Movements and homing of cutthroat trout (Salmo clarki) from open-water areas of Yellowstone Lake by Lawrence Allan Jahn A thesis submitted to the Graduate Faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in Zoology Montana State University © Copyright by Lawrence Allan Jahn (1968) Abstract: Cutthroat trout (.Salmo clarki). showed in-season homing after displacement from _the.ir spawning tributaries to Yellowstone Lake during June-August, 1966 and 1967.- Of. 475 trout tagged and displaced from Clear and Cub creeks to. three release points.. (0.5-22.0 km) in.the lake and to the mouth of Clear Creek,32.4% homed, 7.6% strayed, 2.5% were caught by anglers, and the. remaining were, unaccounted for. .Anosmic and blind- .. anosmic fish homed in significantly fewer numbers than other groups. fIsh released just outside the... mouth.., of the .home.stre.am had the shortest average . homing time, .but the average homing time for fish displaced .22.0 km from the homestream. was shorter than, those displaced 5..0...km away, . Homing per-centages for trout tagged .after tracking were., similar and average homing.. times longer than for. .those used. in. group tagging .experiments. Orientations in the direction between northeast and southeast generally occurred for most fish tracked in .open-water and. were, related to sun azimuth and current. Fish .taken .from the east, side .of ¦ the .lake went west-northwest .when, tracked, late in the .afternoon, .and .fish taken Irom the west side of the lake went .east-southeast .when, .tracked in the morning. The directions of orientation were generally toward the homestreams and sun azimuths. Mean directions for males and females were generally not significantly different.. Average swimming speeds, and vector lengths for males and females were about the same. Immature cutthroat trout could be trained to use a light source as a reference point for orientation.  MOVEMENTS AZD HOMING OF CUTTHROAT TROUT (SAIMO CIARKI) FROM OPEN-WATER AREAS OF YELLOWSTONE LAKE. by LAWRENCE ALLAN JAHN A thesis submitted to the Graduate Faculty in partial fulfillment of the requirements for the degree ' of DOCTOR OF 'PHILOSOPHY in Zoology Approved: Head3 Major Department Chairman3 Examining Committee Graduate Dean MONTANA STATE UNIVERSITY Bozeman3 Montana \ June3 1968 iii ACKNOWLEDGMENT Thanks are due Dr C. J. D. Brown, who directed the study and assisted in preparation of the manuscript, and to Dr J. D. McCleave and Messrs Q. J, Stober and G. W. LaBar who gave many suggestions and help in the field. To my wife, Jane, go special thanks for her continual encouragement and interest in the research work. Excellent cooperation was received from the National Park Service and the U. 8. Fish and Wildlife Service. Dr W. H. Sippel generously loaned a house trailer for use in this study. Certain equipment was provided by the Cooperative Fisheries Unit at Montana State University. Funds were supplied by the Department of Zoology and Entomology, and by grants from the National Science Foundation (grant #GB-3512) and the Office of Naval' Research (grant #NR 301-854, contract nonr 4840) awarded to Dr C. J. D. Brown, Table of Contents Page Acknowledgment .............................................'.......... ill Abstract . . . . . ............. . . . . . . . . . . . . . . . . . viii Introduction .................................... ............... . . . I Methods and Materials ........................................ .. 4 Results ................ . . . . . . . . .................. . . . . 11 Homing Studies .......................- .............. .11 Group Tagging . . . . . . . . . ...................... . 11 Tagging After Tracking .................................... 12 Float-tracking Studies . . . . . . . . . . . ........... . . 20 Experiments from Point 2 . . . . . . . . . . ........... 20 Experiments from Point 3 ................................. 23 Underwater Photographs .................... 29 Training Experiments . . . . . . . . . . . . . . . . . . . . 31 Discussion . . . . . . . . . . . . . i ...................... 33 Literature Cited .................. 37 iv VList of Tables Page. I. Displacement and recapture of Clear and Cub creek trout during June and July, 1966 and 1 9 6 7 .......... . 11 2. Significantly different comparisons" of total recapture calcu­ lated from- Chi-square contingency tables ......... 13 3- Significantly different comparisons of homing calculated from Chi-square contingency t a b l e s ............................... . l4 4. Significantly different comparisons of straying calculated from Chi-square contingency tables . . ............. 15 5. Time (hrs) from release to recapture of Clear and Cub creek trout released during June and July, 1966 and 1967 . . . . . . 16 6. Recapture of Clear and Cub creek trout tagged and released after tracking experiments in 1966 and 1967 . . . . . . . . . 17 7« Significantly different comparisons of total recapture, homing, and straying of trout tagged and released after tracking, calcu­ lated from Chi-square contingency tables ............. . . . . .18 8. Time (hrs) from release to recapture of trout tagged after tracking experiments, 1966 and 1 9 6 7 .................... .. . 19 9. Mean directions (from true North), vector lengths, swimming ■ speeds, Rayleigh tests and homestream tests at J-hr intervals for fish tracked from point 2 (1966) . . . . . . . . . . . . . 21 10. Mean directions and vector lengths at termination of tracking experiments from points 2 and 3,-1966 and 1967, using true North, sun azimuth, and current direction as the zero direction . . . 24 11. Comparisons of direction test (F) values using true North, sun azimuth, and current direction as zero directions '. ". 25 12. Mean directions (from true North), vector lengths, swimming speeds, Rayleigh tests, homestream tests and direction tests MO V for males and females at termination of tracking experi-. ments from point 2 (1966) ............................. .. -26 vi Page 13- Mean directions (from true North), vector lengths, swimming speeds, Eayleigh tests and homestream tests at termination of tracking experiments from point. 3, 1966 and 1967 . . . . . . . . . . 28 l4„ Mean directions (from true North), vector lengths, swimming speeds, Rayleigh tests, homestream tests, and direction tests (F) for males and females at termination of tracking experi­ ments from point 3, 1966 and 1 9 6 7 ............................. 30 List of Figures •vii Page 1. Map of Yellowstone Lake showing release points and locations where experimental cutthroat trout were obtained . . . . . . . 5 2. Results of training experiments using a light source as a reference point for orientation . . ............. . . . . . . 32 v i i i ABSTRACT C u t th r o a t , t r o u t (.Salmo . C la r k i ) . show ed ..in - .se a so n . hom ing, a f t e r .d is ­ p la c e m e n t f r o m - t h e i r .spaw ning t r i b u t a r i e s . t o .Y e l l o w s t o n e Lake d u r in g J u n e - A u g u s t , 1966 a n d 1967 . - Of...475 t r o u t , t a g g e d ' an d d i s p l a c e d from C le a r . .a n d Cub c r e e k s t o . t h r e e . r e l e a s e , p o in t s . . (Q„5-22.=.0, km) i n t h e . l a k e ..and t o t h e m ou th o f C l e a r . .C ra ek ,.„ 3 2 .htfo .homed, 7 - (% s t r a y e d , 2,.5% w e re .c a u g h t by a n g l e r s , and . t h e . r e m a in in g .w are , u n a c c o u n te d .fo r .. . . Anosmi c . a n d b l i n d - .. a n o sm ic f ish ..h om ed , i n . s i g n i f i c a n t ly . f e w e r , . . n u m b e r s . t h a n o t h e r g r o u p s . . . f i s h r e l e a s e d j u s t o u t s i d e the...m outh..,.of...the- .homes.tre.am h a d t h e s h o r t e s t a v e ra g e . . hom ing t im e , b u t . .th e a v e r a g e hom ing, t im e . f o r , .f i s h . . d i s p l a c e d .2 2 .0 km. from t h e hom es traam . w as . s h o r t e r - t h a n , t h o s e . .d i s p l a c e d 5.. O...km aw ay , . Homing ,.p e r­ c e n ta g e s f o r t r o u t t a g g e d . a f t e r t r a c k i n g w e r e . . s im i l a r an d ave rage .,hom ing ... t im e s l o n g e r t h a n fo r . th o s e . . .u s e d . .i n ..g ro u p t a g g in g .e x p e r im e n ts . O r ie n ­ t a t i o n s i n th e . d i r e c t i o n b e tw e e n .n o r t h e a s t . a n d s o u t h e a s t . g e n e r a l l y o c c u r r e d f o r m o s t f i s h t r a c k e d i n .open-r.wat.er and . w ere , r e l a t e d ..to sun a z im u th a n d c u r r e n t . F i s h . ta k e n f r o m . . th e e a s t . s i d e .of ■ th e . .la k e , w en t w e s t - n o r t h w e s t .when, t r a c k e d , l a t e . . . i n t h e . . a f t e r n o o n , .and f i s h t a k e n f ro m t h e w e s t s i d e o f . th e . . l a k e , w en t . . e a s t - s o u t h e a s t .when, t r a c k e d ..in . th e .m o rn in g .. The d i r e c t i o n s o f o r i e n t a t i o n w e re g e n e r a l l y to w a rd t h e h om es tre am s .and su n a z im u th s . .Mean . d i r e c t i o n s , f o r .m a le s ..a n d . fem a le s , w e re .. . .g e n e ra l ly n o t s i g n i f i c a n t l y d i f f e r e n t . . A v e rag e sw imming sp e e d s , a n d .v e c to r .M e n g th s . f o r m a le s an d f e m a le s w e re a b o u t t h e sam e. Im m atu re c u t t h r o a t t r o u t c o u ld b e t r a i n e d t o u s e a l i g h t s o u r c e a s a r e f e r e n c e p o i n t f o r o r i e n t a t i o n . M ovem ents an d .Homing .o f C u t th r o a t . T z o n t ( Salmo c l a r k i ) . . f rom O pen -W ate r A re a s o f Y e llo w s to n e Lake INTRODUCTION O p en -w a te r m ovem ents an d i n - s e a s o n hom ing o f m a tu re c u t t h r o a t t r o u t ( Salmo c l a r k i ) a f t e r d i s p la c e m e n t from sp aw n in g s t r e a m s o f Y e llo w s to n e L ak e , Wyoming w e re s t u d i e d d u r in g t h e t r o u t sp aw n in g s e a s o n s (May t o A u g u s t) o f 1966 and 1967 . Y e llo w s to n e Lake h a s a s u r f a c e a r e a o f 35^- km^, - maximum . . d e p th o f 98 m, mean d e p th o f 42 m, an d i s a t an a l t i t u d e o f 2 ,3 5 8 m (B en so n , 1961 ) . I t i s a g ood p l a c e f o r hom ing and movement s t u d i e s b e ­ c a u s e o f i t s r e l a t i v e l y l a r g e s i z e an d num erou s sp aw n ing t r i b u t a r i e s , and b e c a u s e t h e c u t t h r o a t t r o u t p o p u l a t i o n i s n o t c o n ta m in a te d w i t h s a lm o n id s from o t h e r s o u r c e s . The o b j e c t i v e s w e re t o com pare o p e n -w a te r o r i e n t a t i o n o f c u t t h r o a t t r o u t t a k e n from C l e a r , Cub, P e l i c a n and A rn ic a c r e e k s , and t o com pare t h e hom ing p e r fo rm a n c e o f t h o s e from C le a r and Cub c r e e k s . I n a d d i t i o n , u n d e rw a te r p h o to g r a p h s w e re made i n an a t t e m p t t o a s c e r t a i n i f la n d m a rk s w e re v i s i b l e t o t h e f i s h . L a b o r a to r y e x p e r im e n ts w e re c o n d u c te d t o d e te rm in e i f c u t t h r o a t t r o u t c o u ld b e t r a i n e d t o u s e l i g h t f o r o r i e n - ' t a t i o n . I n - s e a s o n hom ing o f m a tu re c u t t h r o a t t r o u t i n Y e llo w s to n e Lake was o b s e r v e d b y M cC leave ( 1967 ) who d i s p l a c e d 1908 t r o u t and f o u n d , . t h a t 32 .2% hom ed , 6 .2% s t r a y e d , and 1 .5% w e re c a u g h t b y a n g l e r s . P l a t t s (1 9 5 9 ) showed i n - s e a s o n hom ing f o r c u t t h r o a t t r o u t d i s p l a c e d i n a U tah r e s e r v o i r a f t e r spawn was t a k e n . -2 - N a ta l hom ing, s t u d i e s b y B a l l , . in Y e llo w s to n e Lake (1 9 5 5 ) showed t h a t c u t t h r o a t t r o u t , m a rk ed a t ag e .I. .h ad a s t r o n g t e n d e n c y t o r e t u r n t o t h e p a r e n t s t r e a m a s a d u l t s a t ag e I I I o r IV . Cope (1 9 5 7 ) fo u n d t h a t 97# o f t h e r e p e a t sp aw n e rs i n Y e llo w s to n e L ake homed and s u g g e s te d t h a t e a c h s t r e a m h a s i t s own r a c e o f c u t t h r o a t t r o u t . I n - s e a s o n hom ing o f so ck e y e sa lm on (O n co rhyn chu s n e r k a ) and p in k sa lm on ( o . g o r b u s h a ) w as o b s e r v e d b y H a rtm an and R a le ig h (1 9 6 4 ) and H e l l e , ( 1966 ) , r e s p e c t i v e l y . N a ta l hom ing o f sa lm on was r e p o r t e d b y C lem ens e t a l . (1 9 3 9 )? D o n a ld so n an d A l l e n (1 9 5 7 )? J o n e s ( 1 9 5 9 ) , and r e v ie w e d b y E a s i e r (1966). N a ta l and r e p e a t hom ing f o r b row n t r o u t ( Salmo t r u t t a ) w e re o b s e r v e d b y S t u a r t (1 9 5 7 ) an d f o r r a in b o w t r o u t ( Salmo. .g a i r d n e r i ) b y L in d s e y e t a l . (1 9 5 9 ) - I n - s e a s o n and r e p e a t hom ing f o r c h a r ( S a l v e l i n u s . w i l l u g h b i i ) w e re shown by F r o s t ( 1963 ) . P r e v io u s s t u d i e s on o p e n -w a te r m ovem ents o f c u t t h r o a t t r o u t showed t h a t o r i e n t a t i o n w as m a in ly e a s tw a r d and n o r th w a rd from v a r i o u s r e l e a s e p o i n t s i n Y e llo w s to n e L ake ( J a h n 5 1966 ; M cC leav e5 1967 ) . T h is w as a l s o t r u e f o r b l i n d an d an o sm ic t r o u t w h ic h o r i e n t e d a s w e l l a s c o n t r o l t r o u t . H ow ever5 o r i e n t a t i o n w as g e n e r a l l y n o t to w a rd th e home s t r e a m . A s o u th ­ w a rd s h i f t i n mean d i r e c t i o n w as n o t e d f o r t r o u t t r a c k e d a f t e r noon ( J a h n 5 1966 ) . The su n may h av e s e r v e d a s a r e f e r e n c e p o i n t i n o r i e n t a t i o n s in c e t r o u t t r a v e l e d f a r t h e r and show ed a s t r o n g e r te n d e n c y t o go s h o rew a rd from a n e a r - s h o r e r e l e a s e p o i n t on su n n y d ay s t h a n on c lo u d y d a y s . F i s h o t h e r t h a n c u t t h r o a t t r o u t w h ich .u se c e l e s t i a l c u e s f o r o r i e n ­ t a t i o n i n c l u d e young so ck e y e sa lm on (C r o o t5 1965 ) , w h i te b a s s (H o s ie r e t a l -3 - 1 9 5 8 ) , g r e e n s u n f i s h ( Schw assm ann ,. i 960 ; E a s i e r and S chw assm ann , i 960 ) , c i c h l i d s (B raem e r an d S chw assm ann , 1963 ; E a s i e r and S chw assm ann , i 960 ) , a n d p a r r o t f i s h e s (W inn e t a l . , . 1 9 6 4 ) . Cues s u g g e s t e d f o r d e t e c t i o n o f t h e home s t r e a m b y f i s h , i n c lu d e t e m p e r a tu r e (W ard , 1 9 2 l ) , c a rb o n d io x id e (P o w e rs , 1 939 ; P ow ers and C la r k , 1 9 ^ 3 ; C o l l i n s , 1 9 5 2 ) , g r a d i e n t s o f i n o r g a n i c compounds ( E a s i e r , 1966), m i l t (W h ite , 1 9 3 4 ) , an d c h a r a c t e r i s t i c s t r e a m o d o r ( E a s i e r a n d W isby , 1 9 5 1 ) • The l a t t e r i s t h e m o s t g e n e r a l l y a c c e p te d e x p l a n a t i o n f o r d e ­ t e c t i n g t h e home s t r e a m . A t te m p ts t o e x p l a i n m ovem ents i n c l u d e : su n -c om p a ss o r i e n t a t i o n ( E a s i e r e t a l . , 1 9 5 8 ) , c e l e s t i a l n a v i g a t i o n (A d le r , 1963 ) , i n e r t i a l g u id a n c e (B a r low , 1 9 6 4 ) , p o l a r i z e d l i g h t (G ro o t , 1965 ) , an d random movement ( S a i l a and S h ap p y , 1963 ; P a t t e n , 1 9 6 4 ) . E a s i e r (1966) d i s c u s s e d t h e s i g n i f i c a n c e o f t h e s e . U n d e rw a te r p h o to g r a p h s o f t h e su n (B e n d e r s o n , MS, 1963 ) showed many im ag e s o f t h e su n due t o sm a l l w aves on t h e l a k e ' s s u r f a c e . Be s t a t e d t h a t t h e s e m u l t i p l e im ag e s may b e ah a d v an ta g e , f o r o r i e n t a t i o n . T r a in i n g e x p e r im e n t s b y E a s i e r . e t a l . , ( 1958 ) and B raem e r ( i 960 ) 1 show ed c e n t r a r c h i d s t o p o s s e s s a su n -c om p a ss m echan ism . O th e r e x p e r i ­ m en ts d e m o n s t r a te d t h e im p o r ta n c e o f t h e a l t i t u d e and a z im u th o f t h e sun f o r o r i e n t a t i o n o f s u n f i s h and c i c h l i d s ( E a s i e r and S chw assm ann , i 960 ; Schw assm ann an d E a s i e r , 1 9 6 4 ) . METHODS M D MATERIALS R e le a s e p o i n t s -1, 2 , 3 , a n d 4 ( F ig . l ) w e re u s e d f o r .homing, s t u d i e s . T h e se w e re l o c a t e d a t t h e m ou th o f C le a r C re e k , 0 .5 km w e s t - n o r t h w e s t , 5 .0 km w e s t , a n d 2 2 .0 km w e s t - s o u th w e s t o f t h e m ou th , r e s p e c t i v e l y . T r a v e l t im e t o r e l e a s e p o i n t I w as 2 -3 m in u te s , t o p o i n t 2 was 3 -15 m in u te s , t o p o i n t 3 was 8 - l 8 m in u te s , a n d t o p o i n t 4 w as 30 -35 m in u te s , d e p e n d in g on w he re e x p e r im e n t a l f i s h w e re o b t a i n e d and s p e e d o f t h e b o a t . F i s h u s e d i n hom ing s t u d i e s w e re m ov ing u p s t r e a m t o spawn and w ere t a k e n from t r a p s on C le a r an d Cub c r e e k s , l o c a t e d 75 and 150 m, r e s p e c t i v e l y , above t h e i r m o u th s . Homing e x p e r im e n t s w e re c a r r i e d o u t from Ju n e 29 t o J u l y 9 , 1 9 6 6 , and J u l y 11 t o 1 8 , 1967 . A g ro u p o f 2 5 -3 0 t r o u t w e re n e t t e d from t h e t r a p and w e re t a k e n t o t h e b o a t . I n a few i n s t a n c e s , f i s h t a k e n from C le a r C reek w e re c a r r i e d d i r e c t l y t o r e l e a s e p o i n t I . F o u r t y p e s o f e x p e r im e n ta l f i s h w e re u s e d : b l i n d - a n o sm ic , a n o sm ic , c o n t r o l an d n o n - a n e s t h e t i z e d . B l in d - a n o sm ic , a n o sm ic a n d c o n t r o l f i s h w e re a n e s th e t i z e d - i n a 40 m g / l i t e r s o l u t i o n o f t r i c a i n e m e th a n e s u l f o n a t e (M .S .-2 2 2 , S andoz P h a rm a c e u t i c a l s ) . F i s h w e re b l i n d e d b y i n j e c t i n g 0 .0 1 - 0 .1 5 cm3 o f 3$ a q u eo u s b e n z e th o n iu m c h l o f i d e ( P h em e ro l , P a r k e , D a v is and C o .) i n t o t h e i r e y e b a l l s w i th a s y r i n g e (M cC leave , 1967 ) . A j e t o f a i r w as b low n i n t o t h e o l f a c t o r y ch am be rs t o f r e e th em o f f o r e i g n m a t e r i a l an d t h e n p e t r o le u m j e l l y (V a se ­ l i n e , C h e seb ro u g h -P o n d s M fg . C o .) w as i n j e c t e d i n t o th em w i t h a n e e d l e l e s s s y r i n g e , u n t i l t h e a c c e s s o r y cham ber a n t e r i o r t o t h e ey e w as f u l l . An em p ty s y r i n g e w as p l a c e d a g a i n s t t h e n a r e s o f c o n t r o l f i s h . A n e s th e t i z e d -5 - CAN C C U B C 5 KM F ig . I . Map o f Y e llo w s to n e L ake show ing r e l e a s e p o i n t s an d l o c a t i o n s w he re e x p e r im e n ta l c u t t h r o a t t r o u t w e re o b t a i n e d . I , 2 , 3, ^ - r e l e a s e p o i n t s ; A, B - l o c a t i o n s w he re n o n -sp aw n in g and spaw ned- o u t t r o u t w e re c a p tu r e d . - 6- fish were then tagged, placed into the stock tank, .carried to the release point and liberated after recovering from the anesthetic, which was usu­ ally by the time the release point was reached. Non-anesthetized fish were either put into a covered stock tank in the boat, carried to a release point, marked with a numbered alligator clip tag (McCleave et al., 1967) and released, or marked and released at point I. Groups of 25 fish were tagged and liberated at each release point. A total of 50 fish from Clear Creek were released at point I, 50 from Clear Creek and 50 from Cub Creek at point 2, 225 from Clear Creek and 50 from Cub Creek at point 3, and 50 from Clear Creek at point 4. Most recaptures were obtained from the traps on Clear and Cub creeks. Tagged fish were generally removed from the traps in the afternoon but some were removed at other times of the day. The tag number, date, time of day, length and sex of each recaptured fish were recorded. A few tagged fish were taken by anglers. The heads of all recaptured anosmic fish were saved and the olfactory chambers examined to see if the plugs were intact. Release points 2 and 3 were used for tracking experiments. Fish moving upstream to spawn were obtained from the traps on Clear, Cub, and Pelican creeks, with a dip net from Hatchery Creek (3.6 km west of Pelican Creek), and by hook and line 'from Arnica Creek. Non-spawning fish were caught with hook and line 8.4 km west-northwest (point A) and 10.1 km west- southwest (point B), respectively, of the mouth of Clear Creek (Fig. l), - 7- Tracking experiments were conducted from May 31 to July 28, 1966, and June 16 to July 25, 1967. Groups of 2-6 fish were taken to a release point in a covered tub. Four types of experimental fish were used: non- anesthetized, blind, blind-anosmic and control. Treatments for each type were the same as for tagging experiments except that control fish used in comparison with the blind fish were anesthetized only. . A float-tracking device consisting of a 5 cm3 styrofoam (.Dow Chemical Co.) cube connected, by 2 m.of nylon line to an alligator clip was attached to the dorsal fin of each fish at a release point (jahn, 1966). For experiments at point 2, 2 non-anesthetized fish or one blind and one con-' trol fish were liberated at one-minute intervals without attempt to orient them. For experiments at point 3, 2-5 non-anesthetized, 2 blind-ansomic and 3 control, or 3 blind-anosmic and 2 control fish were similarly re­ leased. Aftei the fish were released a drift drogue was placed in'the water to determine currents at the approximate .depth the fish were swimming (Jahn, 1966). Positions of the fish and drift drogue were determined by sighting on landmarks with a sextant. Sightings were taken at y^hour intervals on each fish and the drogue released' at point 2. In a few instances fish were lost for a time. Experiments were terminated either at 2 hours or when experimental fish reached an area where I could see the lake bottom or when windy weather prevented accurate sightings. Only one sighting was taken on each fish and the drogue released at point 3 ~ either one hour -8- after the experiment began, or sooner if the. .wind, interfered with, sightings. This terminated an experiment and the fish ..and drogue were, picked-.up as quickly as possible. Most fish were recovered and the length and. sex of each were determined. Most spawning fish were tagged and released, but non-spawning fish were cut open to determine sex. The fish.tracked at point 2 included 3^ spawning fish from Clear Creek, 26 from Cub Creek and lO from Pelican Creek, and in addition, 21 non.-spawning and 2 spawned-out- fish caught at point A. Those tracked from point 3 included 6l spawning fish from Clear Creek, 20 from Cub Creek, 23 from Arnica Creek and k from Hatchery Creek, and in addition, 24 non-spawning and 6 spawned-out fish caught at points A and B. Underwater photographs were taken to determine if landmarks might be visible. A Nikonos All-Weather camera (Ehrenreich Photo-Optical Industries, Inc.) was attached to the end of a pipe 3 m long so the camera faced upward at an angle of 48° from the vertical (toward the edge of the "fish window", Walls, 1942). Light readings for each picture were taken just under the surface of the lake with a Sekonic Model 1-86 light meter in a waterproof housing (Ehrenreich Photo-Optical Industries, Inc.). Pictures were taken using black and white Tri-X Pan film (Eastman Kodak Co.) from depths of 0.5, i:.0 and 2.0 m at release points 2 and 3» Some were also taken from 1.0 and 2.0 m, 20-80 m from shore. The shutter was released by a cord attached to a.lever while the camera was held in the desired position. An attempt was made to train hatchery cutthroat trout (150-213 mm total length) in the laboratory to use a light source as a reference ~ 9 ~ point for orientation. The training tank (2 m i n dia.) was similar to that used by Easier et al. (1958) and contained l6 wedge-shaped boxes facing outward from a central release chamber. The light source' was above the edge of the tank at an angle of 50° from the center. The tank was com­ pletely enclosed by black curtains which blocked out extraneous light and hid the experimenter from the fish. All fish were trained individually at nearly the same time each day for 6 days in succession with one day's intermission. Two fish were subjected to $ trials per day for 30 consecu­ tive days using a 100-watt light bulb and 6 fish 10 trials per day for 10 consecutive days using a 300-watt bulb. Three fish were trained to go 90° clockwise, 3 90° counterclockwise and 2 toward the light source. Three untrained fish were used as controls. Each fish to be trained was netted from a trough, placed in the ' central chamber of the tank and released after it quieted down. During training only one of the 16 boxes was made available for the fish to hide in. An electric probe was used to shock and direct the fish to the open box. After the fish entered the box, it was left undisturbed for one minute and then netted and returned to the central chamber. This process was repeated for the remaining trials. The number of trials used for training was the same as that for testing, but during testing all 16 boxes were available for the fish to hide in. The tank and position of the light were rotated after each day's training to prevent use of marks on the tank and other cues for orientation. In addition the experimenter changed locations to avoid being used as a reference point. Fish were tested the —10" day after the last training session at the normal training time. Those which oriented .were retested the. following.day without additional training 6 hours after their usual training time. Retention of learning was also tested. Data from tagging and tracking experiments were analyzed with the aid of a computer. Chi-square contingency tables (Steel- and Torrie5 i960) were used to compare, homing, straying and total recapture of each experi­ mental group with every other for tagging experiments., A mean direction (a), a mean vector length (r) (Batschelet5 1965), average swimming speed and average length of fish were calculated for each experimental group used in tracking ,experiments. A Rayleigh test (Greenwood and Durand5 1955) was applied to.each male, female and combined sex group to determine if the distributions were uniform. .A resultant vector F test (Watson and Williams, 1956) was used to compare combined sex groups with each other to see if the mean directions of each pair were significantly different. An R test (Watson and Williams, 1956; Stephens, 1962) was used to determine if the mean direction of each male, female and combined sex group except non-spawning and spawned-out fish was toward the homestream. Current direction and sun azimuth were taken as the zero direction for each fish ' instead of true North. Mean directions, Rayleigh tests and resultant vector F tests were then recalculated for combined sex groups,. Summaries of all these tests are given by Batschelet (1965). The normal approxi­ mation test (Steel and Torrie, i960) was used to determine if experimental fish were trained in the laboratory. RESULTS HOMING STUDIES Fish used in .tagging studies were of 2 types: groups taken from .the traps as contrasted to individual fish tagged after tracking„ Group Tagging. Two hundred non-anesthetized,.50 anosmia, 50 blind- anosmic, 50 controls for anosmia fish and 25 controls for blind-anosmia fish from Clear Creek and 100 non-anesthetized from Cub Creek were used in group tagging.experiments. Forty-one percent of all non-anesthetized fish from Clear Creek homed and 5-5% strayed while 33-0$ of non-anesthe­ tized fish from Cub Creek homed and 15.0% sthayed (Table l) Table I. Displacement and recapture of Clear and Cub creek trout during June and July,.1966 and 1967. (Percentages in parentheses.) Release Origin Group^ Number Number recaptured Year point creek released Home Stray . Angler Total 1966 2 Clear NA 50 20(40.0) 3( 6.0) 0 23(46.0) Cub NA 50 21(42.0) 7(14.0), 2 (4 .0 ) 30(60.0) 3 Clear NA 50 24 (48 .0 ) 3( 6.0) 2 (4 .0 ) 29(58.0) Cub NA 50 12(24.0) 8(16.0) 2(4.0) 22 (44 .0 ) 1967 I Clear NA 50 15(30.0) 5(10.0) 1(2.0) 21(42.0) 3 Clear A 50 6(12.0) l ( 2 . 0 ) 2(4.0) 9(18.0) CA 50 23(46.0) 5(10.0) 2(4.0) 30(60.0) BA 50 2( 4.0) 0 0 2( 4.0) CBA 25 io ( 4 o .o ) 0 0 io ( 4 o .o ) 4 Clear NA 50 23(46.0) 4( 8.0) 1(2.0) 28(56.0) ^ NA - non-anesthetized; A - 1anosmic; BA - blind-■anosmic; CA - control anosmia; CBA - control bIind-anosmic. -12- Twelve percent of ano.smi.c fish from .Clear. Creek homed and 2.0% strayed while 46.0% of control fish homed and 10.0% strayed. Only 2.0% of bIind- anosmic fish from Clear Creek homed while 40.0% cjf control fish .homed. . Significantly fewer anosmic and blind-anosmia fish from Clear Creek homed and strayed than other experimental groups (Tables TI, III, IV"). Significantly fewer non-anesthetized fish from Cub Creek released at point 3 homed than non-anesthetized fish from Clear Creek released af points 3 or 4. Average homing times were less for non-anesthetized fish from Clear Creek released at point I than for any other group (Table V"). Non-anesthe­ tized fish from Clear Creek homed faster on the average from point 4 (22.0 km) in 1967 than from points 2 or 3 (0.5 and 5-0 km, respectively) in 1966. Non-anesthetized fish from Clear and Cub creeks homed in a,bout the same length of time. ' The average homing time of anosmic fish from Clear Creek was greater than any other experimental group, and 63 hours greater than control fish. Blind-anosmic fish from Clear Creek homed as quickly as control fish. .Statistical analyses are not given for homing times since recaptures were not obtained randomly. Tagging After Tracking. Thirty-seven non-anesthetized, 17 biind- anosmic,.8 blind, 10 controls for blind-anosmic fish and 8 controls for blind fish from Clear Creek, 29 non-anesthetized, 6 blind and 6 controls from Cub Creek, and 10 non-anesthetized fish from Pelican Creek were used to determine homing performance after tracking. Homing percentages of -13- Table II. Significantly different comparisons of total recapture .calculated from Chi-square contingency tables. Year Release point Origin creek Group^/ vs. Year Release point Origin creek Group^/ Chx- square^ 1967 3 Clear A 1966 .2 Clear m 13.42** Cub HA 20.06** 3 Clear HA 18.25** Cub HA 9.89* 1967 I Clear HA 8.91* 3 Clear CA 19.86** CBA 8.70*. 4 Clear HA 17.82** 1967 3 Clear BA 1966 2 Cub HA 36.22** 3 Clear HA 34.18** Cub HA 22.40** 1967 I Clear HA 20.62** - 3 Clear CA 36.16** 4 Clear HA 32.29** .a/ Legend as in Table I. b/ ^Significant at P = 0,05; ^Significant at P 0 .01. — l U - — Table III. . Significantly different comparisons of'homing calculated from Chi-square contingency tables. Year Release point Origin creek Group^ vs. Year Release point Origin creek Groups/ Chl“ b/ _ square—' 1966 3 Cub NA 1966 3 Clear NA 4.72* 1967 3 Clear CA 4 .68* 4 Clear NA 3.89* 1967 3 Clear A 1966 2 Clear NA 10.42** Cub NA ' 15.22** 3 Clear NA 17.21** Cub NA 3.91* 1967 I Clear NA 5.82* 3 Clear CA 17.05** CBA 7.0c* 4 Clear NA 15.65** 1967 3 Clear BA 1966 2 Clear NA 20.53** Cub NA 26.59** 3 Clear NA 28.99** Cub NA 11.43** 1967 I Clear NA 14.30** 3 Clear CBA 16.07** CA 28.80** 4 Clear NA 27.10** .a/ k/ Legend as in ^Significant Table I. at P = 0.05; ^Significant at P 0.01. -15- Table IV. Significantly different comparisons of straying calculated from Chi-square contingency tables. Year Release point Origin creek Group^ v s . Year Release point Origin creek Group^/ Chi- ^ square—' 1966 3 Cub NA 1967 3 Clear CBA 3.95* 1967 3 Clear A 1966 2 Cub NA 7.47* 3 Cub NA 8.88* 1967 I Clear NA 3.92* 3 Clear CA 5.96* 4 Clear NA 3.98* 1967 3 Clear BA 1966 2 Clear NA 4.99* Cub NA 13.72** 3 Clear NA 6.26* Cub NA ll.78** 1967 I Clear NA 7 .51* 3 Clear CA 10.30** 4 Clear NA 7.80** — ' Legend as in Table I. ^ ^Significant at P = 0.05; ^Significant at P = 0.01., -16- Release Origin , Humber Home_____ _____ Stray Year -point creek Group— ^ released Ho. _ Range Av. Ho. Range Av,. Table Vo Time (hrs) from release to recapture of Clear and Cub. creek trout released during June and July, 1966 and 1967, 1966 1967 2 Clear NA 50 1—I XO O CXl CM CM I I CO H C— d % CM CM 109 3 26-223 ■ 94 Cub NA 50 117 7 8-100 74 3 Clear NA 50 24 34-392 l48 3 32-250 135 Cub NA 50 12 35-221 131 ‘8 29-249 105 I Clear NA . 50 15 6-142 60 5 19 - ; 94 39 3 Clear A 50 6 121-219 160 I 113 113 CA 50 231 ,22-293 2— ' 96-120 97 5 48-360 165 BA 50 108 O O O CBA 25 10 50-312 113 O O 0 4 Clear NA 50 23 45-216 90 4 45- 96 61 .»/ Legend as in Table I. k/ Does not include one fish whose tag was found in the bottom of the Cub .Creek trap 434 hours after release. sJ Seen in stream, and not caught in' the trap. these -experimental groups of fish (Table V I ) were similar to those used in group tagging experiments, except only one of 10 controls for bIind- anosmic fish homed after tracking. Significantly fewer blind-anosmic fish from Clear Creek homed than all other groups tagged after tracking except non-anesthetized fish from Cub Creek (released at point 3) and controls for blind-anosmic fish (Table VII). Blind and control fish from Cub Creek tracked from point 2 homed equally well.. No fish from Pelican or Arnica creeks were found among the -17- < Release Origin / Number _______Number recaptured______ Year point . creek Grougr-/ released Home _ Stray Angler Total Table VI. Recapture of Clear and Cub creek trout tagged and released after tracking experiments in 1966 and 1967. (Percentages in parentheses.) 1966 2 Clear Cub * Pelican 3 Clear Cub 1967^/ 3 Clear NA 18 6(33.3 ) B 8 4(50.0) CB 8 • 5(62.5) NA 14 7(50.0) B 6 5(83.5) CB 6 3(50.0) NA 10 0 NA 14 6(4 2.8 ) NA 15 3(20.0) NA 5 4(8o.o) BA 17 i( 5.9 ) CBA 10 1(10.0) i( 5.5) 0 7(38.8 ) 0 0 4(50.0) 0 0 5(62.5) 0 0 7(50.o) 0 0 5(83.5) 0 0 3(50.o) 0 0 0 0 0 6(4 2.8 ) 5(33.3 ) 0 8(53.3 ) 0 0 4(80.0 ) 0 :i( 5 .9 ) 2(11.8) 2(20.0)1(10.0) .4(4o.o) NA — non-anesthetized; B — blind; CB — control blind; BA- bIind- anosmic; CBA— control blind-anosmic. b / — Only those released after the fish traps were permanently installed are considered. Fish from Arnica Creek are not included since there was no trap operated there. -18- Table VII. Significantly, different .comparisons, of total recapture, homing, and straying of trout tagged and released after tracking, cal­ culated "from Chi-.square contingency tables. Year Release point Origin creek Group^/ vs. Year Release point .Origin creek Group^ Chi- square—7 Total Recapture 1966 2 Cub B 1967 3 Clear CBA 8.78* 3 Cub NA 3 Clear BA 9.10* Homing 1966 2 Pelican NA 1966 2 Clear NA 4.53* B 6.42* CB 8.65** Cub NA. 7.05** B •12.12** CB 6.15* 3 Clear NA 5.71* 1967 3 Clear NA 10.90** Cub B 1966 2 Clear NA 4.10* ■ 3 Cub NA. 4.26* 1967 3 Clear CBA 6.19* 1967 3 Clear BA 1966 2 Clear NA 4.16* B- 6.18* CB 9.00** Cub NA 7.30** B 13.07** CB 5.61* 3 Clear ■ NA 5.59* ' 1967 3 Clear NA 11.42** 1967 3 Clear NA 1967 3 Clear CBA 5.18* . Straying • 1966 3 Cub NA 1966 • 2 Cub NA 3.95* Pelican NA 5.39* 1967 3 " ' Clear BA 1966 3 ' Cub NA 7.02** 1967 3 Clear CBA 4.10* j/ y c/ Legend as in Table VI. •^Significant at P = 0.05; ^Significant at P =. 0.01. Fish from Arnica Creek were not included since there was no trap operated there. -19- recaptures. The average, .homing times for blind fish .from Clear and Cub creeks- were 78 and l46 hours greater, respectively, than for control fish (Table VIII). Table VIII. Time (hrs) from release to recapture of trout tagged after tracking experiments,.1966 and 1967. Release Origin / Number Home______ ______Stray Year point creek Group— ^ released No. Range Av. No. Range Av., 1966 2 Clear NA 18 B 8 CB 8 Cub NA 14 B 6 CB 6 3 Clear NA. l4 Cub NA 15 1967 3 Clear NA 5 BA 17 CBA 10 —' Legend as in Table VI. Control and non-anesthetized fish 6 29-462 177 . I 297 .297 4 167-392 263 0 0 0 5 - 5-339 185 0 0 0 7 48-340 180 0 0 0 5 102-413 302 0 0 0 3 29-3^0 156 0 0 0 6 104-272 197 0 0 0 3 199-247 215 5 56-103 87 4 36-159 99 0 0 0 I 339 339 0 . 0 0 I 241 241 2 69-214 142 Clear and Cub creeks homed in about the same time from point 2 in 1966. The average homing times of non­ ane sthetized fish from Clear and Cub creeks (tagged after tracking in 1966) from point 2 were 20 and 35 hours less, respectively, than those tagged after tracking from point 3= The average homing times of non-anesthetized fish from Clear and Cub creeks (1966) tagged after tracking from point 2 were 68 and- 63 hours greater, respectively, than similarly treated fish used in group tagging -20- experimentSo The average homing times of non-anesthetized fish from.Clear and Cub creeks (.1.966) tagged after tracking .from point 3 were 39 and 84 hours greater, respectively, than similarly treated fish used in group tagging experiments. FLOAT-TRACKING STUDIES Experiments from Point 2 . A total of fish was tracked from point 2, The experimental groups and directions of orientation were as follows: non-anesthetized fish from Clear Creek — east-northeast; controls for blind fish from Clear and Cub creeks — east; non-anesthetized fish from Pelican and Cub creeks and spawned-out fish from point A — east-southeast; blind fish from Clear Creek and non-spawning fish from point A — southeast and blind fish from Cub Creek — south (Table IX). Vector lengths (r) were significantly greater than zero for non- anesthetized fish from Clear Creek and non-spawning fish from point A. Non-significant r values for other fish may be due to small sample size rather than lack of orientation. R values and average swimming speeds often decreased after the first y-hour interval sighting was made. Blind fish had smaller rvalues than either the control or non-anesthetized fish. Non-spawning fish oriented as well as or better than any other experimental group of fish. Mean directions of all groups of spawning fish at the conclusion of all tracking experiments were not significantly different from the home- stream direction, except for non-anesthetized fish from Pelican and Clear Table IX. Mean directions (from true North), vector lengths, swimming speeds, Rayleigh tests and homestream tests at y-hr intervals for fish tracked from point 2 (1966). Origin creek Groupy/ Number tracked Hr after release ■Mean direction Vector length Speeds (m/hr) Range Average Rayleigh test^/ Homestream t e s t ^ Pelican NA 9 0.5 1250 0 .7797 97-779 434 5.47** 7.02** 3 1.0 223 0 .3730 83-151 ill _b _b 4 1-5 188 0 .1575 71-291 139 _b 0 .6 3 3 2.0 293 0.3620 79-199 158 _b _b . 10 Term. n 4 0 .5057. 79-779 4o8 2 .55 5.06* Clear NA 16 0 .5 83 . 0 .3926 20-622 325 .2.47 . 6.28 i4 1.0 58 0 .2971 82-519 294 1.24 4.16 10 1.5 20 0 .5509 80-512 213 3.04* 5-51* 7 2.0 16 0.8651 45-508 171 5.24** 6.06** 18 Term. 68 0.5445 45-622 323 5-34** 9.80** Clear B 8 0.5 137 0 .2995 178-968 481 0.72 2 .40 6 1.0 78 0 .2863 156-674 345 0.49 1.72 3 1.5 48 0.5900 131-317 231 _b _b 2 2.0 ' 27 0 .4383 12O-289 205 -b _b 8 Term. 130 O.3669 120-968 502 1.08 2 .94 Clear CB 8 0.5 69 0 .6430 259-977 556 3-31* 5.14* 5 ■ 1.0 32 0 .3747 106-558 350 _b 1.87 3 1.5 98 0.1692 129-225 190 _b -b 'I 2.0 330 1.0000 189 189 _b _b 8 Term. 94 . 0 .4l46 189-977 503 1 .38 3 ,31 Cub NA i4 ' 0.5. 228 0.1781 125-760 367 0.44 2 .49 . '11 1.0 248 0.2620 36-473 243 0.76 2.88 8 1-5 319 ' 0.0082. 134-272 214 0.00 0.66 5 - 2.0 31 0.1792 86-255 181 _b 0.90 14 Term. ■ 121 0 .2730 86-760 336 i.o4 3.82 Table IX, Continued. Origin creek Number Group^ tracked '.•Hr after release Mean direction 'Vector length Speeds Range (m/hr) Average Rayleigh test^/ Homestream ' testS/" Cub B . 6 0.5 109° 0.3162 132-569 314 0.60 1.89 5 1.0 113 0 .3623 182-407 272 -b 1.81 4 1.5 57 0.5494 147-484 259 _b 2.19 3 2.0 199 0.2742 124-183 162 _b _b 6 • Term. 175 0 .2057 124-484 285 0 .25 1 .23 ■ Cub CE 6 0.5 99 ". 0 .5488. 332-966 576 . 1.80 3.29** 3 1.0 99 0.7290 217-445 344 _b _b I 1.5 6i 1.0000 168 168 _b _b I 2.0 57 1.0000 143 143 _b _b 6 Term. 98 0.4666 143-966 509 1 .30 2.80 NS 22 0.5 133 0.5445 331-962 592 6.52** -C 7 1.0 181 0.5650 357-650 514 2*23 _c I .1.5 285 1.0000 419 ' 419 _b -C I 2.0 301 1 . 0 0 0 0 ■ 251 251 _b -C 22 Term. 131 0.5849 251-962 586 7 .52** -C 80- 2 0.5 loU 0.8191 533-736 634 _b -C .2 .Term. 104 0.8191 533-736 634 _b -C a/ k/ c/ A/ •^Significant at P = 0.05; **Significant at P = 0.01. Sample too small for test. Does not apply. NS — non-spawning; SO — spawned-out; NA — non-anesthetized; B — blind; controls for blind. CB — -22 - -23- creeks. The..mean ..directions of ..all-groups of fish were .not ..significantly different from, each, other, .except .that tho.se .of. .non-.anes"tihe.t.ize.d.fish from Clear Creek and,non^spawning. fish,.differed, significantly. However, when either the sun,.azimuth or the current direction was used as the zero di­ rection instead .of true. North,...the .mean..directions of these .latter groups were not significantly different. (Tables X, XI). The average.speed ? mean direction, and. vector length for currents were .165 .m/hr, 158° and 0.80.76, respectively. Non-spawning, and. spawned-out .fish,had..the..fastest .average .swimming speeds of all.groups tested, (.586 and .634 m/hr, respectively). Average ■swimming speeds for non-anesthetized, blind and control fish from Clear Creek were 323, 502 and 503 m/hr, respectively, and from Cub Creek 336, 285 and 509 m/hr, .respectively. ,Non-.ane.sthet.ized fish from Pelican. Creek averaged 4o8. m/hr. The mean directions., of. males ..and females were .not .significantly different, except ..for Hind, fish from ,Cub .Creek, .Females ,did .not have consistently greater vector -lengths than.males (Table XII), but they generally had greater average swimming, speeds..... Experiments, from Point.3 » The total numbers of fish tracked from point 3 -in 1966 and 1967 were 59 and 79, respectively. The .experimental. .. groups and directions.of orientation for fish, tracked, i n 1966 were as follows: non-anesthetized. fi sh.-from.. Clear .and ...Cub., creeks ..and. non-spawning fish from points A and B — east-northeast; and spiawned-out fish from points Table X. ■Me-an.,.directi.o.ns. .and. vector lengths, at termination of tracking .experiments from points 2 and 3, 1966 and 196,7, using' true North, sun azimuth, and current di­ rection. as the zero .directions. Zero direction as Year Origin , creek Group-/ No. True North Sun ,azimuth Current Mean Vector direction length Mean direction Vector length Mean direction .Vector length POINT 2 1966 Pelican -NA 10 114° 0.5057 24° 0.5027 65° . 0.2421 Clear NA 18 68 0.5445 319 0.3746 297 0.2236 B 8 130 O.3669 359 0.3677 .26 0.6392 CB 8 94 o.4i46 330 0.6493 9 0.2085 Cub NA 14 121 0.2730 339 0.3751 49 o.i4oi ■ B 6 175 0.2057 ■ 315 0.7240. 343- 0.4335.. CB 6 98 0.4666 323 o.6o4i 329 0.8243 — NS 22 131 0/5849 358 0.7147 303 0.2377 — 80 2 104 0.8191 323 0.8743 258 0.5446 POINT 3 1966 Clear NA lb .63 0.5079 313 0.4992 341 0.3242 Cub NA .15 71 0.4156 288 0.4555 30 0.3623 — NS 2k 75 0.6465 308 0.5217 117 0.5911 — 80 6 123 0.4881 313 0.3278 ll4 0.4237 1967 Clear NALA 13 302 0.9235 3 0.9122 5 0.8708 BA 20 11 0.5130 240 0.4926 32 0.6045 CBA Ik 59 0.3162 296 0.2561 53 0.5212 Arnica NA 23 119 0.2679 335 0.3018 18 0.4608 Cub NA ■ 5 96 O.6561 257 0.7315 166 0.5393 Hatchery NA 4 199 0.5049 82 0.5389 - 304 0.5049 NALA. — non-anesthetized tracked late in the afternoon; BA — blind-anosmic; CBA — controls for blind-.anosmic. Others given in legend for- Table IX. -25 Table XI. Comparisons of direction test (F) values using true North, sun azimuth, and current direction as zero directions. Origin Direction test (F) value •with zero direction as sJ Year creek Groupr-/. vs. Year creek Groups7 North .Azimuth Current POINT 2 1966 Clear NA 1966 -- NS 7.05* 2.27* 0.01 POINT 3 1967 Clear NALA 1966 — NS 58.86** 7.78** 9.53** — SO 24.50** 2.05 10.25** Clear NA 27.74** 5.20* 0.65 Cub NA 23.33** 9.96** 0.82 1967 Clear BA 11.11** 31.10** 2.00 ' CBA 13.32** 3.79 4.6l Arnica NA 23.47** 1.09 0.34 Hatchery .NA. 11.74** 7.79* 3.78 Cub NA 35.95** 26.74** 20.89** 1967 Hatchery NA 1966 mmm NS 7.60* 6.93* 6.35* Clear NA 5.94* 5.93* o.4o Cub NA 4.77* 9.42* 2.27 1967 Clear BA 7.54* 7.53* 3.94 CBA 4.56* 4.62* 4.47 1967 Clear BA 1966 — NS 8.53** 7.35* 2.29 — 80 6.78* 2.09 0.15 .1967 Arnica NA 9.61** 8.19** 0.32 Cub NA 4.99* 0.24 9.92** b/ *Significant at P = 0.05; **Significant at P = 0.01. Legend as for Table X. Table XII. .Mean..direc.tions (from true North), vector lengths, swimming speeds, Rayleigh tests, homestream tests and direction tests (F) for males and females at termi­ nation of tracking experiments from point 2 (1966). Origin creek Group^/ Sex Number tracked Mean direction Vector length Speeds (m/hr) Range Average Rayleigh Homestream Direction test^/ test^ test^ Pelican NA C f 2 230° 0.1132 79-199 139 _b _b 0.57$ 8- 112 0.6448 196-779 475 3.32* 5.16** Clear NA C f 5 9 0.4988 45-351 162 _b 2.49 3.51 9 13 82 0.6757 110-622 386 5.94** 8.79** Clear B C f ' 3 106 0.7271 120-968 468 _b _b ■ 0.68 9 5 173 0.2542 177-843 523 _b 1.27 Clear CB C f 2 74 0.9612 214-537 376 _b _b 0.35 9 6 118 0.2751 189-977 546 0.45 1.65 Cub NA C f 8 162 0.4873 159-760 389 1.90 3.89** 4.54 9 6 50 0.4531 86-568 265 1.23 2.71 Cub B C f 3 166 0.8486 124-402 237 _b - _b 4.98* 9 3 ' 339 o.444o 177-484 334 _b _b Cub CB C f U 93 0.3112 143-688 429 _b 1.24 0.01 9 2 103 0.7826 371-966 668 _b _b — NS C f 10 118 0.4386 251-815 608 1.92 _c 0.349 12 • 137 0.7195 357-962 567 6.21** - C — SO C f 1 139 1.0000 533 533 _b _b 0.00 9 I 69 1.0000 736 736 _b _b a/ y c/ y ^Significant at P = 0.05; ^Significant at P Sample too small for test. Does not apply. Legend as for Table IX. 0.01. rv> ON -27- A and B — east-southeast. Those observed for fish tracked .in 1967 were as follows: blind-anosmic fish from.Clear .Creek .— . .north;.controls for blind-anosmic fish from Clear Creek — east-northeast; non-anesthetized fish from Cub Creek — east; non-anesthetized fish from Arnica Creek — east-southeast; non-anesthetized fish from Hatchery Creek — south-south­ west; non-anesthetized fish from Clear Creek tracked in the late afternoon — west-northwest (Table XIII). Vector lengths (r) were significantly greater than zero for non- anesthetized and blind-anosmic fish from Clear Creek and non-spawning fish from points A and B. Non-anesthetized fish from this creek tracked from point 3 during the late afternoon oriented the best of all experimental groups. Non-anesthetized fish tracked in the late afternoon and blind-anosmic fish from Clear Creek and non-anesthetized fish from Arnica Creek were the only groups whose mean .directions differed significantly from the home- stream direction. The mean direction of non-anesthetized fish from Clear Creek tracked in the late afternoon differed significantly from the mean directions of all other groups (Table XI). These differences became non­ significant when either the sun azimuth or current direction was used as the zero direction instead of true North. However, non-spawning fish and non-anesthetized fish from Cub Creek (1967) differed significantly from non-anesthetized fish from Clear Creek tracked in late afternoon. Eight of 9 significant differences between mean directions of other groups of fish became non-significant when similarly treated (Table Xl). ‘The Table XIII. Mean directions (from true Worth), vector lengths, swimming speeds, Rayleigh tests and homestream tests at termination of"tracking experiments from point 3, 1966 and 1967. Year Origin creek Group^ Wumber tracked Mean direction Vector length Speeds (m/hr) Range Average Rayleigh test^/ Homestream test^/ 1966 Clear WA l4 63° 0.5079 98- 787 396 3.61* 7.11 Cub WA 15 71 0.4156 R51 374 2.59 6.23 — WS 24 75 0.6465 85-1484 545 10.03** _c 80 6 123 0.4881 162- 692 . 458 1.43 C 1967 Clear WALA 13 302 0.9235 136- 959 562 11.08** 12.00** BA 20 ll 0.5130 33- 718 353 5.26* 10.26** CBA .14 59 0.3162 ;213- 639 360 i.4o 4.43 Arnica WA 23 119 0.2679 48- 670 349 1.65 6.l6** Cub WA 5 ■ 96 0.6561 185- 473. 347 ■ _b 3.28 Hatchery WA 4 199 0.5049 26- 413 219 _b 2.01 a/ —' ^Significant at P = 0,05; ^Significant at P - 0,01. I/ c/ Sample too small for test. Does not apply. WA — no'n-anesthetized; NS — non-spawning; SO — spawned-out; WAlA — non-anesthetized late afternoon; BA — blind-anosmic; CBA — controls for blind-anosmic. average speed, mean direction and vector.length for.currents in. 1966 were. 402 m/hr, .25°, and. 0.686? respectively, and in 1967 were 39-8 m/hr, 319°) and 0.5464, respectively. Non-spawning and non-anesthetized fish from Clear Creek tracked .in the late afternoon had the fastest average swimming speeds of all groups tested (545 and 562 m/hr, respectively). In 1966 average, swimming speeds in m/hr for other groups .were .396 and 3?4 for. -non-anesthetized fish from Clear and Cub creeks, respectively, and 458 for spawned.-oUt.. fish. In 1967 they were 349, 34? and 219 for non-anesthetized fish from Arnica, Cub and Hatchery creeks, respectively, and 353 and 360 for blind-anosmic and con­ trol fish from Clear Creek, respectively. The mean directions of males and females were not significantly different, except for the blind-anosmic controls from Clear Creek. Males did not consistently have greater vector lengths than females (Table XIV). However, males generally had greater average - swimming speeds than females released from point 3- UNDERWATER PHOTOGRAPHS Underwater -photographs were taken to see if the images of shoreline features could be recorded photographically at the approximate depths which the fish swam when tracked from points 2 and 3- No land features were visible on pictures taken from depths of 0.5,.1.0 and 2.0 m at points 2 and 3» Clouds were visible on several of these pictures. Tops of trees were distinguishable on a few pictures taken from depths of 1.0 and 2.0 m -29- .Table XIV. Mean .directions (from true North), vector lengths, swimming speeds, Rayleigh tests, homestream tests and direction tests' (F) for males and females at termi­ nation of tracking experiments from point 3, 1966.. and 1967. Origin Year creek Groupr^ Sex Number tracked Mean■ Vector ■ direction length • Speeds (m/hr) Range Average Rayleigh Homestream Direction test--/ test^/ test^/ 1966 Clear NA C f 6 114° 0.1954-161- 766 335 0.22 1.17 I - P Q ? 7 46 ' 0.8722 99- 787 459 5.32** 6.11* -L * C-U Cub NA C f 8 87 0.8124 118- 901 397 5.28** 6.49 4.02 $ 7 3Ul ' 0.2582 .142- 518 347 0.46 1.8l — NS Cf 15 84 ' 0.7926 85-1484 586 9.42* - C 2 04 ? 8 51 0.6491 168- 782 497 3.37* - C 80 C f I 69 1.0000 692 692 -b - C 0.86 9 5 .142 0.4946 162- 670 4 n _b - C 1967 Clear NALA C f I 278 1.0000 277 277 _b _b 0.50 9 8 246 0.9376 136- 959 573 7.03** 7.50#* BA Cf 6 5 0.4607 118- 718 381 1.27 2.76 0.05 9 13 i4 0.5021 33- 713 352 3.27* 6.52* OBA Cf 2 266 0.9925. 251- 357 ,304 -b -b 13.71** 9 10 62 0.7293 213- 639 394 5.31* 7.29* Arnica NA Cf 13 'ioU 0.2730 123- 670 388 O .96 3:54** 0.77 9 9 149 i 0.4094 48- 670 287 • 1.50 3.68** Cub NA Cf 4 81 0.6532 185- 473 330 _b 2.61 0.71 9 1 137 •1.0000 415 415 _b _b Hatchery NA Cf I 154 1.OOO0 287 287 _b _b 0.62 9 3 227 0.4960 26- 413 197 _b -b ^ ^Significant at P = 0.05; "^Significant at P = 0.01. b/ sJ Sample too small for test. Does not apply. I/ Legend as for Table XIII. -30 - (20-80 m from shore). Clouds and trees were only visible on pictures taken when the lake surface was very calm. Even though these images appeared on some photographs, I had no way of knowing whether or not the fish used them for orientation. TRAINING EXPERIMENTS - An attempt was made to train fish to use a light source as a refer­ ence point for orientation. Two fish subjected to 5 trials per day for 30 consecutive days using a 100-w light bulb were not trained at the end of this time (Eig. 2). Three of 6 fish subjected to 10 trials per day for 10 consecutive days using a 300-w light bulb were trained. Two of these tested 6 hours after their normal training time showed no compensation in direction for the change in time. Three untrained fish used as controls • generally swam away from the light source. Retention of learning was shown by one fish tested 3 weeks after the last training session. -31- -32- O light source ► pos i t ion of t ra in ing box • box chosen du r ing t e s t Fig. 2. Results of training experiments using a light source as a refer­ ence point for orientation. A — untrained controls; B 3C — fish subjected to 5 trials per day, after 30 days training; D 3E 3F3G 3H 3 I — fish subjected to 10 trials per day, after 10 days training; J3K — fish tested 6 hrs after normal training time (E and H 3 respectively); L — fish H tested 3 weeks after the last training; * — significant value for normal approximation test at P = 0.05; ** — significant value for Chi-square test at P = 0.01. DISCUSSION Significantly fewer anosmic and' blind-anosmic fish homed than other groups. This could be due to the lack of olfaction or vision and ol­ faction, respectively, or to handling and the trauma of injection of material into the olfactory capsules and eyes. Only 6 of 50 anosmic and ■2 of 50 blind-anosmic fish homed after they were displaced 5.0 km. McCleave (1967) found that 7 of 50 anosmic and 25 of 50 blind fish homed. Thus the combination of olfaction and vision together rather than alone seem important to homing. Olfaction was probably more important as the fish neared the homestream but not important in open water (Easier, 1966; Brett and Groot, 1963)= No difference was noted in the percentage of homing for anesthetized (control) and non-anesthetized fish. This was also found by McCleave (ibid,). Handling during anesthetization and the anesthetic did not affect homing ability. Black and Connor (1964) found that anesthetization of rainbow trout did not change blood lactate of muscle glycogen, but Black and Barrett (1957) found that even minimal handling and transportation over a 2-hr period caused increases in muscular activity and blood lactate in cutthroat and steelhead trout. Ricker (manuscript) suggested that some straying may be an artifact due to "proving", in which a fish may ascend a "wrong" tributary some distance and then reject it. If the fish is caught in a trap on the "wrong" tributary it is recorded as a stray. "Proving" could occur on •Clear and Cub creeks since nearly all average straying times were less than homing times. This was also true for the 1966 data given by -34- McCleave (ibid.). The fact that more Cub Creek than Clear Creek fish strayed might be due to the trap being closer to the lake on Clear Creek (75 m ) than on Cub Creek (150 m). If "proving" did occur a short distance upstream from the mouths of the creeks, then higher straying by Cub Creek fish would be expected. Furthermore3 when fish were caught in the traps, they were assumed to be in the homestream. This may have been an incor­ rect assumption. Average homing times were not always directly related to the distance fish were displaced. Those released just outside the stream mouth had the shortest average homing time, but the average homing time for fish dis­ placed 22.0 km from the homestream was shorter than for those displaced 5.0 km away. It is possible that those fish displaced farthest from the homestream had more opportunity to correct "mistakes" in orientation along the return route, thus arriving in a shorter time. McCleave (ibid.) found an inverse relationship of homing time with distance for fish released in 1966, those being displaced farthest homed fastest. He suggested that displacement may cause physiological and behavioral changes resulting in delay while the trout begins a new sequence of events leading to migration and spawning. The delay could occur near the stream mouth where salmonids are known to congregate before moving upstream. Cope (1956) noted that periodic freshets of cold water cause interruptions in upstream mi­ gration of cutthroat trout. Although homing percentages were similar for fish used in group tagging experiments and after tracking, the latter had greater homing -35- times o Perhaps the fish may have become fatigued after towing the floats. R values and average swimming speeds often decreased after the first y-hr sighting was taken for fish tracked from point 2. This might be due to the fish having a shoreward orientation immediately after release, re­ sulting in termination of the experiment in a short time. Fish swimming after the first sighting may have tired towing the float. Average swimming speeds were comparable to those reported by Jahn (1966) and McCleave (ibid.). Non-spawning fish went the same general direction and had greater r values than other groups of fish. Perhaps these fish were "lost" and followed the sun azimuth, since after correction for sun azimuth the mean angles went from 131° to 358°, and 75° to 308° for those tracked from points 2 and 3, respectively. Spawning and non-spawning white bass tracked in Lake Mendota showed a strong orientation toward the northern spawning ground (Easier et al., 1965; Gardella, MS, 1967)• Mean directions of most groups of fish were not significantly differ­ ent from the homestream direction. The same was true for fish tracked by Jahn (1966). This was probably due to the locations of the release points. By swimming toward the sun they were also heading toward their home streams. Fish tracked by McCleave (1967) had similar mean directions to those of this study and to those of Jahn (ibid.) but were significantly different from the homestream direction. The release points used by McCleave were located in the northern portion of the lake. He suggested that cutthroat -36- trout have the ability to maintain a constant compass direction in the sense of dead reckoning (Type II orientation) rather than the ability to find home by true navigation involving corrective feedback (Type III orien­ tation). The influence of the sun on orientation was shown by fish from Clear Creek (located on the east side of the lake) that went west-northwest when tracked in the late afternoon and by those from Arnica Creek (located on the west side of the lake) that went east-southeast when tracked in the morning. The mean directions of many groups of fish were closer to 0° and vector length values increased when the zero direction was taken at - the sun azimuth. The same was true when current was used as the zero direction. The sun was found important to orientation of cutthroat trout tracked by Jahn (1966) and McCleave (1967). Easier et al. (1958) found that white bass were disoriented under overcast skies. Winn et al. (1964) showed that the sun was important to orientation of parrot fishes, and Groot (1965) found the sun and polarization pattern of the sky to be important in orientation of sockeye salmon. Due to the'small number of training experiments that were conducted, no relationship could be established with the field data concerning orien­ tation. LITERATURE CITED Adler5 H- E- 1963. Sensory factors in migration. Animal Behavior5 .11(4):566-577. Ball, 0. P. 1955. Some aspects of homing in cutthroat trout. Proc-. Utah Acad. Sci., Arts, Lett., 32:75-80. Barlow, J. S. 1964. Inertial navigation as.a basis for animal navi­ gation. J. Theoret. Biol., 6:76-117* Batschelet, E. 1965. Statistical methods for the analysis of problems in animal orientation and certain biological rhythms. Am. Inst. Biol* Sci. Washington, D. C. 57 P*- Benson, N. G. 1961. Limnology of Yellowstone Lake in relation to the cutthroat trout. U. S. Fish and Wildlife Ser. Res. Rpt., 56:1-33* Black, E. C., and I. Barrett. 1957* Increase in levels of lactic acid in the blood of cutthroat and steelhead trout following handling and live transportation. Canadian Fish Culturist, 20:13-24. Black, E. C . , and A. R. Conner. 1964. Effects of MS 222 on glycogen and lactate levels in rainbow trout (Salmo gairdneri). J. Fish. Res. Bd. Canada, 21(6): 1539-1542. Braemer, W. i960. A critical review of the sun-azimuth hypothesis. In: Cold Spring Harbor Symp. Quant. Biol. Biological Clocks, 25:413-427= Braemer, W., and H. 0. Schwassmann. 1963* Vom Rhythmus der Sonnenorient- ierung am Aquator (bei Fischen). •Ergebn. Biol., 26:182-201. Brett, J. R., and C. Groot. 1963. Some aspects of olfactory and visual responses in Pacific salmon. J. Fish. Res. Bd. Canada, 20(2):287-303» Clemens, W. A., R. E. Foerster, and A. L. Pritchard. 1939* The migration of Pacific salmon-in British Columbia waters. In: Migration and conservation of salmon. Publ. Am. Assoc.. Advance. Sci., 8:51-59« Collins, G. B. .1952. Factors influencing the orientation of migrating anadromous fishes, U. S. Fish. Bull., 52:375-396. (Fish, Bull. Wo. 73)* Cope, 0. B, 1956. Some migration patterns in cutthroat trout. Proc.' Utah Acad. Sci.,.Arts, Lett., 33:113-118. -38- Cope, O'. B. 1957- Races of cutthroat trout in Yellowstone Lake. In: Contributions to the study of subpopulations of fishes, U. S. Fish and Wildlife Ser. Spec. Sci. Rpt. Fisheries, 208:74-84. Donaldson, R., and G-. H. Allen. 1957- Return of silver salmon, Oncorhyn- chus kisutch- (Walbaum) to point of release. Trans. Amer. Fish. Soc., 87:13-22. Frost, W. E. 1963. The homing of char Salvelinus willughbii (Gunther) .in Windermere. Animal Behavior,- ll(l):74-82. Garde11a, E. S . MS, 1967. The study of open-water orientation of white bass,.Roccus chrysops (Rafinesque), by the use of ultrasonic tracking methods. M. Sc. Thesis. Univ. Wisconsin. 62 p. Greenwood, J. A., and D. Durand. 1955-. The distribution of length and components of the sum of n random unit vectors. Ann. Math. Statis., 26:233-246. Groot, C. 1965. On the orientation of young sockeye salmon (Oncorhynchus nerka) during their seaward migration out of lakes. Behavior, Suppl. 14. '198 p . „ Hartman, W. L., and R..F. Raleigh. 1964. Tributary homing of sockeye salmon at Brooks and Karluk Lakes, Alaska. J. Fish. Res. Bd. Canada, 21(3)’.485-504. Easier,.A. D. .1966. Underwater guideposts: homing of salmon. Univ. Wise. Press, Madison, Milwaukee, and London. 155 P- Hasler, A. D., H. F. Henderson, R. M. Horrall, and E. 8. Gardella. 1965- Orientation of homing white bass. Am. 'Zopl..j 5(4):383- (Abstract only.) Easier, A. D=, R„ M. Horrall, W. J. Wisby, and W. Braemer. 1958. Sun- orientation and homing in fishes. Limnol. Oceanogr.,- 3(4):353-36l. Easier, A. D=, and H= 0. Schwassmann= i960. Sun orientation of fish at different latitudes. Cold Spring Harbor Symp. Quant = Biol= Bio­ logical Clocks., 25:429-441. Hasldr, A. D=, and W= J. Wisby. 1951° Discrimination of stream odors by fishes and its relation to parent stream behavior. Am. Naturalist, 85:223-238. Helle3 J. H. .1966. Behavior of displaced adult pink salmon. Trans. Am. Fish. Soc.5 95(2):188-195. ' Henderson, H. F. .1963. Orientation of pelagic fishes. (l), Optical prob­ lems (ll) Sonic tracking. Ph..D. Thesis. U. Wise. 135 p„ , Jahn, L..A. 1966. Open-water movements of the cutthroat trout (Salmo clarki) in Yellowstone Lake after displacement from spawning streams. J. Fish. Res. Bd. Canada, 23(10):l475-l485. Jones, J. W. 1959- The salmon. Harper and Bros. New York. 192 p. Lindsey, C. C., T. G. Northcote,.and G. F. Hartman. 1959° Homing of rain' bow trout to inlet and outlet spawning streams at Loon.Lake, British Columbia. J. Fish. Res. Bd. Canada, 16(5):695-719° McCleave, J. D. 1967. Homing and orientation of cutthroat trout (Salmo clarki) in Yellowstone Lake, with special reference to olfaction and vision. J. Fish. Res. Bd. Canada,.24(10):2011-2044. McCleave, J. D., L . A . Jahn, and C. J. D. Brown. 1967° Miniature alligator clips as fish tags. Prog. Fish-Cult.,•29(1):60-6l. Patten, B. C. 1964. The rational decision process in salmon migration. J. Cons. int. Explor. Mer, 28(3) :4lO-4l7. Platts, W. 8. 1959. Homing, movements, and mortality of wild cutthroat trout (Salmo clarki Richardson) spawned artificially. Prog. Fish- Cult., 2l(l);36-38. Powers, E. B. 1939° Chemical factors affecting the migratory movements of the Pacific salmon. Amer. Assoc..Advance. Sci., Publ. No. 8, p. 72-85. -39- Powers, E. B.,, and R. T. Clark. 1943. Further evidence on chemical factors affecting the migratory movements of fishes, especially the salmon. Ecology, 24:109-113. Saila, 8. B., and R. A. Shappy. 1963. Random movement and orientation in salmon migration. J. Cons, intv Explor. Mer, 28(l):153-166. Schwassmann, H. 0. i960. Environmental cues in the,-orientation rhythm of fish. Cold Spring Harbor" Symp., 25:443-450. Schwassmann, H. O., and A. D. Hasler. 1964. The role of the sun's alti­ tude in sun orientation of fish. Physiol. Zool., 37(2) :l63-178. MONTANA STATE UNIVERSITY - BOZEMAN