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UBC Theses and Dissertations

Comparative feeding habits of the fur seal (Callorhinus ursinus), sea lion (Eumetopias jubata) and harbour… Spalding, David Joseph Reede 1963

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COMPARATIVE FUR (EUMETOPIAS  SEAL  FEEDING HABITS  (CALLORHINUS  J U B A T A ) AND ON  THE  OF  THE  U R S I M J S ) , SEA  HARBOUR  SEAL  B R I T I S H COLUMBIA  LION  (PHOCA  VITULINA)  COAST  by  DAVID  JOSEPH  B. A . , U n i v e r s i t y  A  of B r i t i s h  T H E S I S SUBMITTED THE  SPALDING 19£6  IN PARTIAL FULFILMENT  R E Q U I R E M E N T S FOR MASTER  in  Columbia,  OF  THE DEGREE  OF  OF  ARTS  the Department of ZOOLOGY  We a c c e p t t h i s t h e s i s required standard  THE  UNIVERSITY  as c o n f o r m i n g  t o the  OF B R I T I S H COLUMBIA  April,  1963.  In presenting the  this thesis i n p a r t i a l fulfilment of  r e q u i r e m e n t s f o r an a d v a n c e d d e g r e e a t t h e U n i v e r s i t y o f  ' B r i t i s h Columbia, I agree that  t h e L i b r a r y s h a l l make i t f r e e l y  a v a i l a b l e f o r r e f e r e n c e and s t u d y . mission f o r extensive  I f u r t h e r agree that  per-  copying of t h i s thesis f o r s c h o l a r l y  p u r p o s e s may be g r a n t e d by t h e Head o f my D e p a r t m e n t o r b y his  representatives,.  I t i s understood that  cation of t h i s thesis f o r f i n a n c i a l gain w i t h o u t my w r i t t e n  Department o f  < ; 7  permission.  ^^^C5^'^  The U n i v e r s i t y of. B r i t i s h Columbia,. V a n c o u v e r 8, Canada. Date  ^hfa*  /  ^3  copying, or p u b l i -  s h a l l n o t be a l l o w e d  -  i i -  ABSTRACT  Feeding sea  lions  have  (Eumetopias  been  tions  habits  examined  were  made  out  and  object  assessing valuable  stomachs,  2,113  were was  tively teeth sea 6$  longer  lions, of  and  harbour  All  samples  were  grouped  and  comparative  habits made  on  the  harem  bulls;  ulation  fasts  for  seals June. the  on  the  There  three  lions  and  equivalent  a  Skeena i s no  per as  eat  an  the  lion  with  to  season  evidence for  majority days  evidence  harbour  seals  on  of  each year  the  area  the  during  to  fast  sea  annual  British eat  an  fur  rela-  permanent fur  equal to  lion  at  seals, to  11$.  collection  seal  The was feeding  observations rookery  part  competition  estimated salmon  pop-  harbour  least  Columbia  commercial  tract  habits  pupping; for  seal  discussed.  regarding  of  2$ of  feeding  interspecific  the  of  were  of  com-  stomachs  i n the  food  conflicting  only,  appear  and  upon  of  range  habits  period  except  a  upon  digestive  found  amount  day  feeding  River  of  sea  the  harbour  indicate that  studied  1.6$  126  data  species  to  of  393 of  predation  Published  the few  and  Collec-  with  eruption  is little  on  total  vitulina)  A l l pertinent  combined  pinniped A  coast.-  late  reproductive  rookeries  been  (Phoca  and  seasonal  there  of  shore.  d i f f e r e n c e s were  seals  weight  examined:  from have  seals  Columbia  anatomy  digestive tract lion.  (Callhorinus ursinus),  harbour  stomachs  notable  sea  the  data  seal  body  of  miles  stocks.  their  effect  and  effect  fish  seals  British  Comparative  and  i n the  35  the  fur  available. examined  to  the  unpublished  mercially  fur  jubata)  along  published of  of  coast.  of  between Sea  amount catch  and  2.7% level  of  the  annual  i s believed  tion  of  existing  from  waters  assessment offshore  commercial to  salmon  greater of  fur  be  than  seal  collections  herring  of  negligible  and  herring  35  miles  predation  should  be  upon  Predation  importance  stocks.  from  made.  catch.  shore ocean  in  the  at  reduc-  Insufficient precludes salmon.  this  data  an Further  -  x i i -  ACKNOWLEDGEMENTS  The  assistance  and e n c o u r a g e m e n t  o f D r . I . MoT.  Head, D e p a r t m e n t  of Zoology,  over  y e a r s n e c e s s a r y t o complete  the several  gratefully the  acknowledged.  Fisheries  Research  The U n i v e r s i t y  D r . A.  Board's  W.  a l l data  my  t o h i m and t h e F i s h e r i e s  for  thanks their  Mr.  British R.  following  assessing herring  Columbia;  the effect  f o rthis  Messrs.  T.  Mr.  D. B e r v e n  and  M r . D.  Mr.  I . B. M a c A s k i e , Velsen  eries  Board  of  h a s made  I wish  t o extend  o f Canada  P. S h e p a r d  Mr. R.  and  i n Nanaimo.  predation  upon  and s e a l i o n s dangerous.  salmon  The  and  Kelly  o f t h e " T . W. D.  a n d W.  i s difficult,  The c o o p e r a t i o n  t h e number and crew  B o r o e v i c h and crew  of  specimens  of the "Pacific  of the " S t . Joseph";  Islander";  M r . W.  McNaughton  o f Pender  Mr. T. B i n n e r s l e y ,  of the Biological  has cooperated  of the U n i v e r s i t y  M r . G. C. P i k e ,  Station  below has increased  Messrs.  D r . N. J .  acknowledged.  of seals  a n d A.  form  a n d D r . F . H. C. T a y l o r i n  of pinniped  study:  i n draft  S. H o a r ,  Chitty  Mr. F . C. W i t h l e r ,  and crew  Secord;  thesis  D r . W.  a n d D r . D.  and o c c a s i o n a l l y  mentioned  available  F.  study;  this  suggestions:  collecting  unpleasant  Ocean";  read  stocks i s gratefully  those  i n Nanaimo,  Research  of the B i o l o g i c a l  o f D r . M.  The often  have  Dr. J . Bendell  LeBrasseur  assistance  of  necessary f o r this  made m a n y h e l p f u l  Wilimovsky, of  thesis i s  cooperation. The  and  this  Columbia,  H. N e e d i e r , D i r e c t o r  Station  available  of B r i t i s h  Cowan,  Station.  i n the c o l l e c t i o n  M r . W.  Secord Harbour;  P i n c k a r d and Mr.  The Department o f specimens  of F i s h whenever  - xiii  -  possible. I a l s o w i s h t o e x t e n d my h i s e x c e l l e n t photographs, drawings.  and  t h a n k s t o Mr.  t o Mr.  MacAskie  C.  Morley f o r  for his  skull  -  iv -  T A B L E ' OP C ONTENTS Page Abstract  i i  List  of F i g u r e s  List  of Tables  viii x  Acknowledgements  x i i  INTRODUCTION HISTORY A.  OF  1  P I N N I P E D FOOD H A B I T  Feeding coastal  habits waters  of seals  Feeding  habits  of seals  B.  STUDIES outside  1 British  Columbia's 2  i n British  Columbia  waters 1.  Fur seals  2.  Sea l i o n s  3.  Harbour  METHODS AND A.  .'  6  .  7  seals  7  MATERIALS  8  Specimen  collection  8  1.  Fur seals  8  2.  Sea l i o n s  9  3. B.  C.  6  Harbour Analysis  seals of stomach  .. contents  of f u l l n e s s  13 ll).  1.  Degree  15  2.  Numbers  3.  Dominant  if.  Points  15  5.  Volume and w e i g h t s  15  6.  Number  l6  of i n d i v i d u a l s items  15  of occurrences  I d e n t i f i c a t i o n of stomach  DISTRIBUTION,  15  NUMBERS AND  contents  MIGRATORY B E H A V I O U R  22 23  -  v Page  A.  General  habitat  description  23  1.  Fur seals  2k  2.  Sea l i o n s  25  3.  Harbour  26  COMPARATIVE A.  seals  ANATOMY  28  Dentition  .  28  1.  Sea l i o n s  2.  Fur seals  31  3.  Harbour  seals  31  Digestive  tract  32  B.  •.  FEEDING HABITS A.  35  Comparative 1.  2.  Capture  feeding  behaviour  35  of prey  35  (a)  Fur seals  35  (b)  Sea l i o n s  36  (c)  Harbour  36  Feeding  seals  i n relation  B.  Daily  C.  Comparison  D.  Unusual  E.  Comparative 1.  28  food  t o hours  after  consumption of food  stomach  items  Winter-spring  ...  37 38  eaten  feeding  38 1+6  contents  seasonal  sunrise  habits  l+Q 52  (a)  January  52  (b)  February  52  (c)  March  53  (d)  April  53  (e)  May  Sk  -  v i -  Page 2.  55  Summer (a)  Fur seals  55  (b)  Sea l i o n s  5£  (c)  Harbour  56  3.  seals  Fall  F.  56  (a)  Sea l i o n s  56  (b)  Harbour  57  seals  Predator-prey  size  relationships  1.  Interspecific differences  2.  Intraspecific differences  G.  Feeding  habits  58 58  ( f u r seals)  59  and r e p r o d u c t i o n  63  1.  Fur seals  63  2.  Sea l i o n s  61+  3.  Harbour  I}..  Fasting  H.  seals  67 68  I n t e r s p e c i f i c competition  EFFECT  OF S E A L  COLUMBIA'S A.  AND  SEA LION  70  P R E D A T I O N UPON  BRITISH  COMMERCIAL F I S H E R Y  TU-  Fur seals  75  1.  Herring  75  2.  Salmon  3.  Trawl  B.  ,  76  fishery  78  :  Sea l i o n s  80  1.  Herring  80  2.  Salmon  8l  3.  Halibut'  85  1^.  Availability  of f i s h  around, sea l i o n  rocks  ...  85  -  v i i Page  C.  Harbour  seals  87  1.  Herring  87  2.  Salmon  87  CONCLUSIONS A.  89  Effect upon  LITERATURE APPENDIX  1  of f u r seals,  sea l i o n s  commercially  valuable  CITED  . .. .  fish  and h a r b o u r  seals 89 93 100  -  LIST  viii  OP  -  FIGURES Page  Figure  1.  M. V . " P a c i f i c for collecting and s e a l i o n s  Ocean", used e x t e n s i v e l y f u r seals, harbour seals  lions,  Figure  2.  Collecting  Figure  3.  A n a l y s i s of stomach contents. Top: examples from s k e l e t o n c o l l e c t i o n Bottom: w e i g h i n g f u r s e a l stomach c o n t e n t s . .  12  Comparison between a p e r cent by occurrence a n a l y s i s and a p e r c e n t by v o l u m e a n a l y s i s o f c o n t e n t s f r o m 869 f u r s e a l s t o m a c h s (19581961 data)  18 19  Figure  ij..  Figure  6.  Top: 3-1+-month-old f e m a l e s e a l i o n skull Bottom: 15-month-old female sea l i o n skull (b - d e c i d u o u s t e e t h )  Figure  Figure  Figure  Figure  Figure  Figure  Figure  8.  9«  10.  IL  12.  13.  ll]..  15.  in fur  seal  1959'•••  Small  Figure  found  Islands,  5»  7.  cod  Scott  Figure  Figure  black  sea  10  stomach....  L o w e r jaw f r o m 9-month-old f e m a l e sea l i o n , showing permanent canines Center: Young female harbour s e a l s k u l l Bottom: 9-month-old female f u r s e a l s k u l l . . .  H  29  Top:  Fur seal sunrise  stomach volumes  hours  after LpO  Pe c e n t empty s t o m a c h s sunrise (fur seals) r  Mean.stomach" volume hours a f t e r sunrise  and  30  of  and  hours  after 1+1  269  sea  lions,  and 1+2  P e r c e n t empty s t o m a c h s and h o u r s a f t e r s u n r i s e i n a s a m p l e o f 269 sea l i o n stomachs.  1+3  Mean in a  1+1+  s t o m a c h v o l u m e s and h o u r s a f t e r s a m p l e o f 50 h a r b o u r s e a l s  Stomach contents of f u r s e a l s , harbour seals, c o l l e c t e d along of B r i t i s h Columbia C o l l e c t i n g a r e a s on t h e c o a s t (Area IV i n c l u d e s i n l e t s and c h a n n e l s )  sea the  sunrise  lions, coast 1+5  B r i t i s h Columbia a l l protected  A n a l y s i s o f 699 f u r s e a l stomachs c o n t a i n i n g food, showing s e l e c t i v e food preferences a c c o r d i n g t o age  1+9  60  -  F i g u r e 16.  F i g u r e 17.  F i g u r e 18.  F i g u r e 19.  ix  -  Page  Triangle Island. Top: Harbour s e a l h a b i t a t behind b r e a k e r s . Sea l i o n r o c k i n f a r r i g h t b a c k g r o u n d B o t t o m : Sea l i o n r o c k w i t h T r i a n g l e I s l a n d i n background 1  73  Per cent f r e q u e n c y of o c c u r r e n c e of h e r r i n g i n f u r s e a l stomachs o f f s o u t h e r n Vancouver I s l a n d and m i l e s o f h e r r i n g spawn i n B a r k l e y and C l a y o q u o t Sounds (139 s t o m a c h s )  77  Trawl f i s h e r y catch s t a t i s t i c s f o r I96l (White Rocks f i s h i n g g r o u n d s ) , f u r s e a l stomach c o n t e n t s c o l l e c t e d this vicinity  79  1959and from  S a l m o n c a t c h e s ( a l l s p e c i e s ) and t h e d e c r e a s i n g sea l i o n p o p u l a t i o n i n f i s h e r i e s a r e a 12, f r o m 19Bk t o 1961  8I4.  -  X  -  L I S T OP TABLES Table I .  Page  Monthly c o l l e c t i o n dates f o r a l l a v a i l a b l e h a r b o u r . s e a l , f u r s e a l and sea l i o n stomachs  Ik  Table I I .  Coastal habitats  2l|  Table  R a t i o of whole i n t e s t i n e l e n g t h t o body l e n g t h o f f u r s e a l s , sea l i o n s and h a r b o u r seals. Mean l e n g t h s and r a t i o s o f means a r e shown a t t h e b o t t o m o f e a c h r e s p e c t i v e column. Data from animals greater than one y e a r o f age  33  Maximum numbers o f c e r t a i n f o o d i t e m s found i n i n d i v i d u a l stomachs of f u r s e a l s , sea l i o n s and h a r b o u r s e a l s  3&  D a i l y f o o d c o n s u m p t i o n o f p i n n i p e d s as r e p o r t e d i n t h e l i t e r a t u r e , p l u s t h e maximum w e i g h t s o f s t o m a c h c o n t e n t s f r o m i n d i v i d u a l animals c o l l e c t e d i n the f i e l d . .  39  P u r s e a l s t o m a c h c o n t e n t s by m o n t h and area. S o u r c e o f d a t a as i n T a b l e 1  50  H a r b o u r s e a l and s e a l i o n s t o m a c h c o n t e n t s b y m o n t h and a r e a . S o u r c e o f d a t a as i n Table I  51  C o m p a r i s o n o f l a r g e and s m a l l f o o d i t e m s e a t e n by f u r s e a l s and s e a l i o n s . Freq u e n c y e x p r e s s e d as a p e r c e n t a g e o f t o t a l o c c u r r e n c e s of a l l food items f r o m Table vi  6i  A n a l y s i s o f 699 f u r s e a l s t o m a c h s c o n t a i n i n g food showing s e l e c t i v e f e e d i n g b e h a v i o u r a c c o r d i n g to age. (Data from present i n v e s t i g a t i o n only.)  62  C h a n g i n g r a t i o of stomachs w i t h f o o d t o empty s t o m a c h s t h r o u g h o u t t h e p u p p i n g and b r e e d i n g s e a s o n i n 228 m a l e and f e m a l e s e a l i o n stomachs. Pups n o t i n c l u d e d . (Data from present i n v e s t i g a t i o n o n l y . )  65  C o n t e n t s o f 23 s e a l i o n s t o m a c h s f r o m • B a r k l e y Sound: 1I4. c o l l e c t e d i n D e c e m b e r , 1915 (Newcombe e_t a l . , 1918); n i n e c o l l e c t e d d u r i n g the present i n v e s t i g a t i o n . . .  8l  C o n t e n t s f r o m 52 sea l i o n s t o m a c h s f r o m t h e S c o t t I s l a n d s and a d j a c e n t w a t e r s . (Data from p r e s e n t i n v e s t i g a t i o n o n l y . ) . . .  83  Table  III.  IV.  Table V.  Table V I . Table V I I .  T a b l e VLTT.  Table  IX.  Table X .  Table X I .  Table X I I .  and p i n n i p e d d i s t r i b u t i o n .  - xiPage Appendix Table  Appendix Table  I.  II.  S c i e n t i f i c and common names o f f o o d items mentioned i n t e x t  101+  P i n n i p e d stomach c o n t e n t s f r o m c o l l e c t i o n s made i n N o r t h A m e r i c a n w a t e r s and t h e W e s t e r n P a c i f i c ...  110  INTRODUCTION  The order  PInnipedia  fisheries On  the  and  whose  and  hand  may  naturalists  "extinction" Three the  to  seal  coastal  waters  pinnipeds,  where  attempt  these  three  pinnipeds  herring  by  the  sea  to  sea  lions  and  of  the  inshore  populations.  stringent controls, a l l pinnipeds  "The  only  good  favourite expression. lovers  of  the  vigorously  synonomous latter  northern  fur  are  found  fishing the  carried  The  harbour  oppose "slaughter"  and  to  amount  out.  This  habits  the  of  s e a l s has  the  Columbia's  feeding  reference  diet.  the  (Callorhinus  jubata),  seasonal  On  with  in British is  seal  group.  seal  (Eumetopias  particular  their  lion  catches.  i s often  describe  in  sea  advocate  seal  lion  with  species  eaten  and  commercial  i s an  fish  is a  vitulina),  study  valuable  fish  some m e m b e r s  (Phoca  or  whenever  e r a d i c a t i o n , of  Control  northern  harbour  in  affect  s e v e r a l members  arguments  fishermen  i s a.^deadrone"  many  of  seal  complete  c o n t r o l measures.  ursinus),  near  commercial  depredations  other  heated  out  instances  lion)  activities  provoke  carried  hand  some  sea  such  are  one  in  (or  predatory  commercially  salmon  been  of  and  estimated  Appendix•1.  HISTORY  An feeding  OP  P I N N I P E D FOOD H A B I T  extensive  habits,  much  body  of  It  valuable  includes  major p i n n i p e d  waters  of  fish  western Europe,  literature  about  commercially the  of  the  species. food  STUDIES  deals  problem The  habit  North America  of  with  predation  following  studies and  pinniped  summary  carried  Japan.  upon  out  Food  in items  - 2 -  have  been  common sake  of consistency  food  Table  items  Feeding waters  western  in  I includes  habits  prised Dutch both in  more  outside  or by  reviewed. used  both  For  i n this  a n d common  waters.  Rae  the B r i t i s h  names  the  study.  of a l l  annual  items  Pacific  coasts  and  i n the western  This  table  pite  the large  collections  have  caught  seals  valuable  (Phoca  seal  of f i s h  that  fishermen century.  fish  com-  vitulina) i n a c t i v i t y of  (Halichoerus these  grypus)  two s p e c i e s  equivalent  to one-fifth the  inshore  o r home  waters.  eaten  by pinnipeds  on b o t h  the Atlantic  Pacific,  (excluding B r i t i s h  a r e summarized  t h e wide of food  range  items,  on a r e l a t i v e l y  i nAppendix  o f foods however,  made u n d e r  and w e s t e r n t h e terms  Columbia), Table I I .  available. each  few items  (Callorhinus ursinus)  the eastern  been  by  from  f u r seal  i nboth  commercially  of North America  concentrates  on t h e Norwegian  catch  number  extensively  and K r i p o w i t s c h  seals  were  Soastal  carried out  of the twentieth  He c o n c l u d e d  illustrates  The  Hjort  that  than  of harbour  an amount  and  salmon  that  studies  Isles.  and t h e grey  Isles.  British  "Food  the major  Columbia's  (i960) e x a m i n e d t h e p r e d a t o r y  seal  consumed  British  the early part  75% o f t h e f o o d  usually  names,  been  (1907) c o n c l u d e d  during  the harbour  total  scientific  and t h e B r i t i s h  (1933) e s t i m a t e d  annually  names h a v e  of seals  destroying  area,  Havinga  common  i n the studies  (i960) s u m m a r i z e d  Europe  were  that  names  common  (1907) a n d W o l l e b a e k coast  by t h e i r  referredt o .  Rae in  either  and s c i e n t i f i c  Appendix  A.  described  Des-  pinniped  i n any given  has been Pacific.  area.  studied Most  o f two i n t e r n a t i o n a l  programs of i n v e s t i g a t i o n :  (a) I n 1952  a one-year program  u n d e r t a k e n by Japan, the U n i t e d S t a t e s and  Canada t o study  the  d i s t r i b u t i o n , m i g r a t i o n and food h a b i t s of the f u r s e a l . I n 1957  r e p r e s e n t a t i v e s from R u s s i a , Japan, the U n i t e d  and Canada s i g n e d  y e a r s , was  (b)  States  an " i n t e r i m C o n v e n t i o n on C o n s e r v a t i o n  N o r t h P a c i f i c Pur S e a l s " .  This convention,  was  of the  effective for six  d e s i g n e d t o i n v e s t i g a t e the numbers, m i g r a t i o n  and w i n t e r i n g areas of the s e a l s , t h e i r f e e d i n g  routes  habits.and  e f f e c t s upon commercial f i s h , s t o c k s and f i s h i n g gear. Before  1952,  f u r s e a l c o l l e c t i o n s i n the w e s t e r n P a c i -  f i c c o n s i s t e d of 6 l stomachs ( T a y l o r et a l , . , 1955).  During  1952,  under terms of the f i r s t i n t e r n a t i o n a l i n v e s t i g a t i o n , 1,138 stomachs w i t h food were examined from Japanese w a t e r s . f i s h and  s q u i d c o n t r i b u t e d 87$ by volume t o these  ( T a y l o r e_t  aJL.,  1955)-  d a t i o n upon salmon was  contents  These a u t h o r s concluded t h a t s e a l p r e of o c c a s i o n a l and  but t h a t f u r t h e r s t u d i e s should be 1958  Lantern  l o c a l s i g n i f i c a n c e only,  c a r r i e d out.  Studies  since  (Anon., I 9 6 l ) i n d i c a t e t h a t o f f S a n r i k u and Honshu l a n t e r n  f i s h and (3*3l+7  s q u i d c o n t r i b u t e d from 70 t o 90$ by volume  stomachs examined).  from the Sea  of Japan and  Three hundred and the Okhotsk Sea  food.  annually  seventy-tiro stomachs  indicated that whiting  was  the most i m p o r t a n t  I n the w e s t e r n B e r i n g Sea. s q u i d  and  salmonids formed 75$ by volume of the contents  Salmon c o n t r i b u t e d \\.2% by volume t o the c o n t e n t s  of 33 stomachs.  of 17 stomachs  from the salmon f i s h i n g , grounds of the northwest P a c i f i c .  No  c o n c l u s i o n s have as y e t been drawn i n the p r e s e n t i n t e r n a t i o n a l i n v e s t i g a t i o n about the e f f e c t of f u r s e a l s upon Japanese Russian  fisheries.  and  -k In  the eastern  Pacific,  (1892) a n d L u c a s  Alexander  (1899) e x a m i n e d 1I4.O f u r s e a l s t o m a c h s f r o m t h e G u l f o f A l a s k a and  Bering  most and  Sea.  important Bonham  Washington most  food  coast  food  from  fornia  125  stomachs. volume  drawn of  formed  seals  California comprise In  machs. and  that the  were  seal  commercial  that  whiting from 90$  over  No c o n c l u s i o n s thepossible  years  were  effect  o f t h e second  the British  1961): saury,  seals squid  of the contents  examined.  food  items  Piscus  of California,  and hake, each  herring,  (1961)  a serious  Oregon  off  which year.  i n sto-  anchovy  c o n t r i b u t i n g 67$  e_t a _ l .  n o t be c o n s i d e r e d  wintering  predominate  indicated that  (1957)  Columbia  examined  and r o c k f i s h  the important  fisheries  about  four  on anchovy,  could  Cali-  o f the contents  stomachs.  (Anon.,  sample  hake,  c a p e l i n formed  excluding  hake  from  fisheries.  the f i r s t  anchovy,  t o the contents  the fur  two  o f llj.8  1955):  anchovy,  b y volume  Pacific  8 0 a n d 90$  The Washington  rockfish  volume  from  mainly  Oregon waters  smelts,  of ll6  as f o l l o w s  between  the  (1951+) f o u n d  of the contents  of Alaska  investigation,  feed  and h e r r i n g were  et a l . ,  investigation  on e a s t e r n  c o l l e c t i o n s , were  (1936), May (1937)  Alaska.  (Taylor  70$  nearly  t h e 1952  international  were t h e  100 s t o m a c h s f r o m t h e  and Kenyon  Inlet,  clupeids,  I n the Gulf  Results  of  h y volume  the following  of the contents  during  fur  99$  and R a f n  squid  Wilke  and r o c k f i s h  (1952) i n t e r n a t i o n a l p r o g r a m i n t h e e a s t e r n  t o Washington  rockfish  that  Crawfish  first  found  and  by  whiting  Schultz  items.  over  West  The Pacific  items.  and found  comprised  stomachs  salmon,  (19^1) e x a m i n e d a t o t a l  important  herring  Squid,  by  stated  threat to  and Washington.  - 5In  Alaska  the  important  the  total  that  fur  Alaskan  food  waters  (Eumetopias  and have  examined.  (I90i|)and  and  Oregon,- f o u n d  Niggol  the  most  important  valuable  (1918), r e p o r t i n g c a l i f ornianus)  skate,  o ft h e i d e n t i f i e d  a t t h e mouth  concluded fish i n  importance.  Starks  squid,  and sandlance a r e  (i960)  e_t aJL.  commercially  and Zalophus that  whiting  c o n t r i b u t e d 93$ ° y v o l u m e t o  was o f - n e g l i g i b l e  .juhata  salmon  capelin,  p r e d a t i o n upon  Smith  upon  items  contents seal  herring,  shark  from  Sea l i o n  River  "  California  and r o c k f i s h  foods.  of t h e Columbia  on sea l i o n s  were  predation  caused  "much  damage". Iml.er (Eumetopias flatfish and  j_uba_ta)  sandlance  Chernabura  (1962) f o u n d  Mathisen  of  food  i n a sample  Templeman  smelts,  cods' a n d f l a t f i s h e s  e_t a _ l .  seal  In Washington  State  large  o f salmon,  amounts  individual  Squid,  fishermen  octopus,  w h i t i n g and Thorsteinson  r o c k f i s h and  collected  octopus,  items.  c o d and f l a t f i s h ,  i n harbour  examined.'  Salmon  on the A t l a n t i c  1955)«  observed  squid,  Salmon,  along  the Alaska  et a _ l . (1962) e x a m i n e d I l k s e a l i o n s  seals  onh e r r i n g ,  the contents  Alaska.  I n $6 s t o m a c h s  important  Harbour  from  that  Island, -Alaska.  t h e most  mainly  stomachs  predominated  peninsula.  (19J4.7) e x a m i n e d 15 n o r t h e r n s e a l i o n  80$ o f t h e c o n t e n t s  comprised  Lensink  were  and S a r b e r  gr9enlings and smelts occurred  coast  were  the food  stomachs  the harbour  from  seal  (Scheffer,  1928;  most  Newfoundland  i s not believed  b u t may o f t e n c a u s e  and  clupeids,  items  feed  59$ b y v o l u m e  (Fisher  (1957) r e p o r t e d t h a t  once.  o f Canada  which, f o r m e d  o f 201 s t o m a c h s  from  Mackenzie, salmonids,  often and L a b r a d o r . t o consume  financial  loss t o  S c h e f f e r and S p e r r y ,  1931;  - 6 Scheffer and  sculpins  stomachs. eulachon chon,  estimated  of  that  B.  area's  Feeding habits 1.  examined  the  seal  i n 1933  and W i l b y , role  dian  Pacific  diet  coast.  of seals  period.  numbers  Columbia  i n the Copper  equivalent salmon  these  River  eula-  and S a r b e r , authors  estuary  t o two t o t h r e e  des-  p e r cent  catch.  stomachs  from B r i t i s h  Columbia  Columbia  waters  waters  (1952)  studies  stomachs  also  1935  examined.  seals,  A l t h o u g h Canada  (1957)  n o t made  international  These  during  requirements  of  of investigation waters. Canada  knowing  i n British  of each  seal.  from  was a member  investigation  authors  the entire  stomachs  i n Canadian  formed  important i n  they remained  no f u r s e a l  program  herring  the importance  how l o n g  food  a n d 1958  international were  stressed  to assess  o f f the Cana-  examined,  Island.  first  Clemens,  attempted  s a m p l i n g was r e q u i r e d  They  were  1933;  of the ocean  o f fsouthern Vancouver  and t h e d a i l y  collections  second  early  I n t h e 193  Columbia  and Wilby,  i n t h e economy  of migrating  were  (Clemens  These  further  Between  the  salmon  on  salmon,  (Imler  o f t h e c o n t e n t s a n d was o b v i o u s l y  migratory  above,  o n damaged  i nBritish  1936).  that  first  and on h e r r i n g ,  of seals  a n d 1935  suggested  the  seals  annual  of f u r seals  8L$ b y v o l u m e the  95  F u r seals Pur  Hart  area  made  o f salmon  total  flatfish  extensively  i n southeast Alaska  observations  a n amount  i nAlaska feeds  River  harbour  cods,  hy occurrence o f the contents from  and f l a t f i s h  that  Crustaceans, herring,  seal  i n t h e Copper  Prom  troyed  65$  formed  The harbour  cods  19^-7).  19I4J+).  and S l i p p ,  of  British the  mentioned During agreed t o  collect Pacific.  Collecting  1958 t o 196l>  from  Columbia  four  will  years,  2.  were  I norder  to f u l f i l l have  years  British  Canada's  been  or Alaskan  fishermen  many  viewed. Sound,  sea lions,  quota  collected  waters.  during  Collections  when  biology  stomachs  have  an investigation  stomachs  program,  collected  collected  tentatively  n o tp l a y  o f Canada  as important  few stomachs  were  exam-  officials  research  were  evidently was d o n e  on the  and s e v e n t y - f o u r  Pike  (1958)*  the early part  o ft h i s  that  a role  between  by the Fish-  information  hundred  inter-  and i n B a r k l e y  was i n i t i a t e d  1956.  since  during  Inlet  numbers,  t o gather Three  concluded  (Newcombe  of Rivers  Little  during  1915  i nlarge  industry.  Columbia  during  and a g a i n  company  t h e mouth  ofsealions.  been  i nB r i t i s h  Although  when p r e s e n t  merles R e s e a r c h B o a r d general  1913)  and f i s h i n g  thef i s h i n g  a n d 1956,  studied  1915)•  I n two a r e a s ,  affected  first  a n d Newcombe,  ined  often  the four  1963* a t l e a s t .  until  and P r a s e r ,  did  i n 1958 a n d d u r i n g  i nWashington  lions  (Newcombe  8l  i nthe northeast  1*520 s t o m a c h s w e r e e x a m i n e d f r o m  Greenwood  on  year  Sea l i o n s Sea  I9l6  each  a n a d d i t i o n a l 500 s e a l s  be continued  1913  began  c o a s t a l waters.  commitments the  $00 a n d 7 5 ° s e a l s  between  commercially  I nthe seal i o n  reporting latter  valuable diet  fishes  a s was  claimed. 3.  Harbour Fisher  seals (1952) w a s t h e f i r s t  history  of t h eharbour  habits,  particularly  placed  on ther o l e  seal,  i t s  i n t h e Skeena  o fsalmon  t o investigate the l i f e  distribution, River  i n thed i e t .  area.  numbers  and food  E m p h a s i s was  Herring,  s a l m o n and  - 8 rockfish stomachs. species sented  68$  contributed Monetary  which  losses  suffered  approximately ;  realized  harbour  seal  from  most  damaged  a sample  h i s study  predation  upon  Skeena  officials  undertook a control  River. and  when  191+9 b y c o n t r o l  have  been  collected  Investigation  stomachs  were  officials. since  of the F i s h e r i e s  Specimen 1.  1958  f u r seal  25  ward  coast.  of Fisheries  out during  June  p u p p i n g on t h e Skeena during  June  additional  I joined  o f 191+8 stomachs  the Marine  Mammal  MATERIALS  of seal between  Canadian research  than were  i n British  latitude  Flattery  miles  collected  Large  from  collected  t o 55°00'N  inclusive. the B r i t i s h  pelagically,  while  w a t e r s , o r on t h e i r  grounds  centered  concentrations. Cape  35  Columbia  t o the breeding commitments  1+8°00'N  vessels  of January t o June,  more  Specimens  wintering  Quota  lected  some  Research Board.  between  t h e months  collected  migration  areas  t o 196l  stomachs  during were  Columbia either  were  that  Fur seal  latitude Only  Although  collection  From 1,520  carried  examined  when  of the  salmon warranted  Fifty-four  1958,  repre-  he c o n c l u d e d  the Department  program  METHODS AND A.  River  the harbour seals  Forty-five  value  fishermen.  was n o t e x h a u s t i v e ,  On h i s r e c o m m e n d a t i o n s  each year  attack,  of the t o t a l  of five  o f 27  c h i n o o k salmon, the  from harbour seal  control.  of  t o the contents  seven per cent  commercial.catch from Fisher  b y volume  north-  i n the Bering Sea.  most  hunting  numbers  and t h e n o r t h e r n  effort i n  of seals  were  col-  t i p of Vancouver  - 9 Island. Strait  A  small  was  also  wintering  25  each  t o I4.O  During was  when w e a t h e r  morning from  up  by  and  vessel  ticularly  Seals (Figure  were  killed  shot  o r a 3O.O6 r i f l e .  sink  r a p i d l y and  sex  and b r e e d i n g  were  removed,  sacks  and  stored  presence  the  laboratory were  volume  or absence and  nights  means  time,  vessel  concentrations. offshore,  of a  shotgun  dead  date  of the  par-  vessel  with  f u r seals were  and  10$  formalin,  lost  d u e .to  location  barrels  of food  containing  of  food  species  and  noted  the  i n grams  cotton  formalin.  was  n o t empty  capture,  Stomachs  i n  10$  i n the stomach  of contents  (cc),  placed  S.S.G.  do n o t  a'nd^f e e d l n g : b e h a . v i o u r .  weight  which  i n  following  (Figure  numbers  of  3)> indi-  present.  2.  Sea Most  lions specimens  Board  personnel,  saved  or reported  panied  f o r seal  the bridge  i f t h e s t o m a c h was  displacement  possible.  to the coast,  s i x per cent  with  i n wooden  r a n out  favourable.  by  condition,  recorded:  by  viduals  included  out as  the c o l l e c t i n g  o r more  from  about  and  a l l seals  way  Fortunately,  injected  The  data  only  Records  was  sighted  l ) and were  sinking.  i n Hecate  carried  harbour  searching  l a y one  i f the weather  was  returned  In this  the coast,  occasionally  left  collecting  the v e s s e l  nightfall.  down  permitted,  the v e s s e l  shore,  the afternoon  reached  moved The  miles  of adults  sampled.  Hunting, follows:  population  a  were  c o l l e c t e d by F i s h e r i e s  although Department on  commercial  several  of F i s h e r i e s  stomachs.  expedition  f o r five  Research  officials  In addition,  I  weeks  the  during  accomspring  - 10 -  F i g u r e 1.  M. V. " P a c i f i c Ocean", used e x t e n s i v e l y f o r c o l l e c t i n g f u r s e a l s , harbour s e a l s and sea l i o n s .  F i g u r e 2.  C o l l e c t i n g sea l i o n s , S c o t t I s l a n d s ,  1959.  - 12 -  cc M e r l u c e i u s productus  Sebastodes maliqer  gure 3.  Analysis of stomach contents Top: examples from skeleton collection Bottom: weighing fur seal stomach contents.  - 13  of  1959»  collecting  sea  lions  -  f o r mink  food;  115  stomachs  were  examined. Samples haul-out cessful  rocks as  the  were  ( F i g u r e 2); animals  Rifles  were  used  lected  were  similar  that of  volume  some  by  Harbour The  restricted able. in  of  seal  and  substantial  was  found  collect seals  the a  I  throughout  the  while  sexes  both  harbour  seal  fur  for  fur  recorded  when  seals,  for  suc-  Data  the  killed. col-  except contents  field.  seal  and  sea  lion  research,  and  few  specimens  end  to  29  of  during which  .collected of  sink  they  studies  indicates  almost while  in a  fast  Data  recorded numbers  year.  The  are  represented  sea  lion  of fur  in  working kindly the  immediately  upon  swimming  shallow  in  p e r i o d , however, i t boat  sea  could for  kill  and  harbour  lions.  specimens  collected  s e a l s were  approximately  samples.  very  avail-  1961.  recorded for  has  are  Harbour,  collected  of  collecting  sank.  those  fall  mainly  the  Pender  stomachs  the  marksman  calendar  and  not  i n the  sample  good  similar  Table  was  specimens.  of F i s h e r i e s ,  seals before  were  collected  rapidly  Department  seals,  were  that  collect  or  seldom  the  Charlotte Islands  Toward  sank  was  of  Queen  water.  and  sea  rookeries  McNaughton  a  killed,  at  the  W.  saved  Harbour  on  seals  harbour D.  to  those  examined  conjunction with  being  elusive  exclusively  pressure  Messrs  were  to  mainly  collecting  displacement  stomachs  3.  collected  mainly  equally in  females, the  -11+ Table  I.  Monthly c o l l e c t i o n dates f o r . a l l a v a i l a b l e s e a l , f u r s e a l and s e a l i o n stomachs.  No.  Month o f collection  Harbour  Analysis  have  been  noted  --•  5 k 70  7)+l  118  ^  o f stomach  seldom  and s i g h t  Hynes  (1950)> o u t l i n i n g t h e  pinnipeds.  below.  feeding  found.  observations  contents,  several  has also  The c a r n i v o r o u s  i n an aquatic  assessing  contents  occasionally  water  stomach  3  81 10 1+9 3 11+  2,113  under  cussed  lion  393  i s the favoured  habits.  (Scheffer  Scats and and S l i p p ,  1950; W i l k e a n d K e n y o n , 1952; W i l k e a n d K e n y o n ,  1951+), h ^ t t h e y a r e  in  Sea  seal  contents  examination  191+1+; S c h e f f e r ,  pinnipeds,  Collected  17 68 308 861  of investigating pinniped  spewings  for  Fur  126  o f stomach  An  fish  seal  harbour  l  Totals  method  Specimens  1 2 3 1 1 1+7 9 16 19 20 6  January February March April May June July August September October November December  B.  -  stomach  Most  items  a r e consumed 1950).  a r e few ( S c h e f f e r , possible  methods  of  analysing  covered  thepossible  feeding  habits  o f most  f i s h and  leads-to  similar  problems  environment,  contents.  food  These  several  methods  analyses  are dis-  1.  Degree An  has  2.  Total  isms for a  ten-pound  whose  t h e dominant  of  occurrence.  points  of each food  as percentages  This  item are  of a l l food  i s an u n s a t i s f a c t o r y  of prey  stuff  ranges  from  i n which  i s expressed  i n each  category  organ  technique  a stickleback to  each, f o o d  item  as a p e r cent  Volume  weight  and  occurs  frequency  percentage  of rough counts  o r j u d g e m e n t s made'  i s then  a number  item  are then  i n each  (a) the items  of each item  of t h e stomach,  Item  of p o i n t s .  summed a n d p e r -  a n d t h e f'fol.low'i'ng; o n e , h a v e b e e n t h e  (b) an e s t i m a t i o n  i s then  alloted  f o rh a n d l i n g p i n n i p e d  of each food  contribution  fre-  may b e m a d e .  method,  o f two ways:  a s common,  weights  techniques  weighed;  stomach a r e l i s t e d  by each f o o d  calculations  customary  and  items  gained  This  either  size  e t c . , on t h e b a s i s  5«  The  intake  items  food  e y e , and each  centage  i n food  Points Pood  All  of i n d i v i d u a l s  number o f stomachs  as  hy  variations  salmon.  The  quent,  numbers  Dominant  h'  o f t h e stomach  of individuals  i n t h e sample.  a predator  of t h e f u l l n e s s  seasonal  a n d may b e e x p r e s s e d  found  3*  estimate  t o demonstrate  Numbers  tabulated  -  of fullness.  arbitrary  been used  15  t o estimate  contents.  stomach i s c a l c u l a t e d i n  i n each stomach are separate  b y e y e i s made  t o the contents  applied  stomach  of each  t o t h e known w e i g h t the weight  of the  percentage  stomach;  this  of the contents  of the individual  item.  -  The  weights  summed tents  and  may  volume  to by  content  be  that  percentages  weight  1937»  organisms  of  weight  of  that  eaten,  rather  at  time A  Is  to  sum 6.  can  be  This  a  of  out  than fur  total  in a  then  con-  similar;  except  that  weight.  seal  basis  the  of  by  Stomach  programs  have  ( T a y l o r e_t a l . ,  a  each  item  numbers  known  of of  modified  the  the  weight  each food  mean kind  of live  of  i n the  food  stomach  killed.  each  the  item  volume  or  weight  contributes to  and  number  may  of  be  the  (b)  size  i s extremely  of  i f prey  of  summed  of  for  weight  numbers  method  each  difficult does  food and  a l l food  this  stomach.  individuals sizes  to one  can can  the  be  volume  the  most  each  item  estimated counted,  estimate find,  as  Ricker's  of  be  occurs  items.  and  give  item  expressed  study.  analysis  individuals  rarely  each  occurrences  considered  numbers  Only  i n which  occurrences  i f (a)  determined,  been  multiplying  stomachs  total  were  analysis  has  stomach by  occurrences  methods,  contents.  analysis  of  was  The  stomach  the  are  occurrences  these  method,  prey  sample  analysis,  rather  volume  gives  weight  accurately. of  weight  m o d i f i c a t i o n of  number  of  of  i n the  m o d i f i c a t i o n s of  accurate  by  i960)  percentages  Number  weight  cent  predator  third  tabulated;  (1937)  item.  the  Two or  item  than  the  percentages  the  of  carried  international  method  Bogorov,  each  The is  are  i s measured,  a per  i n the  a percentage  analyses  i n both  on  item  I96l).  The (Ricker,  as  described f o r  displacement  Anon.,  the  expressed Volume  calculated  1955;  -  each r e s p e c t i v e food  examined.  fashion  been  of  16  as  from  but  pinniped  i n Figure  $,  - 17 a  stomach  i n which  lengths  or weights  directly.  Large  fish  out  heads  may b e d i s c a r d e d .  later,  fore,  can only  b e made  columns.  Finally,  beak  i s only  size  1962(b));  Clarke, size  and body  pinniped these on  stomachs  down  t o percentages, with  1958  1958,  from  that  much  sample  1959, I960, 1961).  Squid  remains,  usually  lenses,  differ  markedly  from  lack  octopus  Octopus  flesh  of cephalopod were  waters. either  For  be  contents,  based  or a  items.  o f an a n i m a l ' s  i ft h e data  samples  (volume  are scaled  a r e used.  This  i n F i g u r e 1+, data  from  exception,  preyed  indicates  earlier  flesh  was d i g e s t e d more  ever.,  t h e d i s c r e p a n c i e s between and u n t i l  remains,  was r a r e l y  flesh  upon  consisting  fish  their  explained,  beak  showing  Pike  et  squid,  a l . , con-  I}..7$ h y v o l u m e b u t 22.3$ b y o c c u r r e n c e t o t h e  sample.  The  1962(a);  a n y o f t h e commonly  The one m a j o r  only  flesh.  must  of t h e stomach  t h e same r e s u l t s ,  fur seal  from  found i n  Columbia  of the individual  tributes  more  and octopuses  one e x c e p t i o n i s i l l u s t r a t e d  t o 1961  weights  i s no i n f o r m a t i o n a b o u t  British  and i f l a r g e  there-  of vertebral  (Clarke,  the analyses  or weights  taken  of length,  and octopus  of assessing the composition  will  the  of the squids  collected  diet  point,  there  c a n be  and as p o i n t e d  remains  attention  (1950) h a s s h o w n t h a t  methods give  Estimates  of squid  receiving  of occurrence  piecemeal,  the broken  at present  volume  Hynes accepted  just  I concluded  the actual  frequency  from  estimates  weight  reasons  a r e swallowed  of the prey  evidence  found that  o f beaks which  these  than  usually  i n sea l i o n either  i n the morning  rapidly  and eye  fish  include stomachs.  squid or  than  fish,  flesh.  or  How-  two c a l c u l a t i o n s a r e  t o t h e contrary i s produced,  I  Figure  4.  Comparison between a per cent by o c c u r r e n c e a n a l y s i s and a per cent by volume of c o n t e n t s from 869 f u r s e a l stomachs (1958-1961 d a t a ) .  analysis  F i g u r e 5.  S m a l l b l a c k cod found i n f u r s e a l stomach.  - 20 -  believe  the higher  meaningful  volumetric  particularly  later,  while from  Thus,  those  item  from  stomachs  collected  many  or items  importance  one  such  point,  dator item  i n a percentage  errors.  regardless  nightfall  items,  encountered  examining  of that  Ricker  (1937),  salmon  i n the l a b o r a t o r y , found  items  were  eaten,  often  than  the other.  exaggerate  b u t one i t e m  lions fur  i n favour  or harbour  seals  tended moment.  A  the importance However,  selection  were  t o prey  the food  there  frequency of t h a t  seals.  Taylor  non-selective on t h a t  item  have  an  The  contents  the con-  exaggerated  occurrence  item  item.  eaten  i n lesser  o f one would  amounts.  of young  sockeye  two e q u a l l y abundant taken  of occurrence item  taken  f o r such  food  more  analysis  i n lesser  by e i t h e r  e_t aJL.  w h i c h was  more  analysis  consistently  i n their  i s given  I f the pre-  chose  preferences  item  calculations  i n a stomach  of occurrence  i s no e v i d e n c e  o f one f o o d  are f u l l  i n t h e d a y , and t h e  of that  that was  shown  the e a r l y  outweigh  but consistently  a frequency  As  analysis.  on f r e q u e n c y  of the weight  t h e Importance  will  later  by weight  item  during  a r e empty.  stomach w i l l  based  Each  mainly  i n the morning  collected  sample  interpretation.  at daybreak  i n the former  the others,  exaggerate  towards  stomachs  a t e two o r more than  i s t h e more  a n a l y s i s of a small  collected  collected  Percentages avoid  or weight  and f u r s e a l s f e e d  one s t o m a c h  tents  on o c c u r r e n c e ,  susceptible to faulty  sea l i o n s  morning.  based  calculation. A  is  value,  would  amounts.  a consistent  f u r seals,  (1955) c o n c l u d e d  sea  that  f e e d i n g h a b i t s , and easiest  The f o l l o w i n g two o b s e r v a t i o n s  to catch  support  this  at the  conclusion  -  for  a l l three  species  restricted  itself  to  were:  seals,  77$  fur  item;  sea  studied? one  prey  of  78$  lions,  of  seals,  76$  of  item).  (b)  the  total  (lamprey, or  sea  another  sea  lions  item  per  been on  feed,  choose  in  i t s choice  mid-water  the in the  of  sample,  but  as  a more  equal  of  the  occurrence  reported  on  and  one items  predator that  a  caught  anchovy  plus  a  few  herring;  at  the  same  eulachon  and  $0%  and  time  anchovy,  area.  circumstances will  volume  four  time  seals  mainly  collected $0%  one  i n f l u e n c e the  amounts,  one  only  p o s s i b l e food  fathoms  i n the  under  by  may  seal  species  cent  of  at  one  item;  only  Thus,  prey  one  items  not  only  give  described  approximately  (or weight)  in a  above the  large  realistic  and  unbiased  interpretation  of  frequency  of  occurrence  calculations  have  a  sample.  carried  occurred  has  cent out  from  stomachs  as  been  occurrences  example two  per  28-36  consisted  of  food  stomach.  range  only  contained  had  coast  figures  contained had  ejb a _ l . ( 1 9 6 1 )  a fur  summarize,  Per  of  of  abundant  frequency  in a  of prey  at  food  skate)  Columbia  Pike  fishing  food  usually-  (actual  food  identified  a wide  food.  contents  same r e s u l t s  been  have  with with  and  item  i n approximately  To  small  sole  predator  p-er f e e d  with  33  of  Abundance  trawl  most  cent  stomachs  cabezon  same, p o s i t i o n  two  per  and  item  stomachs  British  from.  stomach the  the  the  to  eulachon  perch,  (a) E a c h  stomachs  harbour  In  -  21  of  Table with  follows:  expressed  the as  identifiable VII food  (page were  number  of  a percentage food  51)  items  will  collected  times of  from  the  i n the  clarify sea  a  given total  sample.  item number An  this:  ninety-  lion  breeding  - 22 colonies were in  during  t h e summer. 85  encountered  11  stomachs)  times;  In this  sample, ll|. d i f f e r e n t  rockfish,  contributed  12.9$  11  occurring  to the total  times  diet  items (i.e.,  i n that  area.  C.  Identification A  winter or  o f 1958  salted  all  fish  o f stomach  skeleton  were  bones  saved.  vertebral  column  intact  vertebral  column  were  of  stomach  tive tions in  of f i r s t  1961;  Clothier,  Sunde  and L i n d s e y ,  of  arrangement I  squid  Identification Berry and  (1912).  Wildlife  haemal  arch  the early Frozen  removed and  t h e s k u l l and  the vertebrae  and  i n identification  vertebral  and s p i n e s , were  counts,  rela-  and m o d i f i c a -  particularly  useful  species. was a i d e d  by the f o l l o w i n g  pub-  191+1; C h a p m a n , 19M+; C l e m e n s a n d W i l b y , Gregory,  1958.  Clemens  remains  o f whole  1933;  Hart  Scientific  succeeded  a n d McIIugh,  nomenclature  and W i l b y  which u s u a l l y  i n Seattle  order  identifying a l l  consisted  was f a c i l i t a t e d  was s e n t  and  19^;  (1961).  i n satisfactorily  squids  One s a m p l e Service  the flesh  aids  Total  during  necessary.  t o keep  useful  3)«  of f i s h  follows  and octopus  when  boiled,  and zygapophyses  1950;  never  added  was made  identification  Chapman,  was b e g u n  a s i t was f o u n d  (Figure  the i d e n t i f i c a t i o n  lications:  gently  t h e most  o f parapophyses  Fish  were  An attempt  contents  positions  collection  and specimens  specimens  contents  of beaks  by reference  t o the United  States  f o r identification.  only. to  Fish  -  DISTRIBUTION,  A.  General  habitat  A fur  seals,  cussed  bays  resulted 196l).  been  waters  land  fresh  water  connected  coast  found  dis-  (Cowan  force  (2)  changes.  l y i n g behind,  t o the marine  seals  farther  than  Into  any  the may  two o f w h i c h  1956):  (1)  protection  of a l l oceanographical waters  mouths water  biotic  by, i s l a n d s ,  where  a mixing  - coastal by  area  of  rivers,  from  found  four  points salt and  on  environments.  within  and h a r b o u r shore.  -  rivers.  the d i s t r i b u t i o n of pinnipeds  sea l i o n s  5 miles  the f i r s t  environment  a r e seldom  i n comparison,  (Scagel,  environments  and p r o t e c t e d  (I4.) Fresh  miles  emptying  outside  Coast  - river  II outlines  and have  and G u i g u e t ,  - waters  to the f u l l  occurs.  and d e p t h s , 16,900  categories,  break straits,  These  i n r e l a t i o n t o t h e above Fur  coast;  habits  numerous  a r e many r i v e r s  four  area  (3) Estuaries  Table this  by  help  and i s l a n d s  shapes  conditions.  described  and open  of water  reefs.  lakes  to  i n food  Into  of an estimated  there  biotic  waters  of varying  into  meteorological  and  frequented  i s included  peninsulas  coastal  estuarine  divided  already  bodies or  Columbia  In addition,  Pelagic  and  seals  habitats  and s i m i l a r i t i e s  promontories,  i n a coastline  roughly  from  and h a r b o u r  and i n l e t s  creating  have  BEHAVIOUR  below.  gulfs,  be  of the several  the differences  the B r i t i s h  sea,  MIGRATORY  description  description  Rugged up  -  NUMBERS AND  sea l i o n s  understand  23  5 miles seals  from the  are rarely  - 21+ Table  II.  C o a s t a l h a b i t a t s and p i n n i p e d Seal  Habitat P e l a g i c waters b i o t i c 3oast w a t e r s b i o t i c  area  area  Estuaries Fresh  1.  I n d i c a t e s area  migrations 1953;:  fur  seal  fur  seal  harbour  seal  fur  seal  harbour  sealx  harbour  seal  sea l i o n  x  of g r e a t e s t  f u r seal  sea l i o n  x  females, Islands  o f m a r i n e mammals  sea l i o n  The mature  I n t h e B e r i n g Sea d u r i n g l a t e  Pacific,  and s o u t h e r n  s p r i n g they  cows, y o u n g m a l e s and  October  and November. i n the eastern  Japan i n the western P a c i f i c . arriving  a d i s t a n c e o f up t o 6 , 0 0 0  trip.  pups l e a v e t h e P r i b i l o f  California  return to the P r i b i l o f s ,  covered round  as s o u t h e r n  documented  1 8 9 9 ; Kenyon and W i l k e ,  (Jordan,  and t h e f o u r - and f i v e - m o n t h - o l d  Many move as f a r s o u t h  Males,  except  miles  I n the  i n June  and J u l y ,  e a c h y e a r on  f o r t h e one-and  two-year-olds,  and  many t h r e e - and f o u r - y e a r - o l d s , r e m a i n i n t h e B e r i n g Sea  and  northern  G u l f of Alaska  From p u b l i s h e d the  Pribilof  females  seal herd  life  tables  (Abegglen  et a l . , i 9 6 0 )  one t o f o u r y e a r s  1,250,000  o f age.  Therefore,  1 , 6 5 0 , 0 0 0 f u r s e a l s move s o u t h f r o m t h e B e r i n g  each f a l l ,  a relatively  a l l year.  c o n s i s t s of approximately  and 1 + 0 0 , 0 0 0 m a l e s  approximately Sea  x  preference  m i g r a t i o n i s one o f t h e b e s t  T a y l o r et a l . , 1 9 5 5 ) «  having  present  Fur seals The  their  or sea l i o n s  water  x  distribution.  into  the North  Pacific.  l a r g e p e r cent, winter  Some o f t h e s e ,  perhaps  i n waters w i t h i n 1 5 0 miles  -  off  either  the American  25  or Asian  Seal concentrations studied  by the United  southern  California  -  land  masses.  i n the eastern  States  and C a n a d i a n  t o the Bering  Sea.  Pacific  have  i n v e s t i g a t o r s from  Older  females  farther  south,  and f e w one-, two- and t h r e e - y e a r - o l d  females  travel  south  tions  of younger  coastal  waters.  January  may  the inside  The  majority  and  some  are found  These  seals  remain  s t r a g g l e r s may  are heavy  During  and  three-year-olds moving  Vancouver these the to  Island  seals  middle  remain  of adult during  begin  late  March; between  by i n a  appears  Sound Columbia.  April,  and J u l y . off California, which  first  196l).  their  return to  a n d some  year.  The  twonorth-  o f f southern  the greatest the middle series  and b y  numbers  of A p r i l  o f waves  from  of and five  offshore. information  accurately  t h e numbers  in  Columbia  2.  June  females,  at sea t h e e n t i r e  o f May, p a s s i n g  Sufficient  British  seals  cows f i r s t  Columbia  t h e end o f  Anon,  or  concentra-  British  Many y e a r l i n g s , h o w e v e r ,  are encountered  35 miles  high  particularly  o f mature  males  Charlotte  during  e_t a _ l . , 1 9 5 5 »  (Taylor  Islands.  herd  Columbia,  t h e s p r i n g most  Pribilof  Queen  until  move  i n December  of northern  be found  concentrations  the  ward  Strait,  waters  s t i l l  of B r i t i s h  i n December  appear  and i n l e t s  i n these  Relatively  i n some B r i t i s h  first  i n Hecate  channels  South  appear  seals  be f o u n d  and  there  of Washington.  been  Sea The  Is not available t o  of seals migrating  coastal  through  estimate  or w i n t e r i n g  waters.  lions sea l i o n  migrations  are not f u l l y  understood  at  -26 present,  although  -  i t i s known that much of the  undergoes a seasonal movement.  population  In c o n t r a s t to the f u r s e a l s ,  where the l o n g e s t m i g r a t i o n i s undertaken by the females young males, the sea l i o n cows with pups a p p a r e n t l y  and  remain on  the r o o k e r i e s throughout the e n t i r e y e a r ; males one year  and  o l d e r move from the exposed r o o k e r i e s i n t o the i n l e t s or to rocks c l o s e r t o more s h e l t e r e d bodies  of water.  Barren  cows  and  impregnated cows which have l o s t t h e i r pups on the r o o k e r i e s  may  a l s o move inshore w i t h the males. Winter counts i n d i c a t e that over h a l f the  breeding  p o p u l a t i o n g r a d u a l l y leaves the r o o k e r i e s f o l l o w i n g pupping A p o p u l a t i o n of 1,600  breeding.  animals on the S c o t t  d u r i n g September, I 9 6 0 , had  dwindled t o only 700  and pups) by January, 1961;  200  1962,  April,  A census i n 1956 (~5$)  lions  1957).  o  n  During  these numbers by own,  and  by May  31,  and  sending  cows  1962.  (Pike and  Maxwell,  i960 the Department of F i s h e r i e s reduced out  s e v e r a l h u n t i n g p a r t i e s of t h e i r  by encouraging k i l l i n g f o r mink or pet food.  taken d u r i n g the summer of 1961  (unpublished  A census  data, F i s h e r i e s  Research Board of Canada) i n d i c a t e d there were 1,500  (mostly  i n d i c a t e d 11,000 to 12,000 sea  the B r i t i s h Columbia coast  1959  Islands  animals on Cape S t . James i n  i n c r e a s e d t o 600  had  and  approximately  pups and l+,500 a d u l t s r e s i d e n t i n B r i t i s h Columbia waters.  During  the summer months approximately  or 3»100 a d u l t s , concentrate James and 3.  the S c o t t I s l a n d s  on the two  70$  of t h i s  population,  r o o k e r i e s of Cape S t .  (Pike and Maxwell, 1957).  Harbour s e a l s T h i s s p e c i e s i s regarded  as non-migratory i n the sense  -  of  a  seasonal  population (1952)  Into  noticed  salmon,  while  together studies but  will  of  mile  of  seals To  number  of  seal  migrate  coast.  attached counts  to  are  the not  of  the  that  Pisher  following  seals  herd  Future  seal  movements,  comparable  been  conducted  observations the  fall  there  there  many  the  to  lion.  never  17,000  River  summer.  migration  of  However,  Skeena  harbour  sea  has  large part  may  seals. are  and be  along  made  on  winter, as  field when  many a s  Bounty  one  hunters 20,000  approximately  coast.  to  these  the  early  dispersed,  estimated  seals,  the  a  area.  noticed  during  s h o r e l i n e , or  this  up  However,  that  there  are  20,000  c o a s t a l waters.  through  or  census  widely  17,000  fur  have  extent  seal  summarize,  estimated  Columbia's  on  a l l or  i n d i c a t e s no  suggest  are  of  and  during  the  fur  McNaughton) have  harbour  an  the  1958  animals  (D.  groups  -  population  into  hunters  Columbia  these  the  movement  harbour  since  return  of  determine  trips  per  out  bounty  either  British  seal  a  and  information  A the  or  i n small  present  that  exodus  27  some  available.  of  (— 5 $ )  winter  Confidence  harbour  sea  lions  seals resident i n  addition there  which  waters.  estimate  harbour  In of  6,000  seal  and  Is  an  some  limits numbers  British  unknown of  which  cannot as  and  be  repeated  -  -  28  COMPARATIVE ANATOMY The comparative  anatomy of the d i g e s t i v e  tract,  i n c l u d i n g the d e n t i t i o n , was examined t o add t o our understanding of f e e d i n g h a b i t s . A.  Dentition 1.  Sea l i o n s The formula f o r o t a r i i d m i l k d e n t i t i o n (V. B. S c h e f f e r ,  p e r s o n a l communication) i s : , di A  1 - 2 - 3 o - 2 - 3 '  , d  k  1 c  T'  d  m  0 - 2 - 3 — 2 - 3 - it  Permanent d e n t i t i o n i s : 1 - 2 - 3  1  1 - 2 - 3 - U - 5  0 - 2 - 3 *  1*  1 - 2 - 3 - 4 - 5  By the end of September, at approximately three and a h a l f months a f t e r b i r t h , a l l the permanent d e n t i t i o n i s e v i dent except f o r the two upper and lower canines, which are s t i l l r e p r e s e n t e d by deciduous  teeth.  F i g u r e 6 shows the  permanent d e n t i t i o n at t h i s stage as w e l l as the three  deciduous  post canines s t i l l adhering t o gum t i s s u e beside the permanent teeth. The deciduous  canines p e r s i s t u n t i l February and  March when the young sea l i o n s are e i g h t t o nine months o l d . One male s k u l l ,  c o l l e c t e d March 8 , 1 9 6 l , had two upper canines  p r o t r u d i n g f i v e mm through the gum, the lower l e f t through two mm,  canine was  and the lower r i g h t was not showing (Figure 7 K  F i g u r e 6 i l l u s t r a t e s the permanent d e n t i t i o n at 1 5 months of age. all  The l a s t post canine i s double r o o t e d , while  others are s i n g l e r o o t e d ; crowns are i r r e g u l a r l y  conical.  -  F i g u r e 6.  29  -  Top: 3-4-month-old male sea l i o n s k u l l Bottom: 15-month-old female sea l i o n s k u l l (b = deciduous t e e t h )  F i g u r e 7.  Top:  lower jaw from 9-month-old male sea l i o n , showing permanent c a n i n e s C e n t e r : young female h a r b o u r s e a l s k u l l Bottom: 9-month-old female f u r s e a l s k u l l  - 31 The  lower p o s t canines, p a r t i c u l a r l y the t h i r d and  have v e r y s l i g h t a c c e s s o r y cusps. large.  The  two  Canines  fourth,  of both jaws are  outer upper i n c i s o r s are c a n i n e - l i k e i n form  and t h r e e - q u a r t e r s as long as the canines. 2.  Fur seals The  to  f u r seals.  o t a r i i d d e n t a l formula  (see above) i s a p p l i c a b l e  At b i r t h a l l the permanent d e n t i t i o n i s evident  except f o r the s i x t h upper post canine T h i s appears  (Kuboto and Komuro, 1 9 6 l ) .  shortly after b i r t h .  F i g u r e 7 i l l u s t r a t e s the permanent d e n t i t i o n at e i g h t months of age. canines and  These permanent t e e t h are haplodont,  incisors  with  s i n g l e r o o t e d , and the post canines incom-  p l e t e l y double rooted  ( A l l e n , 1880).  The  canines are l a r g e and  the outer upper i n c i s o r i s s l i g h t l y e n l a r g e d . 3.  Harbour s e a l s No f o e t a l or s k u l l s of pups were examined In t h i s  study.  The  d e n t a l p a t t e r n i s as f o l l o w s ( A l l e n , 1880):  Deciduous t e e t h - i ^  ,  Permanent t e e t h - }• " j- ~ 3 0 - 2 - 3 ' The  c  "p  pc  ^  1  1 - 2 - 3 - U - 5  T'  .1-2-3-5-5  e r u p t i o n of the permanent t e e t h has not been des-  c r i b e d but S c h e f f e r (1958) s t a t e s t h a t the m i l k t e e t h disappear b e f o r e or soon a f t e r b i r t h . approximately of  Young harbour  s e a l s are weaned at  one month of age and p r o b a b l y r e q u i r e a f u l l  set  s t r o n g t e e t h f o r the capture of food. F i g u r e 7 shows the permanent d e n t i t i o n of a young  harbour  seal.  The post canines are double r o o t e d and m u l t i l o b e d ,  except f o r the f i r s t  post canine which i s s i n g l e r o o t e d .  Canines  -  are l a r g e and B.  32  -  the outer upper i n c i s o r i s s l i g h t l y  enlarged.  Digestive tract  species.  The  mouth i s simple  and r a t h e r elongated  The  tongue Is notched at the t i p , perhaps as an a i d  i n sucking from a small t e a t ( S c h e f f e r , 1 9 5 8 ) . leads d i r e c t l y to the simple  An u n u s u a l l y  long  a r e l a t i v e l y short large i n t e s t i n e i s  common t o a l l three p i n n i p e d s . t i o n s of these  esophagus  "J"-shaped stomach, which i s  a l i g n e d w i t h the l o n g a x i s of the body. s m a l l i n t e s t i n e and  The  i n each  The  relative  shapes and  posi-  organs are the same i n each s p e c i e s s t u d i e d .  S e v e r a l authors have mentioned the great l e n g t h of the p i n n i p e d i n t e s t i n e .  Engle  (1926)  found  the whole I n t e s t i n e  of an a d u l t male n o r t h e r n sea l i o n to be about 3 8 times body l e n g t h .  Laws ( 1 9 5 3 )  the southern elephant  found  seal  t h a t the i n t e s t i n e l e n g t h i n  (Mirounga l e o n l n a ) v a r i e d from twenty  to t w e n t y - f i v e times the body l e n g t h . the i n t e s t i n e l e n g t h was  the  1 3 to 2 2 times  Mohr ( 1 9 5 2 ) found  that  the body l e n g t h of  s e v e r a l European p i n n i p e d s . The  r a t i o of body l e n g t h to i n t e s t i n e l e n g t h  examined i n each of the three p i n n i p e d s under study A l l l e n g t h s were taken t o the nearest 1 0 cm. f u r s e a l i n t e s t i n e lengths are approximately  was  (Table I I I ) .  Harbour s e a l  and  the same w i t h a  r a t i o of mean body l e n g t h to mean i n t e s t i n a l l e n g t h of l : l 6 and  1:17,  1:21.  The  respectively.  The  range f o r both groups i s 1 : 1 3  to  sea l i o n body l e n g t h - i n t e s t i n e l e n g t h r a t i o i s n e a r l y  twice as great at 1 : 3 0 , w i t h a range of 1 : 2 3 to  1:35*  Table I I I . Ratio of whole intestine length to body length o f f u r s e a l s , sea l i o n s and harbour s e a l s . Mean lengths and ratios o f means are shown at the bottom o f each respective column. Data from animals greater than one year o f age. Harbour seals  Sea lions  Fur seals Ratio  Body length (cm)  Intestine length (cm)  100 100 110 110 110 120 120 120 120 120 130 130 130 130 140  2000 1790 1910 1670 1740 2500 2340 1630 1640 2170 1810 2080 2240 2030 2230  1:20.0 1:17.9 1:17.4 1:15.2 1:15.8 1:20.8 1:19.4 1:13.6 1:13.7 1:18.1 1:13.9 1:16.0 1:17.2 1:15.6 1:15.9  119  1985  1:17  Body length (cm)  Intestine .length (cm)  150 160 160 180 180 180 190 190 210 220 220 240 250 250 260 270 290 300  4500 4760 4430 4170 4960 5000 4840 5450 5900 6260 6700 8400 7080 7630 8320 8310 9600 10130  216  6469  Ratio  Body length (cm)  Intestine .length (cm)  Ratio  1:30.0 1:29.7 1:27,6 1:23.2 1:27.5 1:27.8 1:25.5 1:28.6 1:28.1 1:28.5 1:30.5 1:35.0 1:28.3 1:30.6 1:32.0 1:29.7 1:33.2 1:29.7  100 100 110 110 120 120 120 140 150  1670 1710 1920 1800 2200 2150 1550 1970 2190  1:16.7 1:17.1 1:17.4 1:16.4 1:18.3 1:17.9 1:12.9 1:14.1 1:14.6  1:30  119  1907  1:16  - 3k There i s no s a t i s f a c t o r y e x p l a n a t i o n f o r the r e l a t i v e l y l o n g p i n n i p e d i n t e s t i n e or why the northern  sea l i o n has an  i n t e s t i n e l e n g t h n e a r l y twice as great, i n r e l a t i o n t o i t s body l e n g t h , as e i t h e r the harbour s e a l or f u r s e a l .  The r e l a t i v e l y  longer sea l i o n i n t e s t i n e may r e s u l t from the g r e a t e r volume of t h i s animal.  However,  the southern  elephant  seal with a  maximum weight of two and one-half tons has a r e l a t i v e l y s h o r t e r t r a c t than the northern  sea l i o n , with a maximum weight of one  ton. Laws ( 1 9 5 3 )  suggested  the l o n g p i n n i p e d  intestine  may be an a d a p t a t i o n t o d i e t ; i n p a r t i c u l a r a'mechanism t o a i d i n the breakdown of the c h i t i n o u s beaks of m o l l u s c s . the d i e t of the three p i n n i p e d s  However,  s t u d i e d here i s q u i t e s i m i l a r  (Figure 1 3 ) , y t marked d i f f e r e n c e s are evident i n the body Q  length - i n t e s t i n a l length r a t i o .  Further studies to investigate  d i f f e r e n c e s at the c e l l u l a r He v e l of the i n t e s t i n e may c l a r i f y t h i s problem. From t h i s b r i e f examination have emerged:  the sea l i o n s ' complete permanent d e n t i t i o n i s  not evident u n t i l the animal and  two anatomical d i f f e r e n c e s  i s e i g h t t o nine months of age,  the body l e n g t h - i n t e s t i n e 3e ngth r a t i o i s approximately  1:30.  I n comparison f u r s e a l s and harbour s e a l s , not as closely-  r e l a t e d taxonomically ities  as f u r s e a l s and sea l i o n s , show s i m i l a r -  i n these two r e s p e c t s :  r a t i o i s approximately  body l e n g t h - i n t e s t i n e l e n g t h  1 : 1 6 i n both cases, and a l l permanent  t e e t h appear before the pups o f both s p e c i e s are t h r e e  months  old. Sea  l i o n s show the only adjustment i n f e e d i n g  behaviour  -  which may  35  -  be r e l a t e d to the e r u p t i o n of permanent d e n t i t i o n :  sea l i o n pups suckle f o r s e v e r a l months (at l e a s t 1 5 months i n some cases) while the f u r s e a l and harbour weaned w i t h i n one to three months a f t e r  s e a l pups are  birth.  FEEDING HABITS A.  Comparative 1.  f e e d i n g behaviour  Capture of prey (a)  Fur s e a l s .  Most f u r s e a l food c o n s i s t s of small  s c h o o l i n g f i s h e s or squids which are eaten beneath the s u r f a c e . Except f o r very small Items,  such as l a n t e r n f i s h , the prey i s  u s u a l l y swallowed  (Figure 5 ) «  head f i r s t  S e a l s have been  observed e a t i n g salmon and r o c k f i s h at the s u r f a c e on f o u r o c c a s i o n s , and a f i s h b e l i e v e d t o be a cod once.  Larger f i s h  such as salmon, cod and r o c k f i s h are brought t o the  surface,  reduced t o p i e c e s by v i o l e n t shaking, and swallowed  piecemeal.  F u r s e a l s waste l i t t l e  of t h e i r p r e y when f e e d i n g .  F i s h f l e s h unaccompanied by bones has been observed d u r i n g the examination of 2 , 0 0 0 r o c k f i s h may (65$)  stomachs.  only twice  However, heads of  sometimes be d i s c a r d e d ; 1 8 out of 2 8 r o c k f i s h  which had not been a f f e c t e d by d i g e s t i o n , l a c k e d heads. E u p h a u s i i d s are f r e q u e n t l y encountered  stomachs c o n t a i n i n g h e r r i n g or r o c k f i s h remains.  i n f u r seal Data com-  p a r i n g frequency of occurrence of euphausiids and the stage of d i g e s t i o n of f i s h remains  i n the s e a l stomach i n d i c a t e  that  these i n v e r t e b r a t e s are found o n l y when the f i s h stomach i s exposed  by d i g e s t i o n .  Such euphausiids had been eaten by  which i n t u r n were preyed upon by  seals.  fish  - 36 Table items  found  under  reduced  Sea l i o n s .  water.  lions  have  and  halibut,  observation  of a sea l i o n  (c) a large while  salmon  larger  harbour  seal  occasions  rockfish,  an octopus  numbers  An adult  salmon an  i n i t s  of certain  jaws.  food  harbour  Small  a r e consumed  seal  was  observed  a t t h e s u r f a c e on one  observed  are probably  IV l i s t s  On e i g h t  stomachs.  or r o c k f i s h  prey  t o t h e s u r f a c e and  (1950) r e c o r d s  with  t h e maximum  sculpin  and e u l a c h o n  food  as h e r r i n g a r e  lingcod,  surfacing  River.  of certain  shaking.  Sleptsov  seals.  (1952)  such  are brought  Harbour  Fisher  Table in  fish  eating  i n sea l i o n  I n t h e Skeena  herring while  IV l i s t s  encountered  sion,  observed  at the surface.  Table  eating  Small  Larger prey  been  numbers  of f u r seals.  to small pieces by violent  sea  items  t h e maximum  i n t h e stomachs  (b) eaten  IV l i s t s  seals  f e e d i n g on  schooling fish, eaten  below  occa-  such  as  the surface,  at the surface.  t h e maximum  numbers  of f i s h  encountered  stomachs.  Table IV. Maximum n u m b e r s o f c e r t a i n f o o d i t e m s f o u n d i n i n d i v i d u a l stomachs o f f u r s e a l s , s e a l i o n s and h a r b o u r seals. Maximum Food  numbers of  item Fur  Squid Dogfish Herring Salmon Eulachon Hake Whiting S a b l e f i's'h Rockfish  seals  Sea  items found stomachs lions  in  Individual  Harbour  2kk 3k 15  7 7  154  1B  18 2 iJ+8  19 7  15  l l 22  seals  -  2.  37  -  F e e d i n g I n r e l a t i o n t o hours a f t e r  sunrise  Both f u r s e a l s and sea l i o n s have l e s s food stomachs as the day progresses  i n their  ( F i g u r e s 8 and 1 0 ) . F i g u r e 8  i l l u s t r a t e s two samples of f u r seal stomachs, one from the G u l f of A l a s k a  and one from B r i t i s h Columbia, r e l a t i n g mean  stomach contentjvolume)and hours a f t e r s u n r i s e .  The A l a s k a  sample shows c l e a r l y t h a t f e e d i n g begins l a t e i n the evening and  reaches a peak some time d u r i n g the hours of darkness.  All  stomachs contained  food e a r l y I n the morning but by 1 1  hours a f t e r s u n r i s e a l l stomachs were empty.  The B r i t i s h  Columbia sample i l l u s t r a t e s the same type of f e e d i n g behaviour. Figure  9 shows the corresponding  stomachs as the day progresses Sea  l i o n stomach contents  i n c r e a s e i n per cent  of empty  f o r the B r i t i s h Columbia  sample.  show a s i m i l a r decrease from a mean  of 1 , 7 3 2 cc at 1 . 5 hours a f t e r s u n r i s e t o only 2 cc a t 1 5 » 5 hours a f t e r s u n r i s e  (Figure 1 0 ) . F i g u r e  1 1 shows the c o r -  r e s p o n d i n g i n c r e a s e i n per cent empty stomachs. In comparison with f u r s e a l s and sea l i o n s the harbour s e a l sample of 5 0 stomachs i n d i c a t e s d a y l i g h t f e e d i n g  (Figure 1 2 ) .  Samples have not been c o l l e c t e d d u r i n g the hours of darkness.  T h i s i n c l u d e s a p e r i o d of f o u r hours f o r f u r s e a l s ,  e i g h t hours f o r sea l i o n s and 1 2 hours f o r harbour s e a l s . No c o n c l u s i o n s  can be reached r e g a r d i n g f e e d i n g h a b i t s of  harbour s e a l s d u r i n g the hours of darkness; f e e d i n g may or may not occur. However, f u r s e a l s and sea l i o n s feed mainly d u r i n g the hours of darkness and the e a r l y morning. d u r i n g the morning c o n t a i n food  Stomachs c o l l e c t e d  and mean volumes are h i g h .  -  38  -  These contents are d i g e s t e d throughout the day and by e a r l y evening B.  stomachs are empty.  D a i l y food  consumption  In order t o f i n d  out the e f f e c t of p i n n i p e d  predation  upon commercially  v a l u a b l e f i s h s t o c k s , an e s t i m a t i o n of d a i l y  food requirements  must be made.  ped food requirements  Table V i n d i c a t e s t h a t p i n n i -  range from two t o eleven per cent of  body weight, w i t h an average d a i l y food i n t a k e of s i x p e r cent of the animals' body weight.  Refinement of these data t o  a l l o w f o r growth, pregnancy, l a c t a t i o n o r hard work ( f o r l o n g migrations) i s impossible; d e t a i l e d requirements C.  of p i n n i p e d s have not been undertaken.  Comparison of food items Pood items  the three p i n n i p e d marized  s t u d i e s of the n u t r i t i o n a l  eaten  identified  i n the stomachs of each of  s p e c i e s under i n v e s t i g a t i o n have been sum-  i n F i g u r e 1 3 , r e g a r d l e s s of date or l o c a t i o n of c o l -  lection. included.  Items which occurred  only once i n the sample are not  T h i s f i g u r e has been arranged  i n such a manner as  to p o i n t out s i m i l a r i t i e s and d i f f e r e n c e s which e x i s t between each of the p r e d a t o r s are shown f i r s t  studied:  and items  food items  common t o a l l three  common t o two o r only one f o l l o w .  The f a c t o r s which prevent  e x t e n s i v e i n t e r m i n g l i n g of  the n o r t h e r n f u r s e a l , sea l i o n and the harbour seal r e s t r i c t movements of t h e i r prey.  do not  Ten of the 2 1 food Items  i n F i g u r e 1 3 , squid, c l u p e i d s , salmon, r o c k f i s h , cod, hake, flatfish,  g r e e n l i n g , lamprey and smelts are common t o a l l  three p i n n i p e d s ; combined they c o n t r i b u t e over 5 0 $ t o the d i e t  - 39 -  Table V. Daily food consumption o f pinnipeds as reported i n the l i t e r a t u r e , plus the maximum weights o f stomach contents from i n d i v i d u a l animals c o l l e c t e d i n the f i e l d .  Species of seal Northern f u r seal  Northern sea l i o n  Authority  Scheffer (1958) Anon. (1962) . Sergeant (1962)  Gray seal  Food intake (lb/day)  Daily food intake as a percentage o f body weight  66 65  4 4  7 6 5  Observed maximum  106  11  10  Scheffer (1958)  600  14  2  490 1500  19 35  4 2  Havinga (1933) Scheffer.(1958)  66 70  3 4  5 6  Observed maximum  62  7  11  150  10  7  Mean  6  Observed maximum  Harbour seal  Body weight (lb)  Myers (1955)  - 40 -  6  Lo  2.  F i g u r e 8.  Fur  10 Hours a f t e r S  Id. sunrise  !¥•  /£>  s e a l stomach volumes and hours a f t e r  16  sunrise.  F i g u r e 9.  Per cent empty stomachs and hours a f t e r s u n r i s e ( f u r s e a l s ) .  - 42 -  IS F i g u r e 10.  J-5"  JJ  7-5" 9'5~ Hours a f t e r s u n r i s e  IIS  13?  Mean stomach volume o f 269 sea l i o n s and hours a f t e r sunrise.  /5-5  - € 3 -  F i g u r e 11>:  P e r c e n t empty stomachs and h o u r s a f t e r s u n r i s e sea l i o n s , 269 stomachs, 130 empty.  llOOr  IO0O  aoo-  ioDO  400  loo-  O  I  =  I  2  *  I  H-  s  •  6  :  I  &  :  I  IO  •  I  12.  Hours o f s u n r i s e  F i g u r e 12. Mean stomach volumes and hours a f t e r s u n r i s e i n a sample o f 50 h a r b o u r s e a l s .  - 45 -  F i g u r e 13.  Stomach c o n t e n t s of f u r s e a l s , sea l i o n s , harbour s e a l s , c o l l e c t e d a l o n g t h e c o a s t o f B r i t i s h Columbia.  of each p r e d a t o r . may  The d i f f e r e n c e s which do e x i s t , however,  be e x p l a i n e d l a r g e l y by d i f f e r e n c e s i n d i s t r i b u t i o n of  each group of p r e d a t o r . and  Most f u r s e a l s are o f f s h o r e (Table I I )  t h e i r d i e t c o n s i s t s l a r g e l y of s m a l l f i s h and squid s c h o o l i n g  at the s u r f a c e .  Sea l i o n s and harbour  s e a l s are i n s h o r e (Table  I I ) ; bottom f i s h and octopus are more important In t h e i r The h i g h percentage due  diet.  of salmon i n the harbour s e a l sample i s  t o 2.9 stomachs c o l l e c t e d i n the v i c i n i t y of salmon spawning  creeks d u r i n g September and October,  1961;  t h i s Is not r e p r e -  s e n t a t i v e of the a c t u a l r o l e of salmon i n the y e a r l y d i e t of these D.  seals.  Unusual  stomach contents  Small pebbles, sand, b i t s of wood or bark, kelp and s m a l l clam s h e l l s have o c c a s i o n a l l y been found i n stomachs of each of the three groups s t u d i e d . ingested a c c i d e n t l y .  I t i s b e l i e v e d these are  However, smooth stones of v a r y i n g shapes  from o n e - h a l f Inch to three inches a c r o s s , are found  so f r e -  q u e n t l y i n sea l i o n stomachs t h a t some f u n c t i o n a l e x p l a n a t i o n Is I n d i c a t e d .  Oneto t e n stones weighing up t o f o u r pounds  were found i n o n e - t h i r d of a l l sea l i o n stomachs examined. S e v e r a l suggestions have been presented i n an to e x p l a i n t h e presence  attempt  of stones i n p i n n i p e d stomachs:  stones are taken a c c i d e n t a l l y when sea l i o n s prey on which have stones grasped  i n their tentacles  (a)  octopuses  ( S l e p t s o v , 1950);  (b) they add b u l k t o the stomach d u r i n g p e r i o d s of f a s t i n g (Howell, 1930,  and Laws, 1956); (c) they a i d i n d i v i n g  and Renard i n Emery, 19I4.I, and Hamilton,  (Murray  1933); (d) they  -kl  -  ( H a m i l t o n , , 1 9 3 3 ) > (e)  macerate stomach p a r a s i t e s  they a i d i n  the p h y s i c a l breakdown o f food i n the stomach (Mathews, Two  1929).  o b s e r v a t i o n s do not support the theory t h a t  stones are i n g e s t e d a c c i d e n t a l l y w i t h octopus remains: stones were found sea l i o n ; up and  i n the stomach of a six-month-old n u r s i n g  a p p a r e n t l y even young animals are capable of p i c k i n g  swallowing such o b j e c t s ;  the stomachs of harbour Although Laws ( 1 9 5 6 ) his  (a)  (b) stones are not found i n  s e a l s which f r e q u e n t l y prey upon octopus.  presented c o n v i n c i n g evidence to support  t h e o r y t h a t stones add b u l k t o the stomach of a f a s t i n g  elephant s e a l , h i s t h e o r y does not apply t o the stones found i n n o r t h e r n sea l i o n  stomachs.  These are found throughout  the  y e a r and i n the stomachs of l a c t a t i n g cows, when n u t r i t i o n a l requirements  are h i g h .  Mathews' ( 1 9 2 9 )  theory t h a t stones a i d i n the  break-  down of food i s supported by evidence from the n o r t h e r n sea lion.  The  sea l i o n t e e t h , p a r t i c u l a r l y the post c a n i n e s , are  designed f o r g r a s p i n g and t e a r i n g r a t h e r than g r i n d i n g 6);  thus, food i s swallowed  i n pieces.  (Figure  As much of the sea  lion  food c o n s i s t s of l a r g e , heavily-boned s p e c i e s the g r i n d i n g activity  of stones i n the stomach would be of great a s s i s t a n c e  i n the p h y s i c a l maceration of f l e s h , bones and  octopus  beaks.  Observations of c a p t i v e animals have shown that such stones are of  e a s i l y r e g u r g i t a t e d , and t h i s occurs a f t e r the d i g e s t i o n food  lion  (Emery, 1 9 1 + 1 ) .  Stones  stomachs are a l s o found  s i m i l a r to those found i n sea  on sea l i o n haul-out r o c k s .  The m a j o r i t y of the f u r s e a l s ' f o o d , and p r o b a b l y t h a t of the harbour  s e a l , i s s m a l l e r f i s h or squid; an  additional  - 1+8 g r i n d i n g mechanism i n the stomach i s not needed. E.  Comparative seasonal f e e d i n g  habits  D i f f e r e n c e s i n f e e d i n g h a b i t s of these three are e v i d e n t ,  pinnipeds  r e l a t i n g t o time of year and a l s o to area.  Accord-  i n g l y , the samples have been grouped as t o season and area of collection. The  f e e d i n g h a b i t s of f u r s e a l s d u r i n g January,  February, March, A p r i l and May are d e s c r i b e d  i n detail  (Table  V I ) ; whenever p o s s i b l e comparisons have been made w i t h the f e e d i n g h a b i t s of sea l i o n s and harbour s e a l s F o l l o w i n g the northward m i g r a t i o n l i o n s and harbour s e a l s remain.  (Table V i i ) .  of f u r s e a l s , sea  The samples from these two  s p e c i e s have been d i v i d e d i n t o "summer breeding"  and "summer  non-breeding" c a t e g o r i e s f o r sea l i o n s , and a "summer" sample f o r harbour s e a l s .  Samples from September 15> t o December 3 0  have a l s o been combined. The  B r i t i s h Columbia coast has been d i v i d e d i n t o  f o u r main areas (Figure ll+) as an a i d t o d e s c r i b i n g f e e d i n g habits.  T h i s f i g u r e a l s o shows the major sea l i o n and harbour  s e a l l o c a l i t i e s mentioned i n the t e x t .  Area I extends from  1+8°0G'N t o 5l°00'N or the n o r t h end of Vancouver I s l a n d ;  area  I I i n c l u d e s waters o f f the west coast of the Queen C h a r l o t t e I s l a n d s ; area I I I i n c l u d e s Hecate S t r a i t , Queen C h a r l o t t e S t r a i t and Dixon Entrance; while  area IV i n c l u d e s a l l p r o t e c t e d  channels and i n l e t s of the B r i t i s h Columbia  coast.  References t o numbers of stomachs i n the f o l l o w i n g account r e f e r t o numbers of stomachs w i t h food  only.  F i g u r e 14.  C o l l e c t i n g areas on the B r i t i s h Columbia c o a s t (Area IV i n c l u d e s a l l p r o t e c t e d i n l e t s and c h a n n e l s ) .  I'iiHLi VI: Fur s e a l stomach contents by month and area.  MONTH AREA Stomachs vtdth food. Stomachs empty. TOTALS SPECIES  I  III  IV  I  III  IV  I  8  1  22  15  69  20  46  334  19  11  118  16  39  41  26  187  36  85  9 17 F2  9  1 F  F  4  F  F  F  %  1  3 3.4  2  6.2  3  19 21.9 3 3.4  4  12.5  3 7  1 1  24 27.6 2 2.3  8  F  6.9 2.3  1 1  1.2 1.2  2  2.3  1  2  7 1  21.9 3.1  1 1 1  9  1 1 4  14  16  1 22 87 100.0  2 3  3.1  32  99.9  III  9  6  324  2  43  9  3  1  912  495  16  1  413  1  53  7  1  1  l^OO  829  25  7  737  3  96  16  4  2  2.1A2  F  F  F  F  %  F  6  4  2 1  7  21.9  II  44.8 4.7  3.1 4 4.6 6 6.9 11 12.6  I  180 19  1  3  IV  2  ' 2 1  I  10.9 0.2  25.0  3.1  F  1 1 1  4  4 14 8.3 30 1 6 6  4.2  2.1  1 1  5  F  1  %  5  1.5  44 1 1 188  13.1 0.2 0.2  4  1.2  34  10.1  1 7 4  0.2 2.1 1.2  3  56.0  0.9  F  3.5 7.5 0.2 1.5 1.5  2 1  3  0.2 0.2  18 28  4.5 7.0 6.2 4.5 0.5  1 4 3 1 1 12 7 2 7 1 8  2  0.2  60  48 100.0 403 100.1  5  11  7  339  9  1  1  28  51.9  2 4 5  3.7 7.4 9.3  3  5.6  1  1.8  0.9  3  5.6  0.2 0.2 3.6 2.1 0.6 2.1 0.2  1  9  16  1 1  9 7  39 1.8 1.8  2  54  100.0  26 9  1 4  2  14  2  1 1 - one empty stomach collected i n area 4 during May not included 2 2 - frequency o f occurrence  6  46 41 1 1  1  13 28 158 6 6 443 24 5 59 48 1 10 15 12  1  1 100.1s  IV  1  0.2 1.2  93  4  11.1  1 1  1.5  0.9  F  6  1.0  0.5  9  F  0.5  2 1  2.1 25 18 2.1 2  TOTALS  JUKE-  IV  III  2 28 58.3 11 22.S 44 1  3 3.4 6 2  %  I.  MAI  APRIL  IV  L o l i e o op. G. maeister Unid. Squid 6 Lamprey Ratfish Herring Shad Clupeids Anchovy Salmon Eulachon Capelin Smelt Saury Hake Whiting 1 Cods King- of-the-s Flatfish Greenling -Pomfret Squaretail -Oman Sablefish Rockfish Stickleback Sandlance Birds 2 Misc.4 Unid. Fish4 TOTALS  MARCH  FEBRUARY  JAN.  Source o f data as i n Table  3 - per cent frequency of occurrence 4 - not used i n calculations  1 1,036  T A B L ^ V I I '• H a r b o u r s e u l and sea lion stomach contents, by month and area. Source of data as i n Table I .  SEA LIONS WINTER MONTH  AREA  Stomachs with food. Stomachs empty. TOTALS SPECIES Shrimp Clamshell Octopus Squid Lamprey Skate Batfish Dogfish Herring Salmon Eulachon Smelt Hake Graycod Whiting Halibut Flatfish Seaperch Mackereljack Sablefish Lingcod Greenling Rockfish Cabezon Sandlance Sea bird Milk Kelp3 Unidentified^ TOTALS  HARBOUR SiiAL  SUMMER  FALL  Dec.  Feb.  Mar.  Apr.  May 15Sept. 15  May 15Sept. 15  IV  IV  IV  IV  Breeding Colonies  NonBreeding Colonies  3  9  2  92  0  2  5  2  14  5  14  4  F  F  F  *2  1  2 3 36 5 1  2.4 3.5 42.4 5.9 1.2  2 5 1 6  2.4 5.9 1.2 7.1  F  l  F -  2 1 1  1  1 1 12  1 1  1 3 1  1  2  17  Mar.  Apr.  May  May 15Sept. 15  Entire Coast  IV  IV  IV  IV  IV  IV  IV  35  35  1  1  2  1  0  26  38  155  22  17  0  1  1  0  1  48  6  247  57  52  1  2  3  1  1  74  44  F  F  F  F  F  3  3.5  3  3.5  3  F  it  1 2.4 5 12.2 2 4.9 2 2  4.9 4.9  1 2.4 9 21.9 1 2.4 4 9.8  12.9  1  1.2  2  4.9  1  6  7.1  4.9  2  25  2 1 3  11  4  85 100.0  F  %  1 1 1 3  2.4 2.4 2.4 7.1  1 3 1 4  2.4 7.1 2.4 9.5  8 19.0 1 2.4 3 7.1 3  7.1  1  2.4  9 21.9  41 99.9  F 2 2 8 1 2  1 2  1  %  Sept. 16 -Dec. 15  F  %  6.5 25.8 3.2 6.5  1 2.2 7 15.2 8 17.4  3 9.7 5 16.1  5 10.8 14 30.4 1  2.2  1  2.2  4 1  8.7 2.2  1  2.2  1 1 1  2.2 2.2 2.2  1  1 3.2 1 3.2  2.4  11  1 - frequency of occurrence  FALL  Feb.  1 1  SUMMER  Jan,  1 2  Sept. 16 -Dec. 15  WINTER  7 22.6  7 16.7  1 3.2 4 1 4  9.5  42 99.9  19  1 1  2  2  2 - per cent frequency of occurrence  1  0  33 100.0  6 46 100.1  3 - not used i n calculations  - 52 1.  Winter-spring (a)  and  are  and  some  and  females,  in  to  sablefish  immature the  be  of  Knight  January. found  the but  some  fur seal  Inlet  and  were  the  most  Male  sea  lions,  stomachs  or  are  pups  are  available  harbour  been  on  the  to  evident  i n a l l northern  that  Strait  the  diet  be  found  Fur  seals  inside  ratfish Three  Saanich  Inlet  herring  and  this  Squid  species  haul-out  waters  January small  identified.  rocks  following There  and  males  time.  during  non-lactating  be  found  are  anywhere  i n Knight  Inlet  Distribution  at  and  sea  this  dogfish.  and  o f f the from  that  west 22  squid  squid  time  some  cows  and  adjacent  herring; no  sea  to  most  lion  along  the  coast.  during January,  a l l species i s  which  was  had  of  formed from  had  quite  f u r seals  and  young  collected primary  secondary mainly over  on  half  feeding  Island. in  item  in  importance. small the  B e r k l e y Sound  been  are  fur  of Vancouver  the  feeding  collected of y e a r  adult  coast  were  were  young  f u r seals  herring  waters  lions,  of  a l t h o u g h more  areas  w h i t i n g and  from  sablefish,  may  contents  indicate  while  on  young  month.  of January,  Stomach Hecate  few  at  Sound  eulachon.  similar  may.also  seen  collected  food  January  mostly  Strait.  rookeries.  collected  (b) F e b r u a r y .  seals  a  found  for this seals  seal,  feeding  plus  in  Charlotte  are  also  were  important  t o be  on  are  Charlotte  i n more p r o t e c t e d  Harbour One  cows  appear  Queen  These  stomachs  Queen  first  Strait,  inlets.  adult  Eight  coast,  seals  i n Hecate  northern  females  cows w i t h  Pur  on  diet. and whiting,  - 53 One F e b r u a r y had  harbour  -  seal collected  i n B a r k l e y Sound d u r i n g  b e e n f e e d i n g on h a k e .  (c) March.  By  l a t e March the young f u r s e a l s  to l e a v e the p r o t e c t e d waters  of B r i t i s h  Columbia's  begin  coast,  w h i l e t h e r e i s an i n c r e a s e i n t h e number o f a d u l t f u r s e a l s appearing o f f Vancouver One collected  hundred  Island.  and  thirty-five  f u r s e a l s t o m a c h s were  d u r i n g M a r c h i n a r e a s I , I I and  from Hecate S t r a i t  indicated  IV.  Twenty  t h a t h e r r i n g was  f e r r e d f i s h , w h i l e s q u i d , w h i t i n g and  stomachs  t h e most p r e - ,  s m a l l s a b l e f i s h were  also important.  A s a m p l e o f 69  t h a t h e r r i n g and  s q u i d were t h e two most i m p o r t a n t i t e m s  t r i b u t i n g 50$  t o the d i e t .  dominately yearlings  stomachs from area I  F u r s e a l s from  collected  indicated con-  i n s i d e waters,  pre-  i n K n i g h t I n l e t , were p r e y i n g  h e a v i l y upon the s q u i d , Gonatus m a g i s t e r . Q u a n t i t a t i v e d a t a on t h e movement o f s e a l i o n s i n B a r k l e y Sound i n d i c a t e t h a t s e a l i o n s r e a c h t h e i r maximum numbers i n M a r c h , p r e s u m a b l y  f o l l o w i n g the h e r r i n g .  move i n t o K n i g h t I n l e t d u r i n g M a r c h and Nine I n l e t and and  sea l i o n  tifiable  Queen C h a r l o t t e S t r a i t d u r i n g M a r c h . times i n a t o t a l  i n Knight Whiting,  herring  of e l e v e n i d e n -  foods. The  M a r c h had  lions  April.  s t o m a c h s were c o l l e c t e d  r o c k f i s h o c c u r r e d seven  Sea  harbour  seals collected  b e e n f e e d i n g on (d)  April.  f u r s e a l h e r d has  during  eulachon.  During A p r i l  reached  i n Knight Inlet  the main  northward-migrating  southern B r i t i s h Columbia  waters,  w h i l e most o f t h e y o u n g f u r s e a l s h a v e moved o u t o f t h e  sheltered  - Bk inside  waters. Three  collected nine  i n areas  stomachs  33I4. s t o m a c h s herring shad,  was  A  Vancouver  Island  again  t h e most  important  food  collected  from Sea  Two  Strait.  southern  Squid  area lions  which,  stomachs  and K n i g h t  fish,  octopus  i nthe  sample o f  indicated  that  species, but squid, were  i n stomachs  prior  of the inlets  Sound  large  were  also  taken  of s i x young  fre-  animals  IV.  m i g r a t i o n back  sea l i o n  and r o c k f i s h  predominated  many  their  i n Hecate  eulachon  stomachs  H e r r i n g predominated  from  stickleback,  throughout  and f o r t y - n i n e f u r s e a l  I , I I I and I V .  collected  quently.  begin  hundred  and i n s i d e  collected  the former  and s k a t e ,  had s c a t t e r e d  passages  probably  t o t h e r o o k e r i e s by t h e end o f A p r i l .  were  Inlet;  to April,  while  during April  had been  the l a t t e r  i n Barkley  feeding  had been  on  rock-  feeding  on  eulachon. Harbour with  no e v i d e n c e  Maude on  seals  of herding.  Island, Strait  over  One h a r b o u r  of Georgia,  the entire  seal  i n April,  coast,  collected o f f  had been  feeding  o f May,  virtually  herring. (c)  May.  all  f u r s e a l s have  fur  seals  the  e n d o f May  areas  left  the early  Hecate  t h e a d u l t s have hundred  comprised  part  Strait  a r e abundant  and a r e a  passed  food  into  i n area  over  the food.  May.  I indicated Salmon  while  Island.  Alaskan  f u r seal  during  collected half  IV waters,  o f f Vancouver  and t w e n t y - s i x  I , I I I and I V c o n t a i n e d  32I+ s t o m a c h s  again  During  o f a l l ages  Three  of  are distributed  waters.  stomachs A  By  large  from sample  that herring  assumed  i t s greatest  - 55 importance it  d u r i n g May i n t h e f u r  contributed  The t h r e e squaretail, southwest  species,  diet  intake  i n one  lion  "summer"  and h a r b o u r  category  of  pomfret  (a)  been f e e d i n g  seal  specimens  been p l a c e d  During June there  mostly young animals o f f  on h e r r i n g , h a k e ,  stomachs  are  were  Islands.  squid  while  ratfish,  saury,  identified.  i n the  of  (nine  seals,  still  greater  were f e e d i n g  seal;  if  m a i n l y on a n  of fourteen  occurrences),  in this  Sea l i o n s .  sample  By l a t e  the  James  and t h e S c o t t  Octopus,  forming nearly half  t h e most i m p o r t a n t f o o d ,  at  5^°21'N-  the  made an  shown i n T a b l e  May and e a r l y J u n e 70$  Islands, of  is  case s q u i d has  than i s  l i o n p o p u l a t i o n have congregated  Cape S t .  collected  also  A m i s t a k e may h a v e b e e n  t h i s was  fur  d u r i n g June  w h i t i n g and r a t f i s h w h i c h  stomach.  few  the  w h i t i n g and l a m p r e y r e m a i n s were  Importance  (b)  a  I s l a n d had  west of  collected  out of a t o t a l  lamprey,  an i n s h o r e  in positioning this  far  appro-  Only nine  from waters  One o f t h e s e n i n e s t o m a c h s ,  contained  136°2li'W,  sea  These  100-150 m i l e s o f f s h o r e ,  unidentified  the  collected  B r i t i s h Columbia.  cod and s q u i d .  have been c o l l e c t e d  Queen C h a r l o t t e  even  miles  Island.  F o r t y - s e v e n - s e a l s from the west c o a s t of Vancouver  typical  200  below.  Fur seals.  migrants,  between  and  Summer  2.  seal  i  food.  stomach c o l l e c t e d  of E s t e v a n P o i n t , Vancouver sea  i n t h i s a r e a when  king-of-the-salmon,  t h a n May 15 and h a v e t h e r e f o r e  priate  late  total  were e n c o u n t e r e d  All later  to the  10.1$  seal  on t h e  rookeries  f u r p u p p i n g and  contents  of of  breeding.  examined,  although r o c k f i s h ,  VI.  dogfish  is  by  and  - 56 salmon  were  stomachs  also  indicates rockfish  sample  that  Harbour  herds  occurs.  Many  River,  (Fisher,  collected sample  seal  octopus,  3.  food  areas  either  down  seals  have  McNaughton  congregated where  apparently remain  However, up  a c c o r d i n g t o D.  along the coastline  herds  break  w h i l e w h i t i n g and  items.  harbour  of these  herds  importance  rocks  together  i n some a r e a s , e . g . , t h e  following  the pupping  o r up r i v e r  period  by t h e end o f  from  stomachs  are available  the Fraser salmon  and Skeena  f o r t h e summer Rivers.  and h e r r i n g  In  months,  this  a r e t h e most  Items.  Fall  months  a r e no f u r s e a l  from  i n British  September Columbia  stomachs  available  t o December. waters  until  This  f o r the  species  January  (Manzer  Is  rarely  and  1956).  Cowan,  (a) begin  coastline. south  Six yearling  or haul-out,  By June,  many  rockfish,  There  found  heavily.  1952).  mostly  important  lions  seals.  t h e e n d o f t h e summer.  Twenty-six  four  food  i n isolated  t h e . a n i m a l s move  June  i s of less  communication),  small  Skeena and  quite  non-breeding,  a r e t h e two m a j o r  (personal  until  from  octopus  (c)  pupping  upon  contained milk. The  into  preyed  from  towards probably  Sea l i o n s .  During the early  t o leave the breeding rocks Males,  and f e m a l e s  the Scott  Islands  the mainland  Inlets.  move n o r t h w a r d s  up b o t h  on Cape  the east  along the  p r o b a b l y move  Vancouver  Sea l i o n s  many s e a  and s c a t t e r  w i t h o u t pups,  towards  fall  Island  or  S t . James  and west  coasts of  - 57 the  Queen  Charlotte  mainland.  The  St.  inside  James,  Rocks, are  sample  most  prevalent  tified  in  one  months  old  animals  of  although  they The  dominately salmon  also  Salmon  the  i)  on  Queen into  the  most  were  Fur  seals:  months squid  as  During  hake  i s the  lions  third  which  salmon pounds,  Scott  are  readily  were  Islands  Columbia  most  have  iden-  during  common d u r i n g  the  break  the  coast  (Clemens  lli-15-month-  four  studied  are  this  small  a l l members relatively  period  Islands, to  Scott  Islands  and  the  and  the  limited  closely.  Charlotte  food  early f a l l  up  movements  streams  diet  collected  spawn;  item  are  when  collections  i n the  Gulf  (mostly (Table  pre-  of  chum  Georgia.  and  VII).  pink  Octopus  eaten-  food  habits  of  these  three  pinnipeds  follows:  Herring  also  and  fall.  the  o f f Vancouver are  Cape  rockfish  from  available for  frequently  summarized  British  Islands,  Isnor  18  the  the  and  where  is fairly  these  important  seasonal  from  the  c o n t r i b u t i n g 30.1i$ t o  squid  be  the  sea  identified  been  stomachs  by  to  Skedans  Salmon  mouths  apparently  not  moving  The may  iili  made  was  salmon) and  have  year  totalling  seals.  is believed  from  were  was  during  seals  of  Strait  Scott  Island,  largely  creek  Hecate  from  species.  o f f the  Milk  Harbour  harbour It  time  species  i n waters  collected  disperse.  Moresby  collected  This  (b)  of  taken  stomach  1961).  Wilby,  stomachs  this  and  across  35  food  is  or  mackereljack,  196l.  and  at  Inlets  Five  September, summer  and  the  available.  were  waters  important  food  into  herds  of  indicates that  the  moved  Islands,  taken  is  the  Island  most and  frequently.  important  food  i n Hecate  Strait,  Salmon  during a l l  assumes  while importance  - 58 only d u r i n g May o f f Vancouver I s l a n d .  Seals i n i n s i d e  waters feed mainly on s q u i d , r a t f i s h and s a b l e f i s h . ii)  Sea l i o n s : all  R o c k f i s h are one of the main food items f o r  sea l i o n s at a l l times of the year.  I n a d d i t i o n to  r o c k f i s h , h e r r i n g are important d u r i n g the w i n t e r ; octopus, d o g f i s h and salmon are taken f r e q u e n t l y by b r e e d i n g animals, while non-breeding the summer.  animals feed h e a v i l y on w h i t i n g d u r i n g  R o c k f i s h , salmon, w h i t i n g and hake are  important food items d u r i n g the f a l l . Iii)  Harbour s e a l s :  During the winter eulachon i s an important  food, p a r t i c u l a r l y i n the i n l e t s .  Summer sampling,  on the Skeena and F r a s e r R i v e r s , I n d i c a t e d t h a t  octopus,  r o c k f i s h and salmon were the important food Items. the f a l l ,  mostly  During  salmon c o n s t i t u t e s n e a r l y o n e - t h i r d of the food  eaten. F.  Predator-prey size r e l a t i o n s h i p s Prey s i z e may have an important b e a r i n g upon the f i s h  s p e c i e s p r e f e r r e d by each r e s p e c t i v e p r e d a t o r and two aspects of  t h i s problem haverbeen  investigated:  (a) d i f f e r e n t f e e d i n g  h a b i t s between sea l i o n s and f u r s e a l s produced fic  size differences;  by i n t e r - s p e c i -  (b) an i n c r e a s e i n prey s i z e w i t h the  i n c r e a s i n g age (and s i z e ) of f u r s e a l s . 1.  Inter-specif1c  differences  Table V I I I compares the importance  of l a r g e and s m a l l  food items i n the d i e t o f f u r s e a l s and sea l i o n s . fur  s e a l weight was only  w h i l e the mean female of  58-265  kg.  29.1  kg w i t h a range o f  The mean  5*9-63.5 kg,  sea l i o n weight was 177 kg w i t h a range  Although no mature b u l l sea l i o n weights were  - 59 taken,  some b u l l s  Professional for  butchers  mink f o o d  table  fishes  i n the  fur  lions'  diet.  In  fish, the  sea  the in  dogfish, lions' As  75$  vicinity  of  the  above  2.  of  contents  comparison,  the  hake,  food  but  only  of  the  harbour  salmon  large  bulls  importance compared  large  halibut 12$  streams  that  the 63$  cod,  1956).  G-uiguet,  taken  lb).  diet:  and of  seal and  of  lingcod  small schooling  11$  to  s p e c i e s of  the  i n the salmon,  fur seals'  rivers  rockof  food.  were  they  sea  \yfo  comprise  stomachs  IX  and  and  of  differences 15  Figure fur  (fur  collected  cannot  be  in  analysed  seals)  summarize  seals,  species which  With  increasing  size  (salmon,  increasingly quency  of  occurrence  by  fur  i n the seals  increasing species  age  of  mentioned  a  the  available  according to occurred  nine  hake,  one  larger  fur seals, are  age.  only  with  and  data  Uniden-  rarely  have  of predator, and  from  group  10T  age  to  not  food  than  fish  become  per  cent  38$  and  groups.  clupeid  larger  other  shad)  three  age  other  the  foods  size  rockfish  year  than  of  thus  occurs  to ten  grouped  above  and  rise  i n the  are  t h e r e f o r e been  age,  cod,  important:  respectively,  have  (1500  and  included.  larger  eaten  estimated  kg  seals'  feeding behaviour  been  (Cowan  illustrates  Intra-specific  tified  kg  manner.  Table on  have  680  weigh  This  90°  weigh  fre37$  Shad  species  and  items.  With  those  d e c r e a s i n g importance  larger in  the  diet. These bearing items  upon  than  comparisons  prey  size.  small fur  show  Large  seals;  sea  that  fur  predator  seals  lions  prey  prey  on  size on  has  larger  larger  a  direct  food  food  items  F i g u r e ."15: A n a l y s i s o f 699 f u r s e a l stomachs c o n t a i n i n g f o o d , showing s e l e c t i v e f o o d p r e f e r e n c e s a c c o r d i n g t o age.  - 61 -  Table V I I I . Comparison of large and small food items eaten by f u r seals and sea l i o n s . Frequency expressed as a percentage of t o t a l occurrences of a l l food items from Table V i .  Predators Prey (large) Sea l i o n s p* Salmon Rockfish Cod Dogfish Hake Halibut Lingcod Mackereljack Sub t o t a l Total occurrences ( a l l species) Per cent  Fur seals P  10 30 20 13 11 1 2 1  59 41 22  88 203 43.4  134 1036 11.9  18 1  481 59 46 39 26  22 203 10.8  651 1036 62.8  12  Prey (small) Clupeids Smelt Sablefish (small) Stickleback Sandlance Sub t o t a l Total occurrences ( a l l species) Per cent  •Frequency of occurrence  - 62 Table IX. Analysis of 699 f u r seal stomachs containing food showing s e l e c t i v e feeding behaviour according to age. (Data from present investigation only.)  Age (years) Food items 1  2  3-4  5-6  7-8  9-10  10+  Totals  77 37.0  38 52.0  45 50.0  59 44.3  35 37.6  18 36.0  49 41.5  301  Clupeids*and smelt  F^ %  Salmon, cod, rockfish, hake and shad  F %  7 3.4  2 2.7  IS.'.' 16.7  25 28.4  28 30.1  19 38.0  44 37.3  140  Squid  F %  89 42.8  16 21.9  15 16.7  13 14.8  15 16.1  8 16.0  13 11.0  169  Sablefish, saury, stickleback and sandlance  F %  35 16.8  17 23.3  15 16.7  11 12.5  15 16.1  5 10.0  12 10.2  110  F %  208 100.0  73 100.0  90 100.0  88 100.0  93 100.0  50 100.0  118 100.0  720  196 261  77 115  98 140  79 80  90 75  48 41  111 65  699 777  Totals  Total food Total empty  3  Clupeids do not include shad. Frequency of occurrence. 'Per cent frequency of occurrence.  - 63 than  G.  the  smaller  Feeding  fur  habits  season  were  reduced  Fur  reduced.  contained Paul  cluded June  and  carried  et_ _ a l the  while  during  they the  however,  196l).  bulls  on  Commander  the  tories  for  less  on  rookeries The  to  to  their  than  pups  seven  days  after  cow  then  goes  to  ing  that  on  the  rookery.  imately  which Her  s i x days.  re-enters  the  sea  not  this  for  their  fur  seal  type  breeding  period  intake  by  of  ones, i n and  of  the  the  two  month by  at  behaviour  ashore,  parturition e i t h e r on  any  time,  and  not  that  takes  day  or  place;  the  day  followon  pup  first  away  the  lasts  for  returns an  for  average  of  one  to  eight  rookery two  days  days;  four  and  each  :  the  l e a v i n g her  She  terrivacancies  Within  occurred, from  harem  give  copulation stay  always  that  days  1953)'  Hoel,  same  have  their  and  three  copulation the  Studies  program  on  of  bulls.  within  and  months  shown  remain  reserve  (1953) c o n -  does  Islands one  St.  territories.  research  males  stomachs  the  Hoel  i n v e s t i g a t o r s have  (Bartholomew  sea  empty  feed  Robben  filled  come  of  maintained  and  one  are  cows  did  Russian  food  Bartholomew  present  that  (Anon,  birth  the  and  (1958) r e p o r t t h a t " o n l y 27  thousands  masters  occur  the  pupping  determine  indicate that  seal harvest".  harem  July  indicated,  data  among  fur  out  the  seals  food  that  during  primarily to  Abegglon  Island  habits  intake.  Available is  reproduction  food  examined  food  1.  seals.  and  Pinniped  -  approx-  then successive  -  trip  to  water  sea  i n August  November, to  becomes  feed  weight  when  for by  females.  supply  (Baker,  1957)  abandoned  by  lack  an  samples  radius  suggest the  available  food,  Pribilof  and  Kenyon,  that  area  2.  Sea  Islands  may  by  the  The and a  they  pups  to  have  the  October  gradually tripled  the  adjacent  lengthy  (Wilke  and  indicate that a  radius  cent  empty  the  1.5  of  but  are  of  the  30  to  to  or  learn their  birth  a  fish.-  seldom  taken  post-partum  1954)  limited  miles  of  a  n  the  Pribilof  collected  seals  within  These  in this  have  d  food  a l . , i960).  t o November  bottom  rookeries  of  Kenyon,  stomachs  2 million  the  trips  only  (Niggol,et  from June  e x p l a i n the  begins  end  made  of June  during  feeding series  In  suggested heavy  during  area  reduced  the  Salmon migrate by  fur  seals  past  (Wilke  that  the  lack  m o r t a l i t y of  of  food  fur  seal  i n May  and  pups.  habits of  the  these  the  (Pike  last  and  week  Maxwell,  1958?  Is  personal  1959)'  relationship  compares  food  August  into  lions  observations  with  seal  for  (1961) has  Pupping  X  cows,  venture  1954)*  this  shown i n  first  from  i n waters  particularly  Chapman  season  are  s i x months  the  finished  the  operations  E i g h t y - f i v e per  30-mile  Table  food  i s available within  during  pups  and  Pur  explanation  stomach  authors  in  of  Dragging  Islands. this  The  October.  provide  pelagic  longer.  themselves.  The may  61i -  between of  samples  male, a n d collected  percentage  samples.  the  of  pupping female from  empty  Normally,  and  sea May  breeding  lions to  stomachs  is  September. to  approximately  those sixty  - 6 5-  Table X. Changing r a t i o of stomachs with food to empty stomachs throughout the pupping and breeding season i n 228 male and female sea l i o n stomachs. Pups not included, (Data from present investigation only.)  Male Food May 2 22-29 Rookeries June 5-18 Rookeries July 3-22 Rookeries September 21-30 Rookeries  Female Empty 10 (41.7)  13 (41.9)  18 (58.1)  16 (76.1)  5 (23.9)  15 (27.2)  40 (72.8)  F  2  7  12 (57.1)  9 (42.9)  F  2  0  16 (64.0)  9 (36.0)  15 (60.0)  10 (40.0)  11 (73.3)  4 (26.7)  2  F  % %  lo F %  •  Frequency o f occurrence 2 \  ,  Empty  14 (58.3)  F  Non-breeding May 21 - August 17  Food  Per cent frequency of occurrence  - 66 per cent of sea l i o n stomachs c o l l e c t e d d u r i n g the d a y l i g h t hours c o n t a i n f o o d . D u r i n g the l a s t week i n Hay males have taken up t e r r i t o r i e s but are f e e d i n g r e g u l a r l y as 58$ of stomachs cont a i n food. the f i r s t of  The females,  which have j u s t s t a r t e d t o pup, show  s i g n s of a decrease  i n food i n t a k e , with only 1).2$  stomachs c o n t a i n i n g f o o d . The next p e r i o d of o b s e r v a t i o n , June 5-18,  i s during  the peak of the pupping p e r i o d and presumably there i s l i t t l e b r e e d i n g a c t i v i t y on the p a r t of the males. 21 males i n d i c a t e s an i n c r e a s e i n f e e d i n g . Is  at a minimum,with  food.  The probable  T h i s sample of Female food  intake  only 27$ of female stomachs c o n t a i n i n g e x p l a n a t i o n f o r the h i g h percentage of  empty female stomachs at t h i s time i s t h a t cows are  remaining  w i t h t h e i r newborn pups. The f i r s t  three weeks i n J u l y i n d i c a t e a complete  r e v e r s a l of the June s i t u a t i o n .  Feeding  i s at a minimum i n  the male p o p u l a t i o n , but i s n e a r l y normal f o r the Although of  females.  the male sample i s small I b e l i e v e the h i g h  empty stomachs  frequency  (seven out of nine examined) a c c u r a t e l y  r e f l e c t s the f a c t t h a t many males are busy m a i n t a i n i n g r i t o r i e s and b r e e d i n g . t i o n i s w e l l i n progress blished study and  The cows have f i n i s h e d pupping,  terlacta-  and normal f e e d i n g has been r e - e s t a -  (57$ of stomachs w i t h f o o d ) .  of sea l i o n b r e e d i n g behaviour  Although  no d e t a i l e d  comparable to Bartholomew  Hoel's (1953) f u r s e a l study i s a v a i l a b l e , i t i s probable  t h a t sea l i o n cows i n c o n t r a s t to the f u r s e a l cows, do not leave t h e i r pups f o r extended p e r i o d s of time.  Food i s  - 67  -  abundant i n the  immediate v i c i n i t y  ( s e e b e l o w ) and  t h e cows' f e e d i n g t r i p s  a few  hours'  last  predominately  a female sample.  tected waters,  mum,  l e a v i n g the  F e e d i n g by t h e  w i t h 65$  By  and  lactating  i n d i c a t e t h a t up  p u p s on  a d u l t cows i s p r o b a b l y  pro-  the  at a maxi-  P u p s h a v e more  make h e a v y  nutritional  known when l a c t a t i o n c e a s e s .  t o 25$  I n some i n s t a n c e s  12  and  However, 15  months  of the y e a r l i n g s are not a y e a r l i n g sea  lion will  supplementing t h i s milk d i e t w i t h f i s h , l i o n was  e.g.,  completely be  nursing,  on J u l y  c o l l e c t e d w i t h m i l k and  a  6,  rat-  i n i t s stomach. Increased  the  September i s  f o r more  cows and  of females s u c k l i n g animals  1959* a y e a r l i n g s e a fish  of  cows.  I t i s not  weaned.  only  time n e a r l y a l l the  of stomachs c o n t a i n i n g f o o d .  demands on t h e  observations  this  pups have d e p a r t e d  t h a n d o u b l e d t h e i r b i r t h w e i g h t and  old  rookeries  are p r o b a b l y  sample, c o l l e c t e d d u r i n g l a t e  many cows w i t h o u t  rookeries.  sea l i o n  duration.  The  b u l l s and  of the  numbers o f s e a  summer months c o u l d  adjacent  to such r o c k s .  3.  on r o o k e r i e s  s e r i o u s l y reduce stocks Exploratory fishing  shown, h o w e v e r , a b u n d a n t f o o d James and  lions  of  (page  supplies adjacent  during  fish 85)  has  t o Cape S t .  the S c o t t I s l a n d r o o k e r i e s . Harbour During  a t a minimum.  seals the  a c t u a l pupping p e r i o d food  Only f i v e  stomachs c o n t a i n e d  food  intake i s i n \\$ c o l l e c t e d  on t h e S k e e n a R i v e r d u r i n g t h e p e a k o f t h e p u p p i n g p e r i o d . long this period  of f a s t  continues  i s not  d e f i n i t e l y known,  How but  - 68 in  t h e case  until  of t h e Skeena  the adults  Prom  Fisher's  seal  pups,  the  i n June,  who  the l a s t  middle  week  This  However,  to  pups,  sea l i o n  this  after  early 11.  that  within  age a r e abandoned  will  over  phenomena  t o by several fast  (Bartholomew  own.  (personal are born  a peak  that  In  are quite  one month  capable  of b i r t h ,  by t h e cows.  o f f a s t i n g among p i n n i p e d s authors.  f o r two months  and H o e l ,  two months  Some while  adult  male  maintaining  has been  northern f u r their  1953); t h e s o u t h e r n e l e p h a n t  i n the wild  a n d 100  days  of f a s t  harem,  that  while  the northern of the year  Pike  most  a at  period  o f a few days  least part  undergoes.when  when d i s c u s s i n g  observes  that  of the population  f a s t i n g by sea l i o n s  Female  of July,  sea l i o n s only. while  i n cap-  (1930) r e f e r s t o t h e "many  sea l i o n  (1958),  sea l i o n ,  Seasonal examined.  a male  Howell  fasts,  i n captivity  weeks"  1958).  harems  seal  (Scheffer,  been  of  and a t  tivity  part  pupping  contrast  1956); a monk s e a l u n d e r w e n t a f o u r - m o n t h f a s t  of  about  t o the sea l i o n  noted pups  pups  reaches  harbour  These  (Laws,  his  area.  by August  the f i r s t  i s comparable  seal  Island  of McNaughton  and p u p p i n g  the- h a r b o u r  only  Fasting  referred  for  that  on t h e i r  by those  Mr. M c N a u g h t o n  themselves  The  seals  o f May  of June.  behaviour.  looking  are feeding  has observed  probably  t o the Gibson  i t i s evident  are strengthened  communication)  population  down r i v e r  (1952) d a t a  born  observations  during  move  River  the food  "...during  a  habits large  i sfasting". and h a r b o u r  do n o t e a t w h i l e  H a r e m b u l l s may maintaining  guarding  seals has  pupping,  not feed f o r  harems.  However,  - 6 9a  prolonged  the  fast  possibility  minimize  the  valuable  least  of  not  such  effect  of  cows part  limited  (a)  i n the of  food Pur  habits  seals:  and  occur take  on  lion  cannot  population;  be  suggested  upon  to  commercially  state  regarding  fast  post-  for  at  this  a frequent  exchange  Stomachs are  Sea  lions:  empty.  pupping to  A  make  of  s u s t a i n the  bably  fast  their  harems.  days  post-partum fast  then  for  not of  part  fast  Harbour fast  i s not  during  pup.  July  seals  when  on  June,  known.  food  the  may  collected  sea  tenidays but  for  is  pup. increased  masters  are  Skeena the  food.  June  cows  intake  although  harem  during  Harem  months;  always  feeding,  the  they  two  about  to  days  known) w h i l e  this  of  for  start  few  not  i n the  forages  a  r a p i d l y growing  during  seals:  and  for  males  fast  found:  Bartholomew  does  young  extensive  occurs  termination  most  pin-  feeding  fast  bulls  Females  period  fast  number  from  of  regarding  male  is contradictory.  found  forced  this  a  f o l l o w i n g was  i n v e s t i g a t o r s have  be  Harbour  evidence  the  bulls  may  the  undergo  harem  place.  Upon  area  indicate that  that  and  (exact  s e a l data  available information  rookeries  the  of  sea  predation  reproduction  Present  during  a  lion  River  the  and  commercially  (c)  occurrence  sea  Skeena  (1953)  Hoel  Russian  to  i n the  June.  behaviour  (b)  an  harbour  Summarizing niped  occur  fishes. The  partum  does  pro-  maintaining  River exact  undergo length  - 70 H.  Interspecific The  term  interspecific and or  survival more  successful species seals,  together  only  lions  and h a r b o u r  along  the coast. During  seals  congregate  fur  seals  i n mid-channel  either  only the  shore  four  eulachon. been  Sixty feeding  groups  of  seals  o f most  Sound.  years,  were  greater  which  approximately than  one m i l e  of the Kleen  areavwas  sampled  i n the direction of  feeding in'the  yearling  Inlet,  the estuary  inshore  Sea  occasionally  there  When t h i s  collected  been  of Knight  at a distance  had been  s e a l s have  exclusively  middle  on  of the Inlet  on s q u i d . this  of four  same p e r i o d  t o t e n were  occasionally into  the river.  fish  four  the growth dominant  together  196l,  March,  of the inlet.  These  During  moving  During  t o an  by another  and B a r k l e y  t h e head  f u rseals had ventured  estuary.  had  Inlet  and two miles' f r o m  a t t h e head  affects  and h a r b o u r  and M a r c h  towards  refers  i960).  s e a l s may b e s e e n  wide.  River  In  i n Knight  miles  from  adversely  (Odum,  sea lions  February  here  o f one s p e c i e s  four  100  as used  which  of•• i n d i v i d u a l s  found  is  competition  interaction  Pur  fur  competition  and w h i t i n g .  r a n g i n g ; mp  t h e middle  One s e a l i o n  30  approximately  of  collected  sea l i o n s  a n d down t h e s h o r e ,  the inlet had been  or the estuary  feeding  on dog-  x  x One Department Inlet,  sea l i o n  of Fisheries  contained  stomach  collected  officials  eulachon.  during  and examined b y April,  i960,  i n Knight  -  Twenty-five in  the estuary  viduals a  were  found  stationary  from  harbour  of the Kleena along  position,  the r i v e r  seals  close  which had  moved  the Kleena  eulachon.  The  and  plus  Kleen  sea l i o n  collected  had  time  solitary  of the i n l e t , Two  indi-  maintaining hair  seals  eulachon.  t h e few f u r s e a l s  e s t u a r y were  m a j o r i t y of the f u r s e a l s  were  feeding  f e e d i n g on  b e e n f e e d i n g on  on  squid,  dogfish  whiting. During  together that one  mile  from  swimming,  lions,  food)  shore;  time  contents  lions  one  harbour  fur  seals  were  Inlet.  and h a r b o u r  the sea l i o n s  and  collected  sea l i o n s  ring  available  that  any a c t i v e  hake  and  f e e d i n g on h a k e .  f e e d i n g on h e r r i n g ,  i n , B a r k l e y Sound  and  the large  at that  time  c o m p e t i t i o n between these when t h e i r  relative  two  than  both  seals. 300 sea  i n the  (four  to  actively  harbour  f e e d i n g on h e r r i n g  i n the area,  particularly  considered.  were  f u r seals ratfish,  was  were  usually  seals  found  greater  25 f u r seals,  of harbour  (two s t o m a c h s ) were seal  were  were  similar  were  seals  sedentary  approximately  number  t h e r e was  The f u r s e a l s  Indicated that  of f u r seals  unlikely,  distribution  f e e d i n g on h e r r i n g ,  sea  the three pinnipeds  t o t h e more  an unknown  were  numbers  although  there  1958,  sea l i o n s  i n contrast  and  Stomach  Sound;  i n Knight  to shore  this  February,  i n Barkley  observed  close  At  seals  at this  some  b e e n f e e d i n g on  harbour  t h e one  found  to the beach.  Therefore,  while  were  Kleen River;  the shore  e s t u a r y had  into  -  71  area.  stomachs  with  smelts,  while  and w h i t i n g ; Although the  both  small  volume  of  her-  of year, i n d i c a t e d species  was  distributions  were  - 72 Sea  l i o n s are  of f u r s e a l s , and on May  21,  -  r a r e l y found o f f s h o r e  i n 30 fathoms of water.  and  hy volume d u r i n g May,  c o n t a i n f l a t f i s h , but  Pur  c o l l e c t e d 10 m i l e s out-  predominately on  196l) had  on u n i d e n t i f i e d f l a t f i s h .  However,  This animal, k i l l e d  waters where f u r s e a l s were f e e d i n g (75$  vicinity  when l o c a t e d are d i f f i c u l t to k i l l .  I 9 6 l , a young sea l i o n was  side T o f i n o  i n the  been f e e d i n g  on  in  herring lingcod  s e a l stomachs o c c a s i o n a l l y  l i n g c o d have never been i d e n t i f i e d  in  stomachs c o l l e c t e d i n B r i t i s h Columbia waters. On T r i a n g l e I s l a n d a small p o p u l a t i o n s e a l s l i v e near 500-600 sea  lions.  The  small r o c k s s i t u a t e d a few yards to one I s l a n d , w h i l e harbour s e a l s h a u l main i s l a n d spend c o n s i d e r a b l e the  outer r e e f s  (Figure l 6 ) .  been seen outside  the  two  species.  identified  i n an examination of 35  l i o n rock or a group been observed fed  s a b l e f i s h , n e i t h e r of which have been s e a . l i o n stomachs w i t h food  Island.  Thus > i n t e r - s p e c i f i c competition  appears to be  neg-  i n B r i t i s h Columbia waters even though i t i s known  t h a t i n s e v e r a l Instances the upon by  p o o l s behind  harbour s e a l s c o l l e c t e d had  and  ligible  the  O c c a s i o n a l l y harbour s e a l s have  no a n i m o s i t y has Two  on  mile o f f T r i a n g l e  time i n p r o t e c t e d  on l i n g c o d  from T r i a n g l e  small  sea l i o n s haul out  on the beaches of  s u r f , near a sea  of swimming sea l i o n s , but between the  out  of 25 harbour  each of the  three pinnipeds-.:.  areas where the three together,  same s p e c i e s  predators  intermingling i s rare.  cate t h a t the same food  species  of f i s h may  Iii the r e l a t i v e l y  (or only two  be  preyed few  of them) occur  When stomach contents i s b e i n g preyed upon by  inditwo,  Figure  16.  Triangle Island Top: harbour s e a l h a b i t a t behind b r e a k e r s . Sea l i o n r o c k i n f a r r i g h t background Bottom: sea l i o n r o c k w i t h T r i a n g l e I s l a n d i n background  - 7k or the t h r e e , predators  i n the same area and  the numbers of p r e d a t o r s  are so few,  so abundant t h a t competition  may  exist.  the prey  are concerned, however,  I n t e r m i n g l i n g of a d u l t f u r s e a l s , sea  l i o n s and harbour s e a l s was  observed d u r i n g June, 1962,  P o r t l o c k Bank, Gulf of A l a s k a ,  30 to liO m i l e s from  Whether or not a c t i v e competition  f o r food  f e e d i n g e x c l u s i v e l y on sandlance. surface e a t i n g r o c k f i s h twice  EFFECT OF SEAL AND  SEA  Sea and  on  the  shore.  occurred  determined as only f u r s e a l s were c o l l e c t e d .  the  species i s  is unlikely.  Where l a r g e r p o p u l a t i o n s competition  and  at the same time,  was  not  These l a t t e r were  l i o n s were observed at salmon once.  LION PREDATION  UPON BRITISH COLUMBIA'S COMMERCIAL FISHERY Two  problems must be faced when c o n s i d e r i n g pinniped  p r e d a t i o n upon the commercial f i s h e r y : and  sea l i o n p r e d a t i o n upon f i s h s t o c k s ;  p r e d a t i o n upon the commercial fisherman study has  attempted to f i n d  (a) the e f f e c t of s e a l (bj the e f f e c t of t h i s and h i s gear.  the answer to ( a ) .  The  (b) r e q u i r e s f u r t h e r i n v e s t i g a t i o n i n the form of and  Interviews  at present  w i t h fishermen.  undertaking The  questionnaires  such a program.  amount of salmon and h e r r i n g eaten by  i n s u f f i c i e n t data t o estimate by f u r s e a l s .  answer to  The Department of F i s h e r i e s i s  and harbour s e a l s has been estimated  eaten  This  i n Appendix 1.  sea  lions  There are  the amounts of h e r r i n g and  salmon  - 75 A.  Fur  seals Species  make u p  a  large  of  Over  contents  examined,  sablefish, herring, fishery  man.  the  of  past  can of  be  fish  small  only  serious,  being  they  hake,  by  as  heavily  the  cod, upon  the  trawl  i t is  these  exploited  predation  are  of  predation  exploited  regarding  f i s h e s as  are  in British  the  total  diet The  of  the  "miles  adult of  estimated  of  by  upon  other  either fished  spas-  q u a n t i t i e s by  fur  seals.  each year  by  In  addition,  intensity  of  the  length  categories  narrow bladed vegetation.  fish  and  species  taken  by  ii3$ t o  contribute  Clayoquot  is  The  on  the  vegetation,  The  of  spawn  of  of  index,  offshore  each  on  of  the  spawn  spawning, the  size  basis  of  deposited  spawn  of  expressed  as  eggs  square  is  consists  deposition.  i s expressed  per  movement  after  index  west  F i s h e r i e s and  numbers or  o f f the  Sounds  computed  deposition  based  the  An  amount  width  seals  with  Department  and of  fur  mid-March.  deposited.  the  inch  and  herring population  spawn"  of  coincides  during  measuring  broad  waters,  migration  Barkley  a peak  favoured  13).  Island  of  five  most  Columbia  northward  out  reaches  the  (Figure  Vancouver  herring  leafed  However,  are  65$  totalled  salmon,  species  Columbia  Herring  seals  of  the  importance  in British  have  potentially  i n very  fur  which  of  i s expressed  Herring  of  flatfish.  present  taken  they  herring,  which  modically  seal diet  years  as  at  l e s s e r economic  fur  regarded  valuable  or  or  include  some  commercially  coast  four  and  and  concern  1.  the  r o c k f i s h and  salmon  No  greater  part  waters.  groups  -  per  inch as  one  of linear  of  "miles  broadof  - 76  -  spawn", i s then c a l c u l a t e d by summing the lengths of a l l spawnings, a f t e r adjustments have been made f o r d i f f e r e n c e s i n i n t e n s i t y and width  (Outram, I 9 6 l ) .  I n d i c e s of abundance f o r 1958,  1959,  have been compared w i t h the per cent frequency h e r r i n g found  i n stomachs c o l l e c t e d  and  Sounds (Figure 17)•  Clayoquot  I960 and  1961  occurrence of  i n waters between B a r k l e y The  trend of a sharp  decrease  i n the s i z e of the h e r r i n g spawning p o p u l a t i o n as e x h i b i t e d by the "miles of spawn" index from 1958  to 1959,  levelling  an i n c r e a s e i n 1961  o f f from 1959  to i960, and  to be f a i r l y w e l l d u p l i c a t e d by the presence stomachs.  f o l l o w e d by a appears  of h e r r i n g i n s e a l  Thus, the magnitude of f u r s e a l p r e d a t i o n upon her-  r i n g i s a p p a r e n t l y r e l a t e d t o the abundance of spawning h e r r i n g . 2.  Salmon Salmon have occurred only 59 times  of  occurrence)  in a total  (5*8%  frequency  of 2113.stomachs examined.  Fur  s e a l s do not appear to show a p r e f e r e n c e f o r salmon and may, two  they  i n f a c t , p r e f e r s m a l l e r f i s h such as h e r r i n g , when the types of prey are a v a i l a b l e .  The  salmon aval l a b i l i t y i s the presence southern Vancouver I s l a n d :  of the t r o l l i n g f l e e t o f f  seals, c o l l e c t e d i n the  of t r o i l e r s presumably have had salmon.  In 1959,  vicinity  an o p p o r t u n i t y to prey upon  D u r i n g i960, i n nine stomachs c o n t a i n i n g food  i n the v i c i n i t y of the t r o l l i n g f l e e t contained  only i n d i c a t i o n of  salmon.  H e r r i n g was  collected  on La Perouse Bank, none  the predominate food s p e c i e s .  s i x stomachs c o n t a i n i n g h e r r i n g were c o l l e c t e d i n an  area where salmon were r e p o r t e d as p l e n t i f u l by  trollers.  D u r i n g the 196l p e l a g i c c o l l e c t i n g program there was  an  apparent  77  lb % frequency occur. M i l e s o f spawn Ik  -  1960  1959  »58  1961  Year F i g u r e 17.  If  Per cent frequency o f o c c u r r e n c e o f h e r r i n g i n f u r s e a l stomachs " o f f s o u t h e r n Vancouver I s l a n d and m i l e s o f h e r r i n g spawn i n B a r k l e y and C l a y o quot Sounds (139 stomachs).  - 78 increaae  of small  reported  by commercial  empty  when  these  negative  coho  collected  increased  abundance There  Trawl The  most  i n seal  f u r seals  stomachs  with  (Figure but  food  be  t o o deep  apparently 'in.the  were  reflected  frequency  under  an  of  occur-  c a t c h of  study.  A  commercial  Strait. during  diet.  data  these  fish  between  18.  There  seal  years.  stomach  not only  between  totalled  contents food  fish,  and a r e  t h e two  Commercial  1951)•  a r e second  o f 38  a v a i l a b l e on t h e g r o u n d s .  ij-5 a n d 63  (Kenyon,  four  or p e t food  relationship  i n Figure  total  Rock  consideration,  include  f o r mink  of bottom  not t o o abundant,  inclu-  Hecate  with  caught  t o 1962  of the White  compared  caught  1959  iden-  fishery.  i n the v i c i n i t y  have  f o r f u r seals  f u r seal  from  across  species  e x p l o i t e d by t h i s  under  been  passes  and s e v e r a l f i s h  collected  i s little  fish  f u r seals  f o r t h e two months  illustrated  mature  i n stomachs  and t h e c o m m e r c i a l  and March,  hunted  species  There  large  are also  representative  statistics  were  Despite  probably  between  o f many  banks,  i n northern  These  also fish  therefore  fishing  were  years,  18).  path  February  statistics  three  of salmon  which  i n the areas  stomachs  ground  for  stomachs  salmon.  stomachs  migratory  trawling  Catch  seal  as  fishery  During sive,  of small  Sounds,  of trollers.  the occurrence  salmon  of the trawl  tified  i n the v i c i n i t y  i n seal  and coho  3.  However,  i s no c o r r e l a t i o n  of salmon  and C l a y o q u o t  196l ( o v e r i 9 6 0 ) ,  during  spring  trollers.  results  increased  rence  o f f Barkley  grey  cod a r e  fathoms,which Whiting,  i n importance  are v i r t u a l l y  sets of  may  although to herring  no s a b l e f i s h  of  F i g u r e 18.  T r a w l f i s h e r y c a t c h s t a t i s t i c s f o r 1959-1961 (White Rocks f i s h i n g g r o u n d s ) , and f u r s e a l stomach c o n t e n t s c o l l e c t e d from t h i s v i c i n i t y .  - 80 commercial  size  i n this  some o f t h e t r a w l  area,  catches;  but small  these  s a b l e f i s h do show I n  smaller f i s h  a r e t a k e n by  seals. Studies  conducted by the F i s h e r i e s R e s e a r c h Board  o f Canada have  shown t h a t  sablefish,  quently  school  together.  When l o o k i n g f o r f i s h  herring  caught  i n h e r r i n g purse  in  l a r g e numbers, o t h e r  (9"-LIL")  Herlinveaux, rise  n  Inlet  were w e l l  I96l).  valuable  than  two s p e c i e s sablefish  Exploratory  fishing  grey  and s a b l e f i s h  mingle with  the h e r r i n g  c o d and f l a t f i s h  remain  upon by f u r s e a l s .  Sea l i o n s Commercially valuable  total grey  sea l i o n  sample.  cod, w h i t i n g ,  rockfish.  Several  fish  contributed  These i n c l u d e h e r r i n g ,  flatfish, o f these  salmon, hake,  halibut, sablefish, fisheries  52.5$ t o t h e  l i n g c o d and  are not f u l l y  utilized  by  man and o n l y t h e h e r r i n g , s a l m o n and h a l i b u t f i s h e r y  be  discussed 1.  Herring  upon h e r r i n g as a f o o d ; diet  will  i n detail.  Compared t o f u r s e a l s , s e a l i o n s  in  with  ( B a r r a c l o u g h and  small whiting  t h e b o t t o m , and a r e s e l d o m p r e y e d  B.  only  o f f t h e bottom  Therefore,  commercially  other  fre-  i n d i c a t e d t h a t h e r r i n g and  o f f t h e b o t t o m and i n some c a s e s  schools; on  (ll -ll|.").  i n Saanich  (12")  small whiting  seines, the  and h e r r i n g  t h a n h e r r i n g , were s m a l l  and s m a l l w h i t i n g  mid-water t r a w l s  whiting  i s h e r r i n g compared  certain localities  approximately  do n o t rejLy so much  10$ o f t h e s e a l i o n s '  t o 1+3$ f o r f u r s e a l s .  sea l i o n s  prey  Nevertheless,  e x t e n s i v e l y upon h e r r i n g  - 81 during close  the to,  winter  herring  As  mentioned  earlier,  lions  are  Sound a  food  octopus the  of  30  winter  29  XI).  rockfish  exclusive diet  of  to  food  on  examined which  the  lions,  from  even  until the  that  sea April.  Barkley  l6 times  the. most  relatively  indicate  Barkley  Each winter,  occurred was  swimming  herring.  into  remaining  items,  However,  sea  fishermen  feeding  spawn.  waters,  been  remains  by  h e r r i n g migrate  Herring,  identifiable  (Table  and  19lii.  have  observed  seines,  months  i n these  stomachs  since  of  item  the  a l s o found  area  total  are  in, their  during  total  and  or  Sound  A  months,  high  important number  h e r r i n g were  i n areas  of  in  of  not  herring  abun-  dance.  Table XI. Contents o f 23 s e a l i o n s t o m a c h s f r o m B a r k l e y S o u n d : 1I4. c o l l e c t e d i n D e c e m b e r , 1915 (Newcombe e t a l . , 1918); n i n e c o l l e c t e d d u r i n g the present investigation.  Frequency  Species  16 3 3 1 1 2 1 1 1  Herring Rockfish Octopus Skate Lingcod Flatfish Whiting Squid Dogfish  for  the sea  55.2 10.3 10.3 3-* 3.5' 6.8 3-5 3.5 3.5  Salmon The  both  Frequency  29  Total  2.  %  fur lion  overall seal and  and  percentage sea  lion  c o n t r i b u t i o n of  diet  5«8$ f o r f u r s e a l s .  i s quite  salmon  similar:  However,  predation  to 5.6$ by  -  -  82  f u r s e a l s begins when salmon are s t i l l A p r i l and May i n waters examined.  o f f s h o r e , d u r i n g March,  Sea l i o n p r e d a t i o n  i n June, and d u r i n g J u l y and August a p p a r e n t l y (Table X I I ) .  begins  increases  F o l l o w i n g the summer b r e e d i n g a c t i v i t y most male  sea l i o n s and females without  pups leave the r o o k e r i e s and  move t o haul-out rocks c l o s e r t o the mainland, o r i n t o the inlets.  During  t h i s time there i s a f u r t h e r p r e d a t i o n upon  salmon. The  S c o t t I s l a n d rookery,  s i t u a t e d at the n o r t h 'end  of Vancouver I s l a n d , i s advantageously  l o c a t e d f o r sea l i o n  p r e d a t i o n upon t h e l a r g e salmon runs moving toward the spawning r i v e r s on the mainland.  During the years under study t h i s pop-  u l a t i o n has v a r i e d from 1 , 7 ° ° t o 1 , 1 0 0 a d u l t s per b r e e d i n g season.  From a t o t a l of 6 3 occurrences  of i d e n t i f i a b l e  food  remains only f o u r ( s i x per cent) were salmon (Table X I I ) . ever, t h i s f i g u r e may be m i s l e a d i n g l y low.  How-  There was v i r t u a l l y  no p r e d a t i o n upon salmon i n t h i s area d u r i n g May, June and September, but salmon occurred  i n three of the f o u r stomachs  c o l l e c t e d d u r i n g J u l y and August.  Commercial catches of  sockeye, coho and p i n k salmon i n f i s h e r i e s area 1 2 , which i n c l u d e s the S c o t t I s l a n d s , r e a c h a peak d u r i n g J u l y and August. Therefore,  the main salmon runs pass these r o o k e r i e s d u r i n g the  months when there are very few data on sea l i o n f e e d i n g h a b i t s . Although  no d i r e c t evidence  the e f f e c t of sea l i o n s on these pares  i s available regarding  salmon runs, F i g u r e 1 9 com-  the t o t a l salmon c a t c h i n area 1 2 w i t h the r e d u c t i o n of  the S c o t t I s l a n d sea l i o n p o p u l a t i o n s i n c e 1 9 5 6 . i n sea l i o n s has not r e s u l t e d In a corresponding  The r e d u c t i o n increase i n  -  the commercial salmon  83  -  catch.  Table X I I . Contents from 5 2 sea l i o n stomachs from the S c o t t I s l a n d s and adjacent waters. (Data from p r e s e n t i n v e s t i g a t i o n only. )  June  1  July  2  August  1  September  TOTALS  Flatfish  1  Ratfish  2  Herring  5  ' Mackereljack  II  Squid  Dogfish  10  Whiting  Rockfish  May  Octopus  Salmon  Month  Hake  Stomach c o n t e n t s ( f r e q u e n c y o f o c c u r r e n c e )  22  16  17 1  *  3 1  6  7  2  1  1  1  1  1  20  Salmon p r e d a t i o n by the Cape S t . James sea l i o n s d u r i n g the summer months of June, J u l y and August may not be as s e r i o u s as around the S c o t t I s l a n d s .  D u r i n g J u l y , the only  month when salmon were encountered In stomachs from Cape S t . James, these s p e c i e s were found once i n a t o t a l of t e n i d e n t i f i a b l e food occurrences. F o l l o w i n g the gradual breakup u l a t i o n , which begins d u r i n g August  of the b r e e d i n g pop-  and e a r l y -September, some  sea l i o n s f o l l o w and prey upon salmon i n the c o a s t a l Stomachs from three female sea l i o n s ,  inlets.  c o l l e c t e d at the mouth  of K l i n k w o l Bay i n the Queen C h a r l o t t e I s l a n d s , October, i 9 6 0 ,  - 81+ -  35  3500  r  30  ra  -  3000  TS  C  o  PH  o M  c  o  •H r r j CVJ •H H  20  -  -  2000  10  -  -  1000  CO  O <•  -P  as co O <D •H O CD  ;E .C rH ra as *H  CO fx,  as •H  o U  <D  s E  o o  1954  1955  1956  1957  1958  1959  i960  1961  Year  Figure  19:  Salmon catches ( a l l s p e c i e s ) and t h e decreasing sea l i o n p o p u l a t i o n i n f i s h e r i e s a r e a 12, f r o m 1951+ t o 1961.  - 85 contained remains of p i n k and chum salmon. pregnant  and had  These three were  t h e r e f o r e moved from a breeding rookery  (pro-  b a b l y Gape S t . James) some time d u r i n g the l a t e summer. 3.  Halibut Although  sea l i o n s eat h a l i b u t , there i s l i t t l e  docu-  mental evidence t o help assess the extent of t h i s damage. i b u t were i d e n t i f i e d  once from a stomach c o l l e c t e d  Hal-  on the west  coast of the Queen C h a r l o t t e I s l a n d s ; a sea l i o n was  observed  e a t i n g a h a l i b u t at the s u r f a c e i n n o r t h e r n Hecate S t r a i t March 6, 1959. i t may  Prom the s c a r c i t y of h a l i b u t i n stomach contents,  be guessed  t o reduce h*  on  t h a t sea l i o n p r e d a t i o n i s not s e r i o u s enough  e x i s t i n g stocks of t h i s s p e c i e s . A v a i l a b i l i t y of f i s h around sea l i o n  rocks  The numbers of f i s h i n the immediate v i c i n i t y of sea l i o n haul-out and b r e e d i n g rocks was was  done with s t a i n l e s s s t e e l j i g s .  investigated.  Fishing  R e s u l t s from e x p l o r a t o r y  f i s h i n g c r u i s e s were a l s o examined. A l a r g e trawling.;ground, 60 square m i l e s i n extent, has r e c e n t l y been found w i t h i n 15 m i l e s of the S c o t t I s l a n d s ' rookeries  ( H i t z et_ al_., 1 9 6 l ) .  fathoms of water, averaged  750  Catches  of rock s o l e , i n 50  l b s per hour.  In deeper tows  (70-120 fathoms) rock f i s h dominated the catches.  Sea  lions  can d i v e t o depths of 100 fathoms, and f r e q u e n t l y d i v e t o 60 and  80 fathoms (Kenyon, 1951). The Cape St. James area was  a l s o examined f o r e v i -  dence of s e r i o u s sea l i o n depredations upon commercially uable f i s h e s .  A v a i l a b l e evidence i n d i c a t e d t h i s t o be  val-  slight.  Waters adjacent t o these r o o k e r i e s are f i s h e d f o r h a l i b u t  and  - 86 have  been  f o r many y e a r s .  Skunggwai, received  Island,  i t s name f r o m  rockfish, was  on Anthony  found  before  T h e new  deserted  15 m i l e s  the large  i n the vicinity  any c o n t r o l measures  north  numbers (Duff were  Indian  village  of these  of fish,  exerted  rookeries,  particularly  1957).  a n d Kew,  of  upon  This  the sea l i o n  population. The ability  following three  of f i s h ,  mostly  observations  indicate the a v a i l -  r o c k f i s h and l i n g c o d ,  around  sea l i o n  rocks: (a)  April sp.)  7, were  Sound, (b)  adult Three  small  ruberrimus)  (Sebastodes  maliger)  at Bright  September and in  ill  large  one h o u r  nursing  reducing  were  lions  strengthened  rocks. over  lingcod,  caught Queen  Three  lingcod  Barkley  two r e d s n a p p e r s spotted half  rockfish  an hour's  Strait,  where  were h a u l i n g o u t . jigged  (Sebastodes  Island  Island,  Charlotte  males,  (Sebastodes  wintering.  within  large  at Sartine  t h e numbers  haul-out  were  r e d snappers  pups  Sea  lingcod  26, i960.  were  and two o r a n g e  Island,  mostly  at Polger  sea l i o n s  (Sebastodes  sea l i o n s ,  a n d two r o c k f i s h  i n 25 m i n u t e s  200  8, I 9 6 l .  March  50  and  Six lingcod  caught  where  fishing  (c)  1958.  where  10 m i n u t e s  i n  ruberrimus)  300  adults  caught  with  250  located.  have  little  of f i s h A  i n the v i c i n i t y  general  the past  o r no e f f e c t  four  observation, years  and r o c k f i s h a r e abundant  near  i n seriously of their which  has been  of c o l l e c t i n g , sea l i o n  rookeries  i s that  rocks.  - 87 C.  Harbour s e a l s P i s h of commercial value comprise Shf° °?  seal diet.  the barbour  These i n c l u d e h e r r i n g , salmon, eulachon, hake,  whiting, f l a t f i s h ,  s a b l e f i s h and l i n g c o d .  Concern i s d i r e c t e d  mainly towards the p o s s i b l e e f f e c t of harbour s e a l p r e d a t i o n upon h e r r i n g and salmon. 1.  Herring T h i s s p e c i e s i s important t o harbour s e a l s ,  the present study may not show i t s true importance. i n d i c a t e s only a 12$ c o n t r i b u t i o n t o the t o t a l d i e t  although The sample  (Figure  13), but h e r r i n g have been found i n stomachs c o l l e c t e d  during  A p r i l , J u l y , September and November - e s s e n t i a l l y throughout the e n t i r e y e a r .  There are few, i f any, complaints from the  f i s h i n g i n d u s t r y r e g a r d i n g harbour s e a l p r e d a t i o n upon h e r r i n g . 2.  Salmon Harbour s e a l p r e d a t i o n upon salmon may be e x t e n s i v e  at c e r t a i n times of the year.  Salmon c o n t r i b u t e d  approximately  30$ t o the contents of a sample c o l l e c t e d f o r the most p a r t near salmon spawning streams d u r i n g the f a l l ;  sampling  that salmon are a l s o eaten d u r i n g the summer months,  indicate  particu-  l a r l y June. However, s e a l s prey on other food even when salmon are abundant.  F i s h e r (1952) d i s c u s s e d the r e l a t i v e Importance  of salmon In. the harbour s e a l d i e t the summer months. numerous,  on the Skeena R i v e r d u r i n g  He noted' t h a t , although salmon were very  other f i s h species were preyed upon, p a r t i c u l a r l y  as the s e a l s moved towards the sea a f t e r pupping.  Since F i s h e r  study, I|5 more stomachs have been c o l l e c t e d from t h i s area and  - 88 -  examined  June,  and  feeding Of  by Department  1959*  occurs  the four  once  Forty  stomachs  Fisher  tions,  also  of  the bay.  Bay,  and  Bay.  1958.  the to are  feeding  little  o f June  at least.  twice,  a lamprey  salmon  migrasalmon.  a harbour seal  there  killed  rockfish,  i n Howe salmon  octopus  movement  of seals  present  i n Luxanna  i n Barkley  had eaten  on  a t t h e head  was no  evident  col-  was f e e d i n g  a creek  w h i c h were  was a l s o  stomachs  hake,  Sound  although  i n the area. on food  stomachs  have  Harbour  t h e summer  been  than  salmon or  recorded  not t o  predation,  but t o  f i g u r e s on numbers o f  seals  are scattered  over  and i t i s n o t adequate  population  I t appears  creeks  other  of seal  and f a l l  i s a total  on salmon.  o f salmon  during  s e a l s were  collected  observations  as t h e r e  into  was n o o b v i o u s  of behaviour  of three  Islands,  contained  (orherring)  on s a l m o n .  during  say that  vicinity  three  the necessity f o raccurate  preying  coast  moving  the possible seriousness  illustrate  19k&»  that  a n d one c o n t a i n e d  Charlotte  stomachs  i n harbour seal  minimize  River  away, w h e r e  there  h e r r i n g were These  seals  These  One h a r b o u r s e a l  spawning  part  occurred  investigation  time  10 m i l e s  Thus,  type  indicating  i n a sample  herring  s a l m o n were  the salmon  This  herring  contained  A t t h e same  greenllng.  following  in  pink  creek.  during  of the Fraser  Bay, Queen  approximately  spawning  empty  salmon  that  the present  i n Luxanna while  River  food,  noted  a t t h e mouth  During  herring  with  were  June,  during  once.  two s t o m a c h s  lected  of these  on t h e Skeena  and f e a t h e r s  collected  of Fisheries o f f i c i a l s  that  of X  only  c a n be r e g a r d e d  seals, a l l  those  i n the  as p o t e n t i a l  predators.  - 89 CONCLUSIONS A.  Effect  of f u r s e a l s , sea l i o n s and  commercially Pur  valuable  harbour s e a l s upon  fish  s e a l s , sea l i o n s and harbour s e a l s eat f i s h  commercial importance, e s p e c i a l l y h e r r i n g and i s the most important  food f o r the m i g r a t i n g f u r s e a l  moving up the B r i t i s h Columbia animals;  i t i s preyed  upon from January t o June.  by  sea l i o n s and  The  t h i s f i s h whenever i t i s mainly  t o t a l tonnage of h e r r i n g  harbour s e a l s has been estimated  (2,14,00-13,250) tons,  herd  Harbour s e a l s  In c o n t r a s t , sea l i o n s feed upon h e r r i n g  d u r i n g the winter months.  Herring  coast, and f o r t h e . w i n t e r i n g  a l s o feed on h e r r i n g and w i l l take available.  salmon.  of  at  eaten  1 2$0 t  or ii$ (1.0-6.2$) of the average annual  commercial c a t c h of 200,000 tons  (Appendix  1}  H e r r i n g are subjected t o i n t e n s e p r e d a t i o n throughout their entire l i f e  c y c l e by many f i s h , b i r d s and  m o r t a l i t y of mature and  maturing f i s h i s up  mammals.  to 80$,  Total  of which  an average of 50-60$ r e s u l t s from n a t u r a l m o r t a l i t y i n ages five  t o twelve years  (P. H. C. T a y l o r , p e r s o n a l  P i n n i p e d p r e d a t i o n , a c c o u n t i n g f o r an estimated  communication). 5$ of the  average annual c a t c h , i s not a s e r i o u s f a c t o r i n h e r r i n g mortality. Salmon a l s o are taken by these M i g r a t i n g f u r s e a l s o c c a s i o n a l l y take fish,  o f f the west coast  predators.  salmon, u s u a l l y small  of Vancouver I s l a n d , as salmon are  moving towards c o a s t a l waters. cannot be evaluated  three  Pur  s e a l p r e d a t i o n upon salmon  u n t i l the numbers of s e a l s p r e y i n g upon  - 90 these  species  can  he  estimated.  particularly  d u r i n g the  the  However,  rivers.  effort  to  congregate  salmon  are  to  salmon.  in  the  mouths  of  Sea as  the  lions and  probably upon  harbour  annually,  chum  four  per  cent;  imately  to  50$  the  salmon  the  salmon, into  make  a  and  special  when  exclusively  of  d u r i n g the  salmon  into  In  bays  seals  collected  summer  months  addition,  and  be  river  sea  mouths,  to  rates  vary  are  was  f o r each  (Appendix  high both  one  species.  Pishing  mortality  of  returning  to  depending  upon  The  seals  take  present an  per  assumed  ocean  1956)'  and  Ricker  adult  species  study  to  2.5$  average  1). water  survival and  of  twentyapprox-  (1962) e s t i vary from  salmon  that of  95$  ranges  (Shepard  indicates  equal  the  average  to  pounds  in fresh  cent  to  sockeye  the  amount  lions  (0.8-1]..7$) o f catch  between  survival  cent  total  sea  (1953) e s t i m a t e d f r e s h w a t e r  Neave  ocean  2.5$  commercial  mortality  by  I4..0 (1.2-7.1) m i l l i o n  i s approximately annual  eaten  of  harbour  diet  rookeries.  to  80$,  diet  upon  moving  abundance,  the  losses  Stevenson, and  upon  i s estimated  per  are  always  their  of  prey  there.  salmon  average  61+$.  from  five  30$  salmon  ocean.  and  restrict to  not  salmon  of  pound  pink  of  salmon  do  amount  Salmon the  seals  seals  streams.  past  follow  which  ll|.8 m i l l i o n  up  prey  total  seals  not  salmon  them  The  mated  do  salmon migrate  prey  and  harbour  form  lions  when t h e  i n areas  available Salmon  fall  Harbour  and sea  the  lions  fishing  mortality. What populations  role  i s not  predators play fully  i n the  understood.  r e d u c t i o n of  these  (1962) h a s  shown  Elson  - 91 that b i r d predation existence  can  the  No  sea.  upon young salmon d u r i n g  t h e i r freshwater  s e r i o u s l y reduce the number of smolt s e n t e r i n g study has  yet been made to determine the e f f e c t  of p r e d a t o r s upon salmon d u r i n g t h e i r ocean Parker  (1962)  has  existence.  estimated, on a t h e o r e t i c a l b a s i s ,  t h a t although a c o a s t a l n a t u r a l m o r t a l i t y f a c t o r could be culated  f o r adult migrant salmon, such m o r t a l i t y was  and  of n e g l i g i b l e i n f l u e n c e  was  slight  on the t o t a l m o r t a l i t y .  study supports these t h e o r e t i c a l  This  conclusions.  I wish to emphasize t h a t knowledge concerning e f f e c t of p i n n i p e d s , f a r from complete. it  Although the  c o a s t a l zone has  been fur  studied,  seals  In a d d i t i o n , v i r t u a l l y n o t h i n g i s known about  the f e e d i n g h a b i t s  of adult  f u r s e a l s which must winter  migrate over much of the mid-North P a c i f i c Ocean. are u s u a l l y s c a t t e r e d few  the  p a r t i c u l a r l y f u r s e a l s , upon salmon i s  Is d i f f i c u l t t o estimate numbers of m i g r a t i n g  i n t h i s area.  cal-  and  difficult  and  These s e a l s  t o hunt; as a r e s u l t very  have been c o l l e c t e d f a r t h e r than 20 0 m i l e s from shore  during  the present p e l a g i c f u r s e a l program. D u r i n g June, 19&2,  however, a Canadian v e s s e l  l e c t e d t h i r t y - s e v e n s e a l s i n the middle of the Gulf Salmon occurred  i n ten of the 26  stomachs w i t h food.  c l u s i o n s can be drawn from such a small  summarize b r i e f l y :  of the  each year sea l i o n s  annual commercial salmon catch and  amount of h e r r i n g e q u i v a l e n t  No  con-  is indicated.  harbour s e a l s consume an estimated amount of salmon to 2.5$  Alaska.  sample although the  d e s i r a b i l i t y of f u r t h e r c o l l e c t i o n s o f f s h o r e To  of  col-  and equivalent  an estimated  to h$> of the annual commercial  - 92 h e r r i n g catch.  P r e d a t i o n at thi.s l e v e l i s not b e l i e v e d to be  a s e r i o u s f a c t o r i n e i t h e r salmon or h e r r i n g m o r t a l i t y .  More  c o l l e c t i n g should be done o f f s h o r e t o determine the e f f e c t of f u r s e a l s upon ocean salmon.  H a l i b u t stocks on the B r i t i s h  Columbia coast appear t o be u n a f f e c t e d by p i n n i p e d  predation.  - 93 LITERATURE  CITED  A b e g g l e n , C. E . , A . Y . R o p p e l a n d P . W i l k e . 1958. seal investigation, Pribilof Islands, Alaska. and W i l d l i f e S e r v i c e . Unpublished report, v i i i  Alaska f u r U. S. P i s h 187 p p .  A b e g g l e n , C. E . , A . Y . R o p p e l a n d P. W i l k e . i960. A l a s k a f u r seal investigation, P r i b i l o f Islands, Alaska. U. S. P i s h and W i l d l i f e S e r v i c e . Unpublished report, v i i i 165 p p . A l e x a n d e r , A. B. 1892. Data on t h e food o f f u r s e a l s collected b y A . B . A l e x a n d e r o n t h e C o r w i n , 1892 ( G u l f o f A l a s k a ) . L i b r a r y o f t h e I n t . P i s h . Comm., S e a t t l e , W a s h . Unpublished A l l e n , J . A . 1880. 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W i l d l i f e M a n a g e m e n t , ^ ( i j ) : 353-359.  - 99  -  T u r n e r , W. 1887. R e p o r t on t h e s e a l s . I n T r a n s p o r t a t i o n of r o c k p a r t i c l e s b y s e a mammals, b y K. 0. E m e r y , J . S e d i m e n t a r y P e t r o l o g y , 11(2): 92-93. W i l k e , P. a n d K. W. K e n y o n . 1952. seals, s e a l i o n s and h a r b o u r M a n a g e m e n t , 16(3)* 396. W i l k e , P. a n d northern  N o t e s on porpoise.  the food of J. Wildlife  fur  K. W. K e n y o n . 1954* M i g r a t i o n and f o o d o f t h e fur seal. T r a n s . 19th N. A m e r . W i l d . C o n f . ,  p p . l4.3O-l4.l4_O. W o l l e b a e k , A. 1907. U b e r d i e B i o l o g i e d e r S e e h u n d e und die Seehundjagel i n europaeischen Eismeer hauptsaechlich n a c h N o r w e g i s c h e n Q u e l l e n . Rapp. Cons. E x p l o r . Mer.,  8:  5-82.  - 100 APPENDIX 1:  A q u a n t i t a t i v e e s t i m a t e of t h e e f f e c t o f s e a l i o n s and h a r b o u r s e a l s on t h e B r i t i s h C o l u m b i a s a l m o n and h e r r i n g fisheries.  Effective ring  eaten  mation:  by p i n n i p e d s  (a) d a i l y  of predators item;  I n order  lowing procedure (a) D a i l y food  (b) Numbers  (b) numbers  on e a c h r e s p e c t i v e f o o d t o the t o t a l  t o complete the c a l c u l a t i o n s  food  below, t h e f o l -  has been f o l l o w e d : T h i s r a n g e s f r o m 2% t o 11$  a mean o f 6 $ ( T a b l e V ) .  o f t h e body  A l lcalculations  vicinity  on how l o n g t h e p r e d a t o r  are "  c o n t r i b u t i o n of each item.  been taken The  daily  the  number  the  per cent  frequency  from Table  intake  T h i s has b e e n  of occurrence  out by m u l t i p l y i n g  by t h e number o f d a y s o f f e e d i n g , by  following calculations  often incomplete;  13.  f r o m mean body w e i g h t ) b y  c o n t r i b u t i o n of t h e p a r t i c u l a r -  calcu-  b a s i s , and  V I and V I I and F i g u r e  (estimated  of predators,  The  Predation  p o p u l a t i o n was i n  c a l c u l a t i o n s have b e e n c a r r i e d  food  The h i g h e s t  of i t s prey.  on a p e r c e n t  the  and d u r a t i o n o f p r e d a t i o n .  o f a p o p u l a t i o n s i z e h a s been u s e d .  i s based  lated  are  prey  c o n t r i b u t i o n of e a c h p r e y  of predators  (c) Per cent  has  intake of each predator;  i n brackets.  estimate  the  on t h e f o l l o w i n g i n f o r -  on 6 $ o f t h e body w e i g h t w i t h t h e p o s s i b l e r a n g e  included  time  o f t h e amount o f s a l m o n and h e r -  must be b a s e d  long they  intake.  weight, w i t h based  food  and how  (c) per cent  Intake.  estimates  food  are based  f u r t h e r s t u d i e s may a l t e r  item.  on d a t a these  which estimates.  A.  Sea l i o n s The  lb;  mean f e m a l e s e a l i o n w e i g h t i s 177 k g , o r J4.50  a representative  sample o f males h a s n o t been weighed.  However, a s l a r g e a d u l t m a l e s f r e q u e n t l y weigh:.!,500 l b , t h e mean f e m a l e w e i g h t h a s b e e n d o u b l e d t o a r r i v e w e i g h t o f 900 l b f o r t h e t o t a l 1.  population  r e q u i r e an e s t i m a t e d  Herring, forming (1,550-8,500) 2.  population.  Herring The  will  o f IL,500 a n i m a l s  ( e x c l u d i n g pups)  87.5 (29.2-l60.li) m i l l i o n l b a n n u a l l y .  10$ o f t h i s  ( F i g u r e 13) w i l l  Salmon  of food  are required;  million lb.  f o r m s 10$ o f t h e d i e t  therookeries  approximately  t o sea l i o n s .  require  one-half, or  and move i n s h o r e  of approximately  O c t o b e r and November when t h e l a t e available  VII).  20.Ii (6-8-37-1+) m i l l i o n  non-breeding element o f t h e p o p u l a t i o n .  lions  o f 3,100 s e a  s a l m o n w o u l d c o n t r i b u t e 1.6 (0.5-3*0)  During the early f a l l  1,500 s e a l i o n s l e a v e the  intake  on t h e r o o k e r i e s f r o m May 15 t o S e p t e m b e r 15 ( T a b l e  D u r i n g t h e s e f o u r months a n e s t i m a t e d lb  c o n t r i b u t e It,650  tons.  S a l m o n c o n t r i b u t e 8$ t o t h e f o o d lions  a t a mean b o d y  to join  Therefore,  3,000 s e a l i o n s  salmon during  salmon runs a r e s t i l l  D u r i n g t h e s e two months 3,000 s e a  9-7 (3-2-17.8) m i l l i o n l b o f f o o d  and salmon  w o u l d c o n s t i t u t e 1.0 (0.3-1.8) m i l l i o n l b . Combining these two e s t i m a t e s c o n s u m p t i o n o f salmon by s e a l i o n s I4..8) m i l l i o n l b .  gives  o f summer and f a l l a figure  o f 2.6 (0.8-  - ro2B.  Harbour  seals  The 1.  mean b o d y  would 2.  of  numbers  entering  salt  Skeena  and  of  from  own  my  others  or  system  seals  on  the  annually  lb.  require  f o r m i n g 12$  of  annually.  on  salmon  (Department  plus  calculations  Skeena  River  system  period  o f 70  days  salmon  Fisheries of  runs  was  i n 37  files). 70  has  days  streams  Runs  of  i n each  Therefore,  to  per numbers  seals,  be  files).  salmon  regarded  seals  An  the  potential  lower the  seals  average  seasonal  a t random  creek  above.  For  o f 1,000  per as  i n the  upriver.  purpose i n the  predation duration  (Department  of a l l species  lasted  stream.  10,000 s e a l s w o u l d  An  officers  mentioned  estimated.  chosen  excluding  I f ten seals  streams  from  creeks  creek i s estimated  population  calculated  may  total  spawning  of f i s h e r i e s  hundred"  been  the  those  900  total  by  per  streams.  i n the  a  seals  seals  River,  these  of  this  9,000 s e a l s may  "several  number  of F i s h e r i e s  Skeena  plus  salmon  accessible  salmon  a maximum,  on  salmon  (1952) e s t i m a t e d t h e r e w e r e 1+00  average  100  coast.  Fisher  of  was  preying  average  multiplying  to ten harbour  working  upon  the  lakes  observations,  t a k e n as  predators  of  seals Herring  a p p r o x i m a t e l y 900  water  five  and  streams  are  River  average  is  food.  of harbour  stream  There  and  l b of  calculating  spawning  such r i v e r s  the  seals  Salmon  e s t i m a t e d by  salmon  harbour  2,600 (8£0-l+,750) t o n s  contribute  The be  23  e s t i m a t e d 20,000 h a r b o u r  (11+.1+-79.2) m i l l i o n  this  of  Herring The  1+3.2  weight  of  an ..  require  1+.2  (I.I+-7.7)  - io'a m i l l i o n l b of food f o r 70 days. would c o n s t i t u t e 1.3  Salmon forming 30$ of t h i s  (O.Ji-2.3) m i l l i o n l b .  When these estimates are combined sea l i o n s  and  harbour s e a l s eat an estimated 7,250 (2,li00-13,250) tons of h e r r i n g and li.O (1.2-7.1) m i l l i o n l b of salmon a n n u a l l y .  The  average annual h e r r i n g c a t c h i s 200,000 tons (Outram, 1 9 6 l ) , and p i n n i p e d p r e d a t i o n , t h e r e f o r e , may  account f o r an amount  e q u i v a l e n t t o 1L$ (1.0-6.2$) of the annual c a t c h .  The  average  annual salmon c a t c h i s 1I4.8 m i l l i o n l b and p i n n i p e d p r e d a t i o n may  account f o r an amount e q u i v a l e n t to 2.5$  the  annual commercial c a t c h .  (0.8-l4-.7$) of  -  Appendix  Table  I.  104  -  S c i e n t i f i c a n d common mentioned i n text.  names o f  food  items  Invertebrates F.  Mollusc a C.  Pelecypoda Y o l d i a rnyalis M y t i l u s sp. Mytilus californianus  C.  shellfish clam mussel mussel  Cephalopoda IS.  Order  Octopoda  octopus  Polypus hongkongensis Tremoctopus sp. S.'  Order  Decapoda  squid  Loli,g;o o p a l e s c e n s Gonatus magi s t e r G. fabricii G6natus sp. G o n a t o p s i s sp. G. borealis O n y c h o t e u t h i s sp. 0. banksii Ommastrepb.es s l o a n i W a t a s e n i a ac i n t i l l a n s Dosidicus gigas Moroteuthis lonnbergii Stenoteuthis bartrami Chiroteuthis veranyi A b r a l i o p s i s sp. P.  Arthropoda C.  Crustacea 0.  Decapoda Upogebia p u g e t t e n s i s Callianassa californiense Cancer oregonensis C. m a g i s t e r C. gracilis  crayfish, lobster, shrimp, crab  -  105  -  Hemigrapsua oregonensis Paguru s sp. P e t r o t i sthes c i n c t i p e s P. eriomerus Pinnixia schmittl Garidae Crago f r a n c i s c o r u m G. stylirostris Pandalus p l a t y c e r o s Vertebrates C.  Chondrichthyes Family  Petromyzontidae  Entosphenus t r i d e n t a t u s Family  Family  suckleyi  dogfish skate  Rajidae  Raja  Family  lamprey  Squalidae  Squalus  R.  Pacific  sp. big  binoculata  skate  Chimaeridae  Hydro l a g u s  colliei  ratfish  Family Pterothrissidae Pterothrissus  gissu  gisu  C..Osteichthyes Family  herrings  Clupeidae  Clupea pallasii C. H a r e n g u s Alosa sapidissima Sardinops melanosticta Family  Engraulidae  E n g r a u l i s mordax E. japonica Family  Salmonidae  Oncorhynchus 0. K i s u t c h 0. k e t a  gorbuscha  (clupeids)  Pacific herring Atlantic herring shad sardine anchovy Northern  anchovy  salmon pink coho chum  salmon salmon salmon  -  106  -  0, nerka 0. tshawytscha Salmo g a i r d n e r i S a l v e l i n u s sp. Family  smelts  Osmeridae'  Hypomesus p r . e t i o s u s  Mallotus =  Tillosus  Ihaleichthys pacificus Osmerus mordax  Family  sp.  macropus  Myctophidae  Electrona  barysoma  lantern  fish  blue  lantern  pearleye  barracudinas  Anotopteridae  Anotopterus  pharao  Family  Ophicnthidae  Family  Scomberesocidae  Cololabis Family  fish  Paralepidae  Magnisudis Family  arrow  Scopelarchidae  Scopelosaurus Scopelarchus linguidens Family  smelt  sp.  T a r l e t o n b e a n i a sp. T. crenularis Lampanyctus sp. L. nannochir' l a t i c f a u d a Myctophum c a l i f o r n i e n s e Notoscopelus elongatus Family  black  Melanostomiat.idae  Tactostoma Family  s u r f smelt capelin eulachon American smelt  Argentinidae .  Bathylagus Family  sockeye salmon s p r i n g salmon steelhead trout  saira  daggertooth snake  eels  Pacific  saury  Atherinidae  Atherinipsis  californlensis  jack  smelt  fish  - 107 Family  -  Exocoetidae  Cypselurus peduro Family Merluceiidae Merluceius  productus  hake  cods  F a m i l y Gadidae Theragra  Pacific  chalcogrammus  Follachius virens Gadus m a c r o c e p h a l u s G. m o r r h u a G. o g a e Melanogramtnus a e g l e f i n u s L o t e l l a sp. Microgadus proximus  whiting (walleye pollock) pollock P a c i f i c cod A t l a n t i c cod Greenland cod haddock Pacific  tomcod  Family Trachypteridae Trachypterus  rexsalmonorum  Family Pleuronectidae Atheresthes stomias Hippoglossus stenolepis Hippoglossoides elassodon H. p l a t e s s o i d e s Glyptocephalus cynoglossus Lyopsetta e x i l i s L. putnam Lepidopsetta b i l i n e a t a Parophrys vetulus Platichthys stellatus Pseudopleuronectes americanus O i t h a r i c h t h y s sp. Family  Embiotocidae  Damalichthy's Cymatogaster  vacca aggregatus  King-of-the-salmon f l a t f i s h , flounder arrowtooth flounder Pacific halibut flathead sole plaice witch flounder slender sole smooth f l o u n d e r rock sole lemon s o l e starry flounder winter flounder f l o u n d e r ( s a n d dab) sea  perches  s i l v e r perch s h i n e r , sea p e r c h  Family Trichodontidae Trichodon trichodon Family  Bramidae  Brama Family  Pacific  raii  pomfret  Scorpidae  Medialuna  californiensis  halfmoon  sandfish  - 108 Family =  Garangidae  Trachurus  Family  symmetricus  .japonicus  Promethichthys Trachurus Family  prometheus  japonicus  cuvieri  barracuda  Arioplopomatidae  Anoplopoma Family  fimbria  P l e u r p g r animus r n o n o p t e r y g u i s P. a z o n u s Ophiodon elongatus Scorpaenidae  sculpins  Scorpaenichthys  marmoratus  Family  Gyclopteridae  Family  Gasterosteoidea  Family  lingcod  yellow rockfish Bocaccio ocean perch widow p e r c h shortbelly rockfish r e d snapper redfish  Cottidae  Gasterosteus  greenling Atka mackeral^  rockfish  Sebastodes sp. 3. flavidus S. p a u c i s p i n i s S. a l u t u s S. e n t o m e l a s S. . j o r d a n i S. r u b e r r i m u s Sebastes marinus Family  sablefish  Hexagrammidae  Hexagrammos s p .  Family  squaretail  Sphyraenidae  Sphyraeiia sp. Family  mackeral (Pacific mackeral) snake mackeral ( b l a c k tuna) horse mackeral  Tetragonuridae  Tetragonurus Family  jack  mackerals  Scombridae  Scomber  mackeral  aculeatus  midshipman lumpsuckers  threespine  stickleback  Syngnathidae  Syngnathus  californiensis  kelp  pipefish  - 109 Family  Bathymasteridae  Bathymaster Family  signatus  Anarrhichadidae  Family  Stichaeidae  Family  Labridae  Tautogolabus Family  Zoarcidae  Family  Ammodytes  Ammodytes Family  hexapterus  woIffishes blennies  cunner eelpouts  sandlance  (launceJP  Batrachoididae  Porichthys  Glass  adsperSUB  searcher  notatus  midshipman (singing fish)  Aves . Aethia c r i s t a t e l l a Oceanodroma homochroa Fulmarus g l a c i a l i s Xema s a b i n i Ptychoramphus aleuticus Braehyramphus marmoratus Synthliboramphus antiquus  ashy p e t r e l fulmar sabine g i l l Cassin's auklet marbled raurrelet ancient murrelet  Appendix Table I I . Pinniped stomach contents from'collections made i n North American waters and the Western P a c i f i c .  Species of seal  Authority-  Month o f c o l l e c t i o n and location  *Number i n sample  I d e n t i f i e d food items (terminology o f each author has been maintained)  Northern fur seal  Taylor et a l . (1955)  Western P a c i f i c (February-June)  1,138  Squid, herring, anchovy, salmon, lantern f i s h , saury, "hake", mackerel, snake mackerel, rockfish, eel, birds.  Northern fur seal  Anon. (1962)  Western P a c i f i c (February-Oc tobe r)  3,769  Squid, gisu, sardine, anchovy, salmon, trout, pearleye, l a n tern f i s h , saury, Sphyraena sp., walleye pollock, L o t e l l a sp., horse mackerel, P a c i f i c mackerel, black tuna, Atka mackerel, Pleurogrammus azonus, Cyclopteridae, Cypselurus piduro, sandlance.  Northern fur seal  Alexander (1892) i n Taylor et a l . (1955)  Gulf o f Alaska  104  Squid, salmon, r o c k f i s h .  Northern fur seal  Lucas (1899)  Gulf of Alaska and Bering Sea ( A p r i l September)  409  Squid, octopus, lamprey, salmon, black smelt, cod, whiting, rockf i s h , c o t t i d , wolf f i s h .  Northern fur seal  Schultz and Rafn (1936)  Washington (spring)  41  Shrimp, squid, lamprey,  Northern fur seal  May (1937)  Washington (spring)  54  Squid, herring.  Northern fur s e a l  Bonham (1941) i n Taylor et a l . (1955)  Washington ( A p r i l )  Northern fur seal  Wilke and Kenyon (1954)  West Crawfish Inlet (December-March)  Squid, shad. 148  Squid, herring, whiting.  herring.  M H O  Species of seal  Authority  Month of collection and location  *Number sample  Identified food items (terminology of each author has been maintained)  Northern fur seal  Taylor et a l . (1955)  California, Oregon and Washington (FebruaryApril)  125  Squid, lamprey, shad, Pacific herring, anchovy, salmon, surf smelt, jack smelt, eulachon, saury, hake, sand dab, sablefish, rockfish, sandlance, bi rds.  Northern fur seal  Taylor et a l . (1955)  Alaska (June-July) . .  116  Squid, capelin, hake, sandlance.  Northern fur seal  Anon. (1962)  California (DecemberApril)  Northern fur seal  Anon. (1962)  Oregon (January-June)  Northern fur seal  Anon. (1962)  Washington (JanuaryApril)  1,781  Squid, octopus, dogfish, shad, herring, anchovy, salmon, surf smelt, eulachon, arrow fish, lantern fish, barracudines, saury, hake, king-of-the-salmon, f l a t f i s h , pomfret, halfmoon, jack mackerel, Pacific mackerel, black cod, rockfish, kelp pipefish, midshipman, birds.  93  Squid, lamprey, shad, herring, salmon, eulachon, Scopelosaurus, lantern fish, saury, hake, kingof-the-salmon, f l a t f i s h , jack mackerel, blackcod, rockfish.  480  Squid, lamprey, shad, herring, anchovy, salmon, surfsmelt, c capelin, eulachon, Osmeridae, lantern fish, saury,hake, whiting f l a t f i s h , sablefish, rockfish, stickleback, sandlance.  Species of seal  Authority  Month o f c o l l e c t i o n and l o c a t i o n  *Number i n sample  1,258  Northern fur s e a l  Anon. (1962)  Alaska (February-June)  Northern sea l i o n  Smith (1904)  C a l i f o r n i a (July-August)  Northern sea l i o n  Starks (1918)  California  Northern sea l i o n  Imler and Sarber (1947)  Alaska (May-August) . . .  Northern sea l i o n  Kenyon and Wilke (1952)  Alaska  Northern sea l i o n  Thorsteinson and Lensink (1962)  Alaska (summer)  56  Northern  Mathison et a l . (1962)  Alaska (summer)  114  13  I d e n t i f i e d food items (terminology o f each author has been maintained) Squid, lamprey, herring, salmon, capelin, eulachon, Osmeridae, lantern f i s h , daggertooth, grey cod, tomcod, whiting, f l a t f i s h , P a c i f i c sand f i s h , Atka mackerel, s a b l e f i s h , Hexagrammidae, rockf i s h , sculpins, Cyclopteridae, searcher, sandlance, b i r d s . Crab, octopus, squid, skate, shark, clupeids, perch, caranagoid f i s h , r o c k f i s h , hogfish. Squid, sardine, salmon, r o c k f i s h .  15  Octopus, skate, salmon, tomcod, whiting, starry flounder, arrowtoothed halibut, h a l i b u t . Cephalopod beak, cod, pollock, flounder, halibut, s t a r r y flounder, sculpin, sandlance. Crab, clam, mussel, s n a i l , squid, octopus, f l a t f i s h , h a l i b u t , greenling, rockfish, c o t t i d s , sandlance, lumpfish. CoeLentenates, segmented worms, sand d o l l a r , common bivalves, shrimp, crabs, isopods, unclass i f i e d crustaceans, lamprey, salmon, smelt, greenling, rockf i s h , sculpin, sandlance.  Species ^ i of s e a l  A  .+ Authority  Month o f c o l l e c t i o n and location  *Number i n , ,, sample 0  tT  r  1/=>  I d e n t i f i e d food items . (terminology o f each author . . . . has been maintained)  California sea l i o n  Smith (1904)  California (JulyAugust)  13  Squid, r a t f i s h , r o c k f i s h .  California sea l i o n  Starks (1918)  California (JulyAugust)  13  Squid, f i s h .  Harbour seal  Fisher (1950)  A t l a n t i c coast of Canada  Harbour seal  Fisher and Mackenzie (1955)  Maritime Provinces (January-December)  Harbour seal  Templeman et a l . (1957)  Newfoundland and  Labrador  96  S h e l l f i s h , clam, mussel, crab, lobster, shrimp, h e r r i n g , salmon, trout, c a p e l i n , smelt, cod, Greenland cod, p o l l o c k , flounder, sculpin, launce, cunner, e e l , eel-pout.  Harbour seal  Scheffer (1928); Scheffer and Sperry (1931)  Washington coast (U.S.A.) (January-December)  95  Crabs, shrimps, c r a y f i s h , squid, octopus, lamprey, skate, r a t f i s h , herring, salmon, hake, cod, tomcod, whiting, flounders, shiner, s i l v e r perch, lingcod, rockf i s h , sculpins, blenny, sandlance, midshipman.  Harbour seal  Imler and Sarber (1947)  Alaska (May-August)  *Stomachs w i t h food only  Squid, small f i s h ( i n c l u d i n g sardines) 201  166  Shrimp, squid, h e r r i n g , shad, smelt, hake, cod, haddock, winter flounder, smooth flounder, u n i d e n t i f i e d f l a t f i s h , rosefish, Gaspereau.  Shrimp, octopus, skate, herring, salmonids, eulachon, cods, flounder, rockfish, sculpin, blenny.  

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