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Behavioural ecology of chum salmon (O.keta) and coho salmon (O. kisutch) alevins in the gravel Dill, Lawrence Michael 1967

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BEHAVIOURAL ECOLOGY OP CHUM SALMON ( 0 . KETA) AND COHO SALMON ( 0 . KISUTCH) A LEVINS I N THE GRAVEL by B.Sc,  LAWRENCE MICHAEL D I L L U n i v e r s i t y o f B r i t i s h C o l u m b i a , 1966  A THESIS SUBMITTED I N PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n t h e Department of Zoology  We a c c e p t t h i s t h e s i s a s c o n f o r m i n g to the required standard  THE UNIVERSITY OF B R I T I S H COLUMBIA O c t o b e r , 1967  In  presenting  for  an.advanced  that  the  Study.  thesis  my  at  in p a r t i a l  the  make  agree  it freely  that  or  representatives.  h iis  of  this  written  thesis  may  for  permission.  Department The U n i v e r s i t y o f B r i t i s h V a n c o u v e r 8, Canada Date  HoNftWlhox  8  Columbia  be  of  for  granted  It  financial  of  the  requirements  B r i t i s h ' Columbia,  available  permission  purposes  by  fulfilment  University  scholarly  publication  without  shall  I further  for  thesis  degree  Library  Department  or  this  for  reference  extensive  by  the  Head  shall  of  of  this  my  that  not  agree  and  copying  is understood  gain  I  be  copying  allowed  J  ABSTRACT  An i n t e g r a t e d l a b o r a t o r y and f i e l d approach was used to study the behaviour and ecology  o f P a c i f i c salmon (genus  Oncorhynchus) a l e v i n s i n the g r a v e l .  The hypothesis  t e s t e d was  that these y o l k sac f r y move throughout the g r a v e l p r i o r to emergence, that t h i s movement has both l a t e r a l and v e r t i c a l components, and that changes i n the p h y s i c a l o r b i o l o g i c a l environment w i l l a l t e r c e r t a i n parameters o f subgravel  behaviour.  Eyed chum salmon (0. keta) eggs were b u r i e d i n i n c u b a t i o n channels a t Robertson Creek, B. C.  Eight  experimental  treatments were chosen, u t i l i z i n g two g r a v e l s i z e s , two b u r i a l depths and two p l a n t i n g d e n s i t i e s .  The f r y were captured a t  emergence by means of s p e c i a l l y designed t r a p s t h a t determination and  o f degree o f l a t e r a l movement, p a t t e r n o f emergence  s u r v i v a l to emergence.  condition  allowed  (weight-length  The f r y were a l s o sampled f o r  r a t i o ) at the time o f emergence.  In the  l a r g e r g r a v e l , s u r v i v a l was g r e a t e r , l a t e r a l movement was i n c r e a s e d , and i n i t i a l emergence was e a r l i e r .  A t the g r e a t e r  b u r i a l depth the emergence p e r i o d was l o n g e r .  At the g r e a t e r  b u r i a l d e n s i t y i n i t i a l emergence was e a r l i e r .  Condition at  emergence was the same i n a l l t r e a t m e n t s . The  behaviour o f coho salmon (0. k i s u t c h ) a l e v i n s was  examined i n s p e c i a l l y c o n s t r u c t e d a q u a r i a , where l i g h t and flow c o n d i t i o n s were as n a t u r a l as p o s s i b l e . f a c t o r s were v a r i e d as i n the f i e l d .  The same environmental  In a d d i t i o n t o a g e n e r a l  d e s c r i p t i o n o f a l e v i n behaviour, d e t a i l e d analyses out on:  were c a r r i e d  v e r t i c a l and l a t e r a l movement, o r i e n t a t i o n , s p a t i a l  d i s t r i b u t i o n , c o n d i t i o n , s u r v i v a l and p a t t e r n o f emergence. the l a r g e r g r a v e l v e r t i c a l and s u r v i v a l was  l a t e r a l movements were i n c r e a s e d ,  h i g h e r , area u t i l i z a t i o n was  at emergence was  poorer.  earlier.  i n c r e a s e d and  V e r t i c a l movement was  were trapped w i t h i n the g r a v e l .  decreased  unchanged by d e n s i t y and  w i t h i n the g r a v e l .  The mean a r e a suggests  competition  r e s u l t s i n d i c a t e t h a t l a r g e r g r a v e l i s b e t t e r than  depth seems unimportant, but  study.  occupied  current.  s m a l l e r g r a v e l f o r the i n c u b a t i o n of P a c i f i c  predation.  because more f r y  The o r i e n t a t i o n of the a l e v i n s i s d i s c u s s e d  i n r e l a t i o n to l i g h t and The  i n i t i a l emergence  At the h i g h e r d e n s i t y the  a l e v i n s moved f a r t h e r towards the i n l e t . per a l e v i n was  g r e a t e r and c o n d i t i o n  At the g r e a t e r b u r i a l depth l a t e r a l  movement towards the o u t l e t was was  In  The  salmon.  should be great enough to  Burial prevent  question of optimum d e n s i t y r e q u i r e s f u r t h e r  Emergence p a t t e r n s may  environmental c o n t r o l .  a p p a r e n t l y be m o d i f i e d  through  -iv  TABLE OP CONTENTS  ABSTRACT TABLE OP CONTENTS LIST OP FIGURES LIST OF TABLES ACKNOWLEDGEMENTS INTRODUCTION METHODS FIELD STUDY Trapping F a c i l i t i e s and Techniques Analysis o f Results ( i ) d i s t a n c e o f m i g r a t i o n through the g r a v e l ( i i ) c o n d i t i o n at emergence ( i i i ) s u r v i v a l to emergence ( i v ) p a t t e r n o f emergence Physical Factors LABORATORY STUDY Experimental Aquaria and Design Observations ( i ) daytime ( i i ) n i g h t time Analysis of Results ( i ) movement i n the g r a v e l ( i i ) o r i e n t a t i o n i n the g r a v e l ( i i i ) s p a t i a l d i s t r i b u t i o n i n the g r a v e l ( i v ) c o n d i t i o n at emergence (v) s u r v i v a l to emergence ( v i ) p a t t e r n o f emergence Physical Factors ( i ) water temperatures ( i i ) oxygen c o n c e n t r a t i o n s ( i i i ) subgravel flow  -V-  Page RESULTS FIELD STUDY Distance o f Migration C o n d i t i o n o f Emergence S u r v i v a l to Emergence P a t t e r n o f Emergence Physical Factors ( i ) oxygen c o n c e n t r a t i o n s ( i i ) water temperatures LABORATORY STUDY Behaviour of A l e v i n s i n the Experimental Aquaria Degree o f V e r t i c a l Movement Degree o f L a t e r a l Movement O r i e n t a t i o n i n the G r a v e l S p a t i a l D i s t r i b u t i o n i n the Gravel C o n d i t i o n a t Emergence S u r v i v a l t o Emergence P a t t e r n o f Emergence Physical Factors ( i ) temperature ( i i ) oxygen c o n c e n t r a t i o n s ( i i i ) subgravel flow  27 27 27 32 36 37 37 37 ij.6 lj.6 53 57 57 62 62 66 66 66  DISCUSSION E f f e c t of Gravel Size E f f e c t o f B u r i a l Depth E f f e c t o f Egg D e n s i t y Responses o f t h e A l e v i n s t o L i g h t Responses o f t h e A l e v i n s t o Current Optimal Conditions o f P l a n t i n g LITERATURE CITED  70 72 73 jl$ 76" 76 79  -vi-  L I S T OP FIGURES  FIGURE  Page  1  C o n c e n t r i c r i n g t r a p s a t Robertson C r e e k .  7  2  A n o t h e r v i e w o f the same t r a p s , showing d u c t s and b a g s .  7  Schematic r e p r e s e n t a t i o n o f the c o n c e n t r i c r i n g t r a p s i n s t a l l e d a t R o b e r t s o n Creek, B. C.  8  l\.  E x p e r i m e n t a l d e s i g n , Robertson Creek t r a p s .  11  5  V-screen i n o p e r a t i o n a t Robertson Creek.  6  Schematic r e p r e s e n t a t i o n o f e x p e r i m e n t a l  3  aquarium.  . 12  18  7  Experimental design, aquaria i n laboratory.  8  Mean d a i l y w a t e r t e m p e r a t u r e s R o b e r t s o n Creek - May + June, 1967 Phases i n t h e b e h a v i o u r o f the a l e v i n s i n the l a r g e g r a v e l , a . a l e v i n moving downward 3 days a f t e r h a t c h i n g ; b . a l e v i n s a g g r e g a t e d on the t a n k bottom, 5 days a f t e r hatching; c. alevins dispersing a l o n g the tank bottom, 31 days a f t e r h a t c h i n g ; d . f r y n e a r emergence, I4.I days a f t e r h a t c h i n g ; e. newly emerged f r y , 36 days a f t e r h a t c h i n g .  39  Phases i n t h e b e h a v i o u r o f the a l e v i n s i n the s m a l l g r a v e l , a . a l e v i n s b e g i n n i n g t o d i s p e r s e , 1 day a f t e r h a t c h i n g ; b. a l e v i n n e a r the tank b o t t o m , I4.2 days a f t e r h a t c h i n g ; c . d i s p e r s i o n o f the a l e v i n s , 1+2 days a f t e r h a t c h i n g .  I4.2  9  10  11  N o c t u r n a l movement o f coho salmon a l e v i n s (53 days a f t e r h a t c h i n g ) i n the s m a l l g r a v e l o f the e x p e r i m e n t a l a q u a r i a . Upper: 2100 h o u r s ( l i g h t s o f f a t 2030 h o u r s ) ; Lower: 2l±00 h o u r s .  19 38  l±$  vii-  FIGURE 12  13 i  11}.  15 16  Page Mean v e r t i c a l p o s i t i o n s o f the a l e v i n s i n the l a r g e g r a v e l . Upper - 8 i n c h b u r i a l d e p t h , l o w e r - 12 i n c h b u r i a l d e p t h . L e f t s i d e - egg d e n s i t y 5 0 , r i g h t s i d e egg d e n s i t y 100.  lj.8  Mean l a t e r a l p o s i t i o n s o f the a l e v i n s i n the l a r g e g r a v e l . Upper - 8 i n c h b u r i a l d e p t h , l o w e r - 12 i n c h b u r i a l d e p t h . L e f t s i d e - egg d e n s i t y 5 0 , r i g h t s i d e egg d e n s i t y 100.  51  Graph o f the a r e a o c c u p i e d by t h e a l e v i n s i n t h e l a r g e g r a v e l . Upper - 8 i n c h b u r i a l d e p t h , l o w e r - 12 i n c h b u r i a l d e p t h . L e f t s i d e - egg d e n s i t y 5 0 , r i g h t s i d e - egg d e n s i t y 100.  59  Mean d a i l y t e m p e r a t u r e s L a b o r a t o r y - A p r i l t o J u l y , 1967. •  67  S u b g r a v e l f l o w t h r o u g h the e x p e r i m e n t a l aquaria.  68  viii  LIST OP TABLES TABLE I.  II.  III.  IV.  V.  VI. VII. VIII. IX.  X.  XI. XII.  Page Mean Distance ( F t . ) o f A l e v i n M i g r a t i o n from Point o f D e p o s i t i o n i n C o n c e n t r i c Ring Traps at Robertson Creek.  28  C o n d i t i o n F a c t o r (k) f o r F r y Emerging w i t h i n Concentric Ring T r a p s . See Text f o r C a l c u l a t i o n o f "k".  29  A Comparison o f the Weights and Lengths of the F r y Produced i n Channel 8 w i t h Those o f the Dyed F i s h Introduced to the Channel and Recaptured.  31  Number o f Days a f t e r P l a n t i n g at which the F i r s t F r y Appeared i n the C o n c e n t r i c Ring Traps.  3k  Number o f Days a f t e r P l a n t i n g a t which the Last F r y Disappeared from the C o n c e n t r i c Ring T r a p s .  3k-  Length o f the Emergence P e r i o d (Days) i n the C o n c e n t r i c Ring T r a p s .  35  Percent of P o s s i b l e Downward Movement i n the Experimental A q u a r i a .  Ii7  Percent of P o s s i b l e Upward Movement i n the Experimental Aquaria.  50  Extent o f L a t e r a l Movement t o the O u t l e t (Expressed as Inches from Center) i n the Experimental A q u a r i a .  5U  Extent o f L a t e r a l Movement to the I n l e t (Expressed as Inches from Center) i n the Experimental A q u a r i a .  5^4-  T o t a l L a t e r a l Movement (Expressed as Inches from Center) i n the Experimental A q u a r i a .  55  Mean O r i e n t a t i o n D i r e c t i o n by Time P e r i o d , f o r Each Treatment i n the Experimental A q u a r i a . D i r e c t i o n s are Expressed as A n g l e s , Counterclockwise from Top C e n t e r .  56  -ixTABLE XIII.  XIV.  XV. XVI. XVII. XVIII.  Page Mean Angle o f O r i e n t a t i o n i n the G r a v e l , E x p r e s s e d as Degrees, C o u n t e r c l o c k w i s e from Top C e n t e r .  58  The Maximum Area U t i l i z e d P e r A l e v i n i n t h e E x p e r i m e n t a l A q u a r i a . E x p r e s s e d as • Square Inches P e r A l e v i n V i s i b l e .  61  C o n d i t i o n I n d i c e s ( k ) o f t h e F r y Emerging from the E x p e r i m e n t a l A q u a r i a .  63  P e r c e n t S u r v i v a l t o Emergence i n t h e Experimental Aquaria.  61).  lumber o f Days a f t e r P l a n t i n g t o F i r s t Emergence i n the E x p e r i m e n t a l A q u a r i a .  65  The E f f e c t s o f I n c r e a s i n g G r a v e l S i z e , B u r i a l Depth, and Egg D e n s i t y on the Parameters Measured i n t h e Study.  71  ACKNOWLEDGEMENTS  The  author wishes t o express h i s g r a t i t u d e t o the  f o l l o w i n g groups and i n d i v i d u a l s : - M r . D. M a c K i n n o n , C h i e f B i o l o g i s t , D e p a r t m e n t o f F i s h e r i e s , for suggesting the problem. - D r . J . T. M a c F a d d e n , now a t U n i v e r s i t y o f M i c h i g a n , f o r the e x p e r i m e n t a l d e s i g n . - t h e Department o f F i s h e r i e s o f Canada, f o r f i n a n c i a l support. - M e s s r s . P. R y a n , D e p a r t m e n t o f F i s h e r i e s E n g i n e e r , a n d G. M c C u l l o c h , U.B.C. Z o o l o g y T e c h n i c i a n , f o r t h e i r assistance w i t h apparatus design. - f e l l o w s t u d e n t s R. B r o c k , B. A y l e s , A . T a u t z , R. Nagano, P. R e i m e r s , a n d p a r t i c u l a r l y B. D a v i e s , f o r t h e i r h e l p w i t h apparatus c o n s t r u c t i o n . - M e s s r s . J . B a k e r a n d G. C l o u t h i e r , f o r t h e i r a s s i s t a n c e w i t h f i e l d data c o l l e c t i o n . - D e p a r t m e n t o f F i s h e r i e s B i o l o g i s t s R. P a l m e r , C. W a l k e r , R. K. K e a r n s , a n d B. L i s t e r f o r t i m e l y a i d d u r i n g t h e project. - D r . T. G. N o r t h c o t e , my f a c u l t y a d v i s o r , f o r h i s a d v i c e and a s s i s t a n c e . - D r s . J . M a c P h a i l , N. R. L i l e y a n d W. S. H o a r f o r t h e i r c r i t i c a l review of the manuscript. - M r s . M. E . T r e b e t t , e d i t o r o f t h e Twin C i t i e s A l b e r n i , B. C., f o r F i g u r e 1 .  Times,  - M i s s J . Towers f o r t y p i n g t h e m a n u s c r i p t a n d J. Stefaniuk f o r the f i g u r e s . - My w i f e , f o r h e r c o n s t a n t a s s i s t a n c e a n d e n c o u r a g e m e n t . The recipient  w o r k was u n d e r t a k e n  o f a N a t i o n a l Research  w h i l e t h e a u t h o r was t h e C o u n c i l o f Canada B u r s a r y .  INTRODUCTION Most phases o f the l i f e h i s t o r y of P a c i f i c salmon are w e l l u n d e r s t o o d as a r e s u l t o f the e f f o r t s of i n v e s t i g a t o r s d u r i n g the p a s t c e n t u r y .  The  not r e c e i v e d the a t t e n t i o n t h a t i t d e s e r v e s .  countless  a l e v i n , however, has The  present  study  i s an attempt to c o n t r i b u t e some knowledge o f t h i s p e r i o d o f the life-cycle . The  eggs of the P a c i f i c salmon, l i k e those o f most  s a l m o n i d s , are l a i d i n an e x c a v a t i o n  i n the stream bed  and are then c o v e r e d by g r a v e l from an e x c a v a t i o n female i m m e d i a t e l y u p s t r e a m .  The  (a redd)  dug by  the  eggs are t y p i c a l l y c o v e r e d by  many i n c h e s of g r a v e l and a f t e r h a t c h i n g  the l a r v a e  (alevins)  must work t h e i r way  t o the s u r f a c e from t h i s d e p t h , w i t h  y o l k sac a t t a c h e d .  Once the y o l k sac has been a b s o r b e d , the  young f i s h i s c a l l e d a f r y .  The  terminology  the  i s t h a t of L a g l e r  (1956).  From h a t c h i n g t o emergence, the a l e v i n may two months w i t h i n the g r a v e l bed. h i s t o r y has  r e c e i v e d but  spend up  That t h i s p e r i o d o f the  to  life  scant a t t e n t i o n i s s u r p r i s i n g , s i n c e i t  i s w e l l a c c e p t e d t h a t m o r t a l i t y i n the e a r l y l i f e of the salmon p l a y s a key r o l e i n d e t e r m i n i n g  adult population density,  t h e r e f o r e the c o m m e r c i a l v a l u e of a p a r t i c u l a r s t o c k o f (Neave, 1953;  and  fish  Royce, 1959).  Much work has  r e c e n t l y been c a r r i e d out c o n c e r n i n g  e n v i r o n m e n t a l r e q u i r e m e n t s o f salmonid a l e v i n s . Gangmark and B a k k a l a  Wickett  (I960), Coble (1961) and M c N e i l  the  (19514-),  (1962) have  -2-  demonstrated that the r a t e of flow of the water w i t h i n  the  g r a v e l , as w e l l as the q u a l i t y o f the water i t s e l f , are great  importance to the  s u r v i v a l o f the eggs, embryos,  a l e v i n s w i t h i n the g r a v e l bed.  of and  In the l a b o r a t o r y , A l d e r d i c e  et a l . (1958), S i l v e r et a l . (1963), Shumway et a l . (1961;) and Brannon (1965) demonstrated the e f f e c t s of d i f f e r e n t concentrations  o f d i s s o l v e d oxygen and water v e l o c i t i e s  on  s u r v i v a l and growth of salmonid a l e v i n s . Gangmark and Bakkala  (I960), Sheridan  and  (I960), and M c N e i l (1962) demonstrated that the redd g r a v e l was emergence.  (1923), Shapovalov and  Shaw and Maga (19ir3), Neave (19lj7), ( 1 9 5 U , Cordone and Phillips  s t a b i l i t y of  an important f a c t o r i n determining  Harrison  Stuart  K e l l y (1961), B i a n c h i  (1965), and  Shelton and  McNeil  s u r v i v a l to  Berrian (1953),  (19l|.0), Campbell  (1963), Cooper (1965),  P o l l o c k (1966) have a l l  demonstrated the d e t r i m e n t a l e f f e c t s of sedimentation  on  embryos and a l e v i n s which r e s u l t from reduced flow and concentrations  i n the  the  salmonid  oxygen  gravel.  Many authors have examined s u r v i v a l to emergence from the g r a v e l .  These i n c l u d e C a r l (19i|0), White  (191^2), Shaw and  Maga (1943 ), P r i t c h a r d (19^7 ), Hobb s (19^8), Briggs (1953), Wales and  P o e r s t e r and  Ricker  P h i l l i p s and  Campbell ( I 9 6 I ) , Coble  and  1966), M e r r e l l (1962), Wickett  (19614.), and Koski  (1966).  The  Coots (1955), Hunter  (1959),  (1961), McNeil (1962, I963, (1962), McNeil and  Ahnell  above s t u d i e s demonstrated that  s u r v i v a l to emergence v a r i e s w i d e l y , and  (1953),  from zero to 100  percent,  that i t i s h i g h e r f o r coho and chinook salmon than f o r chum,  -3p i n k and  sockeye.  S u r v i v a l appears t o be l a r g e l y dependent on  the oxygen a v a i l a b i l i t y i n the g r a v e l , w h i c h i n t u r n depends on w a t e r v e l o c i t y and g r a v e l p e r m e a b i l i t y .  I t may  s p e c i e s have d i f f e r e n t v i a b i l i t i e s , i n t h a t one  be t h a t d i f f e r e n t can  survive  c o n d i t i o n s w h i c h would cause heavy m o r t a l i t y i n a n o t h e r . The  b e h a v i o u r o f the a l e v i n has been s t u d i e d by o n l y a White (1915), Woodhead (1957) and Heard  few a u t h o r s .  (196ii)  examined the r e s p o n s e s of s a l m o n i d a l e v i n s to l i g h t b e f o r e d u r i n g emergence.  B i s h a i ( I 9 6 0 , 1961a, 1961b, 1962a, 1962b)  examined the o r i e n t a t i o n o f s a l m o n i d l a r v a e w i t h r e s p e c t w a t e r c u r r e n t s , s a l i n i t y , pH, Stuart  pressure,  (1953) raade o b s e r v a t i o n s  o f the a l e v i n s of the Loch t r o u t  and oxygen  of migrations  through the  (Salmo t r u t t a L . ) , w h i l e  Roth and G e i g e r ( I 9 6 3 ) , and G e i g e r and  to  concentrations.  (I963) r e p o r t e d on the i n f l u e n c e of s u r f a c e c o n t o u r on behaviour.  and  gravel Marr  their  Roth (I962)  examined the r e s p o n s e s o f brown t r o u t a l e v i n s to g r a v i t y , l i g h t , and c u r r e n t w h i l e i n the g r a v e l bed. Research Board o f Canada, has  R. Bams, of the F i s h e r i e s  conducted s i m i l a r u n p u b l i s h e d  e x p e r i m e n t s on the a l e v i n s o f the sockeye salmon (Qncorhynchus ne r k a ) . Much of the above mentioned work i s i n c o m p l e t e  and  even c o n t r a d i c t o r y , b u t , i n t o t o , s u g g e s t s t h a t salmonid a l e v i n s do i n d e e d move t h r o u g h the g r a v e l p r i o r to emergence. movements may  have a pronounced v e r t i c a l component, the a l e v i n s  moving downward p r i o r to t h e i r upward m i g r a t i o n surface  These  (Roth and  Geiger,  1963).  Stuart  t o the  gravel  (1953) suggested t h a t  the movements have an i m p o r t a n t l a t e r a l component as w e l l , w h i c h  Roth was unable to observe i n h i s c y l i n d r i c a l observation Stuart  experimental  chambers, s i n c e these a l l o w e d no l a t e r a l movement.  (1953) s t a t e d t h a t " m i g r a t i o n . . . was i n a l a t e r a l  d i r e c t i o n and n e v e r d i r e c t l y upwards.  The a l e v i n s  dispersed  i n t o the g r a v e l . . . r a d i a t i n g upwards and outwards, and a p l o t o f t h e i r r e l a t i v e p o s i t i o n s t o o k t h e f o r m o f an i n v e r t e d cone ." T h i s has s i n c e been c o r r o b o r a t e d (0.  by work done on coho salmon  k e t a ) and s t e e l h e a d t r o u t (S. g a i r d n e r i ) a l e v i n s i n Oregon  (H. J . C a m p b e l l , p e r s . comm., I966). Shelton  (1955) demonstrated t h a t such parameters as  s u r v i v a l t o and c o n d i t i o n a t emergence may be a l t e r e d by c o n d i t i o n s w i t h i n the r e d d .  I t may be t h a t such a l t e r a t i o n s a r e  mediated through changes i n a l e v i n b e h a v i o u r . The  hypotheses t e s t e d i n the p r e s e n t s t u d y , t h e n ,  were t h a t the a l e v i n s o f the P a c i f i c salmon move throughout the g r a v e l bed p r i o r to emergence, t h a t t h i s movement has b o t h l a t e r a l and v e r t i c a l components, and t h a t c h a n g i n g the environment may a f f e c t s u b g r a v e l The  behaviour.  e n v i r o n m e n t a l v a r i a b l e s chosen f o r the study were  g r a v e l s i z e , egg b u r i a l d e p t h , and egg d e n s i t y . each were used i n a 2x2x2 f a c t o r i a l d e s i g n .  Two l e v e l s o f  G r a v e l s i z e and  b u r i a l depth were chosen because o f t h e i r importance i n t h e design  o f i n c u b a t i o n and spawning c h a n n e l s .  p a s t h a s been p l a c e d inconceivable  Emphasis i n t h e  s o l e l y on s u r v i v a l t o emergence.  I t i s not  t h a t f a c t o r s such as b u r i a l depth and g r a v e l s i z e  a f f e c t the a r e a o f g r a v e l r e q u i r e d by a group o f a l e v i n s moving towards the s u r f a c e .  I f there' i s c o m p e t i t i o n  f o r f o o d o r space  i n t h e g r a v e l t h e n the a r e a o c c u p i e d b y a group o f a l e v i n s before  o r a t emergence may determine how many eggs may be  p l a n t e d i n a c h a n n e l w i t h o u t a f f e c t i n g subsequent The  survival.  d e n s i t y o f p l a n t i n g was v a r i e d i n a n attempt t o  determine whether c o m p e t i t i o n  a c t u a l l y occurs.  Competition i s  a d i s t i n c t p o s s i b i l i t y i f the a l e v i n s a c t i v e l y f e e d emergence.  Pre-emergent f e e d i n g h a s a l r e a d y been i n d i c a t e d by  the s t u d i e s o f D i l l  1965),  before  Phillips  (I967),  (1953), Burrows 1966), and o t h e r s .  Disler  ( p e r s . comm.  ( p e r s . comm.  I n the p r e s e n t s t u d y , an i n t e g r a t e d f i e l d and l a b o r a t o r y approach was u t i l i z e d t o p r o v i d e  as complete  i n f o r m a t i o n a s p o s s i b l e on t h e e f f e c t s o f the f a c t o r s examined. S i n c e , under f i e l d c o n d i t i o n s , a t l e a s t , i t was not  practical  to c o n t r o l such a s p e c t s o f the environment as oxygen concentration,  subgravel  f l o w , and water temperatures, these  v a r i a b l e s were measured i n o r d e r t o a t l e a s t be a b l e t o a c c o u n t for  them i n d i s c u s s i n g the r e s u l t s o f the  experiments.  -6METHODS FIELD STUDY Trapping F a c i l i t i e s and Techniques The f i e l d the  p o r t i o n o f the experiment was conducted a t  Robertson Creek s t a t i o n o f the Department  of Fisheries of  Canada, l o c a t e d near A l b e r n i , B r i t i s h Columbia.  The  facilities  i n c l u d e d a s e r i e s o f s m a l l i n c u b a t i o n channels, whose f l o w c o u l d be c o n t r o l l e d by means o f s t o p l o g s at t h e i r upstream ends. traps  Fry  ( F i g s . 1, 2, and 3) were i n s t a l l e d i n two o f these c h a n n e l s . The upper f i f t y f e e t o f two a d j a c e n t channels was  chosen and e i g h t  " c o n c e n t r i c - r i n g t r a p s " were i n s t a l l e d i n each.  The t r a p s were m o d i f i e d from a design used by H. J . Campbell o f the  Oregon  State Game Commission  (pera. comm.,1966).  c o n s i s t e d o f f i v e c o n c e n t r i c r i n g s o f 18x16  They  mesh f i b e r g l a s s  screen, supported by l a t h e s and p l a c e d a t o n e - h a l f foot from each o t h e r .  intervals  Each r i n g , t h e r e f o r e , had a diameter one  foot  l a r g e r than the one i n s i d e i t , the t o t a l diameter of each trap being 5 f e e t . and 1-1/2  The screens extended two inches i n t o the g r a v e l  f e e t above the water s u r f a c e Eggs o f the chum salmon  (Fig.  3)»  (Oncorhynchus k e t a ) were  o b t a i n e d from s e v e r a l a d u l t spawners i n the B i g Qualicum R i v e r , B r i t i s h Columbia, on December 9, 1966.  They were mixed  and  h e l d t o the eyed stage a t the Qualicum R i v e r S t a t i o n o f the Department  of F i s h e r i e s .  The eyed eggs were t r a n s p o r t e d to  Robertson Creek and b u r i e d there on February 17, 1967 p o u r i n g them down a 3/V i n c h PVC box.  by g e n t l y  standpipe i n t o a p l a s t i c  Vibert  The boxes were p a r t i a l l y f i l l e d w i t h g r a v e l and had been  -7-  F i g u r e 2.  A n o t h e r v i e w o f the  same  t r a p s , showing d u c t s and b a g s .  Water  LEGEND  o o o 3  3 lO  Q "O  1. 2. 3. 4. 5. 6. 7. 8. 9. 10.  Surface  ELEVATION  3 / 4 inch P.V.C. s t a n d p i p e , through which eggs were deposited. Rubber stopper at base of s t a n d p i p e , to prevent fry exit. Molded plastic Viber box to retain eggs but pass a l e v i n s . Routes of alevin migration through the gravel. Concentric rings of 18 x 16 mesh fiberglass screen. Entrance to duct via metal sleeve Dryerflex hose duct, 4 inches in diameter. Duct passing through 3 inch diameter hole in skirt of 3/16 in neoprene Cotton bags with mesh ends , one per duct. Gravel level.  rubber.  b u r i e d i n the c h a n n e l s the p r e v i o u s day.  The  s l o t s i n the s i d e  o f each box were s m a l l enough t o r e t a i n t h e eggs but l a r g e enough t o a l l o w e x i t o f the a l e v i n s .  The  s t a n d p i p e was  sealed  w i t h a number 3 r u b b e r s t o p p e r a t the p o i n t where i t e n t e r e d the box, t h u s p r e v e n t i n g emergence o f f r y up the s t a n d p i p e . A f o u r - i n c h d i a m e t e r p l a s t i c duct was a t t a c h e d t o each s c r e e n by means o f a t i n s l e e v e p r o j e c t i n g f r o m the downstream end.  The duct was a t t a c h e d t o the s l e e v e w i t h a clamp and t h e n  p a s s e d t h r o u g h a t h r e e - i n c h h o l e i n a p i e c e o f 3 / 6 - i n c h neoprene r u b b e r i n s e r t e d above the m e t a l s l e e v e s i n each o f the o t h e r screens.  Thus, the duct l e a d i n g from the i n s i d e r i n g passed  t h r o u g h each o f the o t h e r f o u r s c r e e n s .  The neoprene  skirts  f i t t e d t i g h t l y around the d u c t s so no l o s s o f f r y c o u l d o c c u r between the two.  Each t r a p had f i v e p i e c e s o f d u c t i n g p r o j e c t i n g  from i t s downstream end, and each duct ended i n a canvas w i t h a m a r q u i s e t t e net I t was  bag  bottom.  i n t e n d e d t h a t the f r y emerging i n each r i n g of  the t r a p would f i n d t h e i r way i n the canvas b a g s .  i n t o t h e d u c t i n g and be c a p t u r e d  I t p r o v e d i m p o s s i b l e , however, t o c a p t u r e  the f r y i n t h i s manner, e i t h e r because t h e f r y c o u l d not  locate  the e n t r a n c e t o the duct o r because w a t e r v e l o c i t y i n the c h a n n e l s was not marked enough t o h o l d them i n the b a g s . r a t e , the emerged f r y remained out.  A few may  At  any  i n the r i n g s r a t h e r t h a n moving  have even v a c a t e d the t r a p s by r e - e n t e r i n g the  g r a v e l and g o i n g under the s c r e e n s .  Consequently the o n l y way  t o a s s e s s the d i s t a n c e o f s u b g r a v e l movement and the c o n d i t i o n o f the emerging f r y was  t o remove them from the r i n g s at n i g h t ,  -10  using a dipnet.  T h i s was done f o u r t i m e s n i g h t l y ( 0 1 0 0 ,  0300,  O^OO, and 0700 h o u r s ) between May 6 and May 1 9 , and t w i c e nightly  (0100 and 0300 h o u r s ) between May 20 and June 2 .  The  t r a p s were a l s o checked each morning a t 0900 h o u r s between May 6 and June 2 .  By June 2 t h e r e were no f i s h l e f t i n the t r a p s .  The  16 t r a p s were p l a c e d i n the i n c u b a t i o n c h a n n e l s a s  shown i n F i g . i i .  Two l e v e l s o f each o f t h r e e f a c t o r s were  s t u d i e d , r e s u l t i n g i n a 23 f a c t o r i a l d e s i g n w i t h two r e p l i c a t i o n s . The  l a r g e and s m a l l g r a v e l s i z e s were 2 i n c h e s t o I4. i n c h e s , and  3/8  inches  t o 1-1/2  inches r e s p e c t i v e l y .  The g r a v e l was graded  and washed, and p u t i n t o the two c h a n n e l s , one g r a v e l s i z e p e r channel, i n e a r l y January, 1967.  The eggs were b u r i e d a t e i t h e r  8 - i n c h o r 1 2 - i n c h depths (measured t o t h e middle o f the V i b e r t b o x e s ) and a t a d e n s i t y o f e i t h e r 50 o r 100 eggs p e r t r a p . t o t a l o f 1200 eyed eggs was d e p o s i t e d  A  i n the two c h a n n e l s .  C a m p b e l l ( p e r s . comm., I 9 6 6 ) r e p o r t e d t h a t coho salmon and  steelhead  t r o u t a l e v i n s moved a maximum o f 17 i n c h e s  when b u r i e d 10 i n c h e s  i n the g r a v e l .  laterally  I t was assumed, t h e r e f o r e ,  t h a t the t r a p s a t Robertson Creek, b e i n g f i v e f e e t i n d i a m e t e r , would c a t c h a l l o f t h e emerging f r y .  To a s c e r t a i n t h i s , and  t o a s s e s s any p o s s i b l e leakage f r o m the r i n g t r a p s , v - s c r e e n s ( i n c l i n e d - p l a n e t r a p s ) were p l a c e d a c r o s s  each c h a n n e l f i f t y  below t h e downstream r i n g t r a p and l i n e d w i t h  feet  polyethylene  s h e e t i n g , o n a l l s i d e s t o p r e v e n t f u r t h e r leakage  (Fig. 5).  They  were c h e c k e d d a i l y f r o m A p r i l 27 t o June 2 , u s u a l l y a t O83O h o u r s i n the m o r n i n g . preserved.  A l l o f the chum f r y c a p t u r e d were r e c o r d e d a n d  One hundred chum f r y were dyed w i t h B i s m a r c k brown  -12-  F i g u r e 5»  V-screen i n operation at Robertson Creek.  and p l a c e d i n each c h a n n e l on May ij. a t 2330 h o u r s .  These dyed  f r y were r e c o r d e d i n the v - s c r e e n c a p t u r e s and used t o determine the e f f i c i e n c y o f the two t r a p s . Analysis of Results An appendix g i v i n g d a i l y t a b u l a t i o n o f a l l the Robertson Creek data i s a v a i l a b l e . Department o f F i s h e r i e s , Resource  C o p i e s a r e on f i l e w i t h the Development Branch i n Vancouver  D r . T. G. N o r t h c o t e a t the U n i v e r s i t y o f B r i t i s h Columbiaj and the a u t h o r . ( i ) d i s t a n c e o f m i g r a t i o n through the g r a v e l The f i s h i n each screened a r e a were r e c o r d e d as n o t e d above.  Appearance i n r i n g s A, B, C, D, and E ( F i g . 3) was  t a k e n t o r e v e a l movement from the p o i n t o f d e p o s i t i o n of .25, .75,  1.25,  1*75,  and 2.25 f e e t r e s p e c t i v e l y .  A mean d i s t a n c e o f  m i g r a t i o n w i t h i n each t r a p was c a l c u l a t e d f o r each day and a composite  v a l u e was determined f o r the e n t i r e emergence p e r i o d .  The l a t t e r was t h e n a n a l y z e d f o r d i f f e r e n c e s r e s u l t i n g  from  t r e a t m e n t s , u s i n g t h e Y a t e s t a b u l a r method o f f a c t o r i a l o u t l i n e i n Davies significant.  (1956).  analysis  I f P <C»05 *ke d a t a was c o n s i d e r e d  S i n c e r e p l i c a t e s o f t h r e e t r e a t m e n t s were  no attempt was made t o e s t i m a t e them.  lost,  I f two r e p l i c a t e s o f a  t r e a t m e n t were a v a i l a b l e they were averaged t o p r o v i d e the v a l u e s used i n t h e a n a l y s i s . ( i i ) c o n d i t i o n a t emergence A l l f r y c a p t u r e d were p r e s e r v e d i n t e n p e r c e n t formalin.  A f t e r a p e r i o d o f a t l e a s t two weeks they were  -111.-  measured t o t h e n e a r e s t m i l l i m e t e r and then d r i e d i n a 37 C oven f o r 2i\. h o u r s b e f o r e b e i n g weighed t o t h e n e a r e s t m i l l i g r a m on an e l e c t r i c balance.  The d a t a f o r b o t h w e i g h t and l e n g t h were  t a b u l a t e d and summed o v e r t h e e n t i r e p e r i o d o f emergence f o r each r i n g a n d each t r a p .  A c o n d i t i o n f a c t o r (k) was then  d e t e r m i n e d f o r each t r a p by u s i n g the f o l l o w i n g f o r m u l a ( m o d i f i e d from L a g l e r , 1956): , _ WEIGHT x 1 0  6  3  LENGTH These were a n a l y z e d by t h e Y a t e s t a b u l a r method.  Replicates of  f i v e t r e a t m e n t s were l o s t a n d no attempt was made t o e s t i m a t e them.  I f b o t h r e p l i c a t e s o f a t r e a t m e n t were a v a i l a b l e ,  they  were a v e r a g e d a s above. ( i i i ) s u r v i v a l t o emergence P e r c e n t s u r v i v a l f r o m each t r a p was determined from the number o f f r y c a p t u r e d . was  solely  The number seen i n the t r a p s  o f t e n g r e a t e r than t h i s , however, and some f r y were  o b v i o u s l y b e i n g l o s t , even through the v - s c r e e n s .  A t the  t e r m i n a t i o n o f the e x p e r i m e n t , each V i b e r t box was removed and the c o n t e n t s examined and enumerated. ( i v ) p a t t e r n o f emergence I t was n o t p o s s i b l e t o compare d i r e c t l y emergence p a t t e r n s between t r e a t m e n t s s i n c e many f r y were l e f t i n the t r a p s f o r days and perhaps weeks b e f o r e t h e y were c a p t u r e d w i t h the d i p n e t .  The o n l y parameters examinable w i t h  r e g a r d t o emergence p a t t e r n w e r e : observed i n t r a p ;  finally  (1) date o f f i r s t f r y  (2) date t h a t l a s t f r y d i s a p p e a r e d from t r a p ;  -15and  (3)  l e n g t h o f emergence p e r i o d .  parameters were a l s o analyzed  d i f f e r e n c e s i n these  by the Yates t a b u l a r method of  f a c t o r i a l a n a l y s i s , summing over two Due  Any  r e p l i c a t e s when a v a i l a b l e .  to an i n o r d i n a t e l y s m a l l p i e c e of data  emergence p e r i o d  i n one  (a one  day  t r a p compared to an average of 10.8  for  the o t h e r s ) the data were a l s o summed over the main e f f e c t s ( f o r example, the two  g r a v e l s i z e s ) and  significant  r e v e a l e d by means o f Student's t - t e s t ( S t e e l Physical  and  differences  T o r r i e , I960).  Factors Although the  c o n t r o l l e d and  equal,  surface flows i n the i t was  two  channels were  thought p o s s i b l e that d i s s o l v e d  oxygen l e v e l d i f f e r e n c e s might i n f l u e n c e the parameters  studied.  E i g h t water samples, t h e r e f o r e , were taken on A p r i l 27,  and  another f o u r on June 11.  These were obtained  by means of a  s t a i n l e s s s t e e l b a r r e l syringe w i t h a probe end i n s e r t e d ten inches  i n t o the g r a v e l through a 3/k  samples were p l a c e d  i n 300 ml BOD  i n c h PVG  b o t t l e s and  standard, unmodified W i n k l e r t e c h n i q u e . proved troublesome i n three and  these were not  standpipe.  The  analyzed  the  Organic  material  of the samples taken on A p r i l  considered  i n the  i n o n l y one  6 to June 2 the  .31  to  taken  time.  not c o n s i d e r e d  study, although P. Ryan (pers. comm., 1966) averaged  standpipes  temperature was  standpipe a t each o b s e r v a t i o n  Flow through the g r a v e l was  27  analysis.  Water temperatures were taken i n a l l of the on A p r i l 27 but from May  by  in this  found t h a t i t  .38 f t ./min. i n mixed g r a v e l at Robertson Creek.  -16-  I n t h i s s t u d y , no comparison o f f l o w was made between the two gravel  sizes.  LABORATORY STUDY T h i s p o r t i o n o f the study was conducted i n a s p e c i a l l y b u i l t l a b o r a t o r y a t the U n i v e r s i t y o f B r i t i s h C o l u m b i a . the coho salmon (Oncorhynchus k i s u t c h ) were u s e d .  Eggs o f  The eyed eggs  were o b t a i n e d f r o m the e x c a v a t i o n o f a s i n g l e redd i n a subchannel  (Department o f F i s h e r i e s d e s i g n a t i o n 3B) o f the  C h e h a l i s R i v e r , B r i t i s h Columbia on March 21, and were p l a c e d i n the e x p e r i m e n t a l a q u a r i a on March 23, 196?. E x p e r i m e n t a l A q u a r i a and D e s i g n S i x t e e n a q u a r i a , m o d i f i e d f r o m a type p r e v i o u s l y employed by R. Bams o f the F i s h e r i e s Research Board o f Canada ( p e r s . comm., 1966) were c o n s t r u c t e d by C a l v e r t Woodworks L t d . , Vancouver, B. C.  Each aquarium measured 21}.—3/U- i n c h e s h i g h ,  26 i n c h e s w i d e , and 2 i n c h e s deep (back t o f r o n t ) .  The base  and end p l a t e s were made o f s o l i d oak and were s l o t t e d t o r e c e i v e the two panes o f 3/8 i n c h p l e x i g l a s s .  P l e x i g l a s s has  the advantages o f h i g h t e n s i l e s t r e n g t h and h i g h i n f r a r e d transmittance glass.  light  (approx. 90%) and t h e r e f o r e was used i n p l a c e o f  I t s p r i n c i p a l disadvantage  was i t s s u s c e p t i b i l i t y t o  scratching. The a r e a o f o b s e r v a t i o n , viewed f r o m the f r o n t , measured 22 i n c h e s by 23 i n c h e s * A p l a s t i c i n l e t p i p e , 1/2 i n c h i n d i a m e t e r , was l o c a t e d t e n i n c h e s f r o m the bottom on the r i g h t  -17side and a 3Aleft was  i n c h p l a s t i c pipe served as the o u t l e t on  side o f each aquarium, one r e t a i n e d between two  i n c h from the t o p .  20 x 20 mesh s t a i n l e s s s t e e l  l o c a t e d i n s l o t s i n each end p l a t e .  amount of water e n t e r i n g each tank was  Nalgene s p i g o t valve on each i n l e t . is  shown s c h e m a t i c a l l y i n P i g . The  Pig.  7.  s e r i e s and  The water was  polyethylene. for  The  circulation.  c o n t r o l l e d with a  design o f the  designated  i n the manner shown i n was  f i t t i n g s were used throughout, 1/2  the i n l e t , and 3/lj. i n c h f o r the o u t l e t p i p i n g .  diaphragm v a l v e s , one  aquarium  framed plywood s h e l v e s ,  d e c h l o r i n a t e d and a l l p i p i n g  Plastic  screens,  6.  tanks were set on dexion  connected i n two  gravel  T h i s p e r m i t t e d an open  water a r e a at the end of each aquarium to improve The  The  the  inch  PVG  (plastic)  on each i n l e t l i n e , p r o v i d e d gross  flow  c o n t r o l f o r each bank o f a q u a r i a . As i n the f i e l d  study, g r a v e l s i z e , b u r i a l depth, and  egg d e n s i t y were each t e s t e d at two were 50  or 100  8 i n c h e s and l-l/l}. to 2-1/2 Eighteen  12 i n c h e s .  Large and  inches and 3A-  The  The  egg d e n s i t i e s  b u r i a l depths were again  small g r a v e l s i z e s were  to 1-l/ij. i n c h e s , r e s p e c t i v e l y .  inches o f g r a v e l were p l a c e d i n each aquarium on  March 18 and 1967.  eggs per aquarium.  levels.  The  the eggs d e p o s i t e d through PVG  p i p e s on March 23,  p i p e s were removed a f t e r d e p o s i t i o n and  this  technique  u s u a l l y allowed the l o c a l i z a t i o n of the eggs i n a s i n g l e small pocket a g a i n s t the f r o n t p l a t e of p l e x i g l a s s . The  tanks were l i g h t e d from 16 inches above the  surface by banks o f 1+0 watt " c o o l w h i t e " f l u o r e s c e n t tubes  gravel  1. 2. 3. 4. 5. 6. 7. 8.  Inlet pipe of 1/2 inch polyethylene pipe. Plastic insert f i t t i n g s in i n l e t and outlet lines. Nalgene inlet valve. Oak end f r a m e , p a i n t e d w i t h Rustoleum enamel. Oak b a s e , p a i n t e d with Rustoleum enamel. Walls of 3 / 8 i n c h p l e x i g l a s s , inserted into grooves and base and s e c u r e d with Silastic adhesive. S t a i n l e s s steel and s c r e e n s , 2 0 x 2 0 mesh. Outlet hose of 3 / 4 inch polyethylene pipe.  in  ends  LIGHT  LT I 100  LIGHT  LIGHT  LT 2  LT 3  LT4  RT I  RT2  RT3  RT4  50  100  50  100  50  100  50  8'  12" REPLICATE  8'  I  LIGHT  2  GRAVEL LIGHT  LIGHT J  100  12' REPLICATE  SMALL  LB I  LIGHT  LIGHT  L  LB 2  LB3  LB4  RBI  RB2  RB3  RB4  50  100  50  100  50  100  50  12'  8' REPLICATE  8'  I  12" REPLICATE 2  LARGE  GRAVEL  U  reconnected  to an I n t e r m a t i c time  n a t u r a l day-night  switch kept a d j u s t e d t o the  rhythm throughout  the course o f the experiment.  L i g h t was l a r g e l y prevented from s t r i k i n g the f r o n t o r back o f the a q u a r i a by means o f b l a c k p o l y e t h y l e n e c u r t a i n s .  Some l i g h t  may have been able to reach a l e v i n s a g a i n s t the g l a s s because o f the l i g h t t r a n s m i t t a n t p r o p e r t i e s o f the p l e x i g l a s s .  At any  r a t e , the l i g h t c o n d i t i o n s were as c l o s e to n a t u r a l as p o s s i b l e . The e n t i r e area was surrounded to p r o v i d e complete darkness  by w a l l s o f b l a c k p o l y e t h y l e n e  when the l i g h t s were o f f , as w e l l  as t o minimize o t h e r extraneous  stimuli.  Observations ( i ) daytime Daytime o b s e r v a t i o n s were begun as soon as h a t c h i n g started.  W i t h a few exceptions these o b s e r v a t i o n s were made  every day from A p r i l llj. to May 18, and every second day from May 18 to June 10 i n the l a r g e g r a v e l (May 18 to J u l y 10 i n the small g r a v e l ) .  The p o s i t i o n and o r i e n t a t i o n o f each f i s h was  recorded by p l a c i n g a g r i d over the aquarium and copying on to a p i e c e o f paper r u l e d out i n the same f a s h i o n .  L i f t i n g the  b l a c k p l a s t i c c u r t a i n a l l o w e d enough l i g h t t o c a r r y out t h i s operation. ( i i ) night  time  Night o b s e r v a t i o n s were made w i t h an i n f r a - r e d (AN/SAR-I4.).  viewer  The i n f r a - r e d l i g h t source c o n s i s t e d o f two s i x  v o l t lamps covered by Kodak Wratten f i l t e r s #87 and operated from the power mains by means o f a t r a n s f o r m e r .  R e s o l u t i o n was  -21-  not a b s o l u t e ,  and i t was o f t e n d i f f i c u l t  f i s h known t o be i n the g r a v e l . o f the n i g h t time o b s e r v a t i o n s  to l o c a t e a l l o f the  F o r t h i s r e a s o n , the r e s u l t s a r e o f a more s u b j e c t i v e n a t u r e  t h a n a r e t h e i r daytime c o u n t e r p a r t s .  Night observations  were  made on A p r i l 18, A p r i l 29, May l l i , May 19, May 29, May 30, June 1, and J u l y 9. I n a d d i t i o n a s e r i e s o f c o l o u r photographs was t a k e n at one hour i n t e r v a l s from 2000 h o u r s on June 7 t o 0900 h o u r s on June 8.  An e l e c t r o n i c f l a s h o u t f i t was u s e d .  Analysis of Results Appendices g i v i n g d a i l y t a b u l a t i o n o f a l l the l a b o r a t o r y data are a v a i l a b l e .  C o p i e s a r e on f i l e w i t h the  Department o f F i s h e r i e s , Resource Development Branch i n Vancouver; D r . T. G. Northcote a t the U n i v e r s i t y o f B r i t i s h Columbia; a n d the a u t h o r . ( i ) movement i n the g r a v e l B o t h the mean l a t e r a l and the mean v e r t i c a l p o s i t i o n s o f the a l e v i n s i n the g r a v e l bed were d e t e r m i n e d f o r e a c h observation  date.  T h i s was done by a s s i g n i n g a number t o each  g r i d s e c t i o n , m u l t i p l y i n g t h i s number by t h e number o f f i s h i n the s e c t i o n , summing o v e r a l l s e c t i o n s , and d i v i d i n g t h i s v a l u e by t h e t o t a l number o f f i s h v i s i b l e .  The mean l a t e r a l and  v e r t i c a l p o s i t i o n s were then p l o t t e d a g a i n s t  time f o r each  t r e a t m e n t , and d i f f e r e n c e s between t h e t r e a t m e n t s a n a l y z e d . The  amount o f downward movement i n the l a r g e  t r e a t m e n t s was e x p r e s s e d as a p e r c e n t a g e o f the d i s t a n c e  gravel from  -22-  the p o i n t o f b u r i a l t o the b o t t o m o f the t a n k .  I n the s m a l l  g r a v e l t r e a t m e n t s , t h e f i g u r e used was a percentage o f the d i s t a n c e from t h e f i r s t p o i n t o f the g r a p h t o t h e bottom o f t h e tank.  T h i s m o d i f i c a t i o n was n e c e s s a r y because t h e eggs were not  as l o c a l i z e d i n t h e s m a l l a s i n t h e l a r g e  gravel.  The amount o f upward movement was c a l c u l a t e d a s a percentage  o f the d i s t a n c e from t h e lowest p o i n t reached to t h e  s u r f a c e o f the g r a v e l . The. parameters chosen t o s t u d y l a t e r a l movement were e x t e n t o f movement t o t h e l e f t and e x t e n t o f movement t o t h e r i g h t , w i t h o u t any c o n s i d e r a t i o n o f the time a t w h i c h occurred.  these  A l l o f the above d a t a were a n a l y z e d by means o f t h e  Y a t e s t a b u l a r method o f f a c t o r i a l a n a l y s i s .  Replicates of four  t r e a t m e n t s were l o s t and no a t t e m p t was made t o e s t i m a t e them. I f b o t h o f the r e p l i c a t e s o f a treatment were a v a i l a b l e ,  they  were averaged t o p r o v i d e the d a t a used i n the a n a l y s i s . ( i i ) o r i e n t a t i o n i n the g r a v e l A l l o f the f i s h e n t i r e l y v i s i b l e on the f r o n t p l a t e were r e c o r d e d as b e i n g o r i e n t a t e d e i t h e r l e f t  (L), right (R),  up ( U ) , o r down ( D ) . These d i r e c t i o n s were c o n s i d e r e d a s the f o l l o w i n g a n g l e s (o(), c l o c k w i s e from t o p c e n t r e : R=270, U=360« Batschelet  L=90, D=l80,  A n a l y s i s was c a r r i e d out u s i n g the method o f  (1965) t o determine  the v e c t o r r e s u l t a n t  empirical circular distribution. following set of equations:  (*£) f o r t h e  T h i s i s determined by t h e  -23-  x = i(coso(^ + coso^ + ...cosO^) = i  S  y = i ( s i n c < + sintxL + . ..sinc< ) = I t * n 1 2 n n ±=x r =yx  2  cosoc^  sincX i  + y2  cos$. = x / r sinvl= y / r i s then determined from t a b l e s . by Groot i n Babine  A s i m i l a r method was  used  (1965) to study the o r i e n t a t i o n o f young sockeye  salmon  Lake. The mean angle o f o r i e n t a t i o n i n the 16 tanks was  compared over the f o l l o w i n g p e r i o d s : May  1-May  10,  May  11-May 20, May  f i r s t h a t c h - A p r i l 30,  21-May 31,  (June 1-July 10 i n the s m a l l g r a v e l ) .  then  and June 1-June 10  Where p o s s i b l e , the data  were summed over two r e p l i c a t e s as above.  The data were a l s o  summed over the e n t i r e p e r i o d of o b s e r v a t i o n , and a n a l y z e d u s i n g the Yates t a b u l a r method. ( i i i ) s p a t i a l d i s t r i b u t i o n i n the g r a v e l When three o r more a l e v i n s were present i n the o b s e r v a t i o n area t h e i r p o s i t i o n s were connected by  straight  l i n e s , and the area c o n t a i n e d w i t h i n these l i n e s measured to the nearest v e r n i e r u n i t  (v.u.) w i t h an area p l a n i m e t e r .  T h i s was  converted to square inches o f g r a v e l by m u l t i p l y i n g the value by .01 s q . i n ./v.u. x 1 6 / l (the s c a l e o f the drawing). o b t a i n e d was  The v a l u e so  then d i v i d e d by the t o t a l number of a l e v i n s observed,  to p r o v i d e a measure of s p a t i a l d i s t r i b u t i o n , square inches p e r  -21+alevin.  T h i s was done f o r each o b s e r v a t i o n day f o r e a c h  aquarium, and t h e d a t a were t a b u l a t e d .  The o n l y f i g u r e t o be  s t a t i s t i c a l l y a n a l y z e d was the maximum a r e a u t i l i z e d p e r a l e v i n , u s i n g the Y a t e s t a b u l a r method, as above. ( i v ) c o n d i t i o n a t emergence P r y were c a p t u r e d w i t h a d i p n e t i n the f o u r i n c h e s o f open w a t e r above the g r a v e l s u r f a c e .  Those emerging i n the  s m a l l g r a v e l were c a p t u r e d i m m e d i a t e l y , b u t those emerging i n the l a r g e g r a v e l o f t e n c o u l d not be c a p t u r e d because o f the ease w i t h w h i c h they were a b l e to r e - e n t e r the g r a v e l .  Those f r y  r e m a i n i n g i n the l a r g e g r a v e l a q u a r i a , a f t e r emergence was deemed complete, were counted out When the g r a v e l was removed (June 17-June 1 9 ) .  A l l f r y were p r e s e r v e d i n 10% f o r m a l i n and  a f t e r a t l e a s t one week were measured t o the n e a r e s t m i l l i m e t e r , d r i e d 2lj. hours i n a 37 C oven, and weighed to the n e a r e s t m i l l i g r a m on an e l e c t r i c b a l a n c e .  The d a t a f o r b o t h weight  and l e n g t h were t a b u l a t e d and summed o v e r the e n t i r e p e r i o d o f emergence.  As w i t h the Robertson Creek d a t a , a c o n d i t i o n  f a c t o r was t h e n c a l c u l a t e d from the f o r m u l a : v  _ WEIGHT x  10  3—  6  LENGTH The d a t a were then a n a l y z e d u s i n g the Y a t e s t a b u l a r method. Two r e p l i c a t i o n s , when a v a i l a b l e , were averaged  as above.  (v) s u r v i v a l t o emergence The p e r c e n t s u r v i v a l was determined number o f samples t a k e n .  s o l e l y from the  A t the end o f the experiment,  organic  -25-  remains i n t h e a q u a r i a were examined b u t were u s u a l l y i n such an advanced s t a t e o f decay as t o be beyond e n u m e r a t i o n .  The  f i g u r e f o r s u r v i v a l t o emergence i s t h e r e f o r e a minimum one, s i n c e t h e r e i s a p o s s i b i l i t y t h a t some f i s h may have been l o s t from t h e system, even though w i r e s c r e e n s i n the t a n k s make t h i s highly unlikely.  The f i g u r e s o b t a i n e d were a n a l y z e d i n the  u s u a l manner t o determine d i f f e r e n c e s a r i s i n g from t r e a t m e n t s . ( v i ) p a t t e r n o f emergence Due t o the ease o f r e - e n t r y by t h e f r y i n t o the l a r g e g r a v e l , the date o f f i r s t emergence i s the o n l y r e l i a b l e parameter t o compare emergence between t r e a t m e n t s . The date o f l a s t emergence was a r b i t r a r i l y s e t a s June 10 i n the l a r g e g r a v e l and J u l y 10 i n t h e . s m a l l g r a v e l , and the date o f maximum emergence was i m p o s s i b l e t o a s c e r t a i n i n t h e l a r g e g r a v e l .  The  d a t a f o r f i r s t emergence were a n a l y z e d f a c t o r i a l l y a s b e f o r e . Physical Factors ( i ) water temperatures Temperatures were r e c o r d e d a t i n t e r v a l s ( u s u a l l y e v e r y second o b s e r v a t i o n d a t e ) w i t h a hand thermometer w a t e r o f each aquarium,  i n t h e open  A c o n t i n u o u s temperature r e c o r d was  a l s o o b t a i n e d f o r one aquarium f r o m May 9 t o J u l y 10 u s i n g a T a y l o r A u t o m a t i c thermograph.  The mean d a i l y t e m p e r a t u r e ,  c a l c u l a t e d a s f o l l o w s , was p l o t t e d . m.d.t. = d a i l y maximum - d a i l y minimum  -26( i i ) oxygen c o n c e n t r a t i o n s Water samples were taken from the a q u a r i a on June f o u r each from the two d i f f e r e n t g r a v e l s i z e s .  16,  These samples  were taken i n the screened area a t the o u t l e t end of the a q u a r i a through a p i e c e of s u r g i c a l rubber t u b i n g . 300 ml BOD  They were p l a c e d i n  b o t t l e s and analyzed by the standard, unmodified  W i n k l e r method.  Organic m a t e r i a l was  negligible.  ( i i i ) s u b g r a v e l flow F i v e a q u a r i a , three c o n t a i n i n g s m a l l g r a v e l and RTi|.) and two  containing large gravel  Rhodamine B dye was  RT2,  (LBI4. and RBI), were  chosen to study t h i s environmental f a c t o r . conducted between June 13 and June 16.  (1/3%,  The t e s t s were  Approximately  1 ml of  i n j e c t e d i n t o the i n l e t p i p e o f each  tank,  above the i n l e t c o n t r o l v a l v e , and i t s d i s t r i b u t i o n p a t t e r n i n the g r a v e l was  recorded a t i n t e r v a l s o f two minutes to  both r a t e of flow and flow c h a r a c t e r i s t i c s .  determine  -27RESULTS FIELD STUDY Distance  of Migration The  Yates method o f f a c t o r i a l a n a l y s i s demonstrated  that the o n l y f a c t o r to a f f e c t s i g n i f i c a n t l y the d i s t a n c e o f migration  i n the Robertson Creek t r a p s was g r a v e l s i z e , i . e .  i n the l a r g e r g r a v e l the a l e v i n s emerged f a r t h e r from the p o i n t of d e p o s i t i o n .  The mean v a l u e s f o r d i s t a n c e o f m i g r a t i o n ,  summed over the e n t i r e emergence p e r i o d , are shown i n Table I below.  The v a r i a n c e  (S^) i s shown i n b r a c k e t s below each  treatment mean. C o n d i t i o n a t Emergence The  a n a l y s i s of variance  r e v e a l e d that there was no  e f f e c t on c o n d i t i o n a t emergence of any o f the f a c t o r s t e s t e d . N e i t h e r g r a v e l s i z e , b u r i a l depth, nor egg d e n s i t y  significantly  changed the value o f the c o n d i t i o n f a c t o r "k" (Table I I ) . The r e s u l t s may not be v a l i d , however, because of the r e l a t i v e l y s m a l l s i z e o f the samples. S u r v i v a l t o Emergence Apparent s u r v i v a l t o emergence was extremely v a r i a b l e , ranging  from 1 to 98% i n the s m a l l g r a v e l , and 3 to 22% i n the  large g r a v e l .  In t o t a l , 156 f r y were captured  from the t r a p s  l o c a t e d i n the s m a l l g r a v e l and i+9 from the t r a p s l o c a t e d i n the large g r a v e l .  -28-  TABLE I . Mean D i s t a n c e ( F t . ) o f A l e v i n M i g r a t i o n f r o m P o i n t o f D e p o s i t i o n i n Concentric Ring Traps a t Robertson Creek  EGG DENSITY  BURIAL DEPTH I N LARGE GRAVEL 8"  BURIAL DEPTH I N SMALL GRAVEL  12"  8;"  12"  50  1.60 (.1123)  1.14-7 (.0937)  0.50 (.0569)  0.1+8 (.0970)  100  1.30 (.031*1)  1.58 (.14-055)  0.75 (.0000)  0.75 ( .0390)  -29-  TABLE I I . C o n d i t i o n F a c t o r (k) f o r F r y Emerging w i t h i n C o n c e n t r i c Ring T r a p s . See Text f o r C a l c u l a t i o n o f "k".  EGG DENSITY  BURIAL DEPTH IN LARGE GRAVEL  BURIAL DEPTH IN SMALL GRAVEL  8"  12"  8"  12"  So  1.29  1.1*2  1.1*0  1.1*3  100  1.1*8  1.37  0.96  1.1*1  -3021  Besides these c a p t u r e s , i n the  May  During the  the v-screen  same time p e r i o d 191  i n the  conducted May  on  s m a l l g r a v e l channel between A p r i l 28  v-screen 16.  f r y were c a p t u r e d  large gravel channel.  the  and  f r y were captured The  dye  from  mark t e s t s  5 i n d i c a t e d t r a p p i n g e f f i c i e n c i e s o f 71% and  from the v-screens i n these two  channels r e s p e c t i v e l y .  3l±%  Prom the  following calculations: x  x  i n  small large  = 100  * 21 71  =  = 100 f 191 34  i t would appear that 562  =  30  5  62  f r y vacated the c o n c e n t r i c  r i n g traps  l o c a t e d i n the  l a r g e g r a v e l , w h i l e 30 f r y d i d the same i n the  small g r a v e l .  The  r e v i s e d t o t a l s f o r the e s t i m a t e s o f s u r v i v a l  t h e r e f o r e become: small gravel = l ^  6  + 3° = 600  l a r g e g r a v e l = *f9 + 562  _  31%  1 0 2  %  600 The  percent  an o v e r e s t i m a t e . weights and  The  s u r v i v a l i n the  reason f o r t h i s i s not  lengths of the dyed f r y captured  were l e s s than the weights and the  large g r a v e l i s c l e a r l y  concentric  lengths  r i n g t r a p s of the  of the  on the  the  v-sereen  f r y captured  in  same channel (Table I I I ) .  y  e f f e c t o f the dye  c l e a r , since  .  .  .  .  .  .  The .  on c a t c h a b i l i t y i s unknown, however.  I t appears obvious, however, t h a t s u r v i v a l was much g r e a t e r i n the  l a r g e g r a v e l than i n the  i s s u b s t a n t i a t e d by the  very  small g r a v e l .  This  f a c t t h a t a l t h o u g h ij.9 dead eggs and Ifl  -31-  TABLE I I I . A Comparison o f the Weights and. Lengths o f the F r y Produced i n Channel 8 w i t h Those o f the Dyed F i s h Introduced to the Channel and Recaptured.  CHANNEL 8 FRY CAPTURES CONCENTRIC RING TRAPS  DYED FISH CAPTURED  MEAN WEIGHT  . 0 6 3 gra.  . 0 6 0 gm.  MEAN LENGTH  35 . 2  314..0 mm.  mm.  -32dead a l e v i n s were found i n the excavated V i b e r t boxes i n the small g r a v e l channel, only two g r a v e l channel c o n t a i n e d  of the boxes from the  eggs ( t o t a l o f 10).  unaccounted f o r i n the s m a l l g r a v e l .  large  Many f r y were  still  They presumably d i e d w i t h i n  the g r a v e l a f t e r l e a v i n g the V i b e r t boxes. Despite  the  low percentage o f c a p t u r e s w i t h i n  r i n g s themselves, the c o n c l u s i o n s l a t e r a l movement are mean d i s t a n c e  s t i l l felt  changed very  to be v a l i d .  l i t t l e from day  that f r y were not moving from one g r a v e l , many f r y may and  drawn regarding  degree o f  T h i s i s because  to day,  indicating  r i n g to a n o t h e r .  have missed the c o n c e n t r i c  the mean d i s t a n c e moved may  be an  the  In the  rings  large  althogether  underestimate.  P a t t e r n o f Emergence The  number of days a f t e r p l a n t i n g when the  appeared i n the revealed  traps i s l i s t e d  that time to f i r s t  i n Table IV below.  emergence was  independently by both h i g h d e n s i t y and i s the most important o f the two It  first The  fry  analysis  significantly  small g r a v e l ; the  increased latter  factors. be  spurious,  however, since emergence began very much l a t e r i n one  treatment  (91.0  i s p o s s i b l e that the  days) than i n the o t h e r s The  was  below.  The  (mean o f 77.9  days).  number of days a f t e r p l a n t i n g at which emergence  deemed complete was  last fry left  s i g n i f i c a n c e may  the  trap.  determined by the These values  a n a l y s i s o f variance  date at which the  are summarized i n Table V  i n d i c a t e s t h a t the 8 i n c h  b u r i a l depth s i g n i f i c a n t l y decreased and  the  small g r a v e l s i z e  s i g n i f i c a n t l y i n c r e a s e d the time to l a s t emergence.  -33-  The l e n g t h o f t h e emergence p e r i o d  (Table V v a l u e  minus Table IV v a l u e ) i s shown i n Table VI below.  The d a t a i s  unworkable, however, because o f t h e z e r o v a l u e i n t h e t a b l e . E x c l u d i n g t h i s v a l u e and summing o v e r a l l o f the t r e a t m e n t s i n each c h a n n e l g i v e s t h e f o l l o w i n g d a t a f o r t h e mean l e n g t h o f the emergence p e r i o d . l a r g e g r a v e l - 10.25 days s m a l l g r a v e l - 11.50 A t-test  days  ( S t e e l e and T o r r i e , I960) shows t h a t these a r e not  s i g n i f i c a n t l y d i f f e r e n t a t t h e .05 l e v e l .  S i m i l a r t e s t s were  c a r r i e d out f o r e f f e c t s o f p l a n t i n g depth (8 i n c h e s = 9.50 days; 12 i n c h e s = 11.714- days) and p l a n t i n g d e n s i t y 10.75 d a y s ; 100 eggs = 10.83. d a y s ) .  (50 eggs =  These t e s t s i n d i c a t e d t h a t  egg d e n s i t y had no e f f e c t on the l e n g t h o f t h e emergence p e r i o d , b u t t h a t i n c r e a s i n g the depth o f p l a n t i n g  significantly  i n c r e a s e d t h e l e n g t h o f the emergence p e r i o d  (at the .05 l e v e l ) .  I n t o t o the a n a l y s i s r e v e a l e d t h a t the f r y b o t h began and completed t h e i r emergence e a r l i e r i n the l a r g e g r a v e l , but t h a t the time t a k e n t o complete emergence was not s i g n i f i c a n t l y s h o r t e r than i n the s m a l l e r g r a v e l .  There was evidence t h a t the  emergence p e r i o d was l e n g t h e n e d by an i n c r e a s e d i n p l a n t i n g depth.  The a l e v i n s b u r i e d a t 8 i n c h e s began t h e i r emergence  from the g r a v e l a t the same time as t h e i r more d e e p l y b u r i e d c o u n t e r p a r t s , but the former completed t h e i r emergence e a r l i e r . P l a n t i n g d e n s i t y had no e f f e c t on the p a t t e r n o f emergence.  -3k-  TABLE IV. Number o f Days a f t e r P l a n t i n g a t which the F i r s t F r y Appeared i n the C o n c e n t r i c Ring T r a p s .  EGG DENSITY  BURIAL DEPTH IN LARGE GRAVEL 8"  12"  BURIAL DEPTH IN SMALL GRAVEL 8"  12"  50  77.0  78.0  79.0  79.5  100  74.5  79.0  91.0  78.5  TABLE V. Number o f Days a f t e r P l a n t i n g a t which the Last F r y Disappeared from the C o n c e n t r i c Ring T r a p s .  EGG DENSITY  BURIAL DEPTH IN LARGE GRAVEL. 8"  12"  BURIAL DEPTH IN SMALL GRAVEL 8"  12"  50  86.0  89.0  88.5  93.0  100  81*.5  90.0  91.0  90.0  -35-  TABLE V I . L e n g t h o f t h e Emergence P e r i o d (Days) i n the Concentric Ring Traps.  EGG DENSITY  BURIAL DEPTH I N LARGE GRAVEL. 8"  12"  BURIAL DEPTH I N SMALL GRAVEL. 8"  12"  50  9.0  11.0  9.5  13.5  100  10.0  11.0  0  11.5  -36-  Physieal Factors ( i ) oxygen  concentrations  Of t h e 8 samples t a k e n from the s t a n d p i p e s  on A p r i l 27,  t h r e e were d i s c a r d e d because o f excess o r g a n i c m a t t e r . remaining  Of t h e  f i v e , t h r e e were f r o m c h a n n e l 7 ( s m a l l g r a v e l ) and two  from c h a n n e l 8 ( l a r g e g r a v e l ) .  Mean v a l u e s o f m i l l i g r a m s o f  oxygen p e r l i t e r were: s m a l l g r a v e l - 19.7 mg O 2 / I . l a r g e g r a v e l - 12.1 mg 0^/1• The  v a l u e f o r the s m a l l g r a v e l i s u n d o u b t e d l y t o o h i g h b u t b o t h  s i t u a t i o n s were s a t u r a t e d o r s u p e r s a t u r a t e d  a t 1*8.1+ F.  Those samples t a k e n on June 11 gave t h e f o l l o w i n g v a l u e s f o r t h e two c h a n n e l s : s m a l l g r a v e l - I3.6  mg O 2 / I .  l a r g e g r a v e l - 11.1 mg 0 ^ / 1 , Again supersaturation i s i n d i c a t e d . concentrations the  I t i s c l e a r t h a t oxygen  i n b o t h c h a n n e l s were not l i m i t i n g f a c t o r s i n  environment. There i s a l s o evidence t h a t the s m a l l g r a v e l  contained  more oxygen t h a n t h e l a r g e g r a v e l , but t h i s may be o n l y an a r t i f a c t o f sampling.  The s t a n d p i p e s  were b u r i e d  slightly  deeper i n t h e l a r g e g r a v e l (x = 8.5 i n c h e s ) t h a n i n t h e s m a l l g r a v e l (x = 7.2 i n c h e s ) because the s h a l l o w e r ones i n t h e l a r g e g r a v e l had t o be r e j e c t e d due t o the l a r g e r amounts o f o r g a n i c m a t t e r i n t h e samples.  -37-  ( i i ) water temperatures The t e m p e r a t u r e s r e c o r d e d i n t h e e i g h t s t a n d p i p e s on A p r i l 27 were a l l i d e n t i c a l (I4.8.I4. F ) .  T h e r e f o r e , o n l y one  l o c a t i o n was s u b s e q u e n t l y used f o r temperature r e c o r d i n g , a standpipe i n channel 8.  The temperature was t a k e n m a n u a l l y a t  each o b s e r v a t i o n t i m e between May 6 and June 2, the p e r i o d o f peak emergence.  The mean d a i l y t e m p e r a t u r e s a r e graphed i n  F i g . 8.  LABORATORY STUDY Of the s i x t e e n t a n k s i n t h e l a b o r a t o r y , o n l y t w e l v e gave u s e f u l d a t a .  The eggs i n LT 1 d i e d because o f a w a t e r  system f a i l u r e , w h i l e those i n LB 1 a p p a r e n t l y d i e d because o f l a c k o f oxygen.  Tanks LT 2 and RT 3 were o f no use f o r most o f  the parameters s t u d i e d ( w i t h t h e e x c e p t i o n o f s u r v i v a l and emergence p a t t e r n ) s i n c e t h e eggs were i n a d v e r t a n t l y b u r i e d i n the m i d d l e o f t h e t a n k and few a l e v i n s c o u l d be seen a g a i n s t the f r o n t p l a t e .  Due to t h e l a r g e amount o f l o s t d a t a , the  t r e a t m e n t s were c o n s i d e r e d t o have had o n l y one r e p l i c a t i o n , and the two r e p l i c a t e s were s i m p l y averaged i f b o t h were complete. Behaviour of A l e v i n s i n the Experimental Aquaria W i t h i n a day o f h a t c h i n g , t h e a l e v i n s moved downward (Fig. 9a).  T h i s downward phase was more marked i n the l a r g e  than i n the s m a l l g r a v e l due t o the d i f f e r e n c e i n ease o f  FIGURE 8,  Mean Daily Water Temperatures-Robertson Creek - May+June,l967  i CO  o 5 5 -  I  -39-  on t h e t a n k b o t t o m , 5 days a f t e r h a t c h i n g (x 7/16).  9c.  Figure  9.  Alevins dispersing along the tank b o t t o m , 31 d a y s a f t e r h a t c h i n g (x 1/3).  Phases i n the b e h a v i o u r of the a l e v i n s i n the l a r g e g r a v e l .  9d.  9e.  F r y near emergence, I4.I days a f t e r h a t c h i n g (x 2 / 3 ) .  Newly emerged f r y , 36 days a f t e r h a t c h i n g (x 1/2).  Figure 9 (cont.).  Phases i n the b e h a v i o u r o f the a l e v i n s i n the l a r g e g r a v e l .  -1*1-  movement t h r o u g h the two m a t e r i a l s .  I n the l a r g e g r a v e l the  a l e v i n s a g g r e g a t e d on t h e bottom o f the t a n k ( P i g . 9 b ) , b u t tended t o more e v i d e n t d i s p e r s a l i n t h e s m a l l e r g r a v e l ( F i g . 1 0 a ) . In b o t h s i t u a t i o n s the a l e v i n s demonstrated what c o u l d be termed " e x p l o s i v e b e h a v i o u r " when c l o s e l y grouped.  T h i s was  c h a r a c t e r i z e d by the r a p i d s c a t t e r i n g o f a group o f a l e v i n s when one member o f the a g g r e g a t i o n would s u b s e q u e n t l y r e f o r m .  moved.  The group o f a l e v i n s  S i m i l a r b e h a v i o u r was noted among  sockeye salmon a l e v i n s by R. Bams ( p e r s . comm., 1 9 6 6 ) , who suggested t h a t i t may be caused by carbon d i o x i d e reaching a threshold  concentrations  level.  As t h e i r y o l k sacs were a b s o r b e d , the a l e v i n s on the bottom o f the e x p e r i m e n t a l  aquaria c o n t a i n i n g the large g r a v e l  s p r e a d out h o r i z o n t a l l y to the extreme r i g h t and l e f t (Pig. 9 c ) .  sides  Prom t h e r e they made s h o r t f o r a y s i n t o the upper  r e g i o n s o f the g r a v e l ( F i g . 9 d ) and f i n a l l y emerged ( F i g . 9 e ) . T h i s p e r i o d w i l l be c a l l e d the upward phase.  The snooperscope  s t u d i e s r e v e a l e d t h a t the a l e v i n s ( o r , more c o r r e c t l y now, f r y ) were more d i s p e r s e d t h r o u g h the g r a v e l d u r i n g the n i g h t . However, much d i s p e r s i o n a n d movement was n o t e d d u r i n g the day time h o u r s as w e l l .  That the f r y were a b l e t o move e x t r e m e l y  e a s i l y t h r o u g h the g r a v e l was e v i d e n c e d by o b s e r v a t i o n s  on  May 3 1 , June 3 , and June 5 o f f r y moving f r o m the bottom o f the t a n k t o the t o p , a t o t a l d i s t a n c e of about 36 i n c h e s , i n a time o f about two m i n u t e s .  Most f r y a f t e r emergence, however, d i d  not appear to r e t u r n t o any g r e a t depth i n the g r a v e l . F r y swimming i n the open w a t e r of the tanks w o u l d r e t u r n t o about  -1*2-  10a.  10b.  Figure 10.  A l e v i n s beginning to d i s p e r s e , 1 day a f t e r h a t c h i n g (x 7/16).  A l e v i n near the tank bottom, 1+2 days a f t e r h a t c h i n g (x 2/3).  Phases i n the behaviour o f the a l e v i n s i n the s m a l l g r a v e l .  -1*3-  F i g u r e 10  (cont.).  Phases i n the b e h a v i o u r o f the i n the s m a l l g r a v e l .  alevins  -kk-  the f i r s t f o u r i n c h e s o f the g r a v e l i f f r i g h t e n e d by a sudden movement.  These f r y were never seen to r e t u r n t o the b o t t o m o f  the a q u a r i a . The  downward phase was much l e s s pronounced i n the  small g r a v e l .  I n o n l y two i n s t a n c e s  (RT 2 and RT  r e a c h the bottom o f t h e t a n k ( P i g . 1 0 b ) .  I n most  d i d alevins instances  downward movement was s l i g h t , and was a s s o c i a t e d w i t h i n a l l d i r e c t i o n s f r o m the p o i n t where h a t c h i n g (Pig. 10c). the  dispersion  occurred  Most o f the a l e v i n s moved upward and out towards  s i d e o f t h e a q u a r i a , a l t h o u g h some moved s t r a i g h t up  (Pig. 11).  T h i s p a t t e r n , i f r o t a t e d through 180 degrees ( i . e .  t h r e e d i m e n s i o n a l ) would g i v e the form o f a rough cone, w i t h the apex s l i g h t l y below t h e p o i n t o f h a t c h i n g . There appeared to be c o n s i d e r a b l e i n the s m a l l g r a v e l .  day time emergence  T h i s was r e l a t i v e l y c l e a r s i n c e the f r y  were unable t o r e - e n t e r t h e t i g h t l y packed g r a v e l a f t e r emergence.  The tanks were o f t e n c l e a r e d t w i c e a day and many  f r y were c a p t u r e d i n the a f t e r n o o n , the morning s a m p l i n g . June 8 ( P i g . 1 1 ) out  i n d i c a t i n g emergence s i n c e  The h o u r l y photographs t a k e n on June 7 -  showed a slow but c o n t i n u o u s movement through-  the n i g h t , w i t h most o f the f r y emerging about O63O h o u r s ,  about t h e time t h a t the l i g h t s came on. The  b e h a v i o u r d i f f e r e n c e s noted above were a l l between  the two g r a v e l s i z e s .  No o b v i o u s d i f f e r e n c e s were n o t e d between  the l e v e l s o f the o t h e r two f a c t o r s , b u r i a l depth and egg density.  -K5-  F i g u r e 11.  N o c t u r n a l movement of coho salmon a l e v i n s (53 days a f t e r h a t c h i n g ) i n the s m a l l g r a v e l of the experimental a q u a r i a . Upper: 2100 hours ( l i g h t s o f f a t 2030 h o u r s ) ;  Lower: 2i*00 hours (x l/k) •  -lj.6Degree  o f V e r t i c a l Movement The a l e v i n s e x h i b i t e d s i g n i f i c a n t l y g r e a t e r movement  during  the downward phase i n the l a r g e g r a v e l than i n the  gravel  (Table  small  V I I ) . The mean v e r t i c a l p o s i t i o n s are p l o t t e d  f o r each a v a i l a b l e r e p l i c a t e o f each treatment i n P i g . 12. analysis also revealed  that the a l e v i n s i n the small  The  gravel  moved downward t o a s i g n i f i c a n t l y g r e a t e r degree when p l a n t e d at lower  density. showed that l a r g e g r a v e l , 8  The a n a l y s i s o f v a r i a n c e  i n c h b u r i a l depth, and egg d e n s i t y of 50 a l l acted to i n c r e a s e the extent  o f movement i n the upward phase  (Table V I I I ) .  The  a n a l y s i s i s not p a r t i c u l a r l y r e v e a l i n g , however, since i t i s b i a s e d by the f a c t that some a l e v i n s were undoubtedly trapped w i t h i n the  s m a l l g r a v e l , and that they were l o c a t e d deeper i n  the g r a v e l when the eggs were p l a n t e d at the deeper l o c a t i o n . Degree of L a t e r a l Movement It i s apparent ( P i g . 13) movement was migration,  towards the i n l e t  t h a t the predominant  i n the upward phase of the  even though movement began towards the o u t l e t  the downward phase  lateral  (most evident  during  i n the l a r g e g r a v e l ) .  Movement towards the o u t l e t was i n the l a r g e r than i n the s m a l l e r g r a v e l  significantly (Table  IX).  greater  The degree  of t h i s movement was a l s o g r e a t e r a t the h i g h e r d e n s i t y and at the deeper b u r i a l depth, a l t h o u g h these e f f e c t s were not as great as that o f the l a r g e r g r a v e l .  -14.7-  TABLE V I I . Percent o f P o s s i b l e Downward Movement i n the E x p e r i m e n t a l A q u a r i a .  BURIAL DEPTH IN LARGE GRAVEL EGG DENSITY  100  BURIAL DEPTH IN SMALL GRAVEL  8"  12"  8"  12"  100.0  100.0  37.0  28.1  100.0  100.0  19.0  17.7  Inches  From  Aquorium  Floor  From  Aquarium  ?  .  Floor  T  •  i-8-  ~I  o r> w m  8-  Jfi-  C  z  m  8  -50-  TABLE V I I I . Percent o f P o s s i b l e Upward Movement i n the E x p e r i m e n t a l A q u a r i a .  EGGDENSITY  BURIAL DEPTH IN LARGE GRAVEL 8"  12"  BURIAL DEPTH IN SMALL GRAVEL 8"  12"  50  90.0  61]..0  80.0  6I4..O  100  69.0  83.0  63.0  1+7.0  8  INCHES  SO  EGGS  6  20  CENTRE  OF  INCHES  100  EGGS  TANK CENTRE  OF TANK  s° a.  = 1 .1 o\  J  !  5  1 10  1 IS  L_ 20  25  -I is~~20  10  301  12  INCHES  50  EGGS  1 25  L 30  J  l_  ~K>  is"  20  25  30  i5  |  10•  '. 15  —20 I  U 301  1 25  l i  S.  10  12 100  CENTRE  OF  15  20  J  25ioTT  U  5  C  -1 »  l_  1 1 1 0 1 5  20  25  301  5  i 10  1 15  1 20  I 25  L U _  STT  ~s  i£ is"  20  ,  ro  M  A L  i n S  n  t h e  Q r g e  9 r Q V e l  2 5  3 0  100. " U  p  I 30  TANK  I  -J5  101  IS1  1  20  25  » l  5  10  15  20  25  13-1 0 £f\i ? «i-!r2!?. Vn e5 0 ,MrightJ side e'gg densityLetr side egg density  1 25  EGGS  CENTRE  30|  10.  15 JUNE  FIGURE  J 20  INCHES  1-4  J  15  p  e  r  8  i n c h  b u r i a l  ^Pth,  lower-12 inch burial depth.  OF  20  TANK—  25 J O  1 '  Ditptocermnt  From  C*ntr»  Dilelocament  From C o n l r t  -53The  a n a l y s i s o f the d a t a shown i n Table I X showed t h a t  l a r g e g r a v e l and low d e n s i t y  significantly  increased  the e x t e n t  o f movement towards the i n l e t . The  t o t a l range o f movement i s o b t a i n e d  by a d d i n g the  f i g u r e s i n T a b l e s I X and X, and i s summarized i n Table X I . Both l a r g e g r a v e l and low d e n s i t y s i g n i f i c a n t l y o f l a t e r a l movement.  increased  the degree  Since these r e s u l t s agree most c l o s e l y w i t h  those o f the a n a l y s i s o f movement to the i n l e t , i t i s c l e a r t h a t movement towards t h e i n l e t was t h e p r i m a r y component of l a t e r a l movement and was more i m p o r t a n t than the movement t o the o u t l e t w h i c h accompanied t h e downward movement i m m e d i a t e l y a f t e r hatching. O r i e n t a t i o n i n the G r a v e l The  most common d i r e c t i o n o f o r i e n t a t i o n $ ) l a y  between 270 and 3bO d e g r e e s , i . e . upwards and towards t h e i n l e t (Table X I I ) . and  T h i s a g r e e s w e l l w i t h the d a t a on mean v e r t i c a l  l a t e r a l p o s i t i o n s p r e s e n t e d above.  Downward o r i e n t a t i o n was  n o t e d i n o n l y a few i n s t a n c e s , a l l i n the s m a l l g r a v e l .  The f a c t  t h a t i t was absent i n t h e l a r g e g r a v e l , where downward movement was most e v i d e n t ,  i s indicative either of a  non-orientated  m e c h a n i c a l " s l i p p i n g t h r o u g h " t o the bottom o f t h e t a n k s , o r o f a r a p i d o r i e n t a t e d movement towards the b o t t o m .  Since the  a l e v i n s i n the l a r g e g r a v e l appeared on the bottoms v e r y soon a f t e r hatching,  i t i s d i f f i c u l t t o determine w h i c h o f these  possibilities i s correct.  No c o n s i s t e n t  d i f f e r e n c e appears t o  e x i s t between the l e v e l s o f t h e o t h e r f a c t o r s examined, i . e . b u r i a l depth and egg d e n s i t y .  -51*-  TABLE I X . E x t e n t o f L a t e r a l Movement t o the O u t l e t (Expressed as Inches from C e n t e r ) i n the E x p e r i m e n t a l A q u a r i a .  EGG DENSITY  BURIAL DEPTH IN LARGE GRAVEL  BURIAL DEPTH I N SMALL GRAVEL  8"  12"  8"  12"  50  6.3  6.2  0.2  1.5  100  5.5  7.8  2.5  1.8  TABLE X. E x t e n t o f L a t e r a l Movement t o the I n l e t (Expressed as Inches f r o m C e n t e r ) i n the E x p e r i m e n t a l A q u a r i a .  EGG DENSITY  BURIAL DEPTH I N LARGE GRAVEL  BURIAL DEPTH I N SMALL GRAVEL  8"  12"  8"  12"  50  8.2  8.3  6.2  k .7  100  2.9  5.1  3.8  2.8  -55-  TABLE X I . T o t a l L a t e r a l Movement (Expressed as Inches from C e n t e r ) i n t h e E x p e r i m e n t a l A q u a r i a .  EGG DENSITY  50 100  BURIAL DEPTH I N LARGE GRAVEL. 8"  •  12"  BURIAL DEPTH I N SMALL GRAVEL 8"  12"  114-.5  li*.5  6.1*  6.2  8.1*  12.9  6.3  l*.6  -56-  TABLE X I I . Mean O r i e n t a t i o n D i r e c t i o n by Time P e r i o d , f o r Each Treatment i n the E x p e r i m e n t a l A q u a r i a . D i r e c t i o n s a r e E x p r e s s e d a s A n g l e s , C o u n t e r c l o c k w i s e f r o m Top C e n t e r .  DATE TREATMENT  May 1 May 10  May 11May 20  May 21May 31  June 1END  DEGREES  DEGREES  DEGREES  DEGREES  DEGREES  o o H  135  338  351  213  270  O  214  284  328  342  354  o o  i+6  360  347  343  358  O  337  333  343  345  356  O  352  27  323  347  357  O  360  88  315  330  334  O O  270  90  50  303  352  5  8  272  277  342  HATCH, April  30  CM H  u\  e  H  GRAVEL  CO  •3 « 3  CM  H  CO  O H  H  O  "LA  -57The  o r i e n t a t i o n data were summarized by t o t a l l i n g  over  the e n t i r e p e r i o d i n which a l e v i n s o r f r y were observed i n the gravel  (Table  XIII).  The  angle of o r i e n t a t i o n was  a n a l y s i s of v a r i a n c e not  s i g n i f i c a n t l y a f f e c t e d by .05  s i z e , b u r i a l depth, or egg d e n s i t y at the S p a t i a l D i s t r i b u t i o n i n the The ( P i g . llj.).  area occupied  The  revealed  that  the  gravel  level.  Gravel by each a l e v i n i n c r e a s e s w i t h time  large f l u c t u a t i o n s are caused by the emergence  from the g r a v e l o f those a l e v i n s nearest  the  surface, r e s u l t i n g  i n a decrease i n the area covered by those s t i l l remaining i n the g r a v e l . exponential  I f these f l u c t u a t i o n s are ignored curves,  g r e a t e r area i n the  and  are a l l s i m i l a r except that they cover a  large gravel treatments.  the a l e v i n s were more d i s p e r s e d a l s o shown by the Table XIV,  the graphs suggest  i n the l a r g e g r a v e l .  a n a l y s i s of variance  of the  which showed that d i s p e r s i o n was  i n c r e a s e d by l a r g e g r a v e l s i z e .  In other words, This i s  data shown i n significantly  Other f a c t o r s had  no  significant  effect. I t i s s i g n i f i c a n t that the mean area a l e v i n was  occupied  per  not a f f e c t e d by the number o f a l e v i n s p r e s e n t ,  i r r e g a r d l e s s of number each a l e v i n occupied area.  T h i s i n d i c a t e s that the  within  the g r a v e l and  the  f i s h were spacing  that competition  may  i.e.  same g r a v e l themselves out  have been o c c u r r i n g .  C o n d i t i o n at Emergence Pry emerging from the  s m a l l g r a v e l were i n s i g n i f i c a n t l y  b e t t e r c o n d i t i o n than those emerging from the  large  gravel  -53-  TABLE X I I I . Mean Angle o f O r i e n t a t i o n i n the G r a v e l , E x p r e s s e d as Degrees, C o u n t e r c l o c k w i s e from Top C e n t e r .  EGG DENSITY  BURIAL DEPTH I N LARGE GRAVEL  BURIAL DEPTH I N SMALL GRAVEL  8"  12"  8"  12"  50  325  314-9  3*4-8  339  100  330  33  357  310  -59ioor  FIGURE 14.-I  Graph of the area occupied by the alevins in the large gravel. Upper - 8 inch burial depth, lower - 12 inch burial depth. Left side - egg density 50, right side—egg density 100.  FIGURE 14.-2  Graph of the area occupied by the alevins in the small gravel. Upper- 8 inch burial depth, lower - 12 inch burial depth.  -61-  TABLE X I V . The Maximum A r e a U t i l i z e d P e r A l e v i n i n the E x p e r i m e n t a l A q u a r i a . E x p r e s s e d as Square Inches P e r A l e v i n V i s i b l e .  EGG DENSITY  BURIAL DEPTH I N LARGE GRAVEL  BURIAL. DEPTH I N SMALL GRAVEL  8"  12"  8"  12"  50  28.06  27 . 3 8  8.64  11.14  100  30.79  28.1*3  6.40  3.23  -62(Table XV).  B u r i a l depth and  egg  d e n s i t y had  no e f f e c t on  the  c o n d i t i o n index of the emerging f r y . S u r v i v a l to Emergence Survival  (expressed  as a percentage o f emergent f r y i n  r e l a t i o n to the number of eggs d e p o s i t e d ) i s summarized i n Table XVI.  The  a n a l y s i s of variance  s i g n i f i c a n t l y lower i n the  showed that s u r v i v a l was  smaller g r a v e l .  The  difference  may  not be as marked as i t appears, however, since even a f t e r J u l y there  were s t i l l many f r y i n the  s m a l l g r a v e l which may  or  12  may  not have emerged a t a l a t e r d a t e . P a t t e r n o f Emergence The  nature of the e x p e r i m e n t a l a q u a r i a  a n a l y s i s of the number o f days t o f i r s t  emergence (Table  Only b u r i a l depth s i g n i f i c a n t l y a f f e c t e d the first  allowed o n l y XVII).  time taken t o  emergence, i . e . deeper b u r i a l depth r e s u l t e d i n  increased  time . It  i s obvious t h a t the  s m a l l g r a v e l g r e a t l y lengthened  the p e r i o d o f emergence, s i n c e some f r y were s t i l l emerging up to J u l y 10.  I t i s suggested that f u t u r e s t u d i e s of t h i s type  would do w e l l t o equip the a q u a r i a w i t h t r a p s to capture any immediately a f t e r emergence.  The  f a c i l i t i e s made i t impossible  to determine the p a t t e r n  emergence, p a r t i c u l a r l y i n the r e a d i l y re-entered.  f a i l u r e to p r o v i d e  such of  l a r g e g r a v e l , which the f r y  F u r t h e r , time of emergence may  important f a c t o r i n any  fry  consideration  be  an  of subsequent s u r v i v a l .  -63-  TABLE XV. C o n d i t i o n I n d i c e s ( k ) o f the F r y Emerging from the Experimental A q u a r i a .  EGG DENSITY  B U R I A L DEPTH I N LARGE GRAVEL 8"  BURIAL DEPTH I N SMALL GRAVEL  12"  8"  12"  50  1.55  1.37  1.72  1.89  100  1.67  1.1*7  1.71  1.93  -61*-  TABLE X V I . P e r c e n t S u r v i v a l t o Emergence i n t h e Experimental Aquaria.  EGG DENSITY  B U R I A L DEPTH I N LARGE GRAVEL  BURIAL DEPTH I N SMALL GRAVEL  8"  12"  8"  12"  50  91*  92  1*6  1*5  100  52  86  76  30  -65-  TABLE  XVII.  Number o f D a y s a f t e r P l a n t i n g t o F i r s t E m e r g e n c e i n t h e Experimental Aquaria.  BURIAL DEPTH I N LARGE GRAVEL EGG DENSITY  BURIAL DEPTH I N SMALL GRAVEL  8"  12"  8"  12"  50  67  71  67  68  100  67  67  67  73  -66Physical Factors ( i ) temperature The  temperature v a r i e d l i t t l e  from one aquarium t o  another, one degree F being the maximum v a r i a n c e encountered. The thermograph  r e c o r d , t h e r e f o r e , g i v e s the approximate mean  d a i l y temperatures f o r a l l o f the a q u a r i a ( F i g . 1 5 ) .  The mean  d a i l y water temperature v a r i e d o n l y l+.i* G (8 F ) over a p e r i o d o f two and one h a l f months, and averaged approximately 5.6 C (10 F ) l e s s than i n the Robertson Creek c h a n n e l s . ( i i ) oxygen c o n c e n t r a t i o n s The mean oxygen c o n c e n t r a t i o n s o f the water i n the two g r a v e l s i z e s were found to be: s m a l l g r a v e l - 12.3 nig 0^/1, l a r g e g r a v e l - 12.1 mg  0^/1.  Both s i t u a t i o n s , then, were w e l l s u p p l i e d w i t h oxygen and t h i s environmental v a r i a b l e was not a l i m i t i n g one i n e i t h e r o f them. ( i i i ) s u b g r a v e l flow The flow c h a r a c t e r i s t i c s observed i n the g r a v e l a r e shown i n F i g . 16.  In the s m a l l g r a v e l , the flow was l i n e a r i n  the middle o f the tank, but tended to upwell a t the edges. through the large g r a v e l was s i m i l a r but more r a p i d .  Flow  Flow rates  through the g r a v e l , c a l c u l a t e d from the time r e q u i r e d f o r the dye to t r a v e r s e the a q u a r i a , were approximately .08 and .20 f e e t p e r minute  i n the s m a l l and l a r g e g r a v e l r e s p e c t i v e l y .  These v a l u e s  are c o n s i d e r a b l y l e s s than the flow r a t e s p r e v i o u s l y observed i n the Robertson Creek channel g r a v e l .  FIGURE 15. Mean  Daily  Temperatures  Laboratory  —  April to  July , 1967.  A  J  •  1  /  / \  1  / 25  —APRIL  30 1  /  {  V  /  -  v  A  •  5  10  15 MAY  20  25  30  5  10  15 JUNE  20  25  30  5  10  15 JULY  20  25  -68-  SMALL GRAVEL  25 minutes to reach left side.  LARGE GRAVEL 10 minutes to reach left side.  Figure  16.  Subgravel  flow  through  the  experimental  aquaria.  -69DISCUSSION  Several the  considerations  d i s c u s s i o n of the First,  species  because of unavoidable i n the  Coho s a l m o n were u s e d  i n the  field.  logical  patterns their the  o f the  life  two  On  the  (1963) on  Geiger  be  (1915) on  i n mind  two  complications, phases o f the  laboratory  and  are  going to  different project.  be  the  same, b e c a u s e  q u i t e d i f f e r e n t a f t e r emergence  trutta,  Salvelinus  Stuart S.  (1953) on  i r i d e u s , and  fontinalis  the  behaviour  o t h e r h a n d , however, t h e work o f  S.  throughout  chum salmon i n  t o assume t h a t t h e  Salmo t r u t t a ;  (1957) on  Woodhead  species  h i s t o r i e s are  gravel.  White  not  borne  above r e s u l t s .  o f s a l m o n were u s e d  I t may  must be  S.  S.  from  Roth  and  trutta;  salar;  and  i n d i c a t e that a l l of  these  species  studied to  d a t e have s i m i l a r b e h a v i o u r i n t h e  early  stages.  Further,  Campbell's u n p u b l i s h e d s t u d y o f coho  and  steelhead  alevins  indicate that  same manner a s t h e studies  of  s a l m o n i d f r y have  b e h a v i o u r may  show g r o s s  r e v e a l a great s t u d i e s may  show t h a t  the  same a s t h o s e  the  behave  Stuart.  i n the  i s true  p l e x i g l a s s would be  although  observations Further well.  study, the a s s u m p t i o n  T h i s may  small  the  Comparative  a l e v i n as  a l e v i n s along  gravel.  i n the  species.  f o r the  laboratory  b e h a v i o u r o f the deeper i n the  in  i n d i c a t e d , however, t h a t  similarities, detailed  this  assumption, p a r t i c u l a r l y a l e v i n s on  s t u d i e d by  many d i f f e r e n c e s between  Secondly, made t h a t  Loch t r o u t  these s p e c i e s  the not  glass be  g r a v e l , where  a  is  is  the  valid  those  e x p o s e d t o much more  light  -70-  than those deeper i n the g r a v e l .  The a l e v i n s i n one aquarium  however, were n o t v i s i b l e b u t showed s i m i l a r emergence p a t t e r n s , c o n d i t i o n a t emergence, and s u r v i v a l t o emergence t o those a l e v i n s exposed t o l i g h t , s u g g e s t i n g  t h a t the e f f e c t of t h e  p l e x i g l a s s on b e h a v i o u r was m i n i m a l . T h i r d l y , i t i s assumed t h a t d i f f e r e n c e s i n t e m p e r a t u r e , oxygen and f l o w c o n d i t i o n s have n o t a f f e c t e d the r e s u l t s . Oxygen was never found t o be i n s h o r t s u p p l y i n t h e l a b o r a t o r y o r the f i e l d .  Therefore,  f l o w r a t e s must have been adequate i n  b o t h s i t u a t i o n s , even though s l o w e r i n the s m a l l e r  gravel.  Temperature c o n d i t i o n s were much l o w e r i n the l a b o r a t o r y , b u t varied l i t t l e  from t a n k t o t a n k .  The e f f e c t s o f t h e t h r e e v a r i a b l e s t e s t e d a r e summarized i n Table X V I I I and w i l l now be d i s c u s s e d Effect of Gravel  i n turn.  Size  I n the l a r g e r g r a v e l the a l e v i n s moved f a r t h e r laterally  (both towards the i n l e t and the o u t l e t ) , towards the  bottom, and towards the s u r f a c e .  They t h e r e f o r e c o v e r e d a  g r e a t e r a r e a o f g r a v e l i n the l a b o r a t o r y .  F o r t h e same r e a s o n  the a l e v i n s emerged f a r t h e r f r o m the p o i n t o f d e p o s i t i o n i n the field.  I n the f i e l d , but n o t i n the l a b o r a t o r y t h e y began t h e i r  emergence e a r l i e r , and, i n b o t h s i t u a t i o n s , completed i t e a r l i e r i n the l a r g e g r a v e l .  S u r v i v a l was much h i g h e r i n t h e l a r g e  g r a v e l i n b o t h s i t u a t i o n s , but the f r y were i n p o o r e r c o n d i t i o n a t emergence f r o m t h e l a r g e g r a v e l , a t l e a s t i n t h e l a b o r a t o r y .  -71TABLE X V I I I .  o +  +  o  O  +  o  o  o  o  o  o  o  +  o  o  •  o  o  o  •  o  1  o  OUTLET  +  +  +  o  1  •  •  •  •  N.E.  525  525  O  o  •  LABORATORY . . STUDY  FIELD STUDY  — •  INCREASING BURIAL DENSITY  INCREASING BURIAL DEPTH  INCREASING GRAVEL SIZE  EFFECTS OF  —  525  1  N.E.  t  1  INCREASING BURIAL DENSITY  DISTANCE OF .MIGRATION  +  N.E.  UP  INCREASING BURIAL DEPTH  525  •  •  N.E. N.E. N.E. N.E.  +  •  IN • Sit t IN .Hi .  +  • 525  .  1  N.E.  o  N.E.  i  N.E.  O  INLET  DOWN  +  £J  TOTAL  I  +  INCREASING GRAVEL SIZE  VERTICAL MOVEMENT  LATERAL MOVEMENT  ORIENTATION I N THE GRAVEL  • 525  o  CONDITION AT EMERGENCE. SPATIAL DISTRIBUTION  *  IN .  SURVIVAL TO EMERGENCE  •  o  TJ F  INITIAL  •  o  N.E. N.E.  FINAL  N.E.  N.E.  LENGTH "NT TP  PATTERN OF EMERGENCE  The E f f e c t s o f I n c r e a s i n g G r a v e l S i z e , B u r i a l D e p t h a n d E g g D e n s i t y on t h e Parameters Measured i n t h e Study. +, I n c r e a s e * -, D e c r e a s e ; 0, No E f f e c t ; N.E., N o t E x a m i n e d  -72-  The  g r e a t e r movement, e a r l i e r emergence and  better  s u r v i v a l were p r o b a b l y the r e s u l t o f more freedom o f movement t h r o u g h the l a r g e r g r a v e l . the l a b o r a t o r y may  The p o o r e r c o n d i t i o n a t emergence i n  have been the r e s u l t of more f r e q u e n t  i n the l a r g e g r a v e l , where t h e r e was with t h e i r large yolk sacs. r i g h t t h e m s e l v e s , may t h u s be  The  l e s s support f o r the a l e v i n s  a l e v i n s , c o n s t a n t l y having to  u t i l i z e more energy f o r maintenance  s m a l l e r a t emergence than t h e i r c o u n t e r p a r t s  smaller g r a v e l .  activity  and  i n the  Such a r e l a t i o n s h i p has been noted p r e v i o u s l y  by b o t h M a r r ( 1 9 6 3 , 1965)  and Bams ( p e r s . comm., 1 9 6 6 ) .  The  l a t t e r i n v e s t i g a t o r suggests t h a t the a l e v i n s i n the absence o f support have a g r e a t e r tendency to a g g r e g a t e , to support each other i n a sense.  Such a g g r e g a t i o n  was  i n d e e d n o t e d i n the  p r e s e n t study d u r i n g the p e r i o d when the a l e v i n s were on  the  bottom o f the a q u a r i a , a t w h i c h time they would have l i t t l e support f r o m the  gravel.  E f f e c t of B u r i a l Depth The  time t o f i r s t emergence ( i n the l a b o r a t o r y ) and  l a s t emergence ( i n the f i e l d ) was a t 12  inches.  The  i n c r e a s e d by b u r y i n g  net e f f e c t , t h e r e f o r e , was  t o t a l l e n g t h o f the emergence p e r i o d T h i s may  >  have been s i m p l y because the a l e v i n s had a  d i s t a n c e to move t o the  the eggs  to i n c r e a s e  as n o t e d i n the  a b l e to p e n e t r a t e  greater depth,  to that depth.  In the l a b o r a t o r y , i n c r e a s i n g b u r i a l depth the amount o f movement t o the o u t l e t and  the  field.  s u r f a c e when b u r i e d a t a g r e a t e r  o r because l e s s l i g h t was  to  increased  d e c r e a s e d the amount o f  -73-  upward movement. be a s c e r t a i n e d .  The reason f o r these r e s u l t s cannot p r e s e n t l y B u r i a l depth had no e f f e c t on s u r v i v a l t o  emergence, c o n d i t i o n a t emergence, o r d i s t a n c e moved f r o m the p o i n t o f d e p o s i t i o n i n the f i e l d . A n o t h e r f a c t o r i n any c o n s i d e r a t i o n o f optimum b u r i a l depth s h o u l d be p r e d a t i o n .  The work of P h i l l i p s and C l a i r e  (1966) i n d i c a t e d t h a t the s c u l p i n , C o t t u s p e r p l e x u s  c o u l d be a.  t  s i g n i f i c a n t p r e d a t o r on s a l m o n i d a l e v i n s , when t h e g r a v e l i s l a r g e enough t o a l l o w a c c e s s t o them. s c u l p i n s were able t o p e n e t r a t e consume a l e v i n s . penetrate  I n one i n c h g r a v e l  approximately  seven i n c h e s t o  S m a l l s c u l p i n s (1.5 i n c h e s ) were able to  l i * i n c h e s i n t o the 1 i n c h g r a v e l .  Obviously,  gravel  s i z e and b u r i a l depth i n t e r a c t , and s i n c e b u r i a l depth has few i f any d e t r i m e n t a l e f f e c t s , and l a r g e g r a v e l many b e n e f i c i a l ones, i t would appear best t o bury eggs a t g r e a t e r depth i n l a r g e r g r a v e l , and n o t n e a r t h e s u r f a c e i n f i n e r m a t e r i a l . E f f e c t o f Egg D e n s i t y H i g h egg d e n s i t y d e c r e a s e d the degree o f v e r t i c a l movement and o f l a t e r a l movement, w i t h t h e e x c e p t i o n o f movement towards t h e l e f t .  There was a l s o some evidence t h a t f r y began  t h e i r emergence e a r l i e r when p r e s e n t The  1967).  density.  a r e a u t i l i z a t i o n on a p e r a l e v i n b a s i s was n o t  a f f e c t e d by the b u r i a l d e n s i t y . competition  a t the h i g h e r  T h i s may be evidence o f  i n t h e g r a v e l e i t h e r f o r oxygen o r f o r food  On t h e o t h e r hand, the a l e v i n s may be spacing  (Dill,  themselves  -71*-  out i n response t o c a r b o n d i o x i d e o r n i t r o g e n o u s waste concentrations.  F u r t h e r work on t h i s s u b j e c t would c e r t a i n l y  appear w a r r a n t e d . Responses o f t h e A l e v i n s t o L i g h t Roth and G e i g e r (1963) found t h a t a l e v i n s o f brown t r o u t were i n i t i a l l y p h o t o n e g a t i v e and moved downward a f t e r hatching.  A f t e r spending some time on the b o t t o m o f the  c o n t a i n e r s they then became p o s i t i v e l y p h o t o t a c t i c , moved back towards the s u r f a c e and emerged. That t h i s was not a response t o g r a v i t y was d e t e r m i n e d by t u r n i n g the c y l i n d r i c a l sideways.  containers  The a u t h o r s c o n c l u d e d t h a t l i g h t was the s i n g l e most  i m p o r t a n t f a c t o r i n a l l o w i n g a l e v i n s to f i n d t h e i r way up and out o f t h e g r a v e l b e d . Bams ( p e r s . comm., 1967 ), on the o t h e r hand, found t h a t l i g h t a c t u a l l y r e t a r d e d emergence and t h a t g r a v i t y was a more important f a c t o r i n s u b g r a v e l o r i e n t a t i o n . The  l a t t e r view seems a more r e a l i s t i c one, s i n c e i t has been  demonstrated by Heard (1961*), a s w e l l as by Roth and G e i g e r t h e m s e l v e s , t h a t l i g h t can p e n e t r a t e centimeters  o n l y i n t o t h e upper few  o f the g r a v e l . I n the p r e s e n t e x p e r i m e n t , the a l e v i n s i n the l a r g e  g r a v e l , i . e . where l i g h t p e n e t r a t e d  the f a r t h e s t , showed more  downward movement and more a c t i v i t y a t n i g h t t h a n d i d t h e a l e v i n s i n the s m a l l e r g r a v e l .  The e x p l a n a t i o n  f o r such b e h a v i o u r comes  from the s t u d i e s o f Woodhead (1957), S t u a r t  (1953) and White  (1915) who found t h a t newly h a t c h e d Salmo l a r v a e were n e g a t i v e l y phototactic.  S t u a r t found t h a t t h e a l e v i n s d u r i n g t h e p e r i o d o f  -75-  f i n a l y o l k a b s o r p t i o n became e i t h e r p o s i t i v e l y p h o t o t a c t i c o r n e u t r a l to  light. L i g h t may  not be of any  a l e v i n s have e n t e r e d the upper few u n c e r t a i n , t h e r e f o r e , why p h o t o t a c t i c but i t may  importance i n n a t u r e u n t i l i n c h e s of g r a v e l .  the  It is  the young l a r v a e are n e g a t i v e l y  prevent  them f r o m premature emergence i f  by chance they are b u r i e d too n e a r the s u r f a c e , o r r e a c h  there  too e a r l y i n t h e i r upward m i g r a t i o n . The  a l e v i n s ' response to l i g h t p r o b a b l y  a c c o u n t s f o r the  l a r g e p r o p o r t i o n of d a y l i g h t emergence n o t e d , p a r t i c u l a r l y i n the s m a l l e r g r a v e l , where the a l e v i n s ( w i t h the e x c e p t i o n those a g a i n s t the g l a s s ) had no e x p e r i e n c e c y c l e u n t i l v e r y n e a r the s u r f a c e . to the s u r f a c e may  w i t h the  of  day-night  Movement t h r o u g h the g r a v e l  be the r e s u l t o f g r a v i t y o r i e n t a t i o n o r the  r e s u l t of i n t e r n a l p h y s i o l o g i c a l f a c t o r s , i . e . motivation, Both o f these need to be examined i n f u t u r e i n v e s t i g a t i o n s . Heard (1961*) a l s o suggests t h a t daytime emergence  may  exceed daytime m i g r a t i o n downstream, s i n c e , once the f i s h have emerged i n t o h i g h l i g h t i n t e n s i t i e s and f i l l e d t h e i r a i r bladders  they seek c o v e r u n t i l n i g h t t i m e  e t a l , 1962).  (Neave, 1955J Hartman  In t u r b i d r i v e r s , m i g r a t i o n s o f p i n k and chum  3almon f r y have a l s o been r e c o r d e d  during d a y l i g h t hours  (Neave, 1955). I t s h o u l d be n o t e d , however, t h a t the s p e c i e s o f Oncorhynchus v a r y i n t h e i r response to l i g h t s i g n i f i c a n c e o f t h i s f i n d i n g to the p r e s e n t a l t h o u g h i t i n d i c a t e s t h a t we  (Hoar, 1958).  The  study i s u n c e r t a i n ,  should a v o i d i n f e r r i n g  the  -76-  b e h a v i o u r o f an e n t i r e genus f r o m s t u d i e s conducted on one two  species.  carried  or  A comparative s t u d y o f a l e v i n b e h a v i o u r should  be  out.  Responses of the A l e v i n s to C u r r e n t White (1915) found t h a t b r o o k t r o u t a l e v i n s were p o s i t i v e l y rheotropic  ( = r h e o t a c t i c ) a t the time o f  a l t h o u g h b o t h B i s h a i (I960) and  Stuart  hatching,  (1953) found t h a t brown  t r o u t a l e v i n s were n e g a t i v e l y r h e o t r o p i c u n t i l y o l k  absorption,  at w h i c h time t h e i r response became a p o s i t i v e one.  Roth  and  G e i g e r (I963) found t h a t brown t r o u t a l e v i n s were p o s i t i v e l y r h e o t a c t i c throughout the e n t i r e a l e v i n s t a g e .  The  e x p e r i m e n t s i n d i c a t e t h a t coho salmon a l e v i n s are p o s i t i v e l y r h e o t a c t i c i n l a t e r s t a g e s , but  show no  present definitely consistent  o r i e n t a t i o n to c u r r e n t f o r the f i r s t few weeks a f t e r h a t c h i n g , d i s t r i b u t i n g t h e m s e l v e s i n a f a i r l y random manner w i t h to  current.  Optimal Conditions The  of P l a n t i n g  p r e s e n t e x p e r i m e n t s o f f e r c o n c l u s i v e evidence t h a t  l a r g e g r a v e l i s the p r e f e r r e d m a t e r i a l f o r a r t i f i c i a l and  respect  incubation  spawning c h a n n e l s , s i n c e i t r e s u l t s i n e a r l i e r emergence  and b e t t e r s u r v i v a l r a t e s .  S e v e r a l f a c t o r s s u g g e s t , however,  t h a t the g r a v e l s h o u l d be o f a more mixed grade t h a n t h a t u t i l i z e d i n these e x p e r i m e n t s .  These f a c t o r s i n c l u d e the  poorer  c o n d i t i o n a t emergence, the p o s s i b i l i t y o f h i g h e r p r e d a t i o n the g r a v e l , and w i d e r s p a t i a l d i s t r i b u t i o n .  in  i  -77-  B u r i a l depth s h o u l d be g r e a t enough to  prevent  p r e d a t i o n but not so deep as to s e r i o u s l y r e t a r d emergence, s i n c e f r y w h i c h emerge over a s h o r t p e r i o d of time and higher water l e v e l s probably downstream m i g r a t i o n .  at  s u f f e r less predation during  their  F u r t h e r , e a r l y emerging f r y o f such  s p e c i e s as coho and c h i n o o k salmon stand a b e t t e r chance o f f i n d i n g s u i t a b l e h a b i t a t s i n the stream c h a n n e l  and  subsequently  have h i g h e r growth r a t e s (Mason and Chapman, 1965). Briggs  (1953) found t h a t coho b u r i e d t h e i r eggs a t an  average d e p t h o f 9.8  inches.  Burner (1951) found t h a t the  average depths o f chum and coho salmon eggs i n the Columbia R i v e r were 8.5  and 8.0 i n c h e s r e s p e c t i v e l y , w h i l e Kusnetzov (1928)  found chum salmon eggs to be b u r i e d 9 t o 10 i n c h e s .  This depth,  i n view o f the e f f e c t s o f g r a v e l s i z e n o t e d i n the p r e s e n t i s probably  study,  optimum.  There i s no e v i d e n c e t h a t e i t h e r of the d e n s i t i e s u t i l i z e d i n t h i s study were h i g h enough t o make c o m p e t i t i o n important may  consideration.  an  Egg p o c k e t s i n n a t u r a l r e d d s , however,  c o n t a i n eggs a t h i g h e r d e n s i t i e s t h a n those  studied here.  The maximum d e n s i t y u t i l i z e d i n the l a b o r a t o r y was  150  eggs  per cubic f o o t . T h i s study, b e i n g one subgravel b e h a v i o u r a l ecology  o f the f i r s t conducted on o f the P a c i f i c salmon, may  the provide  u s e f u l background i n f o r m a t i o n f o r f u t u r e i n v e s t i g a t o r s , suggest t e s t a b l e h y p o t h e s e s f o r them, and  s t i m u l a t e them to  a t l e a s t some of t h e i r e f f o r t s on t h i s rewarding research.  concentrate  f i e l d of  Several future present work.  s t u d i e s have been s u g g e s t e d by t h e  These i n c l u d e m o d i f i c a t i o n o f emergence  through manipulation of environmental c o n d i t i o n s ,  timing  comparative  e t h o l o g i c a l s t u d i e s o f the s a l m o n i d a l e v i n , p a r t i c u l a r l y i n response  t o l i g h t , and s t u d i e s o f i n t e r a c t i o n o r c o m p e t i t i o n  between a l e v i n s w i t h i n the g r a v e l b e d .  Such s t u d i e s  conducted i n the immediate f u t u r e , b o t h because o f t h e o r e t i c a l and t h e i r p r a c t i c a l i m p l i c a t i o n s .  s h o u l d be  their  -79-  LITERATURE CITED A l d e r d i c e , D.P., W i c k e t t , W.P., and J.R. B r e t t , 1958. Some e f f e c t s o f temporary exposure to low d i s s o l v e d oxygen l e v e l s on P a c i f i c salmon eggs. J . P i s h . Res. Bd. Canada, 1 5 ( 2 ) : 229-249. B a t s c h e l e t , E . 1965. S t a t i s t i c a l Methods f o r the A n a l y s i s o f Problems i n Animal O r i e n t a t i o n and c e r t a i n B i o l o g i c a l Rhythms"! American I n s t i t . of B i o l o g i c a l S c i e n c e s , Washington. 57 P P . B i a n c h i , D.R. 1963. The e f f e c t s o f sedimentation on egg s u r v i v a l o f rainbow t r o u t and c u t t h r o a t t r o u t . MSc. T h e s i s , Montana State C o l l e g e , 28 pp. B i s h a i , H.M. i 9 6 0 . The e f f e c t o f water c u r r e n t s on the s u r v i v a l and d i s t r i b u t i o n o f f i s h l a r v a e . J . C o n s e i l 25(2) : 134.-1146. ' 1961a. The e f f e c t of s a l i n i t y on the s u r v i v a l and d i s t r i b u t i o n o f l a r v a l and young f i s h . I b i d 26(2):166-179. _ _ _ ^ _ _ _ _ _ 1961b. The e f f e c t o f p r e s s u r e on the s u r v i v a l and d i s t r i b u t i o n o f l a r v a l and young f i s h . I b i d 26(3):292-311. r  1962a. Reactions o f l a r v a l and young salmonids to water o f low oxygen c o n c e n t r a t i o n . I b i d 27 ( 2) :167-180 . 1962b. Reactions o f l a r v a l and young salmonids t o d i f f e r e n t hydrogen i o n c o n c e n t r a t i o n s . I b i d 2 7 ( 2 ) ; l 8 l - 1 9 1 . Brannon, E . L . 1965. The i n f l u e n c e o f p h y s i c a l f a c t o r s on the development and weight o f sockeye salmon embryos and a l e v i n s . I n t . P a c . Salmon P i s h . Comm., P r o g . Rept. 1 2 : 1 - 2 6 . B r i g g s , J.C. 1953. The behaviour and r e p r o d u c t i o n o f salmonid f i s h e s i n a s m a l l c o a s t a l stream. C a l i f . F i s h and Game, F i s h . B u l l . 9Jt:l-62. Burner, C . J . 1951. C h a r a c t e r i s t i c s of spawning n e s t s o f Columbia R i v e r salmon. U.S. P i s h and W i l d l i f e S e r v i c e , P i s h . B u l l . £2(61) : 9 7 - H 0 . Campbell, H.J. 1954. ^ e e f f e c t s o f s i l t a t i o n from g o l d dredging on the s u r v i v a l o f rainbow t r o u t and eyed eggs i n Powder R i v e r , Oregon. Oregon State Game Comm., Oregon. 3p ( p r o c e s s e d ) . T  C a r l , G.C. 1940* Comparison o f coho salmon f r y from eggs i n c u b a t e d i n g r a v e l and i n h a t c h e r y b a s k e t s . T r a n s . Am. P i s h . Soc. 69:132-134.  -80-  C o b l e , D.W. 1 9 6 1 . I n f l u e n c e o f w a t e r exchange and d i s s o l v e d oxygen .in redds on s u r v i v a l o f s t e e l h e a d t r o u t embryos. T r a n s . Am. P i s h . S o c . 9Otl4.69-l1.7ii. Cooper, A.C. 1 9 6 5 . The e f f e c t o f t r a n s p o r t e d s t r e a m sediments on t h e s u r v i v a l o f sockeye and p i n k salmon eggs and a l e v i n s . I n t . P a c . Salmon P i s h . Comm., B u l l . 17 :1-71. Cordone, A . J . and D.W. K e l l e y , 1 9 6 1 . The i n f l u e n c e s o f i n o r g a n i c sediment on t h e a q u a t i c l i f e o f s t r e a m s . C a l i f . P i s h and Game, 1*7.(2) : 1 8 9 - 2 2 8 . D a v i e s , O.L.(ed.) 1 9 5 6 . D e s i g n and A n a l y s i s o f I n d u s t r i a l E x p e r i m e n t . H a f n e r , New Y o r k . 636 pp. D i l l , L;.M. 1 9 6 7 . S t u d i e s on the e a r l y f e e d i n g o f sockeye salmon a l e v i n s . Can. P i s h C u l t . 39:23-31*. D i s l e r , N.N. 1 9 5 1 . E c o l o g i c a l 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 of t h e development o f t h e Amur autumn chum salmon, Oncorhynchus k e t a ( W a l b . ) . I n : P a c i f i c Salmon: S e l e c t e d A r t i c l e s f r o m S o v i e t P e r i o d i c a l s . I s r a e l Program f o r S c i e n t i f i c T r a n s l a t i o n , Jerusalem I 9 6 I . O f f i c e of Technical S e r v i c e s , U.S. D e p t . o f Commerce, Washington, pp 33-1*1. P o e r s t e r , R.E. and W. R i c k e r , 1 9 5 3 . The coho salmon o f C u l t u s Lake and S w e l t z e r C r e e k . J . P i s h . Res. Bd. Canada, 10(6):293-319.  Gangmark, H.A. and R.G. B a k k a l a , i 9 6 0 . A c o m p a r a t i v e s t u d y of u n s t a b l e a n d s t a b l e ( a r t i f i c i a l c h a n n e l ) spawning streams f o r i n c u b a t i n g k i n g salmon a t M i l l C r e e k . C a l i f . P i s h and Game, 1*6(2) : 151-161*.  G e i g e r , W. and H. Roth, 1 9 6 2 . Beobachtungen an k u n s t l i c h e n F o r e l l e n l a i c h g r u b e n . Schweiz . Z. H y d r o l . 21* : 7 6 - 8 9 . H a r r i s o n , C.W. 1 9 2 3 . P l a n t i n g eyed salmon and t r o u t e g g s . 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Canada, 16(6):835-886. v  K o s k i , K.V. 1966. The s u r v i v a l of coho salmon from egg d e p o s i t i o n to emergence i n three Oregon c o a s t a l streams. MSc. T h e s i s , Oregon State Univ., C o r v a l l i s , Oregon. 8I4. pp. Kusnetzov, I . I . 1928. Some o b s e r v a t i o n s o f the Amur and Kamtchatka salmons. B u l l e t i n o f the P a c i f i c S c i e n t i f i c F i s h e r y Res. S t a . , V l a d i v o s t o k 2 ( 3 ) : 1 - 1 9 5 . F i s h . Res. Bd. Canada, T r a n s l a t i o n #22. L a g l e r , K.F. 1956. 1+21 pp.  Freshwater F i s h e r y B i o l o g y .  Dubuque, Iowa.  M c N e i l , W.J. 1962. M o r t a l i t y o f p i n k and chum salmon eggs and l a r v a e i n Southeast A l a s k a streams. PhD. T h e s i s , U n i v . of Wash., S e a t t l e , Washington. 270 pp. I963. Q u a l i t y o f the spawning bed as i t r e l a t e s to s u r v i v a l and growth of p i n k salmon embryos and a l e v i n s and time of f r y emergence. 16th. I n t . Cong. Z o o l . , Proc. 1:214.2 ( a b s t r a c t o n l y ) . 1966. E f f e c t o f the spawning bed environment on r e p r o d u c t i o n o f pink and chum salmon. U.S. F i s h and W i l d l i f e Serv., F i s h . B u l l . 65(2):495-525. and W.H. A h n e l l , I96I4.. Success o f pink salmon spawning r e l a t i v e t o s i z e o f spawning bed m a t e r i a l s . U.S. F i s h and W i l d l i f e Serv., Spec. S c i . Report, F i s h . I4.69. 15 PP. Marr, D.H.A. 1963. The i n f l u e n c e o f surface c o n t o u r on the behaviour o f t r o u t a l e v i n s , S. t r u t t a L. Anim. Behav. 11(2-3) :1+12. 1965. Tbe i n f l u e n c e of l i g h t and s u r f a c e contour on the e f f i c i e n c y of development o f the salmon embryo. Rep. C h a l l e n g e r S o c , 3(XVII):33 Mason, J.C. and D.W. Chapman, 1965. Significance of e a r l y emergence, environmental r e a r i n g c a p a c i t y , and b e h a v i o u r a l ecology o f j u v e n i l e coho salmon i n stream c h a n n e l s . J . F i s h . . Res. Bd. Canada, 22(1):173-190. M e r r e l l , T.R., J r . 1962. Freshwater s u r v i v a l of p i n k salmon a t Sashin Creek, A l a s k a . I n : A Symposium on Pink Salmon. N.J. Wilimovsky (ed.), U n i v e r s i t y of B r i t i s h Columbia, Vancouver, B. C , i 9 6 0 , pp 5 9 - 7 2 . Neave, F . 19.47 • N a t u r a l propagation o f chum salmon i n a c o a s t a l stream. F i s h . Res. Bd. Canada, Prog. Rept. Pac. Coast Sta., 7 0 : 2 0 - 2 1 .  -82-  Neave, P. 1953* P r i n c i p l e s a f f e c t i n g the s i z e o f p i n k and chum salmon p o p u l a t i o n s i n B r i t i s h C o l u m b i a . J . Pish.. Res. B d . 9(9):1|50-1*91.  1955. Notes on the seaward m i g r a t i o n o f p i n k and chum salmon f r y . J . P i s h . Res. Bd. Canada, 12:369-3714-. P h i l l i p s , R.W. 1965. E f f e c t o f f i n e m a t e r i a l on salmon and t r o u t r e d d s . P r o c . M e e t i n g on E r o s i o n and S e d i m e n t a t i o n i n the N o r t h w e s t , 196*4.-65 F l o o d Season. U.S. Dept. A g r i c u l t u r e , S o i l C o n s e r v a t i o n S e r v i c e , P o r t l a n d , Oregon. , and H . J . C a m p b e l l , 1 9 6 1 . The embryonic s u r v i v a l o f coho salmon and s t e e l h e a d t r o u t a s i n f l u e n c e d by some e n v i r o n m e n t a l c o n d i t i o n s i n g r a v e l b e d s . Pac. Mar. F i s h . Comm. R e p t . 3 4 : 6 0 - 7 3 . , and E.W. C l a i r e , 1966. I n t r a g r a v e l movement o f the r e t i c u l a t e s c u l p i n , C o t t u s p e r p l e x u s , and i t s p o t e n t i a l as a p r e d a t o r on s a l m o n i d embryos. T r a n s . Am. P i s h . S o c . 95(2):210-212. P r i t c h a r d , A.L. 1914-7. E f f i c i e n c y of n a t u r a l p r o p a g a t i o n o f P a c i f i c salmon. Can. P i s h . C u l t . l ( 2 ) : 2 2 - 2 6 . R o t h , H. and W. O e i g e r , 1963. 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