c*> 1 ^  1 • -J CO CO { { C O a> V p o £ <J 6 . K 6 D ro ro KJ < 2 > = ' £ • w aa VP 45 TABLE 6. C o r r e l a t i o n m a t r i x of d i f f e r e n c e s i n a l l e l e f r e q u e n c i e s between a d j a c e n t streams w i t h s i m i l a r d i f f e r e n c e s a t a n o t h e r l o c u s . Each has 35 degrees degrees of freedom. LDH 1.00 .071 .218 SOD MDH LDH SOD MDH 1.00 .01 1.00 One consequence of t h i s p a t t e r n of v a r i a b i l i t y i s t h a t g e o g r a p h i c a l l y c l o s e p o p u l a t i o n s a r e not grouped t o g e t h e r i n a dendrogram based on g e n e t i c d i s t a n c e s . G e n e t i c d i s t a n c e s were c a l c u l a t e d u s i n g N e i ' s (1973) f o r m u l a f o r minimum g e n e t i c d i s t a n c e and t h e s e were used t o c o n s t r u c t a dendrogram u s i n g the UMPGA a n a l y s i s of Sneath and S o k a l (1973). Only the f r e q u e n c i e s a t the LDH-4, SOD and MDH-4 l o c i were' used because f r e q u e n c i e s were not a v a i l a b l e f o r a l l p o p u l a t i o n s a t the IDH l o c i . In the r e s u l t i n g dendrogram ( F i g . 8) streams on the e a s t c o a s t of Vancouver I s l a n d a r e i d e n t i f i e d by s o l i d l i n e s t o show t h a t they do not form a s i n g l e group, but a r e s c a t t e r e d amongst streams from the whole c o a s t a l r e g i o n . The d i f f e r e n c e s r e p o r t e d here a r e s m a l l , n e v e r t h e l e s s they appear t o be r e a l . The Salmon, N o r t h A l o u e t t e and South A l o u e t t e r i v e r s a r e t h r e e t r i b u t a r i e s of the lower F r a s e r . The 46 F i g u r e 8. Dendrogram of the r e l a t i o n s h i p s between c o a s t a l p o p u l a t i o n s u s i n g a l l o z y m e f r e q u e n c i e s a t the LDH-4, SOD and MDH-3 l o c i and N e i ' s f o r m u l a f o r g e n e t i c d i s t a n c e . 47 CC LU CD < LU CC r-.1 1 H 2 54 42 52 13 22 31 32 46 36 5 17 59 6 9 23 26 50 48 4 9 1 9 4 I O 29 51 4 5 H 38 47r SAIvlPLES F R O M East coa s t V a n c o u v e r Is. O ther large g roups of s t reams .1 • I I 16 37 24 40 8 5 3 62 63 15 61 44 60 20 27 .01 .02 .0 3 G E N E T I C D I S T A N C E 48 j u n c t i o n of the N o r t h and South A l o u e t t e i s o n l y a few k i l o m e t e r s below the upper l i m i t of t i d a l i n f l u e n c e and the Salmon R i v e r e n t e r s the F r a s e r a p p r o x i m a t e l y 20 k i l o m e t e r s away. Each of these r i v e r s was r e p e a t e d l y sampled and gene f r e q u e n c y d i f f e r e n c e s a t the LDH l o c u s were c o n s i s t a n t between samples c o v e r i n g a t l e a s t t h r e e year c l a s s e s ( F i g . 9 ) . In c o n t r a s t , SOD f r e q u e n c i e s i n t h e s e same r i v e r s were q u i t e s i m i l a r . The o t h e r example i n F i g . 9 i s the comparison of a l l e l e f r e q u e n c i e s a t the same two l o c i i n samples from Weaver Creek and the C h e h a l i s R i v e r . These streams e n t e r the lower H a r r i s o n R i v e r o n l y a few k i l o m e t e r s a p a r t . A l t h o u g h these examples a r e more s t r i k i n g than most, numerous o t h e r c a s e s of gene f r e q u e n c y d i f f e r e n c e s between v a r i o u s p a i r s of a d j a c e n t s t r e a m s , and even w i t h i n a s i n g l e stream, can be found by comparing the f r e q u e n c i e s g i v e n i n Appendix 2. A number of samples of s t e e l h e a d and rainbow t r o u t were taken from l o c a t i o n s o u t s i d e the main samp l i n g a r e a . Some of t h e s e ( A b u n t l e t Lake, M c C l i n c h n e y R i v e r , Skeena R i v e r , Loon Lake and Pennask Lake) were used t o l o o k more c l o s e l y a t the macrogeographic v a r i a t i o n i n LDH and SOD a l l o z y m e f r e q u e n c i e s . One sample, from H e n r i e t t e Lake was taken i n an attempt t o d e t e r m i n e i f a l l o z y m e f r e q u e n c i e s had changed i n a p o p u l a t i o n t r a n s p l a n t e d from the i n t e r i o r r e g i o n t o the c o a s t a l r e g i o n . H e n r i e t t e Lake i s a t y p i c a l c o a s t mountain l a k e s i t u a t e d near W o o d f i b r e , B. C . ( L a t . 49 38',Long. 123 1 8 ' ) . Between 1934 and 49 F i g u r e 9. Examples of a l l o z y m e f r e q u e n c y d i f f e r e n c e s a t two l o c i i n samples from two s e t s of a d j a c e n t streams i n the lower F r a s e r V a l l e y . r 50 .60 .50 •40 1 CN U"> Q O CO .30 . 2 0 UJ >-U N ^ o =J _j o -J UJ < a. u. .10 •o I Q .30 . 2 0 .10 4 n _ X x N. Alouette S. A louet te Sa lmon Weaver Chehalis 51 1942 t h i s l a k e was s t o c k e d by the B. C. F i s h and W i l d l i f e Branch u s i n g rainbow t r o u t from Pennask Lake i n the B. C. i n t e r i o r . No a u t h o r i z e d s t o c k i n g has taken p l a c e s i n c e and u n a u t h o r i z e d s t o c k i n g i s u n l i k e l y because Woodfibre i s o n l y a c c e s s i b l e by f e r r y and H e n r i e t t e Lake i s a 3 hour h i k e from the end of the road. T a b l e 7 i n d i c a t e s t h a t a l l e l e f r e q u e n c i e s a t the LDH-4 l o c u s have changed l i t t l e , and the SOD l o c u s i s f i x e d f o r the SOD-100 a l l e l l e i n both p o p u l a t i o n s . TABLE 7. LDH and SOD a l l o z y m e f r e q u e n c i e s i n samples taken from Pennask and H e n r i e t t e Lakes i n the summer of 1978. LAKE GENE FREQUENCY (N) LDH SOD H e n r i e t t e .80 (20) 1.00 (20) Pennask .73 (26) 1.00 (26) 52 DISCUSSION The term p o p u l a t i o n s t r u c t u r e i s u s u a l l y a s s o c i a t e d w i t h the m a t h e m a t i c a l models of Wright (1943), M a l e c o t (1967), and Kimura and Weiss (1964), but o t h e r a u t h o r s (eg. S o k a l , 1974; S e l a n d e r and Kaufman, 1975; Smouse and Ward, 1978) have used a l e s s p r e c i s e d e f i n i t i o n of p o p u l a t i o n s t r u c t u r e t o d e s c r i b e v a r i o u s t y p e s of d e p a r t u r e from p a n m i x i a w i t h o u t r e f e r e n c e t o a p r e c i s e m a t h e m a t i c a l model. In t h i s sense, p o p u l a t i o n s t r u c t u r e can be d e f i n e d i n terms of the r e s t r i c t i o n s on the movement of i n d i v i d u a l s , and the genes they c a r r y , between p o p u l a t i o n s . Two methods a r e a v a i l a b l e f o r the study of p o p u l a t i o n s t r u c t u r e . The f i r s t i s d i r e c t o b s e r v a t i o n s of the l i f e c y c l e and e c o l o g y of the s p e c i e s i n q u e s t i o n ; p a r t i c u l a r l y the d i s t r i b u t i o n s of d i s p e r s a l d i s t a n c e s of i n d i v i d u a l s and the s u c c e s s of d i s p e r s i n g i n d i v i d u a l s and t h e i r progeny. P o p u l a t i o n s t r u c t u r e can a l s o be examined i n d i r e c t l y by o b s e r v i n g the v a r i a t i o n i n a l l e l e f r e q u e n c i e s or q u a n t i t a t i v e g e n e t i c c h a r a c t e r i s t i c s between p o p u l a t i o n s s i n c e one of the most im p o r t a n t consequences of s t r u c t u r i n g i s the tendency toward g e n e t i c d i f f e r e n t i a t i o n w i t h i n a s t r u c t u r e d s p e c i e s . P o p u l a t i o n s t r u c t u r i n g does not always r e s u l t i n g e n e t i c d i f f e r e n t i a t i o n , but i t i s a p r e r e q u i s i t e f o r g e n e t i c d i f f e r e n t i a t i o n . My o b s e r v a t i o n s i n d i c a t e t h a t s t e e l h e a d p o p u l a t i o n s a r e 53 s t r u c t u r e d ( i e . g e n e t i c a l l y d i f f e r e n t i a t e d ) over r e l a t i v e l y s m a l l g e o g r a p h i c d i s t a n c e s . On l a r g e r g e o g r a p h i c s c a l e s , p o p u l a t i o n s a r e s t r i k i n g l y s i m i l a r except f o r the l a r g e d i f f e r e n c e s i n the LDH and SOD gene f r e q u e n c i e s between the c o a s t a l and i n t e r i o r r e g i o n s . These f i n d i n g s a r e c o n s i s t a n t w i t h , but c o u l d not be p r e d i c t e d from, what i s known of s t e e l h e a d b i o l o g y and the e f f e c t i v e n e s s of v a r i o u s p h y s i c a l and b e h a v i o r a l b a r r i e r s t o d i s p e r s a l . One of the most o b v i o u s c h a r a c t e r i s t i c s of the s t e e l h e a d l i f e c y c l e i s the apparent l a c k of d i s p e r s a l between p o p u l a t i o n s t h a t are p h y s i c a l l y s e p a r a t e d i n d i f f e r e n t streams. The r a t e of j u v e n i l e d i s p e r s a l between streams i s unknown but i s p r o b a b l y n e g l i g i b l e , p a r t i c u l a r l y i n streams e n t e r i n g d i r e c t l y i n t o the ocean. There i s s t i l l c o n t r o v e r s y c o n c e r n i n g the e x t e n t of a d u l t d i s p e r s a l ( r e f e r r e d t o as s t r a y i n g i n the f i s h e r i e s l i t e r a t u r e ) between stream s . Most of the r e s e a r c h i n t o homing b e h a v i o r i n s a l m o n i d s has c o n c e n t r a t e d on mechanisms of o r i e n t a t i o n or on speed and d i r e c t i o n of ocean m i g r a t i o n r a t h e r than on a t t e m p t s t o measure the a c c u r a c y of homing. The main problem i n e s t i m a t i n g a c c u r a c y i s t h a t i t i s i m p o s s i b l e t o check a l l streams e q u a l l y w e l l . U s u a l l y the p r o b a b i l i t y of r e c o v e r y i s g r e a t e r i n the n a t i v e stream and t h e r e f o r e the s t r a y i n g r a t e s r e p o r t e d by S t a s k o et a_l. (1972) (0.1%) and C a r l i n (1968) (2%) f o r A t l a n t i c salmon a r e p r o b a b l y low. There a r e numerous s i m i l a r s t u d i e s on v a r i o u s anadromous 54 s a l m o n i d s p e c i e s , but i n no case i s t h e r e c l e a r documentation of the a c t u a l p r o p o r t i o n of marked f i s h i n o t h e r streams or the p r o p o r t i o n of unmarked f j s h t h a t a r e s t r a y s (see r e v i e w by H a r d i n - J o n e s 1968; S t a s k o , 1971). In some ca s e s the i n c i d e n c e of s t r a y i n g t o a s i n g l e nearby t r i b u t a r y i s known. Shapavalov and T a f t (1954) e s t i m a t e the s t r a y i n g r a t e between two s m a l l , s i m i l a r c r e e k s on the m i d - C a l i f o r n i a c o a s t t o be 2.6% f o r s t e e l h e a d and 16.5 % f o r coho. S t r a y i n g r a t e s t o o t h e r nearby streams of d i s s i m i l a r s i z e appeared t o be s u b s t a n t i a l l y lower f o r b oth s p e c i e s . E x t r a p o l a t i o n from t h e s e r e s u l t s i s i m p o s s i b l e s i n c e i t i s not known what p r o p o r t i o n of f i s h s t r a y t o nearby streams of s i m i l a r c h a r a c t e r as opposed t o d i s t a n t streams w i t h d i f f e r e n t e n v i r o n m e n t a l c o n d i t i o n s . A f u r t h e r c o m p l i c a t i o n i s t h a t f i s h do not always spawn i n the r i v e r t h a t t hey i n i t i a l l y e n t e r . Shapavalov and T a f t (1954) document a t l e a s t one case where an a d u l t s t e e l h e a d was c a p t u r e d and r e l e a s e d as a s t r a y but was s u b s e q u e n t l y r e c a p t u r e d i n i t s n a t i v e stream. E v i d e n c e of s i m i l a r b e h a v i o r i s p r e s e n t e d by E v e r e s t (1973) f o r summer s t e e l h e a d and i n r e f e r e n c e s c i t e d by R i c k e r (1971) f o r v a r i o u s s a l m o n i d s p e c i e s . As E n d l e r (1977) p o i n t s o u t , gene fl o w i s not e q u i v a l e n t t o d i s p e r s a l of i n d i v i d u a l s i n many s p e c i e s s i n c e immigrant i n d i v i d u a l s and t h e i r progeny are o f t e n not as s u c c e s s f u l as n a t i v e s . Apparent s t r a y i n g r a t e s , t h e r e f o r e , have t o be reduced by some unknown f a c t o r i f they a r e t o be used t o r e p r e s e n t gene f l o w . 55 The o n l y c o n c l u s i o n t h a t can be drawn from t h e s e d a t a i s t h a t s t r a y i n g r a t e s between a d j a c e n t streams a r e p r o b a b l y l e s s than 10%, but the amount and p a t t e r n of s t r a y i n g between nearby and d i s t a n t streams i s not known. T h e r e f o r e we cannot make a p r i o r i p r e d i c t i o n s about the p o p u l a t i o n s t r u c t u r e s of t h e s e s p e c i e s . There i s no c l e a r e v i d e n c e t h a t s t r a y i n g r a t e s are so h i g h t h a t l a r g e s e l e c t i v e p r e s s u r e s would be r e q u i r e d to. induce g e n e t i c d i f f e r e n t i a t i o n between s t o c k s i n a d j a c e n t streams, or so low t h a t even s m a l l s e l e c t i v e f o r c e s or d r i f t would r e s u l t i n d i f f e r e n t i a t i o n . The o t h e r a p r i o r i i n d i c a t i o n of p o p u l a t i o n s t r u c t u r i n g i n anadromous sa l m o n i d s i s the examples of g e n e t i c d i f f e r e n t i a t i o n r e v i e w e d i n the i n t r o d u c t i o n t o t h i s paper. I t i s d i f f i c u l t t o e s t a b l i s h the meaning of such d i f f e r e n t i a t i o n i n terms of the amount of p o p u l a t i o n s t r u c t u r i n g i n the s p e c i e s c o n c e r n e d . Most m o r p h o l o g i c a l or b e h a v i o r a l d i f f e r e n c e s a r e the r e s u l t s of o b v i o u s s e l e c t i v e f o r c e s a c t i n g i n s p e c i a l s i t u a t i o n s and a r e i m p o s s i b l e t o q u a n t i f y i n terms of gene f r e q u e n c y d i f f e r e n c e s . E l e c t r o p h o r e t i c s t u d i e s g e n e r a l l y a r e not d e t a i l e d enough t o d i s t i n g u i s h s m a l l l o c a l d i f f e r e n c e s from d i f f e r e n c e s w i t h i n a s i n g l e p o p u l a t i o n . Thus, w h i l e the d i f f e r e n c e s between the samples from p o p u l a t i o n s i n a d j a c e n t streams may be s i g n i f i c a n t on the b a s i s of a C h i - s q u a r e t e s t most of t h e s e d i f f e r e n c e s may be a s s o c i a t e d w i t h w i t h i n stream v a r i a t i o n . 56 The c l a s s i c a l model of i n t e r p o p u l a t i o n g e n e t i c d i f f e r e n t i a t i o n i n v o l v e s a b a l a n c e between the f o r c e s of d i s r u p t i v e s e l e c t i o n and g e n e t i c d r i f t f o s t e r i n g h e t e r o g e n e i t y and the o p p o s i n g f o r c e s of s t a b i l i z i n g ' s e l e c t i o n and m i g r a t i o n . H e t e r o g e n e i t y of a l l e l e f r e q u e n c i e s a t any l o c u s i m p l i e s t h a t m i g r a t i o n i s not a b l e t o o f f s e t the combined f o r c e s of d r i f t and d i s r u p t i v e s e l e c t i o n . In the absence of s e l e c t i o n , the f o r c e s of d r i f t and m i g r a t i o n a r e s i m i l a r f o r a l l l o c i and t h e r e f o r e h e t e r o g e n e i t y of a l l e l e f r e q u e n c i e s s h o u l d a l s o be s i m i l a r . S e l e c t i v e c o e f f i c i e n t s a t d i f f e r e n t l o c i v a r y w i d e l y however, and t h e r e f o r e t h e r e i s a tendency f o r the amount of a l l e l e f r e q u e n c y h e t e r o g e n e i t y t o v a r y between l o c i . I f s e l e c t i o n c o e f f i c i e n t s a r e unknown, the f r e q u e n c i e s of d i f f e r e n t a l l e l e s w i l l g i v e d i f f e r e n t p i c t u r e s of the degree of p o p u l a t i o n s t r u c t u r i n g . A l l e l e s w i t h s t r o n g d i s r u p t i v e s e l e c t i v e c o e f f i c i e n t s would suggest r e s t r i c t e d gene f l o w , w h i l e those w i t h s t r o n g s t a b i l i z i n g s e l e c t i v e c o e f f i c i e n t s would i n d i c a t e e x t e n s i v e gene f l o w . N e u t r a l a l l e l e s would i n d i c a t e a moderate amount of gene f l o w . A l l of the above c o u l d o ccur i n the same p o p u l a t i o n and the i n t e r p r e t a t i o n depends on which a l l e l e s a r e sampled. U s i n g models such as t h a t of Kimura and Weiss (1964), the v a r i a n c e i n the f r e q u e n c i e s of s e l e c t i v e l y n e u t r a l a l l e l e s can be used t o g i v e a p r e c i s e e s t i m a t e of gene f l o w i f sub-57 p o p u l a t i o n s i z e s (or d e n s i t y i n a c o n t i n o u s p o p u l a t i o n ) and the form of the m i g r a t i o n d i s t a n c e ' d i s t r i b u t i o n a r e known and e q u i l i b r i u m can be assumed. Attempts t o f i t t h e s e models t o r e a l s i t u a t i o n s have been e i t h e r u n s u c c e s s f u l (eg. Eanes and Koehn, 1978) or not v e r y i n f o r m a t i v e (eg. Hedgecock, 1978) because i t i s i m p o s s i b l e t o d e c i d e w hich, i f any, of the a v a i l a b l e a l l e l e s a r e n e u t r a l (or not l i n k e d t o n o n - n e u t r a l a l l e l e s ) or t o s a t i s f y the o t h e r c o n d i t i o n s of the model. In t h i s s i t u a t i o n we a r e f o r c e d t o use l e s s s u i t a b l e l o c i t o p r o v i d e a l e s s p r e c i s e but s t i l l u s e f u l model of p o p u l a t i o n s t r u c t u r e . In such a model p o p u l a t i o n s t r u c t u r e i s no l o n g e r d e f i n e d i n terms of the movement of genes between p o p u l a t i o n s but i n s t e a d i s d e f i n e d i n terms of gene fr e q u e n c y h e t e r o g e n e i t y . I w i l l use the term g e n e t i c s t r u c t u r e t o d e s c r i b e t h i s c o n c e p t . S i n c e s e l e c t i o n p r e s s u r e s v a r y between l o c i , the amount and p a t t e r n of a l l e l e f r e q u e n c y h e t e r o g e n e i t y a l s o v a r i e s between l o c i . A s p e c i e s thus has a number of g e n e t i c s t r u c t u r e s each d e f i n e d by the p a t t e r n of v a r i a b i l i t y a t a s i n g l e l o c u s , but o n l y a s i n g l e p o p u l a t i o n s t r u c t u r e d e f i n e d by the p a t t e r n of movement of i n d i v i d u a l s . In u s i n g the concept of g e n e t i c s t r u c t u r e r a t h e r than p o p u l a t i o n s t r u c t u r e the problems i n v o l v e d i n e s t i m a t i n g p o p u l a t i o n s i z e s , s e l e c t i v e c o e f f i c i e n t s and m i g r a t i o n r a t e s a r e a v o i d e d and an e q u i l i b r i u m c o n d i t i o n i s not assumed. Measurements of the degree of g e n e t i c s t r u c t u r i n g 58 i n a s p e c i e s a r e s t i l l u s e f u l i n u n d e r s t a n d i n g the b i o l o g y of an organism s i n c e g e n e t i c h e t e r o g e n e i t y i s p r o b a b l y the most i m p o r t a n t consequence of p o p u l a t i o n s t r u c t u r e . P o p u l a t i o n s t r u c t u r e w i t h o u t g e n e t i c d i f f e r e n t i a t i o n i s r e l a t i v e l y u n i m p o r t a n t from a p o p u l a t i o n g e n e t i c s p o i n t of view. E s t i m a t e s of the amount of g e n e t i c s t r u c t u r i n g a r e d i f f i c u l t t o o b t a i n from q u a n t i t a t i v e l y i n h e r i t e d c h a r a c t e r i s t i c s because p o l y g e n i c i n h e r i t a n c e and e n v i r o n m e n t a l i n f l u e n c e e s s e n t i a l l y p r e c l u d e the measurement of a l l e l e f r e q u e n c i e s ( L e w o n t i n , 1974). E l e c t r o p h o r e t i c a l l e l e s p r o b a b l y p r o v i d e the best a v a i l a b l e means of e s t i m a t i n g g e n e t i c v a r i a t i o n between p o p u l a t i o n s . S e l e c t i o n c o e f f i c i e n t s of e l e c t r o p h o r e t i c a l l e l e s a r e , however, d i f f i c u l t t o measure. There i s i n c r e a s i n g e v i d e n c e t h a t e l e c t r o p h o r e t i c a l l e l e s a r e not a l l n e u t r a l (see r e v i e w s by H e d r i c k e t a l . , 1976; Johnson, 1973) and t h a t l i n k a g e d i s e q u i l i b r i u m and e p i s t a s i s may p l a y an i m p o r t a n t r o l e i n the maintenance of coadapted gene complexes ( A l l a r d and K a h l e r , 1972; H e d r i c k e_t a l . , 1978). The assumption of. n e u t r a l i t y i s t h e r e f o r e unwarranted even though i t may be v a l i d i n some c a s e s . I t i s not p o s s i b l e t o det e r m i n e w i t h a b s o l u t e c e r t a i n t y i f the s e l e c t i v e c o e f f i c i e n t s of a l l o z y m e v a r i a n t s a r e g e n e r a l l y l a r g e r or s m a l l e r than o t h e r s i n g l e l o c u s systems. I f they a r e l a r g e r than a v e r a g e , then h e t e r o g e n e i t y of a l l o z y m e f r e q u e n c i e s i m p l i e s t h a t o n l y a l l e l e s under s t r o n g s e l e c t i o n w i l l e x h i b i t g e n e t i c s t r u c t u r i n g . I f 59 s e l e c t i v e c o e f f i c i e n t s of a l l o z y m e v a r i a n t s a r e the same or s m a l l e r than average, then h e t e r o g e n e i t y of t h e i r f r e q u e n c i e s i n d i c a t e s t h a t m i g r a t i o n i s s m a l l r e l a t i v e t o the f o r c e s of d r i f t p l u s s e l e c t i o n a t most l o c i . T h i s does not i m p l y h e t e r o g e n e i t y of a l l a l l e l e f r e q u e n c i e s s i n c e f r e q u e n c i e s a t i n d i v i d u a l l o c i c o u l d be e i t h e r homogeneous or heterogeneous depending on the r e l a t i v e s t r e n g t h of s t a b i l i z i n g s e l e c t i o n a t t h e l o c u s i n q u e s t i o n . Most s p e c i e s seem t o e x h i b i t some degree of g e n e t i c s t r u c t u r i n g a l t h o u g h t h i s v a r i e s g r e a t l y among s p e c i e s and among l o c i w i t h i n s p e c i e s . Q u a n t i f y i n g of g e n e t i c s t r u c t u r e g e n e r a l l y i n v o l v e s the use of some measure of g e n e t i c h e t e r o g e n e i t y such as W r i g h t ' s (1966) i n b r e e d i n g c o e f f i c i e n t s or s i m p l e C h i - s q u a r e s t a t i s t i c s which depend on the v a r i a n c e of a l l e l e f r e q u e n c i e s between p o p u l a t i o n s . These t y p e s of a n a l y s e s can be used t o a p p o r t i o n v a r i a b i l i t y i n t o i n t r a - and i n t e r -p o p u l a t i o n components (Workman and Niswander, 1969; Eanes and Koehn, 1978). O c c a s i o n a l l y t h i s h e i r a r c h y i s extended t o i n c l u d e o t h e r l e v e l s of s t r u c t u r i n g ( A v i s e and F e l l e y , 1979; Smouse and Ward, 1978; S m i t h , L a n g l e y and Johnson, 1978). One way t h i s i n f o r m a t i o n can be used i s i n the e x a m i n a t i o n of the g e o g r a p h i c p a t t e r n of g e n e t i c s t r u c t u r e . Of p a r t i c u l a r i n t e r e s t i s the s i z e of a r e a over which gene f r e q u e n c i e s can be assumed t o be homogeneous. I f m i g r a t i o n r a t e s depend on the d i s t a n c e between p o p u l a t i o n s then t h i s a r e a presumably r e p r e s e n t s the 6 0 maximum a r e a over which m i g r a t i o n between p o p u l a t i o n s i s e x t e n s i v e enough t o c o u n t e r the e f f e c t s of s e l e c t i o n and d r i f t on the a l l e l e i n q u e s t i o n . I f s e l e c t i v e c o e f f i c i e n t s a r e s i m i l a r then the s i z e of t h i s a r e a s h o u l d be s i m i l a r f o r two d i f f e r e n t l o c i even though the b o u n d a r i e s of the a r e a s of homogeneity may s h i f t . N o t h i n g can be c o n c l u d e d about the p o s s i b i l i t y of gene f l o w w i t h i n a r e a s of homogeneity because the l a c k of v a r i a t i o n may be due t o e i t h e r s t a b i l i z i n g s e l e c t i o n or e x t e n s i v e gene f l o w . The s i z e of t h e s e a r e a s i s i m p o r t a n t because i t p r o v i d e s a minimum e s t i m a t e of the s i z e and number of s u b p o p u l a t i o n s i n t o which the s p e c i e s i s d i v i d e d . At p r e s e n t t h e r e i s no g e n e r a l l y agreed on t e c h n i q u e f o r measuring the s i z e of an a r e a of homogeneity. S e l a n d e r and Kaufman (1975) and Koehn, Milkman and M i t t o n (1976) s i m p l y i d e n t i f i e d homogeneous u n i t s by v i s u a l i n s p e c t i o n of a l l o z y m e f r e q u e n c i e s . I chose t o measure the s i z e of homogeneous a r e a s u s i n g a n e s t e d ANOVA where lower l e v e l s i n the a n a l y s i s encompass s m a l l e r g e o g r a p h i c a r e a s . There a r e a number of problems i n i n t e r p r e t i n g the r e s u l t s of such an a n a l y s i s . P r o b a b l y the most s e r i o u s i s t h a t b o u n d a r i e s between a r e a s a r e somewhat a r b i t r a r y and t h e r e f o r e may b i s e c t a r e a s of s i m i l a r i t y . The consequences of . t h i s problem a r e p r o b a b l y b e s t i l l u s t r a t e d u s i n g the example of the S t e i n R i v e r , a t r i b u t a r y of the F r a s e r which i s v e r y c l o s e t o the boundary between the i n t e r i o r and c o a s t a l r e g i o n s . Because 61 i t i s a s t e e p , g l a c i a l l y t u r b i d r i v e r i t was a s s i g n e d t o the c o a s t a l r e g i o n and p a i r e d w i t h the a d j a c e n t N a h a t l a t c h R i v e r 35 k i l o m e t e r s downstream. Subsequent e x a m i n a t i o n of the a l l e l e f r e q u e n c i e s r e v e a l e d t h a t the S t e i n R i v e r p o p u l a t i o n was more s i m i l a r t o i n t e r i o r than c o a s t a l p o p u l a t i o n s a t the LDH and SOD l o c i ( T a b l e 8 ) . The r e s u l t of t h i s " m i s t a k e " i s t h a t the TABLE 8. A c o m p a r i s i o n of a l l o z y m e f r e q u e n c i e s a t the LDH-4 and SOD l o c i i n the S t e i n and N a h a t l a t c h r i v e r s v e r s u s the mean f r e q u e n c i e s of c o a s t a l and i n t e r i o r p o p u l a t i o n s . d i f f e r e n c e between the g e o g r a p h i c a l l y l a r g e i n t e r i o r and c o a s t a l r e g i o n s a l s o appears as p a r t of the d i f f e r e n c e a t the g e o g r a p h i c a l l y v e r y s m a l l a d j a c e n t stream l e v e l . G e n e r a l l y the e s t i m a t e of the average s i z e of the a r e a s of homogeneity w i l l be somewhat l e s s than the maximum a r e a over which homogeneity can o c c u r because the b o u n d a r i e s of the a r e a s i n the ANOVA a n a l y s i s w i l l not c o i n c i d e w i t h the n a t u r a l b o u n d a r i e s of a r e a s of gene f r e q u e n c y s i m i l a r i t y . Another way of v i s u a l i z i n g the problem i s t o imagine t h a t by j u d i c i o u s p a i r i n g of a d j a c e n t streams we have e l i m i n a t e d many of the d i f f e r e n c e s t h a t occur between a d j a c e n t streams and a p p o r t i o n e d much of t h i s v a r i a t i o n t o the group l e v e l . The r e s u l t may be a b e t t e r r e p r e s e n t a t i o n I n t e r i o r S t e i n N a h a t l a t c h C o a s t a l LDH .53 .68 .89 .93 SOD .99 1.00 .74 .65 62 of the t r u e p o p u l a t i o n s t r u c t u r e i n the sense t h a t s i m i l a r p o p u l a t i o n s would be grouped more c l o s e l y t o g e t h e r but i t would p r o b a b l y obscure the c o n c l u s i o n t h a t d i f f e r e n c e s can (and do) occur between a d j a c e n t streams. The ANOVA a n a l y s i s , i n s t e a d of d e f i n i n g the a c t u a l s i z e of the a r e a s of homogeneity, d e t e r m i n e s the s i z e of a r e a s between which the i n c i d e n c e of d i f f e r e n c e s i s s i g n i f i c a n t . T h i s method of a n a l y s i s i s a d m i t t e d l y p r i m i t i v e but I am not i n a p o s i t i o n t o d e v i s e a more s o p h i s t i c a t e d approach. D e s p i t e t h i s I b e l i e v e t h a t the r e s u l t s r e f l e c t the r e a l s i t u a t i o n , s i n c e few of the e f f e c t s a r e e i t h e r m a r g i n a l l y s i g n i f i c a n t or i n s i g n i f i c a n t . A v i s e and F e l l e y (1979) have d e a l t w i t h a s i t u a t i o n s i m i l a r t o mine u s i n g both F - s t a t i s t i c s ( i n b r e e d i n g c o e f f i c i e n t s , W r i g h t , 1966) and a n e s t e d ANOVA. T h e i r i n t e r p r e t a t i o n of the r e s u l t s was s i m p l i f i e d because t h e r e were o n l y t h r e e l e v e l s and each l e v e l was c l e a r l y d e f i n a b l e i n terms of d i s t i n c t g e o g r a p h i c a l f e a t u r e s . F-s t a t i s t i c s were u n s u i t a b l e i n my study because two l o c i were d u p l i c a t e d and one l o c u s was o n l y m a r g i n a l l y p o l y m o r p h i c i n many p o p u l a t i o n s . Data from d u p l i c a t e d l o c i whose a l l o z y m e s have the same m o b i l i t y cannot be a n a l y z e d u s i n g F - s t a t i s t i c s because genotypes cannot always be de t e r m i n e d from the zymogram phenotypes. An i n d i v i d u a l w i t h e q u a l doses of two a l l o z y m e s can e i t h e r be a double homozygote or a double h e t e r o z y g o t e . An a l t e r n a t i v e method has been d e v e l o p e d by Cockerham (1969,1973) 63 and used by Smith e t a l . (1978) which i n v o l v e s an ANOVA of b i n a r y d a t a . T h i s method i s more . s o p h i s t i c a t e d but some of i t s assumptions a r e q u e s t i o n a b l e , i t does not a v o i d the major problems o u t l i n e d above and i t has not been w i d e l y used. The method of Smouse and Ward (1978) i s not d i r e c t l y a p p l i c a b l e t o unbalanced d e s i g n s . My r e s u l t s show t h a t t h e r e i s o f t e n s i g n i f i c a n t h e t e r o g e n e i t y between samples w i t h i n a stream and between a d j a c e n t streams w i t h i n a group. The d i f f e r e n c e s w i t h i n streams may be due e i t h e r t o permanent s t r u c t u r i n g w i t h i n a stream or t o temporary d r i f t . Temporary d r i f t c o u l d o ccur each g e n e r a t i o n because a d u l t s w i t h i n a stream spawn as a s i n g l e low d e n s i t y p a n m i c t i c p o p u l a t i o n but j u v e n i l e s do not d i s p e r s e . A sample of j u v e n i l e s c o l l e c t e d a t a s i n g l e p o i n t w i t h i n a stream would t h e r e f o r e be the progeny of a s m a l l number of a d u l t s which may, by chance, not have the a l l o z y m e f r e q u e n c i e s t y p i c a l of the stream as a whole. J u v e n i l e d i s p e r s a l r a t e s and a d u l t d e n s i t i e s appear t o be low enough t h a t most a l l o z y m e f r e q u e n c y d i f f e r e n c e s c o u l d be acc o u n t e d f o r by a s i n g l e g e n e r a t i o n of d r i f t . D i s p e r s a l of f r y d u r i n g t h e i r f i r s t summer can average l e s s than 500 meters. Newly-hatched f r y p l a n t e d i n the s p r i n g moved an average of ca.400 meters ( J . Hume p e r . comm.) and ca.200 meters ( S l a n e y , P o w e l l and Smith, 1980) i n two s m a l l B. C. c o a s t a l streams by the time of a f a l l c e n sus. A t l a n t i c salmon f r y , p l a n t e d as eggs, moved an average of ca.150 meters 64 by the end of t h e i r f i r s t summer ( E g g l i s h a w and S h a c k l e y , 1973). G r e a t e r d i s p e r s a l has been n o t e d i n some c i r c u m s t a n c e s such as where spawning t a k e s p l a c e i n i n t e r m i t t a n t t r i b u t a r i e s ( E v e r e s t , 1973) or where the stream does not c o n t a i n s u i t a b l e w i n t e r h a b i t a t ( B j o r n , 1971). A l t h o u g h d e n s i t i e s may be h i g h e r i n i n t e r i o r streams, u n p r o d u c t i v e c o a s t a l streams g e n e r a l l y have a low d e n s i t y of a d u l t spawners, a s i t u a t i o n which has been e x a c e r b a t e d by o v e r f i s h i n g and l o g g i n g a c t i v i t i e s i n r e c e n t y e a r s . T y p i c a l d e n s i t i e s i n c o a s t a l r i v e r s a r e about 45 a d u l t s / k m i n t h e B i g Qualicum R i v e r ( P e t e r s o n and Lyons, 1968) and 20 a d u l t s / k m i n the Keogh R i v e r (P. Sla n e y p e r . comm.). I f over-summer d i s p e r s a l a v e r a g e s 500 meters and the a d u l t d e n s i t y i s 50 a d u l t s / k m then v i r t u a l l y a l l of the f r y a t a s i n g l e p o i n t w i l l be the progeny of a p p r o x i m a t e l y 50 a d u l t s . A h i g h l y skewed, p o o r l y d e f i n e d d i s t r i b u t i o n of f r y d i s p e r s a l d i s t a n c e s and v a r i a t i o n i n the d e n s i t y of a d u l t s makes i t d i f f i c u l t t o put an e x a c t f i g u r e on the number of a d u l t s . N e v e r t h e l e s s the e x p e c t e d number of p a r e n t s e s t i m a t e d from t h e v a r i a n c e of a l l o z y m e f r e q u e n c i e s between f r y samples from the same stream (Table 4) i s much g r e a t e r than the approximate numbers of p a r e n t s c a l c u l a t e d from f r y d i s p e r s a l d i s t a n c e s and a d u l t d e n s i t i e s . A l t h o u g h t h i s i s not p r o o f t h a t temporary d r i f t i s the cause of the v a r i a t i o n w i t h i n streams i t does p r o v i d e a p l a u s i b l e e x p l a n a t i o n and a l s o i n d i c a t e s t h a t l o n g term s u b d i v i s i o n of the p o p u l a t i o n i n a stream s h o u l d r e s u l t i n v a r i a t i o n g r e a t e r than t h a t o b s e r v e d . Temporal v a r i a t i o n , p r o b a b l y caused by s e l e c t i o n , has been r e p o r t e d i n some s p e c i e s 6 5 ( Daphnia H e b e r t , 1974; V o l e s , Krebs et a l . 1973) and cannot be r u l e d out as a cause of p a r t of the w i t h i n stream v a r i a t i o n i n s t e e l h e a d . D i f f e r e n c e s between year c l a s s e s can be e x p l a i n e d i n the same way because i n a l l c a s e s samples of f r y a r e compared. In most s i t u a t i o n s where l i f e h i s t o r y s t a g e s were compared, however, smolt or a d u l t samples, which p r o b a b l y r e p r e s e n t c l o s e t o a random sample from the whole stream were compared w i t h j u v e n i l e samples. The v a r i a n c e i n t h i s case s h o u l d be l e s s but the number of comparisons i s i n s u f f i c i e n t t o d e t e r m i n e i f t h i s i s so. The d i f f e r e n c e s between year c l a s s e s of a d u l t s t e e l h e a d samples found by C h i l c o t e et a l . (1980) i n d i c a t e t h a t not a l l w i t h i n stream v a r i a t i o n i s the r e s u l t of temporary d r i f t . T h e i r f i n d i n g s are confounded, however because the r i v e r i n which t h i s o b s e r v a t i o n was made r e c e i v e s y e a r l y p l a n t s of l a r g e numbers of f o r e i g n h a t c h e r y r e a r e d s m o l t s . I t s h o u l d be noted t h a t a l t h o u g h e l e c t r o p h o r e t i c v a r i a t i o n does not i n d i c a t e p o p u l a t i o n s u b d i v i s i o n w i t h i n streams i t does not p r e c l u d e i t . A number of c a s e s of s u b d i v i s i o n have been mentioned p r e v i o u s l y ( S m i t h , 1969; R i d d e l l , 1979; R a l e i g h , 1971). The v a r i a t i o n among streams has t o be due t o l o n g - t e r m d i f f e r e n c e s between a d j a c e n t streams s i n c e the among stream v a r i a n c e i s made up of a s i g n i f i c a n t component of v a r i a n c e due t o the e f f e c t of streams a l o n e i n a d d i t i o n t o the v a r i a n c e w i t h i n streams. As d i s c u s s e d e a r l i e r t h i s s u g g e s t s t h a t m i g r a t i o n i s not l a r g e enough t o p r e v e n t d i f f e r e n t i a t i o n 66 between streams even i f the s e l e c t i o n c o e f f i c i e n t s a t the l o c u s i n q u e s t i o n a r e s m a l l . However, i t a l s o i m p l i e s t h a t i f s e l e c t i o n c o e f f i c i e n t s a r e l a r g e enough t o c o u n t e r a c t d r i f t , c o n v e r g e n t s e l e c t i o n can occur i n some c a s e s . I t i s i m p o s s i b l e t o d e termine whether d r i f t or s e l e c t i o n i s the major d i f f e r e n t i a t i n g f o r c e a t t h i s l e v e l . The e x p e c t e d v a r i a n c e of gene f r e q u e n c i e s a t e q u i l i b r i u m depends s o l e l y on the a b s o l u t e number of immigrants per g e n e r a t i o n i f d r i f t and m i g r a t i o n a r e the o n l y f o r c e s a c t i n g . U s i n g an a p p r o x i m a t i o n of the one d i m e n s i o n a l s t e p p i n g model, which would seem a p p r o p r i a t e f o r streams on a c o a s t l i n e , the average number of immigrants per g e n e r a t i o n c o u l d be c a l c u l a t e d from the observed v a r i a n c e of a l l e l e f r e q u e n c i e s . T h i s number would be m e a n i n g l e s s because the a c t u a l number of m i g r a n t s c o u l d be much l a r g e r or s m a l l e r depending on the a c t u a l c o m b i n a t i o n of m i g r a t i o n , d r i f t and s e l e c t i v e f o r c e s . Founder e f f e c t s and b o t t l e n e c k s a r e not as l i k e l y t o o c c u r i n a s p e c i e s w i t h o v e r l a p p i n g g e n e r a t i o n s and s p a t i a l s e p a r a t i o n of a d u l t and j u v e n i l e h a b i t a t s . The f a i l u r e of one or two-year c l a s s e s or s h o r t term d e t e r i o r a t i o n of e i t h e r the j u v e n i l e or a d u l t h a b i t a t would not reduce the e f f e c t i v e p o p u l a t i o n t o the l e v e l s t h a t a r e r e q u i r e d . Thus, the o n l y c o n c l u s i o n t h a t can be made i s t h a t m i g r a t i o n between streams i s on average s m a l l e r than the combined f o r c e s of d r i f t and s e l e c t i o n . W i t h i n groups, l a r g e f r e q u e n c y d i f f e r e n c e s a t one l o c u s 67 between a d j a c e n t streams a r e not a s s o c i a t e d w i t h l a r g e d i f f e r e n c e s a t o t h e r l o c i . T h i s l a c k of c o r r e l a t i o n between l o c i i m p l i e s t h a t most a d j a c e n t streams d i f f e r a t a few of t h e i r l o c i r a t h e r than o n l y a few streams d i f f e r i n g a t most of t h e i r l o c i . T h i s c o r r e s p o n d s t o the s i t u a t i o n i n F i g . 10B r a t h e r than t h a t i n F i g . 10A. P o p u l a t i o n s t r u c t u r i n g a t the stream l e v e l i s t h e r e f o r e not the r e s u l t of a few s p e c i a l c ases i n which a d j a c e n t streams have d i f f e r e n t i a t e d a t most of t h e i r l o c i because d i s p e r s a l between them has been e l i m i n a t e d by a p e c u l i a r s e t of c i r c u m s t a n c e s . T h i s i n c l u d e s the s i t u a t i o n where p o p u l a t i o n s t r u c t u r i n g t a k e s p l a c e on a l a r g e r g e o g r a p h i c s c a l e and the h e t e r o g e n e i t y a t the stream l e v e l r e f l e c t s the r e s t r i c t i o n of gene f l o w and the consequent sharp d i f f e r e n t i a t i o n between a d j a c e n t streams on the b o u n d a r i e s of t h e s e l a r g e r a r e a s . I n s t e a d , the degree of i s o l a t i o n , as i n d i c a t e d by the amount of a l l o z y m e f r e q u e n c y d i f f e r e n t i a t i o n , appears s i m i l a r f o r most p a i r s of a d j a c e n t s t r e a m s . T h i s r e s u l t i n c r e a s e s the p r o b a b i l i t y t h a t d a t a from a d d i t i o n a l polymorphisms would i n d i c a t e a d d i t i o n a l p o p u l a t i o n s t r u c t u r i n g r a t h e r than c o n f i r m p r e - e x i s t i n g p a t t e r n s . S i m i l a r gene f r e q u e n c i e s over wide g e o g r a p h i c a r e a s a r e used by a number of a u t h o r s as e v i d e n c e f o r s e l e c t i o n o p e r a t i n g a t a p a r t i c l a r l o c u s . At the same time Kimura and Ohta (1971) and L e w o n t i n (1974) emphasize t h a t s m a l l amounts of m i g r a t i o n between p o p u l a t i o n s can m a i n t a i n t h i s s i m i l a r i t y even i f 68 F i g u r e 10. An example of two p o s s i b l e r e l a t i o n s h i p s between the p a t t e r n of v a r i a t i o n of the a l l o z y m e s a t two l o c i . 69 A R E A S OF SIMILARITY — — Locus 1 Locus 2 70 a l l e l e s a r e n e u t r a l . As Lewontin (1974) p o i n t s out a m i g r a t i o n r a t e i n the o r d e r of 10 i n d i v i d u a l s per g e n e r a t i o n , i r r e s p e c t i v e of t o t a l p o p u l a t i o n s i z e , can e f f e c t i v e l y p r e v e n t d i f f e r e n t i a t i o n i f the o n l y f o r c e a c t i n g on the p o p u l a t i o n s i s d r i f t . Two g e n e r a l approaches a r e used t o c o u n t e r the argument t h a t s i m i l a r i t i e s a r e the r e s u l t of m i g r a t i o n between p o p u l a t i o n s . Through a c a r e f u l study of the e c o l o g y of a b u t t e r f l y McKechnie, E h r l i c h and White (1975) e l i m i n a t e d the p o s s i b i l i t y of m i g r a t i o n between p o p u l a t i o n s and t h e r e f o r e c o n c l u d e t h a t the s i m i l a r i t y of a l l e l e f r e q u e n c i e s over wide a r e a s i s the r e s u l t of s e l e c t i o n . In s p e c i e s such as s t e e l h e a d where o c c a s i o n a l l o n g d i s t a n c e d i s p e r s a l i s known t o o c c u r , but w i t h an unknown f r e q u e n c y , l o c a l d i f f e r e n t i a t i o n may be e v i d e n c e of l a c k of d i s p e r s a l . The s i m i l a r i t y of a l l e l e f r e q u e n c i e s between groups w i t h i n the c o a s t a l r e g i o n a r e s m a l l i n comparison t o d i f f e r e n c e s between a d j a c e n t streams. Average f r e q u e n c i e s f o r c o a s t a l and i n t e r i o r p o p u l a t i o n s of s t e e l h e a d i n s o u t h w e s t e r n B.C. a r e a l s o s i m i l a r t o those measured i n the n o r t h w e s t e r n U.S. ( A l l e n d o r f , 1975, Ta b l e 9) In c o n t r a s t t o the s i m i l a r i t i e s w i t h i n r e g i o n s , the d i f f e r e n c e s between p o p u l a t i o n s i n the c o a s t a l and i n t e r i o r r e g i o n s a t the LDH and SOD l o c i i n d i c a t e t h a t these two p o p u l a t i o n s a r e i s o l a t e d from one a n o t h e r , y e t a t the MDH and IDH l o c i f r e q u e n c i e s a r e v e r y s i m i l a r . A y a l a e t a l . (1979), A y a l a , P o w e l l and Dobzhansky (1971), C h r i s t i a n s e n and Fr y d e n b e r g (1974) and Richmond (1978) have argued t h a t i f l o c a l d i f f e r e n t i a t i o n or d i f f e r e n t i a t i o n a t o t h e r l o c i i n d i c a t e s a l a c k of gene f l o w then s i m i l a r i t i e s 71 TABLE 9. Average a l l e l e f r e q u e n c i e s f o r c o a s t a l and i n t e r i o r p o p u l a t i o n s of s t e e l h e a d i n s o u t h w e s t e r n B.C. and n o r t h w e s t e r n U n i t e d S t a t e s C o a s t a l I n t e r i o r B.C. U.S. B.C. U.S. LDH-4 1.0 SOD 1.0 MDH-3,4 1.0 IDH-1,2 1.0 .931 .646 .870 .690 .874 .663 .886 .660 .471 .996 .862 .696 .433 .930 .985 .676 between w i d e l y s e p a r a t e d p o p u l a t i o n s are due t o convergent s e l e c t i o n f o r some e l e c t r o p h o r e t i c a l l e l e s . The main problem w i t h both t h i s c o n c l u s i o n and t h a t of McKechnie, E h r l i c h and White (1975) i s the assumption t h a t f r e q u e n c i e s have reached t h e i r e q u i l i b r i u m v a l u e s . C l i m a t i c changes i n the l a s t 10,000 y e a r s mean t h a t many s p e c i e s have expanded or c o n t r a c t e d t h e i r ranges r e l a t i v e l y r e c e n t l y , and t h a t d i s p e r s a l may have been more e x t e n s i v e a t some time i n the r e c e n t p a s t . T h i s i s p a r t i c u l a r l y t r u e i n s t e e l h e a d , where r e t r e a t i n g g l a c i e r s l e f t wide a r e a s of vacant h a b i t a t t h a t were invaded 6,000 t o 10,000 y e a r s ago. The p a t t e r n of v a r i a t i o n o b s e r v e d today may r e p r e s e n t a c o m b i n a t i o n of founder e f f e c t s and f o r m e r l y e x t e n s i v e d i s p e r s a l . I t i s d i f f i c u l t t o know where t o s t o p t h i s argument. D i f f e r e n c e s w i t h i n streams are o b v i o u s l y not the r e s u l t of founder e f f e c t s t h a t o c c u r r e d some 5,000 t o 10,000 y e a r s ago. The same i s p r o b a b l y t r u e f o r d i f f e r e n c e s between a d j a c e n t streams. A l t h o u g h i t cannot be p r o v e n , I b e l i e v e t h a t 72 f o r m e r l y e x t e n s i v e d i s p e r s a l i s not the cause f o r s i m i l a r i t i e s between groups. A l l e n d o r f (1975) and U t t e r and A l l e n d o r f (1977) argue t h a t the s h a r p change i n gene f r e q u e n c i e s a t the LDH and SOD l o c i a t the Cascade C r e s t (between the c o a s t a l and i n t e r i o r r e g i o n ) r e p r e s e n t s a major taxonomic d i v i s i o n of rainbow t r o u t p o p u l a t i o n s i n t o c o a s t a l and i n l a n d forms. A p p a r e n t l y t h e s e forms were i s o l a t e d d u r i n g the l a s t g l a c i a t i o n and have s i n c e m a i n t a i n e d t h e i r i s o l a t i o n . The p r o o f of t h i s h y p o t h e s i s r e q u i r e s t h a t the a l l e l e s i n v o l v e d be s e l e c t i v e l y n e u t r a l , o t h e r w i s e t h i s s u b d i v i s i o n c o u l d have de v e l o p e d s i n c e t h e l a s t g l a c i a t i o n and c o u l d be p r e s e n t a t the LDH and SOD l o c i o n l y . One p r e d i c t i o n of t h i s h y p o t h e s i s i s t h a t the change from h i g h SOD(152) f r e q u e n c i e s ( t y p i c a l of the c o a s t ) t o v e r y low SOD(152) f r e q u e n c i e s ( t y p i c a l of the i n t e r i o r ) s h o u l d occur i n the same g e o g r a p h i c l o c a t i o n as the change from low t o h i g h LDH-4 (76) a l l e l e f r e q u e n c i e s . As shown i n F i g . 11 both Skeena R i v e r s t e e l h e a d and upper Dean R i v e r r e s i d e n t rainbow have low f r e q u e n c i e s of both the LDH(76) and SOD(152) a l l e l e s . T h i s i n d i c a t e s t h a t the c l i n e s i n a l l e l e f r e q u e n c i e s a t t h e s e two l o c i a r e not c o i n c i d e n t i n a l l l o c a t i o n s . Lack of c o n s i s t e n t l y c o i n c i d e n t c l i n e s s u g g e s t s t h a t i n t e r i o r and c o a s t a l p o p u l a t i o n s a r e not c o h e s i v e taxonomic groups. 7 3 Figure 11. Large scale geographic variation in LDH-4 and SOD gene frequencies in B r i t i s h Columbia steelhead. 74 75 Another p r e d i c t i o n of . t h i s h y p o t h e s i s i s t h a t major changes i n a l l e l e f r e q u e n c i e s a t o t h e r l o c i s h o u l d t a k e p l a c e at the Cascade C r e s t . In a t l e a s t two o t h e r p o l y m o r p h i c l o c i (MDH-3 and IDH-3,4) t h e r e i s no s i g n of s u b d i v i s i o n i n t o c o a s t a l and i n t e r i o r p o p u l a t i o n s . The a l l e l e f r e q u e n c i e s a t these l o c i a r e , i n s t e a d , remarkably s i m i l a r . At the AGP-1 l o c u s t h e r e i s a major d i f f e r e n c e i n a l l e l e f r e q u e n c i e s between s t e e l h e a d p o p u l a t i o n s i n the two main i n t e r i o r t r i b u t a r i e s of the F r a s e r (Thompson and C h i l c o t i n R i v e r s ) but no d i f f e r e n c e between the Thompson p o p u l a t i o n and c o a s t a l p o p u l a t i o n s . The d i f f e r e n c e between the Thompson and C h i l c o t i n p o p u l a t i o n s (.27) i s a lmost as l a r g e as the c o a s t - i n t e r i o r d i f f e r e n c e s a t the LDH-4 and SOD l o c i (about .45 and .30 r e s p e c t i v e l y ) . U t t e r and A l l e n d o r f (1977) r e p o r t a s i m i l a r s i t u a t i o n i n the upper Columbia w i t h a l l e l e f r e q u e n c i e s a t a p e p t i d a s e l o c u s . In a d d i t i o n , the A b u n t l e t Lake p o p u l a t i o n on the upper Dean R i v e r p o s s e s s e s a unique a l l e l e a t the LDH-4 l o c u s a t a frequ e n c y of .10. A l l of t h i s s u g g e s t s t h a t the s u b d i v i s i o n of s t e e l h e a d p o p u l a t i o n s a l o n g the Cascade C r e s t may not be any more of a fundamental d i v i s i o n than any of a number of o t h e r s u b d i v i s i o n s w i t h i n the s p e c i e s . Recent e v i d e n c e of b e h a v i o r a l and p h y s i o l o g i c a l d i f f e r e n c e s between LDH phenotypes i n Salmo g a i r d n e r i ( K l a r e t a l . , 1979a, 1979b; Redding and S c h r e c k , 1979; T s u y u k i and W i l l i s c r o f t , 1977) a l s o reduces the v a l u e of t h i s l o c u s as an 76 i n d i c a t o r of h i s t o r i c a l p a t t e r n s of d i s p e r s a l and former s u b d i v i s i o n of the s p e c i e s s i n c e i n f e r e n c e s i n t h i s r e g a r d depend h e a v i l y on the assumption of n e u t r a l i t y . The i n c r e a s i n g e v i d e n c e t h a t some e l e c t r o p h o r e t i c a l l e l e s a r e n o n - n e u t r a l c a s t s s e r i o u s doubts on the v a l i d i t y of any argument i n v o k i n g the a ssumption of n e u t r a l i t y f o r any e l e c t r o p h o r e t i c v a r i a n t even i f t h e r e i s no e v i d e n c e f o r n o n - n e u t r a i l i t y a t the l o c u s i n q u e s t i o n . A c e r t a i n l a c k of c o r r e l a t i o n of i n t r a p o p u l a t i o n d i f f e r e n c e s i n both e l e c t r o p h o r e t i c and m o r p h o l o g i c a l c h a r a c t e r i s t i c s ( S o k a l , 1974; A v i s e , 1974) has p r o b a b l y r e s u l t e d from d i f f e r e n t s t r e n g t h s and s p a c i a l p a t t e r n s of s e l e c t i o n a t d i f f e r e n t l o c i . In some c a s e s e x t e n s i v e d i f f e r e n t i a t i o n has taken p l a c e a t e l e c t r o p h o r e t i c a l l y d e t e c t e d l o c i w i t h o u t c o r r e s p o n d i n g m o r p h o l o g i c a l d i f f e r e n t i a t i o n ( D r o s o p h i l a , A y a l a e t a l . , 1970; brown t r o u t , Ryman e t a l . , 1979) In o t h e r c ases the o p p o s i t e s i t u a t i o n has o c c u r r e d ( D r o s o p h i l a , Carson 1978; d e s e r t p u p f i s h , T u r n e r , 1974 and two C a l i f o r n i a minnow s p e c i e s , A v i s e , Smith and A y a l a , 1975). The r e c e n t r e p o r t t h a t summer and w i n t e r s t e e l h e a d a re not e l e c t r o p h o r e t i c a l l y d i s t i n c t ( C h i l c o t e et a l . , 1980) d e s p i t e e a r l i e r m o r p h o l o g i c a l and b e h a v i o r a l e v i d e n c e of d i f f e r e n t i a t i o n ( S m i t h , 1969) i s another case i n p o i n t . The dangers i n v o l v e d i n u s i n g a s m a l l s ubset of c h a r a c t e r i s t i c s f o r s y s t e m a t i c purposes a re c l e a r . In h i s review of the problem of s p e c i e s d e f i n i t i o n S o k a l 77 (1974) has emphasized the l a c k of congruence between the p a t t e r n s of v a r i a t i o n s of v a r i o u s c h a r a c t e r i s t i c s w i t h i n a s p e c i e s . E h r l i c h and Raven (1969) have argued t h a t n a t u r a l s e l e c t i o n i s more im p o r t a n t than gene f l o w i n m a i n t a i n i n g the s i m i l a r i t y between p o p u l a t i o n s of a s p e c i e s . Both of the s e s t a t e m e n t s seem t o f i t the s i t u a t i o n i n s t e e l h e a d , a s p e c i e s t h a t appears t o be s u b d i v i d e d i n t o a l a r g e number of semi-i s o l a t e d demes t h a t d i f f e r g e n e t i c a l l y from each o t h e r t o v a r y i n g d e g r e e s , but t h a t s t i l l m a i n t a i n a b a s i c m o r p h o l o g i c a l and b i o l o g i c a l s i m i l a r i t y which w a r r a n t s t h e i r i n c l u s i o n i n a s i n g l e s p e c i e s . 78 APPLICATIONS TO STEELHEAD MANAGEMENT S t e e l h e a d and o t h e r anadromous s a l m o n i d s are s u b j e c t t o heavy commercial and s p o r t f i s h e r i e s as w e l l as e x t e n s i v e h a b i t a t d e g r a d a t i o n , and as a r e s u l t a r e among the most i n t e n s i v e l y managed no n - d o m e s t i c a t e d s p e c i e s i n the w o r l d . Because they a r e e a s i l y c u l t u r e d , a major p a r t of t h i s i n t e n s i v e management i n v o l v e s r e l e a s i n g h a t c h e r y - r e a r e d f i s h i n a d d i t i o n t o the more t r a d i t i o n a l management through f i s h i n g r e g u l a t i o n s . F i s h c u l t u r e o p e r a t i o n s d i s r u p t the p a t t e r n of g e n e t i c v a r i a b i l i t y t h r o ugh s e l e c t i o n and e x t e n s i v e t r a n s p l a n t i n g of f i s h between streams. S e l e c t i o n , e i t h e r i n t e n t i o n a l or u n i n t e n t i o n a l , t a k e s p l a c e i n h a t c h e r i e s and i s a s u b j e c t of co n c e r n s i n c e f i s h t h a t become adapted t o the h a t c h e r y environment seem t o be, i n some unknown way, p o o r l y adapted t o the r i g o u r s of the n a t u r a l environment i n which they must s u r v i v e upon r e l e a s e ( R e i s e n b i c h l e r and M c l n t y r e , 1977; F l i c k and Webster, 1964). The e f f e c t of t r a n s p l a n t s i s t o i n c r e a s e gene f l o w between streams i n d i r e c t p r o p o r t i o n t o the numbers of f i s h t r a n s f e r r e d and the number of y e a r s i n which t r a n s f e r s t a k e p l a c e . I f the s e streams were f o r m e r l y i s o l a t e d , or s e m i - i s o l a t e d , from each o t h e r the p o p u l a t i o n i n each stream may be adapted t o i t s n a t i v e environment and be a t a d i s a d v a n t a g e i n f o r e i g n 79 e n v i r o n m e n t s . As a r e s u l t n e i t h e r t r a n s p l a n t e d f i s h nor t h e i r progeny w i l l s u r v i v e as w e l l as n a t i v e f i s h and i n some s i t u a t i o n s t h i s w i l l r e s u l t i n a r e d u c t i o n of the n a t u r a l p r o d u c t i o n of the stream as the n a t i v e gene p o o l becomes c o n t a m i n a t e d w i t h maladapted f o r e i g n genes. T h i s arguement i s s i m i l a r t o t h a t used by S t e a r n s and Sage (1980) t o account f o r the poor s u r v i v a l i n f r e s h w a t e r of progeny of Gambusia from a s m a l l f r e s h w a t e r stream i n Texas. T h i s p o p u l a t i o n c o n t i n u a l l y r e c e i v e d enough m i g r a n t s from a l a r g e a d j a c e n t , b r a c k i s h adapted p o p u l a t i o n t o p r e v e n t l o c a l a d a p t a t i o n t o the f r e s h w a t e r environment. T h i s o c c u r s even though the s e l e c t i v e p r e s s u r e towards l o c a l a d a p t a t i o n appears t o be l a r g e and the s p e c i e s has a demonstrated a b i l i t y t o adapt t o the f r e s h w a t e r e n vironment. As p o i n t e d out by F e l s e n s t e i n (1976) most models of g e n e t i c d i f f e r e n t i a t i o n p r e d i c t a sudden c o l l a p s e i n l o c a l a d a p t a t i o n ( i e . g e n e t i c s t r u c t u r e ) as m i g r a t i o n exceeds a c e r t a i n t h r e s h o l d . T r a n s p l a n t s between streams has s e r i o u s consequences o n l y i f g e n e t i c d i f f e r e n t a t i o n has taken p l a c e between the p o p u l a t i o n s c o n c e r n e d and the t r a n s p l a n t r a t e exceeds the t h r e s h o l d a t which g e n e t i c s t r u c t u r i n g b r e a k s down. I f the s e l e c t i v e f o r c e s on e l e c t r o p h o r e t i c a l l e l e s a r e presumed t o be r e l a t i v e l y s m a l l , p r o b a b l y the most i n t e r e s t i n g c o n c l u s i o n from my d a t a i s t h a t i s o l a t i o n between p o p u l a t i o n s i n a d j a c e n t streams i s such t h a t d i f f e r e n t i a t i o n w i l l o c cur even i n c h a r a c t e r i s t i c s w i t h v e r y s m a l l s e l e c t i v e c o e f f i c i e n t s . 80 Q u a n t i t a t i v e c h a r a c t e r s such as body s i z e , egg s i z e or time of r e t u r n a r e o f t e n thought t o be i m p o r t a n t c h a r a c t e r i s t i c s under the i n f l u e n c e of r e l a t i v e l y l a r g e s e l e c t i v e f o r c e s . T h i s c o n c l u s i o n may not be v a l i d i f the o n l y e v i d e n c e f o r i t , as i s o f t e n the c a s e , i s the f a c t t h a t p o p u l a t i o n s i n nearby streams are d i f f e r e n t . Very s m a l l s e l e c t i v e f o r c e s can r e s u l t i n e x t e n s i v e d i f f e r e n t i a t i o n when gene f l o w i s a l s o v e r y s m a l l . T h i s i s t r u e even f o r c h a r a c t e r i s t i c s such as the r h e o t a c t i c response of f r y from i n l e t and o u t l e t spawning p o p u l a t i o n s where the means through which s e l e c t i o n a c t s i s o b v i o u s . The whole q u e s t i o n of what i s and what i s not an i m p o r t a n t d i f f e r e n c e between two s t o c k s has t o be examined c l o s e l y . Too o f t e n , i m p o r t a n t d i f f e r e n c e s and o b v i o u s d i f f e r e n c e s a r e assumed t o be synonymous when i n r e a l i t y s e e m i n g l y s u b t l e d i f f e r e n c e s can be more , i m p o r t a n t . Without f u r t h e r e x p e r i m e n t a t i o n t h e r e i s no c l e a r way of d i s t i n g u i s h i n g which, i f any, of the many ob s e r v e d d i f f e r e n c e s between two p o p u l a t i o n s a r e b e i n g m a i n t a i n e d by s t r o n g s e l e c t i o n and which are b e i n g m a i n t a i n e d by weak s e l e c t i o n a c t i n g i n the absence of gene f l o w . Even i f the o b s e r v a t i o n of g e n e t i c d i f f e r e n c e s , e l e c t r o p h o r e t i c or o t h e r w i s e , g i v e s no i n d i c a t i o n of the importance of each d i f f e r e n c e , i t does imply t h a t the p o p u l a t i o n s i n q u e s t i o n a r e t o some degree g e n e t i c a l l y i s o l a t e d from each o t h e r . In i t s e l f t h i s would s i m p l y i n d i c a t e t h a t some 81 c a u t i o n s h o u l d be e x e r c i s e d i n p l a n n i n g any t r a n s p l a n t program. The problem i s t h a t i t i s d i f f i c u l t t o know when, and when n o t , to e x e r c i s e c a u t i o n . G e n e t i c d i f f e r e n t i a t i o n has o c c u r r e d due t o a wide v a r i e t y of e n v i r o n m e n t a l d i f f e r e n c e s and not always i n o b v i o u s ways. Two m o r p h o l o g i c a l l y s i m i l a r r o c k f i s h s p e c i e s which l i v e a t d i f f e r e n t depths have e l e c t r o p h o r e t i c a l l y i d e n t i c a l LDH isozymes but the s e enzymes d i f f e r i n t h e i r r e a c t i o n r a t e s a t d i f f e r e n t p r e s s u r e s ( S i e b e n a l l e r and Somers, 1978). Water p r e s s u r e i s a l s o i m p l i c a t e d as the cause of the g e n e t i c d i f f e r e n c e i n the a b i l i t y of two l a k e t r o u t s t o c k s t o r e t a i n gas under p r e s s u r e s i n c e f i s h from a deeper l a k e were a b l e t o m a i n t a i n h i g h e r p r e s s u r e s ( I h s s e n and T a i t , 1974). S c h a f f e r and E l s o n (1975) c o n c l u d e d t h a t d i f f e r e n c e s i n average age of f i r s t m a t u r i t y between A t l a n t i c salmon p o p u l a t i o n s a r e an a d a p t i v e response t o d i f f e r e n c e s i n the h a r s h n e s s of the f r e s h w a t e r environment and the r i c h n e s s of ocean f e e d i n g grounds. The a b i l i t y t o home t o a p a r t i c u l a r stream was g e n e r a l l y thought t o be m a i n l y the r e s u l t of a l e a r n e d i m p r i n t i n g p r o c e s s u n t i l Bams (1976) demonstrated t h a t p i n k salmon c a r r y i n g n a t i v e genes had a much h i g h e r p r o p e n s i t y f o r homing t o the Tsolum R i v e r than f i s h c a r r y i n g f o r e i g n genes. In each case i t i s easy t o see why the d i f f e r e n c e has o c c u r r e d , once i t has been demonstrated. I t would have been d i f f i c u l t , however, t o p r e d i c t a p r i o r i the o c c u r r e n c e and mechanism of g e n e t i c d i f f e r e n t i a t i o n . The i m p l i c a t i o n i s t h a t the apparent e n v i r o n m e n t a l s i m i l a r i t y between two streams a l s o cannot be used as an argument f o r g e n e t i c s i m i l a r i t y s i n c e the i m p o r t a n t 82 habitat differences may be more subtle than those detected by a s u p e r f i c i a l survey. Given the lack of gene flow and the p o s s i b i l i t y of subtle environmental differences i t would s t i l l be surprising i f important genetic differences were found between a l l , or even most, populations in adjacent streams but again i t i s impossible to predict where differences w i l l occur. This lack of information makes i t d i f f i c u l t to develop a sound policy on the genetic implications of salmonid f i s h e r i e s management. However, since f i s h e r i e s management w i l l proceed with or without a genetic p o l i c y , there is a need to develop a set of guidelines which can be added to as information becomes ava i l a b l e . Speculative comments on e f f e c t s of selection in hatcheries have been made elsewhere (e.g. Reisenbichler and Mclntyre, 1977) and this discussion w i l l be limited to the e f f e c t s of transplants. The major goal of any transplant .policy should be to prevent the loss, p a r t i c u l a r l y the i r r e v e r s i b l e loss, of useful genetic v a r i a b i l i t y . Different types of genetic v a r i a b i l i t y are maintained by selective forces ranging from weak to strong. V a r i a b i l i t y maintained by weak forces i s vulnerable since small increases in migration rates ( i . e . transplants) w i l l destroy i t . Such variation may have l i t t l e e f f e c t on the v i a b i l i t y of transplanted stocks but includes c h a r a c t e r i s t i c s such as color 8 3 p a t t e r n s or s u s c e p t a b i l i t y t o a n g l i n g which may be worth p r e s e r v i n g f o r t h e i r a e s t h e t i c or management v a l u e . At the o t h e r end of the s c a l e i s v a r i a b i l i t y t h a t i s m a i n t a i n e d by s t r o n g s e l e c t i v e f o r c e s which w i l l have a d r a m a t i c impact on the s u c c e s s of t r a n s p l a n t e d f i s h but w i l l be l e s s v u l n e r a b l e t o d i s r u p t i o n by i n c r e a s e d m i g r a t i o n . My r e s u l t s i m p l y t h a t the whole range of v a r i a b i l i t y can be p r e s e n t a t the a d j a c e n t stream l e v e l i f i t can be assumed t h a t the s e l e c t i v e f o r c e s a c t i n g on e l e c t r o p h o r e t i c v a r i a b i l i t y a r e r e l a t i v e l y s m a l l . V a r i a t i o n due t o weak s e l e c t i v e f o r c e s can o n l y be m a i n t a i n e d by a complete absence of t r a n s p l a n t s and i t s l o s s w i l l p r o b a b a l y be i r r e v e r s i b l e . V a r i a t i o n due t o s t r o n g s e l e c t i v e f o r c e s w i l l o n l y be d e s t r o y e d by l a r g e s c a l e , c o n t i n u o u s t r a n s p l a n t s . I t s l o s s s h o u l d be a t l e a s t p a r t i a l l y r e v e r s i b l e but c o n t i n u i n g h i g h e r m o r t a l i t i e s of t r a n s p l a n t e d f i s h and t h e i r progeny w i l l o c c u r . The two main reasons f o r t r a n s p l a n t i n g s t e e l h e a d a r e t o a i d the r e c o v e r y of d e p l e t e d s t o c k s and t o augment s t o c k s , u s u a l l y by many times t h e i r e x i s t i n g numbers. Augmentation always i n v o l v e s p l a n t i n g s m o l t s on a c o n t i n u i n g , y e a r l y b a s i s s i n c e the d e s i r e d p o p u l a t i o n i s g r e a t e r than the f r e s h w a t e r environment can s u p p o r t . Recovery s t o c k i n g can i n v o l v e any l i f e h i s t o r y s t a g e , and i s g e n e r a l l y s h o r t term and does not exceed the c a r r y i n g c a p a c i t y of the f r e s h w a t e r environment. In each case the reason f o r t r a n s p l a n t i n g f o r e i g n s t o c k r a t h e r than 8 4 u s i n g n a t i v e f i s h i s economic. I t i s cheaper t o c o l l e c t eggs and r e a r f i s h i n one l a r g e f a c i l i t y than t o use a number of s m a l l e r f a c i l i t i e s . Managers of l a r g e h a t c h e r i e s a r e r e l u c t a n t t o r a i s e eggs c o l l e c t e d from a number of d i f f e r e n t streams because each s t o c k i s a p o s s i b l e source of d i s e a s e c o n t a m i n a t i o n . S i n c e r e c o v e r y s t o c k i n g i n v o l v e s a l a r g e number of d i f f e r e n t streams, n a t i v e s t o c k s h o u l d be used t o p r o t e c t p o s s i b l y u s e f u l , but not s t r o n g l y s e l e c t e d , g e n e t i c v a r i a t i o n . In s p e c i e s such as s t e e l h e a d where h a r v e s t i s i n the form of a t e r m i n a l f i s h e r y such s t o c k i n g can be s h o r t term s i n c e h a r v e s t can be r e g u l a t e d . In coho salmon where a mixed f i s h e r y o c c u r s , c h r o n i c o v e r h a r v e s t i n g w i l l be a problem and the use of n a t i v e s t o c k s may not be p r a c t i c a l s i n c e r e c o v e r y s t o c k i n g w i l l have t o be e s s e n t i a l l y c o n t i n u o u s . I f augmentation i s l i m i t e d t o a s m a l l p r o p o r t i o n of streams, f o r e i g n f i s h c o u l d be used. The r e s u l t would be t h a t weak s e l e c t i v e d i f f e r e n t i a t i o n would be l o s t i n t h e s e streams but c o n s e r v e d i n un s t o c k e d a r e a s . S t r o n g l y s e l e c t e d d i f f e r e n c e s may r e s u l t i n a l o s s of n a t u r a l p r o d u c t i o n i n some streams but the c o s t of t h i s l o s s would p r o b a b l y be o f f s e t by the economies of s c a l e of a l a r g e r h a t c h e r y . Most of the above i s s p e c u l a t i v e and not r e a l l y new. What i s new i s the g e o g r a p h i c s c a l e on which management d e c i s i o n s have t o be made. G e n e t i c d i s t i n c t i v e n e s s i s not e n t i r e l y a f u n c t i o n of d i s t a n c e s i n c e p o p u l a t i o n s i n a d j a c e n t streams can 8 5 be more d i s t i n c t than t h o s e i n streams s e p a r a t e d by hundreds of m i l e s . The p o s s i b i l i t y of l o c a l a d a p t a t i o n has t o be c o n s i d e r e d a t the s c a l e of a s i n g l e , r e l a t i v e l y s m a l l r i v e r system as w e l l as on a broad r e g i o n a l b a s i s ; 86 LITERATURE CITED A l l a r d , R. W. and R. L. K a h l e r . 1972. P a t t e r n s of m o l e c u l a r v a r i a t i o n i n p l a n t p o p u l a t i o n s , p. 238-254. P r o c . I I B e r k e l e y Sym. Math. S t a t , and Prob. V o l . V D a r w i n i a n and Non-Darwinian E v o l u t i o n , U n i v . of C a l i f . P r e s s . A l l e n d o r f , F. W. 1973. G e n e t i c v a r i a t i o n , i n h e r i t a n c e and p r e l i m i n a r y p o p u l a t i o n d i s t r i b u t i o n of some p r o t e i n s of Salmo g a i r d n e r i . M.Sc. T h e s i s , U n i v e r s i t y of Washington. A l l e n d o r f , F. W. 1975. G e n e t i c v a r i a b i l i t y i n a s p e c i e s p o s s e s s i n g e x t e n s i v e gene d u p l i c a t i o n : G e n e t i c i n t e r p r e t a t i o n of d u p l i c a t e l o c i and e x a m i n a t i o n of g e n e t i c v a r i a t i o n i n p o p u l a t i o n s of rainbow t r o u t . Ph.D. T h e s i s . U n i v e r s i t y of Washington. A n t i f e a u , T. 1977MS. Thompson R i v e r s t e e l h e a d s u r v e y . U n p u b l i s h e d m a n u s c r i p t p r e p a r e d f o r the B. C. F i s h and W i l d l i f e Branch. A n t o n o v i c s , J . 1971. The e f f e c t s of a heterogeneous environment on the g e n e t i c s of n a t u r a l p o p u l a t i o n s . Amer. S c i . 59: 593-599. A s p i n w a l l , N. 1974. G e n e t i c a n a l y s i s of N o r t h American p o p u l a t i o n s of the p i n k salmon, Oncorhynchus gorbuscha, p o s s i b l e e v i d e n c e f o r the n e u t r a l mutation-random d r i f t h y p o t h e s i s . E v o l . 28: 295-305. 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The i n t e r p r e t a t i o n of p o p u l a t i o n s t r u c t u r e by F - s t a t i s t i c s w i t h s p e c i a l r e g a r d t o systems of m a t i n g s . E v o l . 19: 395-420. Appendix 1. General information on samples taken during the course of the study. Under the LHS ( l i f e h i s t o r y stage) heading: FR = f r y , PA = parr, SM .= smolt, AD = adult steelhead, RE = adult resident rainbow. Location i s given i n terms of the g r i d system used by the Gazetteer of Canada. Dashes i n the space for the MDH 3,4-72 a l l e l e indicate that i t could not be distinguished from the MDH 3,4-67 a l l e l e and therefore the two frequencies have been summed and the two a l l e l e s treated as one. In two a l l e l e systems only the frequency of the most common a l l e l e i s given. No. Name LHS Date Location S A LDH 4-M P -100 L E S SOD-100 I Z MDH 3-E -100 / A L 67 L O 72 Z Y M L18 E AGP-F R E Q U 100 IDH 3,4-100 E N C 72 I E 48 S 124 1. Abuntlet RE Aug 15/78 52 125 NE 47/0, .84 .10* 47/1, .0 42/0, .881 0 .119 0. .000 0 .000 47/1 .0 47/0.735 0 .260 0 .005 0.000 2. Atnarko AD Nov/77-Apr/78 52 125 SW 73/0. .986 66/0, .727 73/0, .925 0, .068 - 0 .007 29/0, .940 54/0.597 0 .282 0 .056 0.065 3. Babine SM May/79 55 127 NW 28/0. .982 28/0, .982 25/0, .920 0 .040 0. .000 0 .000 28/1 .000 20/0.687 0 .150 0 .150 0.013 4. Big Qualicum FR July 15/78 49 124 SW 63/0. .897 58/0, .647 60/0. .875 0 .100 0. ,025 0. .000 27/1, .000 5. Bertrand 1 FR Sept 1/77 42 122 SW 21/0. .857 21/0, .762 20/0, .700 0 .300 0. .000 0 .000 10/1, .000 20/0.750 0 .125 0 .125 0.000 Bertrand 2 FR Sept 1/77 35/0. .971 35/0, .614 35/0. .857 0, .143 - 0 .000 17/1. .000 0/0.000 0 .000 0 .000 0.000 6. Brohm FR Aug 12/77 49 123 NE 39/1.000 38/0. .737 39/0, .808 0, .192 - 0, .000 12/1. .000 38/0.671 0 .171 0 .158 0.000 Brohm FR Aug 21/78 34/0. .956 34/0, .779 35/0. .843 0, .086 0. ,014 0. .057 0/0. .000 Brohm FR Sept 26/77 37/1. .000 35/0. .729 36/0. .833 0, .139 0. ,000 0. .028 5/1. .000 28/0.688 0 .205 0 .107 0.000 Brohm PA Aug 12/77 69/0. .993 69/0. .783 69/0. .913 0. .065 0. 014 0. .007 16/1. .000 67/0.701 0 .179 0 .112 0.007 7. Bridge SM May 30/77 50 121 NW 30/0. .500 30/1. .000 30/0. .867 0. .100 0. 017 0, .017 55/0, .780 8. Chapman FR Aug 24/78 49 123 SW 40/1. ,000 39/0. .449 40/0. .900 0. .025 0. 075 0. .000 20/1. .000 9. Cheakamus FR Sept 26/77 49 123 NE 48/0. ,958 43/0. .744 41/0. .890 0. .085 0. 024 0. .000 9/1. .000 42/0.649 0. .185 0 .107 0.060 *LDH-4(123) 10. Chehailas FR Aug 29/78 49 121 SW 38/0 .908 37/0 .608 38/0 .921 0 .066 0 .000 0.013 Chehailas FR Aug 9/78 29/0 .862 29/0 .638 29/0 .897 0 .086 0 .017 0.000 12/0.980 21/0 .643 0 .262 0 .095 0 .000 Chehailas SM May 15/77 29/0 .776 29/0 .517 29/0 .914 0 .052 0 .034 0.000 13/0.962 7/0 .679 0 .214 0 .071 0 .036 11. Chilko 1 FR Sept 13/78 52 123 SE 40/0 .637 40/0 .962 40/0 .800 0 .200 0 .000 0.000 20/0.7l2 40/0 .544 0 .106 0 .106 0 .244 Chilko 2 FR Sept 13/78 38/0 .618 40/1 .000 40/0 .700 0 .300 0 .000 0.000 20/0.750 38/0 .572 0 .086 0 .125 0 .217 Chilko AD Oct/77-Feb/78 12/0 .708 12/1 .000 7/0 .643 0 .357 - - - 0.000 3/0.714 11/0 .477 0 .227 0 .091 0 .205 12. Chilliwack AD Jan/78-Apr/78 49 121 SW 19/1 .000 16/0 .563 16/0 .906 0 .094 - 0.000 4/1.000 17/0 .603 0 .103 0 .074 0.221 Chllliwack 4 PA Sept 17/77 32/0. .984 32/0. .734 32/0 .891 0 .031 0. .063 0.016 5/0.864 32/0 .781 0 .148 0, .070 0 .000 Chilliwack RE July 8/78 10/0. .850 10/0.700 10/0, .800 0. .150 - 0.050 Chilliwack 1 FR Sept 13/77 51/0. .912 51/0. .676 51/0, .863 0. .069 0. .039 0.029 7/1.000 50/0. .680 0. .190 0.075 0, .055 Chilliwack 2 FR Sept 14/77 60/0. .875 60/0. .700 60/0. .958 0. .042 0. .000 0.000 11/0.977 59/0. ,733 0. .178 0. ,076 0. .013 Chilliwack 3 FR Sept 13/77 20/1. .000 20/0. ,700 20/0. .875 0. ,075 0.000 0.050 10/1.000 20/0. .750 0. ,137 0. 112 0. ,000 Chilliwack 4 FR Aug 11/77 34/0. 971 32/0. 578 34/0. ,809 0. 118 0. 074 0.000 6/0.923 34/0. 713 0. 213 0. 074 0. 000 Chilliwack 5 FR Sept 13/77 104/0. 957 96/0. 677 105/0. 843 0. 067 0. 076 0.014 31/0.992 92/0. 688 0. 193 0. 090 0. 030 13. China FR July 30/78 49 124 SW 38/0. 974 36/0. 486 38/0. 803 0. 092 0. 105 0.000 19/1.000 14. Copper SM May/79 54 128 NE 21/1. 000 21/0. 938 21/1. 000 0. 000 0. 000 0.000 21/1.000 20/0. 624 0. 150 0. 150 0. 038 15. Cougar FR July 28/78 49 124 NW 38/0. 974 37/0. 311 38/0. 868 0. 105 0. 026 0.000 19/1.000 38/0. 605 0. 178 0. 178 0. 039 16. Coquihalla AD Oct/78 49 121 SE 12/0. 792 12/0. 917 12/0. 917 0. 042 - - - 0.042 6/0.958 11/0. 500 0. 261 0. 196 0. 043 Coquihalla FR Sept 8/78 39/0. 782 39/0. 821 39/0. 962 0. 038 0. 000 0.000 19/0.962 37/0. 709 0. 115 0. 128 0. 047 17. Coquitlam 1 PA Sept 15/77 49 127 SW 44/0. 852 35/0. 700 44/0. 852 0. 148 - 0.000 22/1.000 Coquitlam SM May/77 46/0. 902 43/0. 558 46/0. 859 0. 141 - - _ 0.000 23/1.000 o o Coquitlam 1 FR Aug 8/77 38/0 .908 38/0 .842 38/0 .776' 0 .224 - - - 0 .000 19/1 .000 Coquitlam 1 FR Sept 15/77 40/0 .887 40/0 .650 40/0 .850 0 .150 - - - 0 .000 20/1 .000 38/0 .553 0 .270 0 .171 0.007 Coquitlam 1 FR Aug 15/78 40/0 .912 40/0 .650 40/0 .925 0 .075 0 .000 0 .000 0/0 .000 Coquitlam 2 FR Aug 15/77 60/0 .825 59/0 .695 57/0 .772 0 .228 - - - 0 .000 30/1 .000 59/0 .653 0 .182 0 .131 0.034 Coquitlam 3 FR ~ Sept 15/77 40/0 .837 39/0 .731 39/0 .756 0 .205 - 0 .038 20/1 .000 36/0 .639 0 .222 0 .125 0.014 Coquitlam 4 FR Sept 18/77 37/0 .905 37/0 .716 37/0 .946 0 .054 - 0 .000 18/1 .000 36/0 .667 0 .160 0 .167 0.007 Coquitlam 1 PA Jun 24/78 39/0.897 39/0, .705 37/0 .919 0, .054 0 .027 0 .000 19/1 .000 18. Deadman FR Aug 8/77 50 120 NW 43/0, .407 43/1, .000 42/0, .869 0, .131 - - - 0 .000 21/1 .000 41/0 .622 0 .116 0 .232 0.030 Deadman PA Aug 17/77 53/0, .425 53/1, .000 53/0. .943 0. .057 - 0 .000 26/1, .000 49/0, .658 0, .122 0, .199 0.020 19. Dean AD Aug/78-Oct/78 52 126 NW 45/1. .000 42/0. .821 26/0, .981 0. .000 0 .019 0, .000 11/1. .000 32/0, .664 0, .164 0. .047 0.125 20. Englishman FR J u l 29/78 49 124 SE 33/0. .985 25/0, .540 33/0. .788 0, .152 0, .061 0. .000 21. French FR July 6/78 49 124 SE 51/0. .990 50/0, .580 51/0. .902 0. .010 0. .088 0, .000 25/1. ,000 22. Gold AD Jan/77-Apr/77 49 126 NE 47/0.957 41/0. .622 46/0. ,957 0. ,043 - - - 0. .000 10/1. ,000 11/0. .591 0. ,068 0. ,273 0.068 Gold FR Sept 6/77 60/0. ,917 60/0. ,692 60/0. ,867 0. 117 0. .017 0. .000 30/0. ,992 58/0. .733 0. ,134 0. 116 0.017 Gold PA Sept 6/77 19/0. 895 19/0. 684 19/0.921 0. 079 0. .000 0. .000 9/1. 000 17/0. ,721 0. 132 0. ,132 0.015 23. High F a l l s FR Aug 21/78 49 123 NE 37/0. 973 34/0. 794 40/0. 887 0. 100 0. .012 0. 000 24. Headquarters FR Aug 26/77 49 125 NE 64/0. 906 54/0. 657 61/0. 770 0. 213 0. 016 0. 000 28/0. 973 49/0. 694 o: 219 0. 046 0.041 Headquarters FR J u l 4/78 40/0. 987 39/0. 885 38/0. 605 0. 184 0. 211 0. 000 20/0. 962 25. Henriette PA J u l 1/77 49 123 NE 20/0. 800 20/1. 000 70/0. 80 0. 000 0. 000 0. 20 20/1. 00 20/0. 662 0. 163 0. 175 0.0 26. Keogh PA May/77 50 127 NE 53/0. 972 11/0. 864 53/0. 811 0. 189 - 0. 000 20/1. 000 Keogh 1 FR Oct 21/77 40/0. 962 40/0. 750 39/0. 769 0. 115 0. 103 0. 013 0/0. 000 37/0. 669 0. 155 0. 162 0.014 Keogh 2 FR Oct 21/77 20/0. 900 19/0. 658 17/0. 794 0. 000 0. 206 0. 000 0/0. 000 19/0. 750 0. 053 0. 197 0.000 Keogh 3 FR Oct 21/77 56/0,955 55/0 .782 53/0.802 0, ,038 0, ,132 0,028 20/0,938 54/0,665 0. 161 0 .165 0, .009 27. K i r by FR . Aug 27/77 48 123 SW 21/0.810 17/0 .559 19/0 .632 0. 263 0. ,026 0, .079 10/1 .000 20/0.700 0.150 0 .075 0, .075 28. Kispiox SM May/79 55 127 SW 26/1. .0 26/0 .923 26/0, .981 0. 019 0. ,000 0, .000 26/1 .0 19/0.658 0. 158 0 .184 0. .0 29. Kleindale FR Aug 24/78 49 123 NE 46/0. .880 6/0 .583 46/0, .891 0. 011 0. 098 0, .000 4/0 .938 30. Lakelse FR Aug/79 54 128 SW 13/1. .000 13/0 .923 13/0, .923 0. 077 0. 000 0, .000 13/1, .000 9/0.694 0. 167 0, .111 0. ,028 31. L. Campbell SM May/77 49 122 SW 39/0. .910 39/0. .679 39/0, .885 0. 115 - - - 0. .000 19/0, .974 L. Campbell FR J u l 13/78 37/0. .932 37/0. .595 37/0. .986 0. 014 0. 000 0. .000 18/0, .986 34/0.640 0. 191 0, .147 0. .022 32. L. Qualicum FR J u l 27/78 49 124 SE 40/0. .900 31/0, .694 40/0. .925 0. 075 0. 000 0. .000 20/1, .000 40/0.650 0. 162 0, .150 0. .037 33. Loon Lk. RE J u l 4/78 50 121 SE 22/0. .43 22/1.0 20/0. .25 0. 05 0. 000 0. .000 17/1, .0 34. Louis FR Oct 1/78 51 120 SE 54/0. .250 56/1. .000 56/0. .964 0.036 0. 000 0. .000 6/1.000 43/0.590 0. 272 0. .116 0. ,023 35. McClinhney FR Aug 16/78 52 125 SE 40/0. .75 40/0. .20 20/0. .700 0. 300 36. Nahatlatch SM May/77 49 121 NW 19/0. .868 19/0. .816 19/0. .974 0. 026 - 0, .000 Nahatlatch 1 FR Sept 30/77 41/0. .878 41/0. .683 42/1. .000 0. 000 - 0. ,000 21/0. .976 41/0.604 0. 226 0. .134 0. .037 Nahatlatch 2 FR Sept 11/78 39/0. .910 39/0. .795 39/0. .923 0. 077 - 0. .000 17/0.985 39/0.654 0. 167 0. .109 0. ,071 37. N. Aloulette FR Aug 21/78 49 122 SW 40/0. .775 37/0. .703 39/0. ,923 0. 077 -N. Aloulette PA May 15/77 36/0. ,639 37/0. .716 37/0. ,892 0. 068 - - - 0. ,041 11/1.000 18/0.681 0. 167 0. .139 0. ,014 N. Aloulette PA Jun 28/78 * 22/0. .750 21/0. ,595 22/0. ,909 0. 091 - - - 0. ,000 6/1.000 N. Aloulette FR Aug 16/77 33/0. 803 33/0. ,576 33/0. 818 0. 152 - 0. 030 16/1. ,000 23/0.707 0. 141 0. ,141 0. 011 38. Nanaimo. FR Aug 15/78 49 124 SE 40/1. 000 40/0. ,512 40/0. 938 0. 037 0. 025 0. 000 20/0. ,975 32/0.628 0. 140 0. ,147 0. 085 39. Nicola FR Oct 2/77 50 121 SE 36/0. 514 36/1. ,000 36/0.819 0. 181 - 0. 000 18/1.000 34/0.684 0. 103 0. 213 0. 000 Nicola PA Oct 2/77 41/0. 500 41/1. ,000 41/0. 890 0. 110 - 0. 000 20/1. ,000 25/0.680 0. 120 0. 200 0. 000 40. N i l e FR J u l 29/78 49 124 SW 37/1. 000 39/0. ,821 39/0. 667 0. 269 0. 064 0. 000 19/1. 000 o to 41. Pennask RE J u l 3/78 50 120 SE 26/0 .730 26/1 .000 26/1 .0 42. Puntledge AD Mar/77 49 125 NW 35/0 .986 35/0.671 35/0 .943 0, .014 0 .043 0 .000 16/0 .953 33/0 .576 0 .227 0 .152 0 .045 43. puinsam AD Mar/77 49 125 NW 110/0 .955 98/0 .587 107/0 .869 0, .075 0 .056 0 .000 53/1 .000 42/0 .637 0 .155 0 .107 0 .101 Quinsara FR J u l 7/78 29/1. .000 26/0, .538 29/0 .914 0, .052 0 .034 0 .000 14/0.893 Quinsam FR Sept 6/77 44/0 .977 44/0, .602 45/0 .911 0, .056 0 .033 0 .000 0/0 .000 42/0 .613 0 .196 0 .107 0 .083 44. Roberts FR Aug 24/78 49 123 SW 40/0 .975 36/0, .472 40/0 .837 0, .112 0 .050 0 .000 20/0 .950 45. Rosewall FR J u l 28/78 49 124 SE 36/0. .917 34/0. .574 40/0 .887 0. .112 - 0 .000 20/1 .000 46. Ruby FR Aug 26/78 49 121 SW 39/0, .897 39/0. .705 39/0, .910 0. .064 0, .026 0 .000 19/0 .962 47. S. Alouette AD Apr/78 49 122 SW 13/0, .885 13/0. .615 13/0, .962 0. .038 - 0, .000 S. Alouette FR Aug 17/77 64/0.938 64/0. .563 64/0, .969 0. .008 - - - 0.023 32/1, .000 55/0, .705 0. .186 0, .109 0, .000 S. Alouette FR Sept 20/77 28/0. .911 27/0.593 28/1. .000 0. ,000 - 0, .000 14/1. .000 25/0. .680 0. .210 0, .100 0. .010 S. Alouette SM May/77 35/0. .886 35/0. ,786 35/0. .914 0. ,086 - - - 0. .000 17/0.943 S. Alouette PA May/77 40/0. ,887 40/0. ,650 40/0. .938 0. 063 - 0. .000 20/1. .000 S. Alouette PA Jun 28/77 41/0. ,927 41/0. 524 40/0. ,950 0. 050 - - - 0. ,000 19/1. .000 32/0. .586 0. ,188 0. .172 0. ,055 48. Salmon FR J u l 13/78 49 122 SW 39/1. ,000 38/0. 803 39/0. ,718 0. 192 0. ,090 0. ,000 19/1. ,000 Salmon PA May/77 93/0. 984 60/0. 775 92/0. .853 0. 120 0. ,022 0. ,005 32/0. ,977 52/0. 668 0. ,168 0. .149 0. ,014 Salmon SM May/77 59/1. ,000 58/0. 534 59/0. ,771 0. 212 0. ,008 0. ,008 29/1. ,000 52/0. 635 0. ,221 0. ,139 0. ,005 Salmon FR J u l 29/77 50/1. 000 39/0. 872 40/0. ,787 0. 188 0. 012 0. ,012 20/0. 950 33/0. 705 0. 212 0. 083 0. 000 49. S a r i t a FR J u l 29/78 49 124 NW 40/1.000 40/0. 750 41/0. 768 0. 110 0. 122 0. 000 20/0. 987 37/0. 669 0. 162 0. 128 0. 041 50. Seymour FR Aug 16/77 49 122 SW 22/0. 909 6/0. 750 21/0. 881 0. 071 0. 048 0. 000 8/1. 000 12/0. 688 0. 083 0. 208 0. 021 Seymour FR Aug 28/78 40/0. 950 40/0. 737 40/0. 813 0. 063 0. 125 0. 000 20/1. 000 38/0. 671 0. 072 0. 197 0. 059 51. Silverhope FR Sept 13/78 49 121 SE 40/0. 837 40/0. 587 40/0. 850 0. 112 0. 037 0. 000 20/0. 975 40/0. 631 0. 188 0. 087 0. 094 o f 52. Sliamon FR Aug 27/77 49 124 NW 39/1 .000 38/0.421 53. Sooke FR Oct 5/78 48 123 SE 40/0 .975 40/0.662 54. Stamp FR J u l 28/78 49 124 SE 40/0.987 38/0.724 55. Stawamus PA Aug 12/77 49 123 NW 30/1 .000 30/0.583 56. Stein SM May/77 50 121 SW 36/0 .681 36/1.000 57. Thompson AD Oct/76-Feb/77 50 121 SW 50/0.440 50/1.000 58. Trent • FR J u l 4/78 49 124 NW 52/0, .913 52/0.452 59. Tugwell FR Aug 24/77 48 123 SW 48/0.875 43/0.709 60. Weaver SM May/77 49 121 SW 55/0. .909 55/0.545 Weaver 1 FR Sept 21/77 40/1. .000 39/0.474 Weaver 1 PA Sept 21/77 26/0. .962 26/0.346 Weaver 2 FR Aug 9/77 40/0. ,975 40/0.512 Weaver 2 FR Sept 21/77 36/1. ,000 35/0.486 Weaver 3 FR Sept 21/77 56/0. ,973 54/0.398 Weaver 3 FR Aug 17/78 40/0. 987 39/0.538 61. Wilfred FR J u l 28/78 49 124 NW 40/1. 000 37/0.378 62. Wilson FR Aug 24/78 49 123 SW 36/1. 000 34/0.382 63. Wolfson FR Aug 24/78 49 124 NW 10/1. 000 10/0.350 39/0.897 40/0.900 40/0.975 30/0.883 30/0.883 • 49/0.857 50/0.820 48/0.792 55/0.855 40/0.975 26/0.750 40/0.787 36/0.819 47/0.702 40/0.938 39/0.821 37/0.932 10/0.900 0.103 0.075 0.025 0.117 0.117 0.143 0.070 0.208 0.145 0.000 0.096 0.037 0.028 0.074 0.000 0.103 0.054 0.000 0.025 0.000 0.000 0.110 0.025 0.115 0.175 0.153 0.223 0.063 0.077 0.014 0.100 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.038 0.000 0.000 0.000 0.000 0.000 0.000 0.000 18/0.986 20/1.000 15/1.000 18/0.958 25/0.980 26/1.000 19/1.000 27/1.000 20/1.000 13/1.000 20/1.000 18/1.000 26/1.000 20/1.000 19/0.947 16/1.000 5/1.000 31/0.694 0.153 0.129 0.024 36/0.618 0.208 0.153 0.021 30/0.633 0.208 0.142 0.017 41/0.701 0.177 0.122 0.000 38/0.626 0.226 0.077 0.071 '33/0.720 0.205 0.076 0.000 46/0.663 0.212 0.114 0.011 36/0.674 0.146 0.125 0.056 31/0.573 0.250 0.097 0.081 10/0.600 0.275 0.050 0.075 O 105 Appendix 2. Expected Mean Square (EMS) and Anova tables for the hie r a r c h i c a l analysis of square foot arc sine transformed a l l e l e frequencies at four l o c i . LDH-4 EMS TABLE EMS (Regions) a 2 e + 2.193 a 2 + s 3.839 a2 + 1 7 g .701 a 2 r EMS (Groups) a 2 e + 2.105 a 2 + s 3.110 a2 • g EMS (Streams) a 2 e + 1.688 a 2 s EMS (Samples) a 2 e ANOVA TABLE Source of Sum of Mean True F Level of Variance Variation DF Squares Square (DF) Significance Component Regions 1 2.2233 2.2233 58.05 ( 1, 17) ** 2.194 Groups 24 . 7399 .0308 .83 (24, 16) N.S. 0.0 Streams 17 .5593 .0329 6.22 (17, 44) ** .0151 Samples 44 .2326 .0053 SOD EMS TABLE EMS (Regions) a 2 e + 1.058 a 2 + s 1.113 a2 + 3. g 920 o 2 r EMS (Groups) a 2 e + 2.372 a 2 + s 4.015 a2 g EMS (Streams) a 2 e + 1.620 a 2 s EMS (Samples) a 2 e ANOVA TABLE Source of Sum of Mean True F Level of Variance Variation DF Squares Square (DF) Significance Component Regions 1 0.6342 0.63426 69.4 ( 1, 19) ** 0.4108 Groups 23 1.2769 0.05551 1.91 (23, 20) N.S. 0.00584 Streams 25 0.5523 0.02220 2.93 (25, 50) ** 0.00895 Samples 50 0.3784 0.00757 106 MDH - 3 (Region and Groups Pooled) EMS TABLE EMS (Groups) a 2 + 2.224 a 2 + 3.803 a 2 e s c EMS (Streams) a 2 + 1.586 a 2 e s EMS (Samples) a 2 , 1 e 1 ANOVA TABLE Source of Var i a t i o n Groups Streams Samples DF 26 27 51 Sum of Squares 0.4748 0.4807 0.4236 Mean Square 0.01826 0.01780 0.00830 True F (DF) 0.845 (26, 20) 2.143 (27, 51) Level of Signif i c a n c e N.S. * Variance Component < 0 0.00598 IDH - 3, 4 EMS TABLE EMS (Regions) o 2 + 1.806 a 2 + 4.359 a 2 + 10.780 a 2 ^ e s g r EMS (Groups) a 2 + 2.151 a 2 + 3.130 a 2 e s g EMS (Streams) a 2 + 0.685 e EMS (Samples) o 2 g ANOVA TABLE Source of Va r i a t i o n DF Sum of Squares Mean Square True F (DF) Level of Significance Variance Component Regions 1 0.00645 0.00664 1. 198 ( 1, 4) N.S. 0.00009 Groups 16 0.09288 0.00580 1. 085 (16, 4) N.S. 0.00120 Streams 12 0.03332 0.00278 1. 763 (12, 29) N.S. 0.00175 Samples 29 0.04565 0.00157 i 

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