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The sunken gill-net fishery, and an analysis of the availability of the dog-fish (Squalus suckleyi Girard)… Barraclough, W. Edward 1948

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3  3'/  THE SUNKEN GILL-NET FISHERY, AND AN ANALYSIS OF THE A V A I L A B I L I T Y OF THE DOG-FISH ( S q u a l u s  suckleyi  Girard)  AND THE SOUP-FIN SHARK ( G a l e o r h i n u s g a l e u s I N B R I T I S H COLUMBIA WATERS FROM  1943 TO  Linnaeus) 1946.  BY  W. E d w a r d  A T h e s i s submitted  Barraclough  i n Partial Fulfilment of  The R e q u i r e m e n t s f o r t h e D e g r e e o f MASTER OF ARTS in  the Department of ZOOLOGY  THE UNIVERSITY  OF B R I T I S H COLUMBIA  April,  1948  TABLE OF  CONTENTS Page  I.  1  INTRODUCTION A.  The  B. ' D e s c r i p t i o n  II.  2  Problem and  3  D i s t r i b u t i o n of Each Species  1.  The  Dog-fish  (Squalus s u c k l e y i )  2.  The  Soup-fin  Shark  galeus)......  4  DOG-FISH FISHERY IN B R I T I S H COLUMBIA...  3  P r o d u c t i o n o f O i l From the L i v e r s of the D o g - f i s h . D e s t r u c t i o n o f F i s h i n g Gear and F o o d F i s h by the Dog-fish C. I n t r o d u c t i o n o f O r i e n t a l s t o t h e D o g - f i s h F i s h e r y . D. V a l u a t i o n o f the D o g - f i s h and D o g - f i s h L i v e r s E . P r e s e n t U s e s o f D o g - f i s h L i v e r O i l a n d Body O i l . . .  5 7 9 9 10  THE  12  HISTORY OF  THE  (Galeorhinus  3  A. B.  III.  SUNKEN GILL-NET FISHERY IN B R I T I S H COLUMBIA  A.  The  E a r l y Sunken G i l l - n e t  B.  The  Modern Sunken G i l l - n e t  1.  12  Fishery  13  Fishery  D e s c r i p t i o n o f G e a r and  a. B o a t s (1) Small Boats (2) L a r g e B o a t s b . Drum and R o l l e r s c. N e t s d. G l a s s B a l l F l o a t s e. Lead L i n e f . B u o y L i n e s , Buoys', 2. F i s h i n g M e t h o d s 3. C a r e o f the N e t s Other S p e c i e s of F i s h Caught 1. I n H e c a t e S t r a i t 2. E a s t C o a s t o f V a n c o u v e r 3. West C o a s t o f V a n c o u v e r  13  F i s h i n g Methods  t  C.  D.  Selectivity  o f the  and by  Anchors..-. Sunken G i l l - n e t s . .  Island Island  Sunken G i l l - n e t  24  Length Frequency D i s t r i b u t i o n of Dog-fish b y S u n k e n G i l l - n e t s and b y O t t e r T r a w l s IV.  TOTAL CATCH S T A T I S T I C S OF THE SHARK IN B R I T I S H COLUMBIA  V.  DESCRIPTION AND ANALYSIS OF THE DOG-FISH AND SOUP-FIN SHARK A.  S e l e c t i o n and  Source  DOG-FISH AND '  Caught 24  SOUP-FIN  A V A I L A B I L I T Y OF  of Data  13 13 13 14 15 16 18 18 18 20 20 20 21 22  26  THE 29 29  Page B. E s t i m a t i n g Changes i n t h e A v a i l a b i l i t y  a n d Abundance 30  of F i s h Populations C. M e a n i n g D. A n a l y s i s  of A v a i l a b i l i t y  o f the Catch Records o f Dog-fish L i v e r s  b y Sunken G i l l - n e t 1.  32  and Abundance  Boats F i s h i n g  Landed  The T o t a l L a n d i n g s o f L i v e r s b y S u n k e n G i l l - n e t  2. The A v e r a g e  33  i n Hecate S t r a i t  Boats33 34  C a t c h p e r Boat p e r Month  3.- The A v e r a g e C a t c h p e r T r i p p e r B o a t p e r Month 35 4 . The A v e r a g e C a t c h p e r B o a t p e r Month and t h e A v e r a g e C a t c h p e r T r i p p e r B o a t p e r Month f o r E a c h Y e a r a s a Whole 35 5 . The I n d e x o f t h e A v e r a g e C a t c h p e r B o a t p e r M o n t h and the I n d e x o f t h e A v e r a g e C a t c h p e r T r i p p e r B o a t p e r Month a s D e t e r m i n e d b y t h e M e t h o d o f L i n k R e l a t i v e s . 37 6.  7.  Comparison o f t h e Average C a t c h p e r Boat per.Month f o r t h e Same Sunken G i l l - n e t B o a t s F i s h i n g i n Adjacent Years  38  The I n d e x o f t h e T o t a l L a n d i n g s o f D o g - f i s h L i v e r s made b y t h e Same S u n k e n G i l l - n e t B o a t s F i s h i n g i n A d j a c e n t Y e a r s , a s Determined b y the Method o f L i n k Relatives ,  40  E. Analysis  o f the Catch Records o f Soup-fin Shark  Landed b y S u n k e n G i l l - n e t  Boats F i s h i n g  Livers  i n H e c a t e S t r a i t . 42  1. The T o t a l L a n d i n g s o f L i v e r s b y S u n k e n G i l l - n e t B o a t s 42 2. The A v e r a g e 3. 4.  C a t c h p e r Boat p e r Month  The A v e r a g e C a t c h p e r T r i p p e r B o a t p e r M o n t h The A v e r a g e C a t c h p e r B o a t p e r M o n t h and t h e A v e r age C a t c h p e r T r i p p e r B o a t p e r M o n t h f o r E a c h Y e a r a s a Whole  43 43  43  5.  The I n d e x o f t h e A v e r a g e C a t c h p e r B o a t p e r M o n t h a n d the Average C a t c h p e r T r i p p e r Boat p e r Month, as Determined by the Method o f L i n k R e l a t i v e s 44  6.  Comparison o f t h e Average C a t c h p e r Boat p e r Month f o r t h e Same Sunken G i l l - n e t - B o a t s F i s h i n g i n A d jacent Years  7.  The I n d e x o f t h e T o t a l L a n d i n g s o f S o u p - f i n S h a r k L i v e r s made b y t h e Same Sunken G i l l - n e t B o a t s  44  Page Fishing i n Adjacent Years, as Determined by the Method of Link Relatives  45  F. Summary, Discussion, and Conclusions of the Results of the Analysis of the Data from Hecate S t r a i t  46  G. Analysis of the Catch Records of Dog-fish Livers, landed by Sunken G i l l - n e t Boats Fishing o f f Barkley'.. Sound on the West Coast of Vancouver Island, f r o m 1944 to 1946., 51  VI. VII. VIII.  1. The T o t a l Landings of Dog-fish Livers by Sunken G i l l - n e t Boats  52  2. Catch per Unit of E f f o r t  52  5. Average Catch per Boat per Month  53  H. .Summary, Discussion, and Conclusions of the Results of the Analysis of the Data from Barkley Sound and Hecate S t r a i t  53  ACKNOWLEDGEMENTS  56  REFERENCES APPENDIX  *  ;  57 61  ABSTRACT As World  the requirements II,  War  (Squalua  the l i v e r s  s u c k l e y i ) and  became one  the P a c i f i c  Columbia  s o u p - f i n shark  from  caught  from  sharks  the l i v e r s  from  caught  by  The  relatives  of e f f o r t  availability  Hecate  s t r a i t was  fishermen's  slight  increase during  The a v a i l a b i l i t y g r e a t l y f r o m 1944 shark  fishery The  sunken  boat  the  the  tally livers  gill-nets. of the data of  to  the t o t a l  determine l a n d i n g s of  the average  catches per  i s used  or r e l a t i v e  boat  t r i p p e r month.  i n the a n a l y s i s and  the  determined.  a b u n d a n c e of t h e d o g - f i s h i n  to d e c l i n e f r o m  1943  t o 1945 w i t h a  1946. of  the s o u p - f i n s h a r k was  t o 1946.  i n Hecate  decline  greatly  l a n d i n g of the  o f f B a r k l e y sound i s  found  catch  of t h e - i n d i v i d u a l  eaeh a r e a under i n v e s t i g a t i o n ;  The m e t h o d of l i n k  the  on t h e w e s t c o a s t of V a n c o u v e r  included the a n a l y s i s  c a t c h e s p e r month; and a v e r a g e  catch per unit  dropped  i n . H e c a t e s t r a i t and  Methods employed i n t h e a n a l y s i s the a v a i l a b i l i t y ,  Under  i n t e n s i t y , the  has  the a n a l y s i s  o r f i s h r e c e i p t s of each t h e s e two  (Galeorhinus galeua)  o r r e l a t i v e abundance of  o f f B a r k l e y sound  i s l a n d were d e t e r m i n e d  dog-fish  1944.  Changes i n t h e a v a i l a b i l i t y  slips  coast  s o u r c e s of v i t a m i n " A " .  sharks i n B r i t i s h  d o g - f i s h caught  increased during  w  increasing fishing  the years f o l l o w i n g  d o g - f i s h and  A  tt  s o u p - f i n shark  of t h e p r i n c i p a l  t h e s e two  during  from  the  p r e s s u r e o f a h i g h and of  for vitamin  I n t h e y e a r 1946,  s t r a i t was  almost  i n the a v a i l a b i l i t y  a  found  to  decline  the soup-fin failure.  of t h e d o g - f i s h and  the  drop i n the related  average v i t a m i n  to t h e  removal  c l a s s e s from the On the  the west  that the since  oil is  of t h e  closely  older  age  population. coast  of Vancouver i s l a n d ,  fishing  availability  unit  of  effort  over a p e r i o d  of t h e  sunken g i l l - n e t s  select; dog-fish greater  the  p e r gram of l i v e r  (one of  d o g - f i s h has  off Barkley sunken  sound  gill-net  24 h o u r s ) i n d i c a t e d increased  i n each year  1944. The  of no  n  or p o s s i b l e d e p l e t i o n  i n d e x of r e t u r n p e r  75 f a t h o m s l o n g  *A  commercial value  meshes.  (7  i n c h s t r e t c h e d mesh) were f o u n d  t h a n 76 (less  cm.  t h a n 76  i n length. cm.)  tend  to  Small  dog-fish  to p a s s  through  I.  INTRODUCTION  The production of o i l from the l i v e r s of the dog-fish (Squalus suckleyi Girard) was one of the e a r l i e s t f i s h i n g act i v i t i e s carried on i n B r i t i s h Columbia.  This o i l was used  mainly for l i g h t i n g and l u b r i c a t i n g purposes.  With the d i s -  covery of vitamin "A i n the l i v e r s of the dog-fish, a very M  s i g n i f i c a n t and important use f o r these l i v e r s was disclosed. The vitamin "A" content of the soup-fin shark  (Galeorhinus  galeus Linnaeus) was found to be even greater than that i n the l i v e r s of the dog-fish.  As the demands and requirements f o r  vitamin "A" increased during World War I I , the P a c i f i c coast dog-fish and soup-fin shark l i v e r s became one of the p r i n c i p a l sources. For the past few years the soup-fin shark has been the major source i n the production of vitamin "A" supply i n the United States (Ripley 1946).  The catch, however, dropped so  seriously i n American waters that the soup-fin shark was r e placed by the dog-fish. In B r i t i s h Columbia there has been a f a i r l y intensive f i s h e r y f o r the soup-fin shark during recent .years.  At the  same time the i n t e n s i t y of the dog-fish f i s h e r y has increased ;  greatly u n t i l i t now ranks with the important B r i t i s h Columbia.  fisheries i n  As a r e s u l t of the high and increasing f i s h -  ing i n t e n s i t y , the catch of the dog-fish and soup-fin shark has dropped greatly i n the years following 1944.  It  has  2 -  seemed u n l i k e l y tha;t a s u f f i c i e n t  c o u l d be m a i n t a i n e d a t t h i s h i g h l e v e l adequate The  i n f o r m a t i o n concerning the  abundance o f any  stock which  known b e f o r e t h e r a t e maximum r a t e be  d e t e r m i n e d so t h a t  be m a i n t a i n e d f o r f u t u r e  A.  The An  i n v e s t i g a t i o n was  must  determined. must  be The  also  and p r o d u c t i v e p o p u l a t i o n  may  utilization.  on the west  undertaken t o determine the  or r e l a t i v e  s o u p - f i n s h a r k caught  i n Hecate  c o a s t o f Vancouver  s t r a i t and  or f i s h r e c e i p t s o f each o f t h e s e two  b o a t s and r e c o r d e d b y t h e  a n a l y s i s of these data to determine the t o t a l  sound  were d e t e r m i n e d f r o m t h e  fisherman's landing of the l i v e r s gill-net  o f f Barkley  and  island.  analysis of i n d i v i d u a l , t a l l y s l i p s  sunken  changes  abundance o f t h e d o g - f i s h  Changes i n t h e a v a i l a b i l i t y  1.  but  lacking.  i s e x p l o i t e d b y man, be  stock  Problem  i n the a v a i l a b i l i t y  by  stook has been  o r t h e optimum y i e l d  a stable  stable  of exploitation  o f e x p l o i t a t i o n may  of e x p l o i t a t i o n  and  catch of l i v e r s  s h a r k s caught  industry.  the a v a i l a b i l i t y ,  The include:  from each area under  investigation; 2.  the average  c a t c h p e r b o a t p e r month;  3.  the average  c a t c h p e r t r i p p e r b o a t p e r month;  4.  the average  c a t c h p e r b o a t p e r month and  the  average  c a t c h p e r t r i p p e r b o a t p e r month f o r e a c h y e a r a 5.  as  whole;  the i n d e x o f the average  c a t c h p e r b o a t p e r month,  and t h e i n d e x o f t h e a v e r a g e  catch per t r i p  per  -  3 -  boat per month, as determined by the method of l i n k relatives; 6.  comparison for  o f the average  c a t c h per boat per month  the same sunken g i l l - n e t boats f i s h i n g i n adjacent  years; 7.  the index of the t o t a l c a t c h of the same sunken net  boats f i s h i n g i n adjacent y e a r s as determined  the method o f l i n k 8.  gillby  relatives;  the c a t c h p e r - u n i t - o f - f i s h i n g  effort.  A knowledge o f the h i s t o r y of the f i s h e r y and a d e t a i l e d d e s c r i p t i o n o f the e a r l y and modern s u n k e n - g i l l - n e t methods are p e r t i n e n t t o an understanding of the  B.  fishing  problem.  D e s c r i p t i o n and D i s t r i b u t i o n of Each S p e c i e s . 1.  The D o g - f i s h (Squalus- s u c k l e v i )  The d o g - f i s h ( F i g . 1) i s a member of the f a m i l y S q u a l i d a e , which i n c l u d e s another member i n B r i t i s h Columbia waters, the s l e e p e r shark (Somniosus m i c r o c e p h a l u s ) . s i z e of s l i g h t l y over f i v e f e e t .  Dog-fish a t t a i n a  The head i s f l a t t e n e d  v e n t r a l l y and-the mouth i s v e n t r a l i n p o s i t i o n .  I t has  g i l l openings a n t e r i o r to the p e c t o r a l f i n s , and a l a r g e r a c l e c l o s e behind the eye. ceded by a l a r g e s p i n e .  dorsofive spi-  The two d o r s a l f i n s are each p r e -  There i s no a n a l f i n .  Small placoid  s c a l e s cover the gray to l i g h t brown d o r s a l s u r f a c e and the d i r t y white v e n t r a l s u r f a c e . G i r a r d was  the f i r s t  t o d e s c r i b e the d o g - f i s h i n  and a c c o r d i n g t o Clemens and W i l b y (1946) i t was  1854  f i r s t recorded  '•'Fig; 1 Sketch  of D o g - f i s h . Squalus  Fig. Sketch  of Soup-fin shark.  suckleyl  (Girard)  2  G a l e o r h i n u s g a l e us (Linnaeui  - 4 in  British The  the  Columbia  b y J . K. L o r d i n 1866 a s A c a n t h i u s  suckleyi.  words g r a y - f i s h a n d d o g - f i s h a r e synonomous, b o t h t o  commercial The  range  northwestern 2.  f i s h e r m a n and t o t h e i n d u s t r y . of t h i s  s p e c i e s i s from  southern C a l i f o r n i a t o  Alaska.  The S o u p - f i n S h a r k  (Galeorhinus galeus)  T h i s s h a r k i s one o f t h e two members o f t h e f a m i l y C a r charinidae  found  blue  (Prionace glauca).  shark  attains a size and t h e s n o u t The  fifth  sal of  Columbia.  extends  and l a s t  s i xfeet.  gill  opening  the s p i r a c l e ,  I t s head i s d e p r e s s e d opening.  i s l o c a t e d above t h e s h o r t e n e d situated  behind the eye,  No s p i n e s p r e c e d e  t h e b o d y and i s d e e p l y n o t c h e d , lobe o f t h e f i n . There  caudal peduncle. the body.  Small placoid  The c o l o u r i s d a r k  is  t h e two d o r -  The c a u d a l f i n i s c o n s i d e r a b l y s h o r t e r t h a n  the upper  i s the  ( F i g . 2)  w e l l b e y o n d t h e v e n t r a l mouth  An a n a l f i n i s p r e s e n t .  fins.  The o t h e r member  The s o u p - f i n s h a r k  of s l i g h t l y over  pectoral finland small.  i n British  the r e s t  forming a large lobule'on a r e no l a t e r a l k e e l s o n t h e  s c a l e s cover t h e surface o f  gray t o dark b l u e on t h e d o r s a l  s u r f a c e , o f t e n w i t h a p u r p l i s h t i n g e , becoming p a l e r t o a dusky white The  on t h e v e n t r a l  surface.  s o u p - f i n shark was f i r s t  d e s c r i b e d by Linnaeus i n  175&, a n d , a c c o r d i n g t o C l e m e n s and W i l b y (1946) was f i r s t recorded from B r i t i s h  Columbia  California  still  and r e f e r  zvopterus  (Ripley  The  range  list  i n 1891. to this  Publications  from  s p e c i e s as G a l e o r h i n u s  1946).  i s from  southern C a l i f o r n i a  t o northwestern  Alaska.  II.  A.  HISTORY OF THE DOG-FISH FISHERY IN BRITISH COLUMBIA  Production of O i l from the Livers of the Dog-fish. O i l extracted from the l i v e r s of the dog-fish ranks as  one of the e a r l i e s t products of the f i s h i n g industry i n B r i t i s h Columbia.  Lord  (1866)  noted that the P a c i f i c coast Indians  extracted the clear o i l from the f a t t y l i v e r s by heat and pressure for t h e i r domestic uses.  A few years l a t e r the  production of d o g - f i s h " l i v e r o i l gave employment to a large number of persons along the seaboard of the Province, opening a valuable industry to both the native fisherman and the European.  Anderson  (1877)  estimated the outlay necessary f o r  two men to commence operations to f i s h dog-fish, as follows: Boat, with oars and s a i l  $60.00  .  $18.00  Try-pot 1,000 yards manilla rope, 1 3/4 i « a  600 J.P. cod-hooks, No. 3, per cwt., $1.50 6 doz. cod-lines. O i l casks at s i x cents per gallon. A net, f o r catching herring f o r b a i t , cost from  $150  to  $200  and was used i n common by many  - fishermen i n the same neighbourhood. The annual y i e l d to the fisherman was estimated at from 40 to 150 barrels of o i l . 30 to 40 gallons of o i l .  Each b a r r e l contained approximately This o i l was valued at f o r t y cents  a gallon i n V i c t o r i a . Large quantities of o i l , were consumed f o r l u b r i c a t i n g  - 6-  and l i g h t i n g purposes i n the extensive saw-mills at Burrard i n l e t , i n the coal-mines at Nanaimo and Departure hay and by numerous steamers and s a i l i n g vessels frequenting these waters (Anderson 1877). Two of the l i g h t stations on t h i s coast burned dog-fish o i l exclusively.  The o i l was daimed-to give a luminous and  b r i l l i a n t l i g h t and, besides, was cheaper than any other o i l that could be imported during t h i s period (Cooper 1874). During the spring of 1877 an establishment employing white fishermen was formed on the Queen Charlotte islands f o r c o l l e c t i n g dog-fish o i l (Anderson 1878), but two years later the Skidegate O i l Company l a r g e l y employed Indian labour secured from the v i l l a g e s around them (Anderson I 8 8 0 J . The l i v e r s of the dog-fish (theonly part of the shark processed i n 1879) were f i r s t steamed i n large vessels, i n which the o i l collected at the., top.  After separation, the  o i l was again subjected i n another vessel to a c e r t a i n degree of heat, thus d i s s i p a t i n g very minute water ^ a r t i c l e s .  This  refined o i l was sealed i n f i v e gallon cans, two of which were packed i n a case f o r shipment to ready markets (Anderson 1880). The quality of dog-fish o i l could not be excelled f o r l u b r i c a t i n g purposes at t h i s time.  In A p r i l 1881 the best  q u a l i t y l i v e r o i l was used on the "H.M.S. Rocket" as a lubr i c a t i n g o i l f o r the engines, and i t was found that, the dogf i s h o i l was superior to the vegetable o i l s from Rangoon, used on Her Majesty's ships (Anderson 1882). Carcasses of the "piked dog-fish", as the dog-fish was more commonly c a l l e d then, were not used as a source of o i l  - 7 to any great extent.  In 1880 two q u a l i t i e s of o i l were pro-  cured from the dog-fish at the r e f i n e r y on the Queen Charlotte islands; one o i l of superior q u a l i t y was refined from the l i v e r s alone, and the other from the carcasses of the f i s h (Anderson 1882).  Sometimes the Indians attempted to extract the o i l from the carcasses of the dog-fish i n a very primitive fashion. After cleaning the f i s h , they would cut them into pieces, b o i l them i n vats, place them i n large tubs, and the squaws would press the- o i l out by tramping with t h e i r f e e t .  This made a  very i n f e r i o r o i l which was mostly used f o r dressing skins, and f o r greasing skidways on logging roads (Mowat 1888). At t h i s time B r i t i s h Columbia was not permitted to share the p r i v i l e g e s of the Washington Treaty, and a very heavy duty was placed on the highly prized dog-fish o i l , almost preventing i t s export to -the United States.  A limited quantity of o i l  was exported to China, Honolulu, and to many manufacturing firms i n the United States (Anderson 1884).  Since the ex-  port market of o i l was very l i m i t e d , commercial f i s h i n g f o r the dog-fish almost ceased and, as a r e s u l t , a reduction occurred i n the number of g a l l o n s of o i l produced  B.  (see Table I I ) .  Destruction of F i s h i n g Gear and Food F i s h by the Dog-fish With the reduction i n f i s h i n g e f f o r t , dog-fish appeared  to increase i n numbers i n coastwise waters, and became a source of great annoyance to fishermen i n other branches of the f i s h i n g industry.  I t was claimed that the dog-fish would  - 8 not  only  out t h e f i s h  hooks, l e a v i n g o n l y claims sion  by the fishermen,  of k i l l i n g vast  livers  f i s h e r m e n who stroyed  valuable  of B r i t i s h casses  Columbia  "whitefish",  (1908)  sea-lion.  creased  Pacific  the years  names a s  "flake". a  t h a n t h e h a i r s e a l and  due t o r e p l a c e m e n t  that  o f dog-  carbide.  the d o g - f i s h  on  c o a s t were c a u g h t i n l a r g e q u a n t i t i e s f o r e x p o r t  t o the U n i t e d  Although great  continued  car-  T h i s product has appeared  1916-18  The name " g r a y - f i s h " was g i v e n t o  States.  the c e s s a t i o n o f h o s t i l i t i e s  cattle  the d o g - f i s h  t h a t t h e d o g - f i s h h a d become  d o g - f i s h marketed as f r e s h f i s h  after  that  o i l f o r l i g h t i n g purposes by calcium  was e x p o r t e d  as  recommended  One o f t h e r e a s o n s t h a t t h e d o g - f i s h h a d i n -  t o the f r e s h f i s h market. the  because i t de-  the Dominion F i s h e r i e s Commission  to the f i s h e r i e s  I t was n o t u n t i l the  unless  some o f t h e c o m p l a i n t s f r o m many  t h e i r numbers was p r o b a b l y  liver  Commis-  i n t h e same  t i m e s under such trade  reported  o f these  along the  be d i s c o n t i n u e d  c o u l d be u t i l i z e d  " o c e a n w h i t e f i s h " , and  s e r i o u s menace  fish  fish,  on t h e  f o r the use o f the  the d o g - f i s h a s a pest  at various  (1916)  Taylor  the  should  be m a r k e t e d a s a f r e s h f i s h .  the market  more  food  In spite  Columbia F i s h e r y  numbers o f d o g - f i s h ,  alleviate  deplored  1887).  t h a t the system p r e v a i l i n g  b o d i e s o f the d o g - f i s h To h e l p  (Mowat  the B r i t i s h  f o r o i l purposes only,  manner.  on  the heads  (1893) recommended  coast  the  l i n e s but would a l s o e a t the f i s h  and n e a r l y t h e whole T h i s market  disappeared  o f W o r l d War I .  numbers o f whole d o g - f i s h were  and c h i c k e n  food  catch  (Cunningham  1920),  utilized  the d o g - f i s h  t o work h a v o c w i t h t h e f i s h e r m e n ' s n e t s .  The  British  - 9 Columbia F i s h e r i e s Commission o f mended, t h e r e f o r e , t i o n p l a n t s be other  on  the  utilization  e n c o u r a g e d i n some way,,  assistance,  placed  that the  (1923)  1922  and  that there  catching  be  of t h i s  The  p a i d f o r the Motherwell  tariff  hindered  catching (1923) the  of  such f i s h  considered  to American fishermen.  since The  C.  Introduction 1923  During O r i e n t a l s was fisheries. hook and  crease the  afforded  Dog-fish  i n the  Valuation  of  not  y e a r 488  the until  dog-fish  Dog-fish 1938  pest.  Fishery  on t h e  was  number o f O r i e n t a l f i s h e r m e n to  and  that  $4  issued  to  cod  number  ton  of  l i c e n c e s were o p e r a t i n g ,  Table for  I).  At  dog-fish  this fishery.  fishermen  substantially. as  in-  livers.  number o f  fishery increased  a gradual  (see  per  Dog-fish  the  Canadian  t o O r i e n t a l s , many J a p a -  Thus, there  p r i c e o f $3  the  s a l m o n and  placed  licences given  industry.  should  protection  licences previously  r e s t r i c t i o n was  low  this  many w h i t e f i s h e r m e n f r o m e n t e r i n g  gaged i n t h e this  no  the  re-  Fordney-McCumber  waters of  considerably  dog-fish  same t i m e t h e  I t was  number o f  reduced  to t h i s  i n the  discouraged  D.  the  Since  line  nese t u r n e d  of O r i e n t a l s to  a bounty  t h u s l i m i t e d the  f i s h e r m e n i n a t t e m p t i n g to r i d the  or  whatsoever  products from  tariff  tariff  reduc-  Commission a l s o  that the  the  by  i f necessary.  market of d o g - f i s h  Canadian establishments,  recom-  financial  restriction  commended, a f t e r f u r t h e r i n v e s t i g a t i o n , t h a t be  pest  e i t h e r by  no  of d o g - f i s h .  strongly  enIn  oompared t o o n l y  161  Table I L i s t o f D o g - f i s h l i c e n c e s I s s u e d and O p e r a t i n g i n B r i t i s h Columbia from 1922 t o 1 9 4 6 .  White 1922 1923 1924 1923 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946  Indian  Others*  Cancelled  . 25  219  149  90 32 9 9 31 23 ' 43 56 169 P  164  357 1,026 1,807 2,745 2,031  143  11 35 2  1 1 11 20 12 2 121 208  242  320 135  1 82  54  3  Total  '  191 238 228 213 123 65 120 88 81 94 299 258 239  419  166 177 237  3  421 422  2  245 134  320 74 152 112  124  1 1 1  ]_**  4**  M o s t l y Japanese f i s h e r m e n . B r i t i s h s u b j e c t s o f Chinese  161 488 365 406 898 1,235  2,049  3,066 2,170 1,405  origin.  -loin  the p r e v i o u s y e a r  issued  continued  the whole f i s h i n 1937,  lb. 34  continued  to r i s e .  c e n t s i n 1942,  l b . i n 1944.  The  p e r t o n i n 1937,  f r o m |6 1943.  The  that  i s the  I).  t o i n c r e a s e as t h e  t o 16  cents per  before  (see Table  t o $8  The price  the  fishing  o f the  L i v e r s rose t o 23  price  t e s t e d f o r the  licences  livers  and  6 cents  from  c e n t s i n 1943,  and  per to  o f whole d o g - f i s h i n c r e a s e d  i n 1940  d o g - f i s h l i v e r s are bought l i v e r s are  number o f  t o $70  and "on  test"  potency  i n d u s t r y pays f o r the  per  at  ton i n  present,  of vitamin  l i v e r s f r o m the  "A" fisher-  men.  E.  Present Uses of Dog-fish Although  content in  1929  this min  determined  o i l i n 1927  1929),  and  i t was  "A"  were n e e d e d .  The  a s a new  source  The  the  vitamin  v i t a m i n "D"  when new  l i v e r s of the  of  2.7  of  vita-  i n 1943  million and  when  dollars,  seventh  stood  i n the  list. dog-fish l i v e r  i n the  o i l i s u s e d e x t e n s i v e l y as a b l e n d i n g  p r e p a r a t i o n of p o u l t r y o i l s .  In  1932,  developed.  T h i s o i l c o n t a i n s the necessary  and  vitamin  from high-grade  "D"  at the  Pacific  Station, a medicinal o i l "Thalattol"  was  For  I I that  d o g - f i s h became i n c r e a s -  among B r i t i s h C o l u m b i a f i s h  Fisheries Experimental  oil.  "A"  content  sources  o f v i t a m i n "A"  d o g - f i s h , w i t h a market value  Canadian  the  Body O i l .  n o t u n t i l W o r l d War  d i s c o v e r y became v e r y i m p o r t a n t  in t h i r d place  oil  liver  (Broeklesby  i n g l y important the  (1927)  Broeklesby  o f the  L i v e r O i l and  dog-fish liver  vitamin o i l and  a number o f y e a r s t h i s m e d i c i n a l o i l h a s  "A" pilchard  been s u p p l i e d  - 11 to the Dominion Indian Department f o r d i s t r i b u t i o n to i t s wards i n B r i t i s h Columbia, Saskatchewan, and the Northwest T e r r i t o r i e s (Swain 1944). Brocklesby (1941) r e l a t e s that both the l i v e r o i l and body o i l s can be used i n the leather trades and also i n i n secticide ing.  sprays f o r codling-moth control and f o r tree band-  He also mentions that the body o i l and the lower grades  of l i v e r o i l and mixed o i l s of the dog-fish, have been used i n s t e e l tempering and i n the manufacture of sheep and c a t t l e dips.  The meal from the dog-fish i s a valuable f e r t i l i z e r be-  cause of i t s high nitrogen content.  - 12 -  III.  A.  THE SUNKEN GILL-NET FISHERY IN BRITISH COLUMBIA  The E a r l y Sunken G i l l - n e t Fishery. In the e a r l y 1920*8 representations were made to the De-  partment of F i s h e r i e s by the Japanese  and other fishermen f o r  the use of o l d sockeye nets to capture the dog-fish.  These  discarded linen nets were the f i r s t sunken g i l l - n e t s to be used i n capturing dog-fish.  A number of graycod and red snappers  were also tangled i n the nets.  These nets were i n continuous  operation throughout the year i n the Gulf of Georgia by the Orientals and a small number of white fishermen u n t i l A p r i l  28, 1939.*  In t h i s year the f i r s t r e s t r i c t i o n s were imposed  and, thereby, f i s h i n g f o r dog-fish was prohibited i n an area around Pylades Channel ( F i g . 3)«  Further l e g i s l a t i o n p r o h i b i -  ted fishermen from catching dog-fish with sunken g i l l - n e t s from the 1st of November i n eaoh year to the 31st of Maroh i n the following year.**  Fishermen using sunken g i l l - n e t s were not  numerous i n comparison with those f i s h i n g with the conventional long-line gear, which could be operated throughout the year without any r e s t r i c t i o n s .  In e a r l y 1942, when the cotton sunken  g i l l - n e t was introduoed into B r i t i s h Columbia and the power drum on the g i l l - n e t boats used f o r l i f t i n g such nets from the *  (Order i n Council, A p r i l 28, 1 9 3 9 ) , Special Fishery Regulations f o r the'Province of B r i t i s h Columbia, 1939«  ** (Order i n Council, September 25, 1940), S p e c i a l Fishery Regulations f o r the Province of B r i t i s h Columbia, 1941.  Fig* 3 Prohibited area f o r sunken g i l l - n e t s i n the S t r a i t of Georgia,  1939.  -  13  -  sea bottom was perfeoted, the sunken g i l l - n e t f i s h e r y became an important part of B r i t i s h Columbia's f i s h i n g industry.  B.  The Modern Sunken G i l l - n e t Fishery. 1.  Description of Gear and Fishing Methods a. Boats There i s a considerable range i n the size and  the equipment of the boats used i n catching"dog-fish and soupf i n shark.  They range from the small salmon g i l l - n e t boats to  the larger vessels used i n the salmon purse-seine, the trawling and the halibut f i s h e r i e s .  Despite the d i v e r s i t y i n s i z e s ,  the boats may be grouped into two size classes whioh may f o r purposes of description be c a l l e d small and large. ( 1 ) Small Boats The small boats are e s s e n t i a l l y the salmon g i l l - n e t boats equipped with a r o t a t i n g drum f o r l i f t i n g t h e i r nets.  The boats range from 28 feet to 3 4 feet i n length, 7  feet to 9 feet i n beam and 3 tons to 6 tons i n weight.  Gaso-  line marine engines of various designs and manufacture, ranging from 7 to 1 1 5 horse-power, supply the motive power.  There  i s sleeping accommodation f o r one or.two men In the bow.  Many  boats do not carry a dinghy but some have just enough room to carry one fastened along the side or on top of the small cabin. A port view of a t y p i c a l small sunken g i l l - n e t boat i s shown i n F i g . 4 . ( 2 ) Large Boats The larger vessels range i n length from 45 to 55 f e e t , with beams from 10 to 1 6 feet, and tonnages  Fig.  4  A t y p i c a l small sunken g i l l - n e t boat.  Fig.  5  The drum of a small sunken g i l l - n e t boat  - 14 from 10 to 2,5.  Although a few of the larger vessels are powered  by gasoline engines, most of them are driven by d i e s e l engines with horse-power ratings of 60 to 165.  Sleeping accommodation  f o r a crew of four t o s i x men i s provided f o r by t i e r e d bunks below the deck i n the bow.  Usually the captain sleeps i n the  p i l o t house or wheel-house on the deck.  A row boat may be  carried on the port side, lashed to the r a i l i n g on the p i l o t house, or i t may be secured above the pilot-house ( F i g . 8 ) . b.  Drum and R o l l e r s . The drums are constructed of wood of a size  suitable to the i n d i v i d u a l boat.  They range from 3 to 4 feet i n  diameter and about 4 feet along the a x i s .  Some of the larger  drums are constructed of s t e e l but these drums are not i n common use among the f i s h i n g f l e e t .  The wooden drum i n use today  i s shown i n F i g . 5«  -  '  The drum i s turned by a shaft leading from the engine -through a series of chain drives and a transmission system to a gear drive.mounted on the axle of the drum.  An old auto-  - motive clutch geared from the engine was the f i r s t transmission system used to supply the motive power f o r the g i l l - n e t drum. Many are s t i l l i n use by the smaller boats..  One fisherman i s  able to control the speed of the r o t a t i n g drum and remove the dog-fish from the net as the l a t t e r i s l i f t e d over the stern of the boat. On the stern of the boat i s mounted a "Y" r o l l e r ( F i g . 6) whioh prevents the net from becoming entangled'in the propeller. . I t also acts^as a guide i n keeping the net i n the correct plane when the net i s wound on the drum.  Fig. 6 The  "V"  roller  on t h e s t e r n o f a s m a l l  Fig. A dog-fish  c o m i n g o v e r t h e bow gill-net  sunken g i l l - n e t  boat.  7 roller  boat i n Hecate  of a larger strait.  sunken  - 15  -  Some of the larger boats are equipped with bow r o l l e r s (Fig. 7), seas.  whioh enable the vessels to l i f t the nets i n rougher  These are not power driven as were the bow r o l l e r s of  the Columbia r i v e r g i l l - n e t and "diver-net" boats (Anon 1951)• c. Nets The sunken g i l l - n e t for dog-fish i s made of cotton web with a stretched mesh size of 6 1/2 or 7 inches. Mesh size i s almost i n v a r i a b l y 7 inches at the present time, but both 6 1/2 and 7 inoh mesh nets were used by some f i s h e r men i n 1943 and 1944.  Each net i s about 50 fathoms long although  some of the f i r s t nets constructed i n B r i t i s h Columbia were as long as 75 fathoms.  The depth of the net i s 25 meshes or about  14 f e e t . Webbing i s marketed to the wholesale dealer i n bales containing 910 fathoms of white cotton web, weighing about pounds.  273  The wholesale merchant t r e a t s the white web with a  solution of "tanbark" referred to as "cutch" whioh protects the web from b a c t e r i a l deoay.  The cost i s 5 1/2  cents per  pound of web to the fisherman. Nets that are treated with "Cuprinol" (Anon. 1940) are said to remain wet f o r long periods of time without r i s k of b a c t e r i a l decay or overheating.  Many  fishermen treat the web with "cutch" or "tanbark" extracts from one of several o r i e n t a l woods.  Similar extracts are made from  oak bark, hemlock bark, japonica, or quebracho ( F i r t h and Carlson 1944). Specifications of the dog-fish web are as follows:  -  Twine Size  Mesh Size inches  16  -  Depth i n Meshes  Length of Bale fathoms  12 thread  6 1/2  25  900  15 thread  7  25  910  The prioe of dog-fish web  to the fisherman was 57 cents  per l b . per bale i n 194-5, 62 1/2  cents i n 194-6, and f l . 1 0 per  l b . per bale i n 194-7. Some fishermen carry a few fathoms of the larger mesh size webbing f o r catching soup-fin sharks. the soup-fin shark web  are as follows:  Twine Size  Depth:in Meshes .  Mesh Size inches  S p e c i f i c a t i o n s of  Length of Bale fathoms  21 thread  10  24  500  24 thread  10  22  500  Nets are hung on the "cork l i n e " of 1/2 or 5/8 inch manllla or s i s a l rope. nets.  Proper f u l l n e s s of the web  i s important i n the  Too much or too l i t t l e web may a f f e c t the wearing qua-  l i t y , as well as the e f f i c i e n c y of the net.  Sunken nets as a  general rule are hung on the one-half (l/2) basis; that i s , a net of 100 f a . stretched measurement w i l l be only 50 f a . long when hung on the "cork l i n e " ( F i g . 10). with cotton  The nets are hung  hanging twine, u s u a l l y 56 thread, but running to  54 thread or heavier, depending on the preference of i n d i v i d u a l fishermen. d.  Glass B a l l F l o a t s . The glass b a l l f l o a t s most oommonly used on  sunken g i l l - n e t s are 4 1/2 inches i n diameter although 5 and  6 inch glass b a l l s have been used,  Buoyancy of the 4 l/2 inch  size i s rated at 15 oz. with the 5-inch b a l l f l o a t i n g 23 oz. and the 6-inch diameter doubling t h i s buoyancy to 46 oz. (Anon. 1943).  Spacing of the glass b a l l s along the "cork-line" varies  somewhat with preference of the fisherman.  Usually they are  placed about 1 1/2 fathoms apart f o r the 4 1/2 inch size (Fig. 10). The glass b a l l s are "trapped" i n "covers" ( F i g . 11) made of tarred seine web of 1-ineh mesh.  Sometimes t h i s i s done by  lacing pieces of t a r r e d web of the proper dimensions into a part i a l sack and, when the glass b a l l i s inserted, the pouch i s then completed with close l a c i n g .  Another method, which i s  widely used, i s the k n i t t i n g of web about the glass b a l l i n diamond-shaped meshes or i n square meshes of beeket twine. Before the glass b a l l f l o a t was f u l l y developed on t h i s continent, a suitable f l o a t f o r submerged f i s h i n g presented a problem.  The f l o a t must be able to withstand high water pres-  sure without breaking or becoming water-logged and must be e a s i l y handled.  Cedar f l o a t s treated with hot p a r a f f i n , coal  t a r , pine t a r , or linseed o i l were used i n some experiments with "diver set-nets" (Anon. 1942)in catching soup-fin sharks o f f the Columbia r i v e r and i n the submerged g i l l - n e t f i s h e r y i n Alaska f o r king crabs (Carlson 1942).  A satisfactory float  was found to be the empty "stubby" beer b o t t l e , with a buoyancy of approximately 7 ounces when sealed with standard lacquered metal caps with cork d i s k inner l i n i n g .  I t was during the  summer of 1940 that J". T. Barnaby, U. S. F i s h and W i l d l i f e Service, constructed a submerged tangle net i n which the  Fig. 8 The captain on the bridge i s scouting f o r his marker pole, i n d i c a t i n g p o s i t i o n of the sunken g i l l - n e t i n Hecate s t r a i t .  Fig. 9 A m a r k e r p o l e and buoy " S c o t c h m a n " i n Hecate s t r a i t .  - 18 "stubby" beer b o t t l e s were f i r s t used as f l o a t s (Carlson 1942). e.  Lead Line. The lead weights on the "lead l i n e " keep the  net  i n place on the sea bottom while the glass f l o a t s keep i t  upright i n the water.  The lead l i n e i s 1/2-inch or 5/8-inch  rope with 4 oz. lead weights strung along the rope and the weighting  Is such that the buoyancy of the glass b a l l f l o a t s i s de-  f i n i t e l y overcome.  About one pound of lead i s placed on each  fathom of lead l i n e (Figs. 10 and 11). f.  Buoy Lines. Buoys, and Anchors. An anchor b r i d l e from 4 to 6 fathoms long i s  formed at the end of the " s t r i n g " of nets from the "cork l i n e " and the "lead l i n e " . small loop.  These, when joined, form an "eye" or a  The anchor i s attached to the "eye" by the anchor  line of 21 thread s i s a l rope from 1 to 2 fathoms long. anchor sea  weighing  The dory  from 45 to 75 pounds holds the net on the  bottom against the actions of the t i d a l currents.  The buoy  line extends from the anchor to the buoy and marker pole on the  surface of the water ( F i g . 10). 2.  Fishing Methods. From three to f i v e nets are joined into one " s t r i n g "  or a "gang" (Whitehead 1930) of nets, and fished as one unit of 150 to 250 fathoms i n length. marker pole (Fig.  In s e t t i n g ^ net ( F i g . 10), a  9) and buoy are f i r s t put out, then the buoy  line with the anchor attached follows.  The boat moves ahead  under power with the d i r e c t i o n of the t i d e , while the net i s payed out from the rotating drum.  Another marker pole and  RED  CANVAS  DIAGRAM  FLAG  SET  -14'-16'  BAMBOO  POLE  / R E D BUOY K E G  12  SEINE  SASH  CORKS  WEIGHTS  Fig.  10  OF A  SUNKEN  TO CATCH  GILL-NET  DOG-FISH  - 19 buoy Is attached to the other end of the net.  A " s t r i n g " of  nets i s usually l e f t i n the water from 12 to 24 hours.  Upon  returning to the f i s h i n g grounds the fisherman l i f t s the marker and buoy into the boat and fastens the buoy l i n e to a loop of rope on the axle of the drum.  The buoy l i n e and the  net are now l i f t e d from the sea bottom by the r o t a t i n g drum. The speed of the rotating drum i s governed by the clutch mounted nearby.  I t may take from 1 to 2 hours to l i f t a " s t r i n g " of  nets, depending on the weather and the number of dog-fish caught i n the net.  A ^ s t r i n g " of nets i s reset on the same grounds i f  a good catch has been made, otherwise grounds are sought where better f i s h i n g has been reported-.- The dog-fish and other species of f i s h (see F i g . 11 and F i g . 13) are picked out of the net as they come over the stern r o l l e r i n the small boats or the bow r o l l e r i n the large boats. F i g . 7, shows a dog-fish coming over the bow r o l l e r of one of the larger boats and i n F i g s . 11 and 13, the fisherman i s removing the dog-fish from the net on the same boat. After f i s h i n g operations the boats enter sheltered bays where the l i v e r s are removed from the dog-fish i n t o 40 pound capacity t i n s .  The carcasses are thrown over-board.  They are  not discarded on the f i s h i n g grounds as the Canadian fisherman believe the l a t t e r w i l l become fouled, thus preventing further catches.  The-American otter trawl f l e e t , however, operating i n  Hecate s t r a i t , discard a l l the carcasses on the f i s h i n g grounds. International f i s h i n g regulations prohibit these vessels from trawling'within three miles of the shoreline but they are permitted to seek the shelter of a Canadian port during a storm.  Mg.  F i g . 12  11 _  " P i c k i n g " a $ d o g - f i s h from the g i l l - n e t . N o t e t h e f e m a l e d o g - f i s h on d e c k and t h e r o c k s o l e c a u g h t i n t h e mesh.  Winding  t h e sunken g i l l - n e t o n t h e drum o f a large boat.  - 20 -  In Hecate s t r a i t the length of a t r i p may he from 1 to 7 days, depending upon the weather and the number of dog-fish or soup-fin shark caught.  On the west coast of Vancouver i s l a n d ,  o f f Barkley sound, the boats return to the f i s h i n g camp every evening to market the dog-fish l i v e r s and other fresh f i s h caught• The f i s h i n g camps i n Skidegate i n l e t at Queen Charlotte C i t y are shown i n F i g . 14.  The camp i s a large scow with a  store and an ice-house f o r freezing the l i v e r s and fresh f i s h . 3.  Care of the Nets. Eaoh week the nets are mended and cleaned i n a solu-  t i o n of copper  sulphate to prolong t h e i r usefulness. Generally,  25 to 40 pounds of copper sulphate (bluestone) are dissolved i n about 29 gallons of water ( F i r t h and Carlson 1944).  Exact  proportions are seldom used, the strength being determined the colour of the solution. ¥  by  The bluestone i s placed i n a bur-  lap sack and worked through the water i n a large- wooden tank, then the nets are immersed i n the solution.  After bluestoning,  the nets must be washed i n water as the solution i s acidic and w i l l i t s e l f rot the nets.  The scow in'the background of F i g .  14, contains bluestone tanks and drying racks f o r the nets.  C.  Other Species of F i s h Caught by Sunken G i l l - n e t s . 1.  In Hecate S t r a i t . Although the 7-inoh mesh net was designed to cap-  ture dog-fish, other species of f i s h are taken on the gear. A number of soles are taken but these along with gray cod,  Fig. "Picking"  13  d o g - f i s h f r o m the sunken g i l l - n e t i n Hecate s t r a i t .  Fig.  o f a l a r g e boat  14  Two f i s h i n g camps i n S k i d e g a t e i n l e t , queen C h a r l o t t e i s l a n d s . Note b l u e s t o n e t a n k s on a scow i n t h e c e n t e r background.  - 21 -  skate, halibut and others are usually returned to the sea because there i s not a ready market f o r them i n t h i s area.  Oc-  casionally a few lingcod and blackcod are caught an are marketed along with t h e i r l i v e r s . On June 18,  194-6, the following numbers of f i s h were noted  to be caught by 5 " s t r i n g s " or a t o t a l of 25 sunken g i l l - n e t s . The nets were set i n 14 fathoms, o f f Skidegate bar i n Hecate strait. 166  butter sole  (Isopsetta i s o l e p i s )  sand sole  (Psettichthys melanostictus) ....  125  rock sole  (Lepidopsetta b i l i n e a t a )  38  gray cod  (Gadus macrocephalus)  13  halibut  (Hippoglossua 3 t e n o l e p i s )  dog-fish  1 457  female male  57  Other sets were observed on d i f f e r e n t boats f i s h i n g i n t h i s area and similar catches were recorded. 2. I  East Ooast of Vancouver Island. The sunken g i l l - n e t proved to be very e f f e c t i v e i n  capturing large numbers of lingcod (Ophidon elongatus) i n the s t r a i t of Georgia, when set on the lingcod r e e f s .  On June 9,  1942*, fishermen using g i l l - n e t s , set-nets, and sunken g i l l nets were prohibited from marketing lingcod caught by such gear. *  *  (Order i n Council, June 9, 1942, P.O.  4877), Special Fishery  Regulations f o r the Province of B r i t i s h Columbia,  1942.  - 22 Gn May 300  26,  1944,  a s p e c i a l set was made on a lingcod reef,  f a . east of Pinnacle  of nets, 300  point near Departure bay.  The " s t r i n g "  f a . long with a mesh size of 6 l / 2 inches,  had  been set i n 50 f a . of water for only 12 hours and when l i f t e d the writer observed the following number of lingcod captured: lingcod (male)  56  (13  alive)  lingcod (female)  76  (43  alive)  Only 5 male and 6 female dog-fish were caught. I t was  estimated that nearly  2,000  pounds of lingcod  (averaging 15 l b s . each) were taken from t h i s sunken g i l l - n e t . I t i s evident that i f t h i s f i s h e r y were i n t e n s i f i e d , these sunken g i l l - n e t s could deplete i n a short time many of the lingcod banks i n the gulf of Georgia. By the Order i n Council of July 7, nets were prohibited from operating  i n a l l the coastal waters  of B r i t i s h Columbia after December 16, l a t e r amended on A p r i l 16,  1944**, sunken g i l l -  1944.  This order  was  1945*** to apply only to the gulf  of Georgia and c e r t a i n other f i s h i n g l o c a l i t i e s . • 3»  West Coast of Vancouver Island. On the mud  bottom of the waters o f f Barkley sound  lingcod and s a b l e - f i s h or black cod (Anoplopoma fimbria) **  (Order i n Council July  7,  1944,  5207),  P.O.  are  Special Fishery  Regulations^jfor the Province of B r i t i s h Columbia,  1944.  16,  February  *** (Order i n Council A p r i l  28, 1946,  P.O.  736;  O.C.  1945,  April  P.O.  18,  2649;  1946,  O.C.  P.C.  1525),  c i a l Fishery Regulations for the Province of B r i t i s h Columbia,  1946.  Spe-  -  23  -  caught i n the sunken g i l l - n e t s along with dog-fish i n s u f f i cient quantity to be r e a d i l y marketed.  Nets set i n c e r t a i n  areas may have lingcod and black cod tangled i n the web  one  day and when set i n the same area on other occasions neither species may be caught. The following species and t h e i r numbers were recorded from 10 d i f f e r e n t sets made by boats f i s h i n g o f f Barkley sound i n June,  1944:  Hag-fish (Folistotrema s t o u t i i ) . Dog-fish (Squalus suckleyi) .. B i g skate (Raja binoculata) Rat-fish (Hydrolagus c o l l i e i ) Spring salmon (Oncorhynchus tahawytscha) .. Gray cod (Gadus macrocephalua) 77777777 Bocaccio (Sebastodes paueispinis) Yellow-tailed r o c k - f i s h (Sebastodes flavidus) .... Sebastodes spp Lingcod (Ophiodon elongatus) S a b l e - f i s h (Black cod) (Anoplopoma fimbria) Long-jaw flounder (Atheresthea stomias) T Halibut (Hippoglossua stenolepls) .. .7 B r i l l (Eopsetta jordani) ......7*  2 1,028* 1 175** 6 1 5 3 3 62 4 245** 2 52 1  Crabs (Cancer magiste'rT *  This i s an estimated number, based upon counted random samples of dog-fish l i v e r s of known weights and the t o t a l weight of a l l the dog-fish l i v e r s .  ** This number i s i n part  estimated.  The following species of f i s h were recorded from different landings i n Barkley sound; soup-fin shark (Galeorhinus galeus), green sturgeon  (Aoipenser m e d i r o s t r l s ) , p i l c h a r d (Sardinops  oaerulea), herring (Clupea p a l l a s i l ) , eoho salmon (Oncorhynchus kisutch), hake (Merluccius productus),  red-striped r o c k - f i s h  (Sebastodes p r o r i g e r ) , flat-head sole (Hippoglossoides e l a s sodon), rock sole (Lepidopsetta b i l i n e a t a ) , lemon sole (Parophrys vetulus), wolf-eel (Anarrhichthya ocellatus) -, wry-mouth  - 24 (Delolepis giganteus). I t was observed o f f Barkley sound that the hag-fish (Polistotrema s t o u t i i ) w i l l eat the l i v e r s from the dog-fish when the nets are l e f t i n the water f o r more than 12 hours. The writer has removed as many as four hag-fish from the body f  cavity of a single dog-fish.  D. S e l e c t i v i t y of the Sunken G i l l - n e t . i  The sunken g i l l - n e t has not only proven an e f f e c t i v e means of capturing dog-fish but i t also tends to select the length of the dog-fish; small ones tend to pass through the webbing, thus eliminating those of no commercial value. than 76 om.  Male dog-fish less  long contain so l i t t l e vitamin "A" that they are of  no appreciable value.  Few female dog-fish are mature at 76  cm.  and only about 50 peroent of males become mature at t h i s s i z e .  Length-Frequency D i s t r i b u t i o n of Dog-fish Caught by Sunken G i l l - n e t s and by Otter Trawls Figures 15 and 16 i l l u s t r a t e the length-frequenoy  distri-  butions of dog-fish caught i n sunken g i l l - n e t s o f f Barkley sound during the months of June and August r e s p e c t i v e l y , i n 1944.  During these two months a greater percentage of males  than females was  taken.  F i g . 17 i l l u s t r a t e s the length-fre-  quency d i s t r i b u t i o n pf dog-fish caught by sunken g i l l - n e t s i n Hecate s t r a i t during June 1946.  A greater percentage of f e -  male dog-fish were caught by the sunken g i l l - n e t s during t h i s period i n Hecate s t r a i t .  Figures 18 and 19 i l l u s t r a t e the  w LENGTH  FREQUENCY  DISTRIBUTION  CAUGHT  BY S U N K E N  GILL-NETS  OF D O G - F I S H OFF  SOUND IN J U N E 1 9 4 4 MEASUREMENTS MADE FROM 7 DIFFERENT  BARKLEY  "SETS"  FEMALES  eo  85  LENGTH  100  CM.  F i g . 15  105  110  118  LENGTH  FRENQUENCY  DISTRIBUTION  CAUGHT  BY  GILL7NETS  SUNKEN  SOUND MEASUREMENTS  IN MADE  OF  OFF  AUGUST  1944  FROM  DIFFERENT  10  DOG-FISH BARKLEY "SETS"  i 100  105  i  i  i  i  i  i  i  i  i  i  i  i  30  SS  SO  as  70  7S  80  88  90  9S  100  108  LENGTH  F i g . - 16  CM.  i'T  110  116  i 120  i — i — r 110  118  '120  LENGTH CAUGHT  FREQUENCY  STRAIT MEASUREMENTS  69  DISTRIBUTION  BY S U N K E N  70  76  IN  GILL-NETS  SS  DOG-FISH  HECATE  JUNE 1 9 4 6  MADE FROM  SO  OF IN  9 b  95  LENGTH  7 DIFFERENT "SET"  100  105  110  115  120  CM.  J  Fig.  17  - 25 length-frequency  d i s t r i b u t i o n s of d o g - f i s h caught by  sunken  g i l l - n e t s and o t t e r t r a w l s r e s p e c t i v e l y o f f the west coast of Vancouver i s l a n d . ( F i g . 18)  The  d o g - f i s h caught by the sunken g i l l - n e t s  were caught o f f B a r k l e y sound while those  the o t t e r t r a w l s ( F i g . 19)  were taken o n l y 10 m i l e s northward,  o f f F l o r e n c i a i s l a n d and A m p h i t r i t e and 18  caught by  point.  F i g u r e s 15,  16,  17,  show t h a t the sunken g i l l - n e t s tend to s e l e c t the l a r g e r  d o g - f i s h over 76  cm. which have l i v e r of s i g n i f i c a n t  value w h i l e , F i g . 19  i l l u s t r a t e s the l a r g e number of o t t e r  t r a w l caught d o g - f i s h t h a t a r e l e s s than 76 no a p p r e c i a b l e v a l u e .  commercial  cm. which are o f  I t i s e v i d e n t t h a t the o t t e r t r a w l does  not s e l e c t the d o g - f i s h when f i s h i n g on the  sea bottom and  a l s o catches l a r g e i n d i v i d u a l s when they are p r e s e n t on t r a w l i n g grounds.  the  thus  LENGTH  FREQUENCY  CAUGHT BY SUNKEN SOUND MEASUREMENTS  DISTRIBUTION GILL-NETS  IN  JUNE  MADE  FROM  Fig." 18  OF  OFF  DOG-FISH BARKLEY  1945 8  Dl F F E R E N T S  "SETS"  LENGTH  FREQUENCY  CAUGHT  BY  POINT  DISTRIBUTION  OTTER- TRAWLS  C BARKLEY  SOUND)  OF DOG-FISH  OFF AMPHITRITE  IN JUNE AND JULY  1945 MEASUREMENTS  MADE FROM 8 DIFFERENT "DRAGS'  I 5  o z UJ  a  55  60  65  70  75  60  I5  I 0  F i g . 19  65  90  95  i100  i  105  r  110  - 26 IV.  TOTAL CATCH STATISTICS OF THE DOG-FISH AND  SOUP-FIN SHARK  IN BRITISH COLUMBIA  T o t a l .catch s t a t i s t i c s are of value wherever a mass of data exists- and wherever those f a c t s can he expressed quantit a t i v e l y i n a form suitable f o r analysis.  Catch s t a t i s t i c s  of a commercial f i s h e r y help to constitute a s c i e n t i f i c background for f i s h e r y regulations and management.  Intelligent  management cannot be conducted without s t a t i s t i c s .  The  catch,  which i s indicated by quantitative u n i t s , varies from year to year and the quantitative units form a means of expressing  the  economic condition of the f i s h e r y .  may  T o t a l catch s t a t i s t i c s  indicate the changes, i f any, i n the abundance of f i s h on the grounds, but usually are too involved to r e v e a l the e x i s t i n g state of abundance of a commercially exploited f i s h e r y population. The annual production and value of dog-fish l i v e r o i l and body o i l from I876 to 1945 1887  a record was  liver o i l .  are given i n Table I I .  From 1879  kept of the production of refined dog-fish  Separate catch s t a t i s t i c s f o r the production of  l i v e r and body o i l were not kept again u n t i l the year  1940.  The commercial development of refined dog-fish l i v e r o i l i n B r i t i s h Columbia was  f i r s t centered on the Queen Charlotte  islands at Skidegate, where production of l i v e r o i l and body o i l oontinued for a number of years.  Before 1900,  a small  amount of seal and porpoise o i l was included i n the t o t a l amount of dog-fish l i v e r and body o i l produced. The amount of dog-fish l i v e r and body o i l produced i n  to  Table  II  Production of Dog-fish Liver o i l and Body o i l from 1876 to 1945.  1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 .1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919  Dog-fish Liver and Body O i l  Refined Dog-fish liver Oil  Gallons  Gallons  Value  12,780 20,000 27,000 37,000 40,000 45,000 40,000 20,000 67.500  1,500.00 11,000.00 14,850.00 20,350.00 22,000.00 24,800.00 20,000.00 10,000.00t 33,750.00  50 ,124 115 ,495 150 ,516 104 ,475 119 ,362 142 ,240' 196 ,407 217 ,419 10 ,000 22 ,200 25 ,000 40 000 64 345 141 ,420 162 ,264 249 ,500 259 554 172 250 143 000 135 ,000 61 500 . 95 500 124 525 145 ,200 128 100 152 ,100 161 ,950 223 ,550 192 ,750 175, 990 125 265 116, 640 142 480 209, 950 77 240 •75 550 85, 826 144 ,050 41 249 33 ,565 7 505 44 820 ,53 383. 54 954  Value 25 ,024.00 46 ,198.00 60 , 2 0 6 . 4 0 41 , 7 9 0 . 0 0 47 ,744.80 56 , 8 9 6 . 0 0 78 ,562.80 86 , 9 6 7 . 6 0 3 ,500.00 5 ,550.00 10 ,000.00 16 000.00 32 ,172.50 70 ,710.00 81 ,132.00 124 ,750.00 129. .046.20 68 900.00 57 ,200.00 54 ,000.00 24, 600.00 28 650.00 37 357.00 43 560.00 35 227.50 45 ,630.00 56 ,682.50 78 ,242.50 67 462.50 61 596.50 43, 8 4 2 . 0 0 40 474.00 56, 646.00 64 122.50 26 767.00 24 262.00 29 075.00 46 690.00 12 481.00 12 363.00 23, 8 9 2 . 0 0 53 383.00 35 097.00  Table I I  1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939  1940 1941  Dog-fish Liver and Body Oil  Refined Dog-fish Liver Oil.  Gallons  Gallons  55,669 44,700 75,461 180,318 241,376 354,853 217,150 375,130 411,208 459,575 114,558 170,271 35,147 117,600 203,930 122,380 164,643 124,464 113,360 130,044  Value | 31,155.00 7,110.00 22,655.00 64,696.00 88,855.00  Dog-fish Body Oil  Dog-fish Liver Oil  Gallons  Value . #  Gallons  95,484 71,582  20,997.00 29,569.00  lb. 433,667 334,696 163,103  Value # 31,135 16,756 8,263  Dog-fish Body Oil 1942 1943 1944 1945 *  Gallons* 390,300 301,226 146 793  $  138,180.00 119,120.00 122,513.00 22,229.00 19,362.00 4,629.00 13,170.00 25,205.00 23,744.00 34,745.00 28,074.00 18,802.00 38,177.00  Dog-fish Body Oil 1942 1943 1944 1945  Value  64,269 212,175  Value $ 84,405.00 531,355.00  Dog-fish Liver Oil lb. 2,802,277 3,509,213 4,909,808 3,880,433  Value i 1,178,242.00 2,028,875.00 3,661,131.00 2,337,267.00  Dog-fish Body Oil  Gallons* • 2,538,863 3,179,347 4,4481286 3;515,663 Sp. gr. of Dog-fish Liver Oil at 25°C. - 0.906  - 27 B r i t i s h Columbia was r e l a t i v e l y constant from 1877 to with the exception of minor f l u c t u a t i o n s .  A drop i n production  of o i l ensued following the outbreak of World War I . f'boom" years which followed (1927 to 1929)  1940,  With the  an increase i n e f -  f o r t , indicated by the increase i n the number of licences, r e sulted i n a decided inorease i n t o t a l production (Table I I ) . During the decade that followed the output returned to i t s former l e v e l of production. U n t i l 1941 the demand f o r dog-fish l i v e r and body o i l never attained a magnitude of importance.  During t h i s year  the need f o r vitamin "A", which i s stored i n the l i v e r of the dog-fish, became very apparent and the dog-fish assumed a degree of importance with a r e s u l t i n g sudden i n f l u x of fishermen to t h i s f i s h e r y (Table I ) .  The output of l i v e r o i l soared to  unpreoendented heights during the four years following 1941 (Table I I ) . In 1942 the amount of l i v e r o i l and body o i l produced was recorded i n pounds.  These f i g u r e s have been converted  into gallons for comparison with the previous years,. After the  o i l has been removed from the body of the dog-  f i s h the remainder after processing i s marketed as meal and f e r t i l i z e r (Table I I I ) . The production of body o i l ceased after 1944.  Since the dog-fish were caught only f o r t h e i r  l i v e r s after t h i s year the carcasses were discarded. Some fresh dog-fish have been marketed i n c e r t a i n years (Table IV), but the fresh f i s h has not met the general approval ..of the fresh f i s h market.  The quantity of whole dog-fish  caught and landed i n B r i t i s h Columbia from 1916 to 1944 i s presented i n Table IV.  Table  III  'Production of Dog-fish Hfeal and F e r t i l i z e r from 1892 to 1944. Dog-fish Meal and fertilizer  Dog-fish Meal and Fertilizer Tons  Value |  1892 15 1893 15 1894 30 1895 15 1896 50 1897 1898 200 1899 550 1900 200 1901 300 1902 150 1903 1,060 1904 ' 607 1905 872 1906 140 1907 1,294 1908 84 1909 . 487 266 1910 1911 1912 150 1913 1,649 1914 1,244 1915 953 1916 1917 1,220 1918 1,802  375.00 375.00 600.00 375.00 1,000.00 6,000.00 16,500.00 6,000.00 9,000.00 4,500.00 31,800.00 18,210.00 26,160.00 3,570.00 32,362.50 2,352.00 13,636.00 ,700.00 5,097.00 59,254.00 .47,432.00 36,477.00 70,164.00 18,198.00  Tons 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944  ,  Value 4  1,800 --"• 19^756.00 466 39,147.00 489 27,010.00 911 48,926.00 .-r 823 . 43,447.00 1,709 94,303.00 2,468 1,752 2,512 145,449.00 3,658 3,626 173,254.00 899 45,165.00 1,010 34,869.00 264 7,018.00 786 23,580.00 1,135 39,510.00 768 22,924.00 1,065 34,906.00 833 26,740.00 1,262 42,807.00 925 36,322.00 1,285 63,210.00 1,051 69,062.00 914 60,872.00 708 41,857.00 330 21,136.00  Table  IV  Quantity of Dog-fish (whole f i s h j uaught and Landed i n B r i t i s h Columbia from 1916 to 1944  Weight Landed cwt. 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944  5,460 11,200 59,194 50,920 15,000 52,560 40,240 48,640 74,000 74,040 78,380 112,700 230,557 259,540 98,680 112,348 28,020 79,609 117,020 76,800 116,140 113,220 159,690 114,816 141,350 142,999 100,540 78,924 24,339  Value # 1,911 4,480 29,607 17,822 4,550 12,998 10,085 12,812 23,150 22,212 23,514 39,445 . 80,694 90,839 30,372 22,929 4,203 13,789 21,921 15,360 26,309 32,428 27,087 23,888 57,236 100,965 12,055 9,865 25,606  Marketed Fresh Value cwt. $ 5,460 11,200 59,194  1,911* 4,480* 29,607*  340 3,920 45,951  68 1,274 2,310  5,843  13,117  * Exported to the United States  - 28  -  F i g . 20 i l l u s t r a t e s the t o t a l landings of dog-fish l i v e r s for B r i t i s h Columbia from 1937 to 1946.  The value of the l i v e r s  and the average price per pound paid to the fishermen i s given i n Table V.  The catch of the dog-fish dropped greatly i n the  years following 1944 as indicated by the quantity of l i v e r s landed, ( F i g . 20).  This drop i n t o t a l catch indicated that  the high f i s h i n g i n t e n s i t y was possibly e x p l o i t i n g the dogf i s h beyond the l i m i t s of a stable and productive l e v e l . Although the soup-fin shark i s not nearly as abundant as the dog-fish i n B r i t i s h Columbia waters, i t s l i v e r s provide a substantial part of the vitamin A" M  supply.  The vitamin  "A"  content of the- soup-fin shark l i v e r s i s even greater than that in the l i v e r s of the dog-fish. F i g . 21 i l l u s t r a t e s the t o t a l landings of soup-fin shark l i v e r s i n B r i t i s h Columbia from 1940 to 1946.  There was  marked drop i n the landings of l i v e r s during the years and 1946.  The  a 1945  value of the soup-fin shark l i v e r s and the mar-  keted value of the l i v e r o i l i s given i n Table VI.  Fig.  20  Table  V  Quantity and value of Dog-fish Livers Landed i n B r i t i s h Columbia from 1937 to 1946.  Weight Landed lb.  value $  Average Price £ to Fishermen per l b .  1937  178,900*  10,702;  6  1938  933,300**  49,271°  6  1939  308,047***  19,063°  6  1940  1,566,500  86,192  6  1941  3,552,576  331,737  9  1942  4,241,256  688,040  16  1943  5,121,186  1,344,858  25  1944 • 7,769,564  2,661,573  34  1945  5,821,849  1,833,210  31  1946  2,844,217  888,075?  32.5  * A l l l i v e r s exported. ** A l l l i v e r s exported with the exception of a small proportion used by local chemical and fishery companies in experimental vrork. *** Figure estimated from vitamin o i l Production plus quantity exported. • ° Marketed values of l i v e r s only.  Fig.  21  Table  VI  Quantity of Soup^-fin Shark Livers Landed i n B r i t i s h Columbia with Marketed values of the Livers and Liver O i l .  height Landed lb.  Value § Landed Marketed  1940  2,600  1,090  2,094  700  1,400  1941  23,191  51,509  68,122  10,266  23,262  1942  48,768  136,137  168,596  18,375  126,461  1943  31,922  86,300  99,931  12,926  78,886  1944  61,510  218,337  300,641  34,690  288,436  1945  35,341  140,103  168,702  20,967  162,154  1946  9,005  23,973  37,186  5,005  32,870  Liver O i l Marketed lb. value  - 29 -  V.  DESCRIPTION AND  ANALYSIS OF  F I S H AND  A.  Selection Before  soup-fin must be  and S o u r c e  THE  A V A I L A B I L I T Y OF  DOG-  SOUP-FIN SHARK  of  Data.  an a n a l y s i s o f t h e a v a i l a b i l i t y o f t h e d o g - f i s h and  s h a r k may  be  available.  accomplished,  adequate  from  men,  catch.  the  catch  statistics  F o r a n a l y s e s i t i s n e c e s s a r y t o know t h e  individual landings of l i v e r s and  THE  locality  o f each  all,  o r n e a r l y a l l the  In B r i t i s h  fisher-  Columbia,  neither  the Dominion nor  the P r o v i n c i a l F i s h e r i e s  Department  collect  catch s t a t i s t i c s  that  analysis  the  a v a i l a b i l i t y and  caught  i n these  a r e a d e q u a t e f o r an  abundance o f  have f o r many y e a r s had  (Conner  1937)  logical  s t a t i s t i c s was  of F i s h  and  the  o f F i s h and  Game  of the f i s h e r y  o f complete  inaugurated.  The  and  statistics.  informative bio-  California  and  Game.  One  one  to the f i s h The  on  Fish receipts,  forms s u p p l i e d by  copy c o v e r i n g each buyer,  and  sale  the t h i r d  Division  or "pink t i c k e t "  recorded i n almost  any  to s p e c i a l desirable  t a b u l a t i n g machines  or t a l l y  the D i v i s i o n  goes t o the  the  form,  of  system are Fish  fisherman, to  the  data from t h e r e -  cards which are  (Conner  slips  or "pink t i c k e t "  D i v i s i o n then t r a n s f e r s  pro-  1931  of the r e c o r d e d d a t a . I n  collection  made I n t r i p l i c a t e ,  Hollerith  fishes  Game have what i s known a s t h e " p i n k t i c k e t "  collecting  ceipt  the D i v i s i o n  a clearer picture  blems because o f the n a t u r e  Division.  important  waters.  I n the S t a t e o f C a l i f o r n i a ,  of  commercially  of  s o r t e d and  by e l e c t r i c a l l y  1935)*  operated  -30-  For the a n a l y s i s i n t h i s sary to c o l l e c t bulate, i t . slips,  such d a t a from the f i s h i n g  The d a t a were  or f i s h  study i t therefore  receipts,  l a n d i n g s from a l l - p a r t s  collected  study. ness  from the i n d i v i d u a l  of the B r i t i s h  Columbia  tally  shark  I t i s n o t e s s e n t i a l t o have a  o f e v e r y l a n d i n g made f r o m e a c h  I n u n d e r t a k i n g an a n a l y s i s  slip  or f i s h  receipt  liver  c o a s t , where-  area  of a v a i l a b i l i t y ,  under complete-  i n d a t a adds t o the a c c u r a c y o f the i n v e s t i g a t i o n .  tally the  record  neces-  i n d u s t r y and t o t a -  o f t h e d o g - f i s h and s o u p - f i n  e v e r r e c o r d s were t o b e f o u n d . complete  became  Each  i n d i c a t e s the date, place o f s a l e ,  d e a l e r ' s name, t h e f i s h e r m a n ' s name, t h e name o f t h e b o a t ,  weight  and v a l u e o f the d o g - f i s h and s o u p - f i n  landed, as w e l l  as t h e w e i g h t s  shark  of the v a r i e t i e s  livers  of fresh  •  fish  i  landed. ial  The d a t a on t h e s e r e c e i p t s were t h e n c o m p i l e d on s p e c -  forms,  listing  t h e f i s h e r m a n ' s name and b o a t , and t h e l o -  c a l i t y where t h e f i s h were  B.  caught.  E s t i m a t i n g Changes i n t h e A v a i l a b i l i t y  and Abundance o f  Fish Populations. Exploitation  o f any v i r g i n  abundance o f t h e f i s h tive  fisheries  p o p u l a t i o n on w h i c h  administration  tent o f the e x p l o i t a t i o n measures o f f i s h  f i s h e r y t e n d s t o change t h e i t depends.  Effec-  depends u p o n knowledge o f t h e e x -  and i t s c o u r s e .  In general, direct  populations are not f e a s i b l e , but r e l a t i v e  e s t i m a t e s c a n be o b t a i n e d f r o m a n a l y s e s o f f i s h e r i e s  statistics".  As  include  a rule,  detailed  such s t a t i s t i c s  a r e most u s e f u l when t h e y  a c c o u n t s o f t h e amount o f f i s h i n g e f f o r t  and l o c a l i t i e s  -  fished.  31  -  In most f i s h e r i e s , t o t a l catch i s too involved with  the amount of f i s h i n g e f f o r t to r e f l e c t well the changes i n the abundance of f i s h on the grounds.  Knowledge of f i s h i n g  costs i s useful i n i n t e r p r e t i n g f i s h e r y production f i g u r e s . In order to obtain f i s h e r y s t a t i s t i c s i n the most u s e f u l form, p i l o t house record books have been used i n the herring (Tester 1945), the p i l c h a r d , and the halibut f i s h e r i e s on the p a c i f i c coast..  Some fishermen on sunken g i l l - n e t boats keep  p i l o t house record books of t h e i r  own.  As a r u l e , calculations of return per u n i t of f i s h i n g e f f o r t i s one of the most valuable indices of a v a i l a b i l i t y and abundance.  Should the amount of e f f o r t that Is used, vary  from year to year, catch per unit of e f f o r t may  not be used  d i r e c t l y to indicate the r e l a t i v e abundance or a v a i l a b i l i t y , without  considering the actual amount of e f f o r t used i n suc-  cessive years. unassessable  Conclusions can be d i s t o r t e d by cumulative  changes i n the q u a l i t y of the e f f o r t .  The  and  theore-  t i c a l r e l a t i o n s h i p of catch per unit e f f o r t to abundance and rate of e x p l o i t a t i o n has been discussed by Ricker (1940). The return per-unit-of-effort-•- has been used i n the h a l i but investigations (Thompson, Dunlop, and B e l l 1 9 3 1 ,  Thompson  and B e l l 1934), and i n the study of the depletion of the black cod by B e l l and Gharrett (194$). i e s was  the "catch per-skate".-  The index used i n these The  stud-  "catch per-seine-day"  has  been used by Tester (1945) i n the herring fishery; the catch "per-boat-week", the "catch per-boat-per-night",  by S i l l i m a n  and Clark ( 1 9 4 5 ) , and "catch per-lunar month" (Clark  1939)  i n the pilchard f i s h e r y i n v e s t i g a t i o n .  Kelez  Rousefell and  -  (1938)  use  the  "catch  t o n s as  i n i n d e x o f the  C.  Meaning of A v a i l a b i l i t y In t h i s  study o f the  ability" will  the  availability  and  f o r the  and  relative  soup-fin  fishery.  abundant, t h a t i n great  The  i s , the  amount o f t h e  to the  relative  the  only  these  t h e y may  Availability,  to that  h o r i z o n t a l and  "avail-  dog-fish  and  subjected  in this  soup-fin  waters but  sunken g i l l - n e t s .  tion within  and  a c t u a l numbers o f  term a p p l y i n g  gill-nets  Availability  dog-fish  q u a n t i t i e s i n the  salmon f i s h e r y .  shark,  s h a r k i n the w a t e r s o f B r i t i s h C o l u m b i a  sunken g i l l - n e t  30-39  per boat o f  Abundance.  dog-fish  r e f e r , t o the  n o t mean a b u n d a n c e .  able  -  per-seven-day p e r i o d  net  soup-fin  32  sense  to  does  s h a r k s may  be  s h a r k s may  be  not  be  avail-  therefore, i s a  p a r t o f the  v e r t i c a l range  total  of the  populasunken  and m o v i n g a r o u n d a c t i v e l y enough t o become emmeshed  i n them. Tn the  the  analysis of  unit of e f f o r t  fish  and  nets  fished.  per  soup-fin  i s the  Should  average boat  there  be  boat from year to.year, number o f n e t s  dicate  a decline  from Hecate  c a t c h p e r month o f  independent of the  a d e c l i n e i n the  even though there  f i s h e d per boat, i t w i l l  i n the  availability  strait,  o f the  number  average i s an  dogof  catch  increase  certainly i n -  dog-fish  and  soup-  shark. On  the  west c o a s t  o f Vancouver i s l a n d ,  more d e t a i l e d i n f o r m a t i o n men  statistics  shark l i v e r s ,  i n the  fin  catch  i n c a t c h i n g the  of the  d o g - f i s h was  effort  o f f Barkley  expended by  a v a i l a b l e f o r the  the  sound fisher-  period  of  -  time under i n v e s t i g a t i o n .  33  -  In t h i s area catch per sunken  gill-  net  (75 fathoms,) per day (24 hours) w i l l be used i n determining  the  a v a i l a b i l i t y of the dog-fish.  D.  Analysis of the Catch Records of Dog-fish Livers Landed by Sunken G i l l - n e t Boats Fishing i n Hecate S t r a i t . 1.  The T o t a l Landings of Livers by Sunken G i l l - n e t Boats. In Hecate s t r a i t ( F i g . 22), the sunken g i l l - n e t f i s h -  ery  commences i n May and usually terminates at the end of October.  F i g . 23 i l l u s t r a t e s the decided increase In t o t a l catch from 1943 to 1944. landed i n 1944.  In 1946 the t o t a l catch was only h a l f the amount About 24 per cent of a l l the dog-fish l i v e r s '  landed i n B r i t i s h Columbia i n 1944 was caught by sunken  gill-  net boats f i s h i n g i n Hecate s t r a i t from May u n t i l October.  Dur-  ing the same months i n 1945 and 1 9 4 6 , sunken g i l l - n e t boats i n Hecate s t r a i t caught 30 per cent and 32 per cent r e s p e c t i v e l y of the t o t a l catch landed i n B r i t i s h Columbia.  During.1945  there was nearly double the number of sunken g i l l - n e t boats f i s h ing i n Hecate s t r a i t (Table 7) as there was i n 1944, but the t o t a l weight of l i v e r s landed by the boats was s l i g h t l y lower in  1945 than i n 1944.  Poor weather conditions during the summer  months of 1945 hindered the f i s h i n g e f f o r t of some of the smaller boats, thus contributing to the smaller catch. F i g . 24 i l l u s t r a t e s the t o t a l catch.of dog-fish l i v e r s for each month from 1943 to 1 9 4 6 .  The largest catches were  made during.the months of June and July i n 1944 and 1 9 4 5 . 1946  the months of greatest t o t a l eatches were i n June and  In  GRAHAM ISLAND  MORESBY ISLAND  PACIFIC OCEAN QUEEN CHARLOTTE SOUND  F i g . -22 The  shaded a r e a i n d i c a t e s for  the g e n e r a l f i s h i n g  the sunken g i l l - n e t s  i n Hecate  grounds strait.  Fig.  23  TOTAL.  WEIGHT BOATS  MAY  OF D O G - F I S H FISHING  JUNE  IN  LIVERS HECATE  LANDED STRAIT  JULY  F i g . 24  EACH MONTH  FROM  AUGUST  1943  TO  BY SUNKEN  GILL-NET  1946  SEPTEMBER  OCTOBER  - 34 - August. 2.  The  Average  C a t c h per Boat  When t h e a v e r a g e of a v a i l a b i l i t y ,  F o r e x a m p l e : - two  a month, and e a c h b o a t  day.  One  boat  every f i f t h its  caught  the  day.  The  catch per t r i p days  t h e month i s t h e and  The  catch per boat ability.  per t r i p  Both, o f t h e s e two  s t r i p e d bass  (Roccus  1933); and  (Clark  1931)'.  lineatus)  illustrates  f o r t h e y e a r s 1943  1943  the  and  1946.  tuna  The  landed  d a t a from both  t h e number o f  the  the  avail-  a v a i l a b l e d u r i n g t h e month o f J u n e .  stati-  s t u d i e s o f the white (Whitehead  1930);  sea the  1930),  (Craig  thynnus),(Whitehead californicus)  catch per boat  p e r month  d u r i n g t h e month o f  1945  the  average  T h i s method o f a n a l y s i s  and  of  days  give i n d i c e s of  (Paralichthys  average  boat  i s discounted.  (Thunnus  halibut  t o 1946.  I n 1944  that  c a t c h a t the end  of C a l i f o r n i a  t h e d o g - f i s h were most a v a i l a b l e in  the o t h e r boat  o f the boat  of C a l i f o r n i a  the C a l i f o r n i a  25  and  methods o f a n a l y s i s o f c a t c h  in.availability  the b l u e f i n  1931);  Fig.  each  p e r month b o t h  (Cynosoion n o b i l i s )  Clark  same amount o f f i s h  c a t c h p e r b o a t p e r month and  s t i c s have been used bass  days  s m a l l boats are used, because  average  trip  twenty  same f o r e a c h b o a t .  p e r t r i p made b y e a o h c l a s s o f b o a t  index  per  i s f o u r times g r e a t e r t h a n the  l a n d e d i t s c a t c h e v e r y day b u t  large  boats f i s h e d  l a n d s i t s c a t c h e v e r y day,  catch every f i v e  that  c a t c h p e r month i s u s e d a s an  c h a n g e s i n the number o f f i s h i n g d a y s  are d i s c o n t i n u e d . in  per Month.  indicates August  t h e d o g - f i s h were most The  y e a r 1945  shows a  AVERAGE LIVERS  CATCH PER LANDED  IN  BY  HECATE  >• <  s  z 3 ->  BOAT SUNKEN STRAIT  PER  MONTH  GILL-NET FROM  .  o 1944  .,  • 1945  ,  ^  Fig.  <  25  1946  1946  o3  ->  TO  FISHING  1943  .  3  DOG-FISH  BOATS  1943  e  ->  OF  Ul  in  0 . 1 O-  o  - 35 decided drop i n the a v a i l a b i l i t y from 1944, while i n the year 1946 the- a v a i l a b i l i t y increased over the previous year. The sources of error i n t h i s graph are discussed l a t e r i n the text. 3.  The Average Catch -per T r i p per Boat per Month. The average catch per t r i p per boat i s determined by  d i v i d i n g the monthly catch of a l l the—boats by the number of t r i p s that a l l the boats made i n each p a r t i c u l a r month. The comparison between the methods of using the average catch per boat per month and the average catch per t r i p per boat by months i s made to indicate the effect each successive year.  of the longer t r i p s i n  I t i s seen (Table VII) that there has  been a general drop i n the average number of t r i p s per month since 1 9 4 3 , except during the months of June i n 1944, and the months of August and September i n 1946. Like the other method (Fig. 23) of analysis F i g . 26 i n d i cates the a v a i l a b i l i t y of the dog-fish to be greatest during the month of August i n 1943 and 1946. The year 1945 shows a decided drop i n the a v a i l a b i l i t y compared with 1944. 4.  The Average Catch per Boat per Month and the Average Catch per T r i p per Boat per Month f o r Bach Year as a Whole. F i g . 27 i l l u s t r a t e s the weighted average catch per  boat per month and the weighted average catch per t r i p per boat per month.  The average catch i s weighted by the different  number of boats f i s h i n g each month and the changes i n the number of t r i p s made f o r each month.  Although 'the average catch per  boat per month dropped greatly during 1945, the average catch  Table . v i i The Average Number of Trips per Boat per Month made by Sunken Gill-net Boats Fishing in Hecate S t r a i t from 1943 to 1946.  1943  1944  1945  1946  May  2  2.92  1.30  1.50  June  4  4.72  3.80  3.07  July  4.80  3.58  3.32  3.41  August  4.67  3.84  3.44  4.48  September  3.93  3.24  2.00  4.66  October  5.32  3.71  3.00  2.75  Average No. of Trips Each Year  4.61  3.84  3; 14  3.44  1  AVERAGE OF  CATCH  DOG-FISH  BOATS  PER  LIVERS  FISHING  IN  TRIP  PER  LANDED  HECATE  BOAT BY  MONTH  SUNKEN  STRAIT  •  PER  FROM  1943  GILL-NET TO  1946  • 1943  •  • 1944  1  f 1945  .  o 1946  15 14 13 12 in a  z  1 1  o u. o  Io 9  3  8  in  ° LiJ . <r a Z  '  7 6 «  4 3  \  -  -  2  _ A_.  1  1  1  1  1  1-  JUNE  JULY  AUG.  SEPT.  OCT.  '  MAY  0  -  -  36  -  per t r i p per boat dropped only s l i g h t l y .  These two graphs  indicate lower a v a i l a b i l i t y during the years 1943 and 1945 and an increase i n the a v a i l a b i l i t y during 1946. The graphs i n F i g . 27 give a somewhat d i s t o r t e d picture of the actual conditions. Consider the following s i t u a t i o n : A limited population i n a certain l o c a l i t y is..being fished with a fixed, amount of gear.  I f the number of boats and gear i s  doubled, the t o t a l catch would not double because of competition among the increased gear.  I t i s probable  that each boat  i n operation would catch less f i s h than i f only the smaller number were operating.  Such a s i t u a t i o n occurred i n Hecate  s t r a i t from 1943 to 1945. During 1946 the number of sunken g i l l - n e t boats f i s h i n g i n Hecate s t r a i t was much less than i n 1945  (Table 7 ) .  There are many cumulative  factors which would  tend to increase the average boat catch i n 1946. Some of these factors may be discussed.  The general drop i n the average  number of t r i p s per month since 1943 could indicate a greater amount of e f f o r t expended by the fishermen before a landing of dog-fish l i v e r s was made.  This would tend to increase the  average catch per t r i p per boat per month.  Some of the men on  the larger boats may have had more resolution and experience to f i s h i n bad weather i n 1946.  This would increase t h e i r aver-  age monthly landings of dog-fish l i v e r s .  These p o s s i b i l i t i e s ,  coupled with a r i s i n g value of the dog-fish and soup-fin shark l i v e r s would tend to keep the fishermen on the f i s h i n g grounds f o r longer periods*  r 37 5•  The Index of the Average Catoh per Boat per Month and the Index of the Average Catch per T r i p per Boat per Month as Determined by the Method of Link Relatives. Link r e l a t i v e s are determined by comparing the catch  i n one month, with the catch i n the same month i n the previous year, or i n each successive year.  In the analysis presented  here, the year 194-3, was used as the base year.  Each month of  t h i s year was compared with the same months i n each of the successive years.  Chaddock ( 1 9 2 5 ) describes t h i s method of  analysis i n d e t a i l , and i t has been used i n the analysis of boat catches i n the C a l i f o r n i a halibut f i s h e r y (Clark 1 9 3 1 ) . For example:- i f 8, 1 2 , 6 , and 3 are the values of the average catch per boat per month i n the successive years 1 9 4 3 to 1 9 4 6 ; the r e l a t i v e for the second year, 1944, using the f i r s t year ( 1 9 4 3 ) , as a base, i s 1 2 * 8 = 1 . 5 0 ; the t h i r d r e l a t i v e i s 6 + 1 2 » 0 . 5 0 , and the fourth r e l a t i v e f o r the year 1 9 4 6 would be 3 * 6 « 0 . 5 0 . These r e l a t i v e s must now linked together by what i s termed the chain r e l a t i v e .  be  The  f i r s t year of the series, 1 9 4 3 , i s the base year, and i s therefore 1 0 0 percent.  The chain r e l a t i v e f o r 1944 would be 1 0 0  multiplied by I . 5 0 « 1 5 0 percent; the chain r e l a t i v e f o r 1945 would be 1 5 0 x 0 . 5 0 = 7 5 percent; and the chain r e l a t i v e for 1 9 4 6 would be 0 . 7 5 x 0 . 5 = 3 7 1 / 2 percent.  The chain  r e l a t i v e f o r the years 1944 to 1 9 4 6 would then be 1 . 5 , 0 . 7 5 , and  O.375. In F i g s . 2 8 and 2 9 the indices show that the a v a i l a b i l i t y  of the dog-fish i n Hecate s t r a i t was greatest i n 1944 f o r the months of June, July, and October.  In the month of May,  1945,  INDEX  OF T H E A V E R A G E  DOG-FISH FISHING  LIVERS IN  HECATE  CATCH  LANDED STRAIT  BY  PER  BOAT  SUNKEN  FROM  ?  PER  MONTH  GILL-NET  [ 9 4 3  TO  OF  BOATS  1 9 4 6  DETERMINED BY THE METHOD OF LINK RELATIVES AUGUST  MAY  JULY  OCTOBER  200  20 0  I 50 -  I 50  100  100  50  50  0  0 to CD  lO  ro  CT>  O)  f i g . 28  <J>  If)  10  <7>  on  INDEX OF  OF THE AVERAGE  DOG-FISH FISHING  LIVERS  IN HECATE. DETERMINED  CATCH  LANDED  PER TRIP  PER BOAT  PER MONTH  GILL-NET  BOATS  BY SUNKEN  STRAIT  FROM  1 9 4 3 TO 1 9 4 6  BY THE METHOD OF LINK RELATIVES AUGUST  MAY 150  200|—  100  150 100 - •  50  50-  0 300r-  JUNE  250 200 150 Z U 100 h  LU  a. 300,—  JULY  OCTOBER  250  250p  200-  200 —  150  150 -  100  100 —  50  50-  0  0 —  CT)  CT)  ID  10  ff>  CT)  Fig.,  29  ro CT)  flfl-  fl-  CT)  CT)  10 flCT)  -  38  -  the a v a i l a b i l i t y index r i s e s when compared with May. 1944, i n d i c a t i n g a possible e a r l y movement of dog-fish i n Hecate s t r a i t f o r that year.  The index remained high during June but  f e l l very sharply f o r the r e s t of the year, depicting the poor catches which were made by the sunken g i l l - n e t boats during that year. In 1946 the index of the average catch per boat per month and the average catch per t r i p per boat per month increased f o r the months of June, July, August, and September.  The,index of  the average catch per boat per month and the average, catch per t r i p per boat per month increased abruptly during the months of August and September.  This agrees with increased i n the  average catch per boat per month and the average catch per t r i p per boat per month f o r t h i s year, 1946, as shown i n F i g s . 25 and 26. When the years as a whole are compared with each other (Fig. 3 0 ) ,  the index also shows that the a v a i l a b i l i t y was  greatest i n 1944 and that the year 1946, shows a d e f i n i t e i n crease i n a v a i l a b i l i t y over the previous year.  Less competi-  t i o n between gear and improved weather conditions would probably increase the y i e l d of the boat catches during some of the months i n 1946 when compared with 1945.  6.  Comparison  of the Average Catch per Boat per Month  for the Same Sunken G i l l - n e t Boats Fishing' i n Adjacent Years. This method of estimating a v a i l a b i l i t y has been employed i n various f i s h e r y investigations.  I t makes  some  INDEX  OF  THE  GILL-NET  AVERAGE  BOATS  CATCH  FISHING  IN  HECATE  DETERMINED BY THE INDEX OF THE AVERAGE  CATCH PER  BOAT  OF  PER  DOG-FISH STRAIT  METHOD  FROM  OF  MONTH  LIVERS  LINK  AVERAGE  LANDED  1 9 4 3 TO  200  rZ UJ o rr  1  50  1  00  t— Z UJ o  —  3d  \/  or 100 UJ a 50  1  <fr *  0)  1  1  CT)  01  lO *  to *  :  1943  1  MONTH  1  A  1 50  50  0  I—  OF THE  PER TRIP PER BOAT  PER 200  SUNKEN  1946  RELATIVES INDEX CATCH  BY,  F i g . . 50  o  — / -  -  1  to *  <?  CT) CT) CT)  I - l  \n *  | CT)  - 39 allowance f o r the increase i n the f i s h i n g e f f o r t (the increase i n the average number of nets per boat) that occurs i n each successive year. men  Information obtained from a number of f i s h e r -  along the coast revealed that the number of nets each sunken  g i l l - n e t boat used increased gradually i n each successive year from 1943 to 1946.  I t has been roughly estimated that the  number.of nets per boat i n 1946 has doubled since 1943.  This  means that the e f f o r t expended by each fisherman i n 1946 was much greater than i n 1 9 4 3 . The boats f i s h i n g i n 1943 were compared with the same boats f i s h i n g i n 1944; boats f i s h i n g i n 1944 were compared with the same boats f i s h i n g i n 1 9 4 3 , and the same comparison made f o r the years 1 9 4 5 - 4 6 .  was  The increase i n the number of nets  per boat between two successive years i s not nearly as great as the increase over a four year period.  Each boat w i l l also  reach an optimum number of nets with which to f i s h .  This method  of comparing only the same boats f i s h i n g i n adjacent years, tends to equalize the e f f e c t of the increase, or decrease, i n the number of nets per boat from 1943 to 1 9 4 6 .  However, the  increasing number of nets over the f l e e t w i l l produce a cumul a t i v e error no less than by other methods. In F i g . 3 1 the average catch of dog-fish l i v e r s per boat per month landed by the same boats f i s h i n g i n the years 44,  1943-  indicates the comparitively high a v a i l a b i l i t y i n 1 9 4 3 , when  the f i s h e r y with sunken g i l l - n e t s i n Hecate s t r a i t commenced. This information has not been borne out f u l l y by any of the other methods of analysis. When the years 1944-45 are compared ( F i g . 32) a v a i l a b i l i t y  AVERAGE LIVERS BOATS  CATCH LANDED FISHING  PER BY IN  BOAT THE  PER  MONTH  SAME  ADJACENT HECATE  OF  DOG-FISH  SUNKEN YEARS  GILL-NET  1943-44  STRAIT  1943  o  a  o  1944  5  y-  <  F i g . . 31  o o  IN  AVERAGE  CATCH  PER  BOAT  PER  MONTH  LIVERS  LANDED  BY  THE  SAME  SUNKEN  BOATS  FISHING  IN"  ADJACENT  YEARS  HECATE  OF  DOG-FISH  GILL-NET 1944-45  STRAIT  -o 19 44 -o  194.5  3  o  >< 3  <a 3  <  F i g . , 32  Q. ui  tt  o  o  IN  -  is  greatest  then f a l l s  ing boat  1946  strait  i n . 1946  could exceed  that  the average  33 i l l u s t r a t e s  boat  fish-  catch per  c a t c h i n 1945.  boat  July,  This  August,  (Fig. 25).  catch increased  the average  c a t c h per boat  i n the y e a r s  1945-46.  a b r u p t l y i n t h e month o f A u g u s t ,  p e r month  The b o a t 1946,  but the  c a t c h e s f o r t h e o t h e r months a l m o s t p a r a l l e l e d t h e  c a t c h e s made i n t h e p r e v i o u s y e a r . the  t w o - t h i r d s t h e number  the average  t h e same b o a t s f i s h i n g  average  shows t h a t  i n t h e month o f June and  o c c u r r e d d u r i n g t h e months o f J u n e ,  Fig.  32 a l s o  t h e number o f b o a t s f i s h i n g f o r d o g - f i s h i n  T h i s would i n d i c a t e  and September  for  i n 1945 was g r e a t e s t  was r e d u c e d by a l m o s t  i n 1945.  situation  Fig.  o f f s h a r p l y i n the f o l l o w i n g months.  During Hecate  y e a r , 1944.  i n the e a r l i e r  the a v a i l a b i l i t y  40 -  availability  of the dog-fish  T h i s sudden i n c r e a s e i n  i n August,  1946,  i s probably  closely related  w i t h t h e v a r i e d mass movements o f d o g - f i s h i n  Hecate  The a b r u p t i n c r e a s e  August,  strait. 1946  i n a v a i l a b i l i t y during  a s shown i n F i g . 33 i s a l s o i n d i c a t e d  i n Figs.  25 and 2 6 .  7.  The I n d e x  o f the T o t a l Landings  of Dog-fish Livers  Made b y t h e Same Sunken G i l l - n e t Adjacent Years  as Determined  Boats F i s h i n g i n  b y the Method  of Link  Relatives. The  index calculated  from the t o t a l  c a t c h p e r month  f r o m t h e same b o a t s f i s h i n g  i n a d j a c e n t y e a r s , and t h e i n d e x  calculated  c a t c h per boat  from t h e average  same b o a t s f i s h i n g  p e r month f r o m t h e  i n a d j a c e n t y e a r s w o u l d be i d e n t i c a l .  Only  AVERAGE LIVERS BOATS  CATCH LANDED  FISHING  PER BY IN  BOAT THE  PER  SAME  ADJACENT HECATE  MONTH SUNKEN  YEARS  OF  DOG-FISH  GILL-NET 1945-46  IN  STRAIT  1945  -9  •-e 1946  i i  i  \ \  \  o o.  < o  < z  o o  - 41 the  same number of boats are compared i n each month between  two successive years.  I t would simply mean d i v i d i n g the t o t a l  catch of any month i n 194J and the t o t a l catch of the same month i n 1944 by a common denominator. The index of the t o t a l landings of dog-fish l i v e r s each month made by the same sunken g i l l - n e t boats f i s h i n g i n adjacent years ( F i g . 34), d i f f e r s i n many d e t a i l s from the i n dex of the average catch per boat per month (Fig. 2 8 ) , and the average catch per t r i p per hoat per month (Fig. 2 9 ) .  The i n -  dices i n F i g . 34 give a clearer picture of the a v a i l a b i l i t y i n 1943, when the sunken g i l l - n e t fishery commenced i n Hecate strait.  I t would seem probable that the abundance, Or the  t o t a l number of dog-fish must have been greater i n 1943 than during the following years, when enormous numbers of t h i s species were- taken from the B r i t i s h Columbia waters.  F i g . 34  shows that the a v a i l a b i l i t y of dog-fish i n Hecate s t r a i t varies from year to year, and does not always follow the same course at the same time each year. part by the r e l a t i v e the  The abundance i s represented i n  abundance or a v a i l a b i l i t y calculated from  analyses of boat catches. Although very large numbers of  dog-fish were removed from Hecate s t r a i t i n 1944 and  1943,  Figures 2 8 , 2 9 , and 34 indicate an increase i n a v a i l a b i l i t y , during the months of August and September i n 1946-. When the t o t a l landings of dog-fish l i v e r s from the same sunken g i l l - n e t boats f i s h i n g  i n adjacent years are linked t o -  gether by the method of chain r e l a t i v e s ,  a more accurate and  clearer picture of the a v a i l a b i l i t y of the dog-fish i n Hecate s t r a i t , from 1943 to 1946, i s demonstrated ( F i g . 33).  The  •f-  INDEX  OF THE CATCH  SAME SUNKEN YEARS  OF DOG-FISH  GILL-NET  BOATS  LIVERS  FISHING  1945-46,  LANDED  BY T H E  IN THE ADJACENT  1943-44,  1944-45,  IN HECATE  DETERMINED  BY THE METHOD OF LINK RELATIVES  AUGUST  MAY 150  150 -  100  100 — «  50  50 -  O  0JUNE  SEPTEMBER  UJ  o  or u  0.  Fig.-  34  STRAIT  INDEX OF THE TOTAL CATCH OF DOG-FISH LIVERS LANDED BY THE SAME SUNKEN GILL-NET BOATS FISHING IN THE ADJACENT YEARS 1943-44, 1944-45, 1945-46 IN HECATE STRAIT DETERMINED  BY THE  METHOD  OF  LINK  RELATIVES  100 UJ  o or LU Q.  50  0  1  1  1  1  ro  <fr  oi  ot  <fr  <tf-  F i g . .35  L  m  t£>  Oi  oi  ^  *  - 42 index of the a v a i l a b i l i t y ( F i g . 33) drops from the year 1 9 4 3 to 1943, and then increases s l i g h t l y i n 1946.  E.  Analysis of the Catoh Records of Soup-fin Shark Livers Landed by Sunken G i l l - n e t Boats Fishing i n Hecate  Strait.  The catch s t a t i s t i c s of the soup-fin shark are analysed by the same methods employed i n the analysis of the dog-fish statistics.  1.  The Total Landings of Livers by Sunken G i l l - n e t Boats. The t o t a l landings of soup-fin shark l i v e r s f o r each  year are graphed i n F i g . 3 6 .  The t o t a l landings f o r the year  1944 represent the absolute minimum, since some of the records from one company were missing f o r that year.  In spite of t h i s ,  1944 represents the year of the greatest landings of soup-fin shark l i v e r s from Hecate s t r a i t .  The year 1944 also represented  the year of the greatest landings of soup-fin shark l i v e r s for the Province.  In the years 1943 and 1944 about 40 per cent of  a l l the soup-fin shark l i v e r s landed i n B r i t i s h Columbia were caught by sunken g i l l - n e t boats f i s h i n g from May to October inclusive, i n Hecate s t r a i t .  The sunken g i l l - n e t boats landed  43 per cent and 40 per cent of the t o t a l landings f o r the Province i n the years 1943 and 1946 respectively. Table VTII l i s t s the t o t a l weights of soup-fin shark l i v e r s landed each month by sunken g i l l - n e t boats f i s h i n g i n Hecate s t r a i t from 1943 to 1946.  The months of the greatest landings  i n the year 1943 were August and September.  July was the peak  Fig..  36  Table  VIII  T o t a l Weight ( l b . ) of S o u p - f i n Shark L i v e r s l a n d e d each Month b y Sunken G i l l - n e t B o a t s f r o m H e c a t e S t r a i t , f r o m 1943 t o 1946.  1943  1944  61  May  1945 4 •  1946 .2  June  40  4,147  3,219  752  July  1,027  13,732  9,795  2,071  August  6,256  5,857  2,329  480  September  4,525  445  254  208  310  8  165  3  Total  13,058  24,250  15,766  3,516  Weighted average catch per boat per month  225.14  66.44  23.57  14.90  October  - 43 -  month i n each of the three years, 1944, 1 9 4 3 , and 1 9 4 6 . '  2.  The Average Catch per Boat per Month. F i g . 37 i l l u s t r a t e s the average catch per boat de-  creasing from 1943 to 1 9 4 6 . Although more soup-fin shark l i v e r s were landed i n the year 1944, the a v a i l a b i l i t y dropped considerably below the previous year f o r a short period during the months of August and September.  The graph indicates the  month of August as the month of greatest a v a i l a b i l i t y f o r the year 1 9 4 3 .  In 1944, 1 9 4 3 , and 1946 the month- of July was the  month of the greatest average catch per boat.  3•  The Average Catch per T r i p per Boat per Month. The average catch per t r i p per boat per month ( F i g .  38)  almost follows the same representative pattern as depicted  in Fig. 3 7 .  In the year 1 9 4 3 , F i g . 38 shows the a v a i l a b i l i t y  was greatest i n the month of August, whereas F i g . 37 shows that the  a v a i l a b i l i t y was greatest i n the month of J u l y .  This d i f -  ference i s only very s l i g h t when the small amount of l i v e r s landed i s considered.  4.  The Average Catch per Boat per Month and the Average Catch per T r i p per Boat per Month f o r Each Year as a Whole. F i g . 39 i l l u s t r a t e s the continued drop i n the a v a i l -  a b i l i t y of the soup-fin shark from 1943 to 1946.  The a v a i l -  a b i l i t y calculated from the average catch per boat per month  AVERAGE SHARK "  CATCH  LIVERS FISHING  PER  BOAT  PER  MONTH OF SOUP-FIN  LANDED BY SUNKEN IN  HECATE  GILL-NET  BOATS  FROM 1943 TO 1946  STRAIT  1943 —  1944  o  » 1945 o  1946  3  oa.  aa. a  ID  <  z  <  F i g . 37  O  o  AVERAGE  CATCH  PER  SOUP-FIN  SHARK  LIVERS  BOATS  FISHING  TRIP  PER  BOAT  LANDED  IN HECATE STRAIT  •  • 1943  0  o  1 e  BY  PER  MONTH  SUNKEN  FROM  1943  1944  • 1945 o 1946  1 60 15 0  140 130  a z  •D  o  120  —  1i0  —  100  —  >>  90 80 70 60  —  50  —  40  —  30  —  20  —  1 0  —  0 (9 <  F i g . 38  a. in  in  OF  GILL-NET TO  1946  44 and the average catch per t r i p per boat per month both i l l u s trate the marked decline from 1943 to 1946. The a v a i l a b i l i t y for the years 1943 and 1946 i s extremely low when compared with the year 1943.  5.  The Index of the Average Catch per Boat per Month and  • the Average Catch per Trip per Boat per Month, as Determined by the Method of Link Relatives. The two graphical presentations of the a v a i l a b i l i t y (Figures 40 and 41) are very s i m i l a r .  Both of these figures  demonstrate the sudden increase i n the a v a i l a b i l i t y f o r June 1944 and the Increase i n the a v a i l a b i l i t y f o r July 1944, when compared with July 1943.  In the years 1945 and 1946 the a v a i l -  a b i l i t y dropped to a very low degree. The index of the average catch per boat per month and the index of the average catch per t r i p per boat per month f o r each year as a whole ( F i g . 42) indicates a decided drop i n a v a i l a b i l i t y from 1943 to 1946.  6.  Comparison of the Average Catch per Boat per month f o r the Same sunken G i l l - n e t Boats Fishing i n Adjacent Years. This method of analysis demonstrates that the average  catch per boat per month increased sharply f o r a l l months i n 1944 when compared with the months i n 1943 ( F i g . 43). This r e s u l t , i l l u s t r a t e d i n F i g . 43, i s p a r t l y the reverse of the r e s u l t s i l l u s t r a t i n g the average catch per boat per month ( F i g . 37) and the average catch per t r i p per boat per month (Fig.  38).  INDEX  OF THE AVERAGE  SOUP-FIN FISHING  SHARK  LIVERS  IN HECATE DETERMINED  CATCH  PER BOAT  P E R MONTH OF  LANDED BY SUNKEN GILL-NET  STRAIT  FROM  1 9 4 3 TO 1 9 4 6  BY THE METHOD OF LINK RELATIVES JULY  T i g , 40  BOATS  INDEX  OF THE AVERAGE CATCH PER TRIP  MONTH  OF SOUP-FIN  GILL-NET  BOATS  SHARK  FISHING 1943  LIVERS  IN HECATE STRAIT TO  0  % i  »  c  "  "> * '  i  O  >  <  *  l*> *  3  BY SUNKEN FROM  1946  DETERMINED BY THE METHOD OF LI^K  CO *  PER BOAT PER  LANDED  >  F i g . - 41  o>  RELATIVES  ^  -  <J>  l  O  <f>  m  0">  INDEX BY  OF T H E  SUNKEN  AVERAGE  GILL-NET  CATCH  BOATS  OF  SOUP-FIN  FISHING  1943  SHARK  IN H E C A T E  LIVERS  STRAIT  LANDED  FROM  TO 1 9 4 6  DETERMINED BY THE METHOD OF LINK RELATIVES INDEX OF THE INDEX OF THE AVERAGE CATCH PERBOAT PER MONTH AVERAGE CATCH PER TRIP PER BOAT PER MONTH 100  100  £75  UJ  UJ  0 or UJ 5 0 0. 25  /-\  0  —  -  0 or _ UJ 5 0 0. 25  ro *t 0)  1  05  lO 0)  (0  \  -  U 0)  Fig._ .42  —  >^-fr 0>  lO 0) <t  <0* o>  AVERAGE LIVERS  CATCH  PER  BOAT  PER  LANDED  BY  THE  SAME  FISHING  IN  ADJACENT  \ \  /  —  \  ;  —  \ \  /  \ \  / / / /  —  /  /  /  \ \ \ . \ \ \ \\ \\  -  —  e>  o  — —  100  —  —  /  /  /  / |,  0 YEARS  1 9 4 5 -- 4 6  —  —  —  —  JUNE  JULY  AUG.  0  MAY  100  F i g . 4J  — —  1945 1946  —  —  1944 1945  OCT.  200  o  1944 - 4 5  YEARS  UJ 5  \  \  0. \  /  r  ii C3  1943 1944  SEPT. —  Z> O Q.  STRAIT  V  / /  §  SHARK BOATS  ;\  / /  /  CO  HECATE  — — /  1 00  IN  SOUP-FIN GILL-NET  1943 - 4 4  400  200  OF  SUNKEN  YEARS  YEARS  30 0  MONTH  - 45 Figures 37 and 38 picture the a v a i l a b i l i t y to be greater f o r the months of July and August i n 1943. When the months of the years 1944-45 and the years  1945-  46 are compared, the average catch per boat per month landed by the same boats f i s h i n g i n these adjacent years f a l l s s t e a d i l y with each successive year.  In 1946 the a v a i l a b i l i t y became so  low that the soup-fin shark fishery almost disappeared from Hecate s t r a i t .  7.  The Index of the Total Landings of Soup-fin Shark Livers made by the Same Sunken G i l l - n e t Boats Fishing i n Adjacent Years, as Determined by the Method of Relatives . The indices graphed i n F i g . 44 check f a i r l y c l o s e l y  for a l l months, except September, with the indices graphed i n Figures 40 and 41.  Figures 40 and 41 i l l u s t r a t e the picture  for a l l the boats f i s h i n g i n Hecate s t r a i t while F i g . 44 i l l u - . strates the picture of the a v a i l a b i l i t y f o r the same boats f i s h i n g i n adjacent years.  F i g . 44 indicates an increase i n  the a v a i l a b i l i t y of the soup-fin .shark i n September 1946 when compared with September 1945; and an increase i n a v a i l a b i l i t y i n September 1945 when compared with September 1943* F i g . 45 i l l u s t r a t e s the average catch of soup-fin shark l i v e r s , per month f o r each year as a whole, landed by the same boats f i s h i n g i n adjacent years i n Hecate s t r a i t .  The index  r i s e s abruptly In 1944, when compared with the base year 1943• The index of a v a i l a b i l i t y f a l l s just as abruptly i n 1945 reaches a low index i n 1946.  and  INDEX THE  OF T H E C A T C H SAME  YEARS  SUNKEN  1943-44,  OF S O U P - F I N  GILL-NET  BOATS  1944-45,  SHARK  LIVERS  FISHING  1945-46,  LANDED  IN H E C A T E  STRAIT  DETERMINED BY THE METHOD OF LINK RELATIVES AUGUST  JUNE  400r—  200 SEPTEMBER  100  300  Ul O  200 —  or Ul 0-  J ULY  100  200  to  to 01  at  F i g . ,44  BY  IN T H E A D J A C E N T  INDEX  OF THE TOTAL CATCH OF SOUP-FIN  SHARK LIVERS LANDED BY THE SAME SUNKEN GILL-NET BOATS FISHING IN THE ADJACENT YEARS 1943-44, 1944-45, 1945-46, IN HECATE STRAIT DETERMINED  BY T H E  2 50  2 00 tZ LO  ° cr  150  METHOD  OF  LINK  RELATIVES  A  L  J  [ A  j  CL LU  100  1  Fig.  4$  1  1 1946  1  1944  0 '-  1945  50 :  - 46 -  F.  Summary, D i s c u s s i o n , the A n a l y s i s o f t h e  and  soup-fin  boats i n Hecate l y s i s of the plexity, crease  o f the  Data from Hecate  A number o f methods o f d o g - f i s h and  Conclusions  s t r a i t has  catch records  landed  by  been presented.  sunken The  in total  general  catch  v a r i a t i o n s o f the  statistics,  of  methods o f of  increase  The  and  deand  graphical  illu-  s t r a t i o n s have b e e n u s e d t o r e p l a c e wordy d e s c r i p t i o n s o f cussing  a v a i l a b i l i t y by  From i n f o r m a t i o n veys o f the  gathered  i n the  of capture  field  o f the  and  by  f o u n d t h a t the  migrates i n t o Hecate s t r a i t  north  f o r the  i s shown b y  from the  c h a n g e s i n the  and  their  d i r e c t i o n o f movements b y  the in  enter Hecate  strait. very  'capture  The  strait  they the  In the  availabi-  are p a r t l y r e s t r i c t e d  late  tend  to  vulnerability  summer o f  men  were l a r g e , and  t r a v e l l e d t o s e t t h e i r n e t s was  were p r o b a b l y t i o n o f the  1 9 4 3 , the  distance  great.  These  f i s h i n g o n l y a s m a l l p a r t o f the  actual  d o g - f i s h i n Hecate  not  the  strait  of  travel  y e a r when s u n k e n - g i l l - n e t s were u s e d i n H e c a t e s t r a i t , fishermen's boat catches  in  b a r r i e r s on b o t h s i d e s  thus i n c r e a s i n g t h e i r  f i s h i n g gear.  of  Evi-  When t h e v d o g - f i s h  d o g - f i s h become b u n c h e d , and  large schools, by  periods  indivi-  dog-fish  each year.  d i f f e r e n t months i n e a c h y e a r .  reach  detailed sur-  d o g - f i s h by  d u a l b o a t s d u r i n g e a c h month, i t was  lity  dis-  e a c h method o f a n a l y s i s .  precise area  dence o f t h i s  ana-  com-  t o t h e more s e a r c h i n g  v a l i d methods o f e s t i m a t i n g a v a i l a b i l i t y .  the  gill-net  a v a i l a b i l i t y have b e e n t r e a t e d i n o r d e r  from the  of  Strait.  analysing'the  shark l i v e r s  Results  to first  the  the  fisher-  fishermen popula-  at t h a t time, or of  the  4  -  -  47  population which had been i n Hecate s t r a i t .  In the year  an i n t e n s i f i e d f i s h e r y occurred as a r e s u l t of the large of dog-fish during the l a t e r summer months i n 1943.  catches  Large num-  bers of American trawlers entered Hecate s t r a i t i n 1944  and  t o t a l landings of dog-fish and soup-fin shark l i v e r s was largest i n the h i s t o r y of B r i t i s h Columbia.  1944,  The large  the  the catches  raise doubts as to what quantity of dog-fish and soup-fin shark can be taken from the f i s h e r y and yet leave a s u f f i c i e n t number of the specier-s to propagate.  In the year 1945,  availability  of the dog-fish and soup-fin shark dropped so abruptly that many fishermen considered the f i s h e r y i n that year almost a failure.  The number of sunken g i l l - n e t s used i n 1945  doubled the number that was used i n 1944.  almost  The dog-fish enter-  ing Hecate s t r a i t i n 1945 were not only confronted by an  ex-  temely large b a r r i e r of sunken g i l l - n e t s but an increased number of otter-trawls.  This increase i n the number of boats r e -  duced the average catch per boat when compared with the year.  previous  Undoubtedly the increased competition between gear and  the poor weather conditions during the summer months i n  1945  were two detrimental f a c t o r s influencing the catch. In 1946  the number of fishermen entering the f i s h e r y i n  Hecate s t r a i t declined.  The dog-fish which entered the  strait  i n 1946 were not subjected to the intensive f i s h e r y that occurred i n the previous years.  The a v a i l a b i l i t y increased s l i g h t l y  i n 1946 during the months of August, September, and October. This may  indicate a later period of migration for the dog-fish  when compared with the previous  years.  From the analyses of the catch records of sunken g i l l - n e t  - 48 boats, i t i s now evident that the fishable population of dogf i s h which enters Hecate s t r a i t should only be subjected to a fishery" by a limited number of boats and gear.  This i s an eco-  nomic conclusion, not a b i o l o g i c a l one. The analyses of the catch records'indicate a d e f i n i t e decline i n abundance of the dog-fish i n Hecate s t r a i t but i t i s not possible to state that t h i s constitutes depletion.  The problem needs at least one  more season of i n v e s t i g a t i o n . A d e f i n i t e decision i s therefore reserved because of the influence of two important factors which have not been studied s u f f i c i e n t l y to give results.  conclusive  These two f a c t o r s are:-  1.  the changes i n the t o t a l amount of e f f o r t .  2.  the .influence of hydrographic conditions.  In addition to the decline i n a v a i l a b i l i t y of dog-fish and the t o t a l landings-of l i v e r s from Hecate s t r a i t from 1944 to 1946  there has been a noticeable decline i n the vitamin "A" po-  tency of the dog-fish l i v e r s from 1944 to 1947. The average vitamin "A" potency ( i n USP units per gram of l i v e r o i l ) of l i v e r s from dog-fish caught i n the same area i n Hecate s t r a i t by sunken g i l l - n e t s has declined with each succeeding year since 1944. The decline i n the vitamin "A" potency of the l i v e r s has been of great concern to the fishermen and the f i s h ing industry.  I t means that the t o t a l poundage of l i v e r s from  dog-fish caught i n Hecate> s t r a i t i n 1947 would represent a lower stock of vitamin "A" f o r the same weight of l i v e r s r e covered from dog-fish caught by the same gear and i n the same area as i n 1944. The decline i n potency of vitamin "A" i s indicated i n  Table  IX.  The  49  a v e r a g e number o f USP  o i l were t e s t e d f r o m l i v e r s by  sunken g i l l - n e t s  islands in  -  of October i n each year.  min  "A"  beginning  economic problem i s p a r t i c u l a r l y "A"  per  and  pound o f l i v e r  problem i s concerned w i t h the  decline  i n the  and  the  d e c l i n e i n potency of  has  brought  Hecate  about t h i s  o f the  "A"  of the  liver  The  decline  landed.  The  d o g - f i s h i n Hecate "A"  o i l and  i n the  in biothe  strait  livers.  What  livers  per  r e l a t i o n s h i p between  l i v e r and  the  the  o f the  length.  from  o f the  livers.  than d o g - f i s h of the  d o g - f i s h and  higher  i n vitamin  "A"  livers  and  darker  i n c o l o u r t h a n the  "A"  dark l i v e r s  same s i z e  I t i s known t h a t  "A"  liver  characterconcentration are  positively  the  vitamin  "A"  con-  L i v e r s f r o m immature d o g - f i s h  F i s h with  t h a t the  Vitamin  the  There i s a l s o a c l o s e a s s o c i a t i o n  only a small percentage of vitamin larger fish.  physical  p e r c e n t a g e o f o i l i n the  sexual maturity  centration  the  d o g - f i s h a r e w e l l known.  correlated with  livers.  one.  d e c l i n e i n average potency of  concentration  o f the  the  the  vita-  r e l a t i o n s h i p between  vitamin  f a c t s concerning  istics  with  the  strait?  Certain vitamin  until  a biological  conoerned w i t h  logical  availability  o f May  "A"  This d e c l i n e i n potency of  i s b o t h an e c o n o m i c p r o b l e m  potency of vitamin  only  Livers tested for vitamin  from the  end  the  liver  s t r a i t n e a r the. Queen C h a r l o t t e  F i g . 22).  t a b l e I X were l a n d e d  gram o f  removed f r o m d o g - f i s h c a u g h t  i n Hecate  (shaded area  u n i t s per  the  and  found i n the  darker  concentration  l a r g e s t male and  livers than the female  smaller f i s h  livers  appear t o mature  sex w i t h  contain of  earlier  light, coloured g e n e r a l l y average lighter  coloured  d o g - f i s h have  of e i t h e r sex.  livers  Further,  Table  IX  The average number o f USP u n i t s p e r gram of l i v e r , o i l d e t e r mined from the l i v e r s o f the d o g - f i s h t a k e n from d o g - f i s h t h a t were caught o n l y by sunken g i l l - n e t s i n Hecate s t r a i t near the Queen C h a r l o t t e i s l a n d s f r o m 1944 t o 1947. Average number o f USP u n i t s p e r gram of liver o i l *  T o t a l poundage o f dog-fish livers analysed  1944  14,648  148,191  1945  13,183  514,000  1946  9,784  446,448  1947  9,075  572,486  These f i g u r e s , were d e t e r m i n e d f r o m d a i l y l i v e r o i l a n a l y s e s made a v a i l a b l e by the f i s h i n g i n d u s t r y w h i c h i n c l u d e d as many s e p a r a t e l a n d i n g s o f d o g f i s h l i v e r s as p o s s i b l e .  \  -  there  i s a seasonal  ample—dog-fish  variation  In general  liver  of l i v e r  potency i n the winter  a s compared w i t h  liver;  liver  and l i v e r  min  "A" p e r l i v e r . Since- the l a r g e r d o g - f i s h  min by  "A"  "A"  than the s m a l l e r  of livers  grounds.  contain  have a  livers;  could  T h i s would  greate  more o i l  p o t e n c y ; more  a higher  vita-  concentration  dog-fish, the decline  i n vitastrait  be a t t r i b u t e d t o t h e r e m o v a l o f t h e  o r t h e movement o f t h e s e  o f d o g - f i s h caught  o f the  removed f r o m d o g - f i s h c a u g h t i n H e c a t e  sunken g i l l - n e t s  larger dog-fish  small f i s h ,  o i l o f a higher  which  t h a n i n t h e sum-  f o r dog-fish  w e i g h t t o body weight; darker  per  of vitamin  p o t e n c y as f o r e x -  and s e x , have l i v e r s  i t has been found t h a t  same s e x , l a r g e f i s h , ratio  i n the l i v e r  o f t h e same s i z e  produce a g r e a t e r mer.  -  5 0  suggest  that  l a r g e r f i s h from the  the decline  i n sunken g i l l - n e t s  in  i n Hecate  availability strait i s  c l o s e l y r e l a t e d t o removal or p o s s i b l e d e p l e t i o n o f the o l d e r age  c l a s s e s of d o g - f i s h from the p o p u l a t i o n . Sanford  the  and Bonham (1946) i n d i c a t e t h a t  determining  factor i n vitamin  independent o f the l e n g t h in  a length frequency  t i o n s h i p between l i v e r length  of the d o g - f i s h .  same s i z e are  and sex t h a t  probably  subjected  the o l d e r  "A" p r o d u c t i o n  of the dog-fish.  category  age i s p r o b a b l y  that  there  i n the l i v e r  They found t h a t was a n i n v e r s e  c o l o u r and t h e a v e r a g e p o s t e r i o r I t was assumed t h a t  forfish  the d o g - f i s h with  the darker  since  spines  their blunt  t o wear f o r a l o n g e r  time.  Their  spine  livers  w o u l d have b e e n  observations  o f the spine  able  s p e c i m e n s o f t h e same  where  rela-  o f the  t h a t the d i f f e r e n c e i n the l e n g t h among t h e l a r g e r f i s h ,  with  showed  was most n o t i c e size  - 51 might have d i f f e r e d considerably i n rate of growth.  This would  indicate that the darkest l i v e r s with the highest vitamin "A" concentration are found i n the dog-fish which grow the slowest. A question a r i s e s .  Why was the drop i n the a v a i l a b i l i t y  of the soup-fin shark more pronounced than the drop i n the a v a i l a b i l i t y of the dog-fish? There may be two reasons: 1.  The soup-fin shark i s more vulnerable to capture by the sunken g i l l - n e t s than the dog-fish. or  2.  The soup-fin shark has been subjected to an intense f i s h e r y i n the United States f o r a number of years. Thus when the i n t e n s i t y of f i s h i n g f o r t h i s species suddenly increased over the whole of the migratory range, the a v a i l a b i l i t y of the soup-fin shark would suddenly drop i n the l o c a l i t i e s which represent the l i m i t s of i t s migratory range.  Foerster (1945) r e -  ported the- possible movement of soup-fin sharks from C a l i f o r n i a to B r i t i s h Columbia when a female soupf i n shark tagged i n C a l i f o r n i a waters was captured inside Bajo' reef, Nootka sound, on the west coast of Vancouver i s l a n d .  G.  Analysis of the Catoh Records of Dog-fish Livers. Landed by Sunken G i l l - n e t Boats F i s h i n g o f f Barkley Sound on the West Coast of Vancouver Island, from 1944 to 1946.  - 52 -  1.  The T o t a l L a n d i n g s o f D o g - f i s h L i v e r s b y Sunken net  Boats.  The of dog-fish Barkley for  Gill-  h i s t o g r a m ( F i g . 47) i l l u s t r a t e s  livers  sound  l a n d e d b y sunken g i l l - n e t  ( F i g . 46), from  1944 t o 1946.  1943 were n o t a v a i l a b l e .  The l a r g e s t  the t o t a l  catch  boats f i s h i n g o f f Catch  statistics  catch of dog-fish  l i v e r s was made i n 1944. Fig.  48 i l l u s t r a t e s  e a c h month f r o m fish  the t o t a l  1944 t o 1946.  Catch per Unit The  from t h a t  fishery  i n Hecate  every day.  strait,  The f i s h i n g  travelling  "unit  of e f f o r t "  catch i s landed  and K i l d o n a n  1 hour  to 2  camps.  a n d t h e amount o f f i s h i n g ' t i m e of this unit.  For this  i s d e f i n e d a s one s u n k e n g i l l - n e t  over a period  o f 24 h o u r s .  f i s h i n g e f f o r t was c a l c u l a t e d  f o r each  c a t c h , and t h e i n d e x o f r e t u r n p e r u n i t each  differs  o f the i n t e n s i t y o f f i s h i n g e f f o r t  i n the calculation  thoms) f i s h i n g  a r e o n l y about  time f r o m the f i s h i n g  " u n i t " must be e s t a b l i s h e d included  o f f B a r k l e y sound  and a t B a m f i e l d , U c l u e l e t ,  hours  the computation  year.  c o m p a n i e s have camps on t h e o u t e r i s -  4 6 ) . The f i s h i n g g r o u n d s  of  l a n d i n g s o f dog-  i n that each b o a t ' s  (Fig.  In  livers  of Effort.  f o r dog-fish  l a n d s o f B a r k l e y sound,  the  The g r e a t e s t  l i v e r s were made i n t h e month o f June i n e a c h  2.  be  landings of dog-fish  f i s h e r m a n ' s c a t c h was d e t e r m i n e d  a must  survey (75 f a -  T h e number o f u n i t s fisherman's  daily  of fishing effort f o r  by d i v i d i n g  c a t c h b y t h e number o f u n i t s o f f i s h i n g e f f o r t .  the d a i l y There  was a  Fig* The  46  shaded a r e a i n d i c a t e s the g e n e r a l f i s h i n g s o u n d , on t h e west  coast  g r o u n d s f o r t h e sunken g i l l - n e t s o f f B a r k l e y o f Vancouver  island.  TOTAL  WEIGHT  MONTH, LANDED BARKLEY  OF DOG-FISH BY  SUNKEN  LIVERS  SOUND, ON THE WEST FROM  EACH YEAR  GILL-NET  1944  COAST  OF VANCOUVER  TO 1945  I 946  F i g . 47  AND  BOATS FISHING  F i g . 48  EACH OFF ISLAND  - 53 s l i g h t increase i n the actual number of nets per boat each year but the length of the,net was found t o decrease s l i g h t l y each year, according to each fisherman's i n d i v i d u a l preference. This index of return per unit of f i s h i n g e f f o r t forms a basis f o r comparing the monthly and yearly landings of dog-fish l i v e r s . The index can thus be used to formulate the monthly and yearly a v a i l a b i l i t y of the dog-fish. In the month of June, the index of return per unit of f i s h i n g e f f o r t f o r the dog-fish i s greatest f o r the years 1944 and 1946 ( F i g . 49). F i g . 49 also i l l u s t r a t e s that the a v a i l a b i l i t y of the dog-fish has increased i n each succeeding year since 1944.  There may be a s l i g h t error i n the index of r e -  turn per unit of f i s h i n g e f f o r t f o r 1946, since no allowance i s made f o r the improvement i n handling the gear.  3.  Average Catch per Boat per Month. The average catch per boat per month i s much lower  o f f Barkley sound when compared with the average catch per boat per month i n Hecate s t r a i t (Tables X and 9) but the average catch per boat per month o f f Barkley sound increased from 1944 to 1946.  This i s just the reverse of the s i t u a t i o n found by  analyses of catch records from Hecate s t r a i t .  H.  Summary, Discussion, and Conclusions of the Results of the Analysis of the Data from Barkley sound and Hecate s t r a i t . Either of the two factors or a combination of the following  two f a c t o r s could i n i t i a t e a movement of dog-fish o f f the B r i t i s h  )  !  OF T H E  INDEX  DOG-FISH BOATS  LIVERS  FISHING  WEST  RETURN  COAST  P E R - U N I T - O F -EFFORT  LANDED  SUNKEN GILL-NET  BY  OFF BARKLEY OF  FOR  SOUND  VANCOUVER  ON  ISLAND  THE FROM  1944-1946  1944 1 945  1946  35  V  \ \ \ \ \ \  30  \ \  25  -  \  ^\  -  20  X UJ  * \ 15  -—  -  N ^ \  \  N  -  \  10  —  1  1  1  1  1  J ULY  AUGUST  SEPT.  0  JUNE  5  MAY  o z -  =  I j  F i g - 4-9  Table  X  Average Catch (lb.) per Boat per Month of Dog-fish Livers landed by Sunken G i l l - n e t Boats f i s h i n g o f f Barkley Sound on the West Coast of Vancouver Island, from 1944 to 1946  1944 May  ;  1945  1946  970.2  1,580.2  June  1,342.2  2,160.4  2,691.1  July  1,284.4  1,549.3  1,198.7  August  1,196.1  1,222.0  September  694.6  Weighted average catch per boat per month  .1,164.4  1,724.9  '  2,044.4  -  -  54  Columbia coast a r e : 1.  a migration  2.  a m i g r a t i o n i n d u c e d by s e x u a l  i n search of food.  Both o f these f a c t o r s  conditions.  a r e g o v e r n e d by h y d r o g f a p h i c  t i o n s which c o n t r o l the d i r e c t i o n ,  s p e e d , and s e a s o n a l  condifluctua-  t i o n s o f t h e i r movements. In  1944  t h e -abundance  o f t h e d o g - f i s h was  h i g h enough t o  maintain a successful fishery,  b o t h o f f t h e west  Vancouver i s l a n d  strait.  of  and i n H e c a t e  d o g - f i s h dropped g r e a t l y i n Hecate  the  west  coast o f Vancouver i s l a n d .  c o n d i t i o n s were s u c h t h a t lation  of dog-fish  strait  d i d not occur u n t i l  the  month o f J u l y  west  Vancouver increase  of d o g - f i s h  fishery  of e f f o r t sound  and  September.  for dog-fish, i n  ( F i g . 49)  may  be  t e n d e d t o r e m a i n o f f t h e west  of dog-fish  o f t h e movement o f t h e d o g - f i s h i n t o Hecate  strait  and n o t b y t h e n o r t h e r n e n t r a n c e . have m i g r a t e d i n t o H e c a t e spit.  strait  Evidence o f t h i s  i n Hecate  i n 1946,  the  from the  strait.  t h e g r e a t e r numbers o f t h e  i n the a v a i l a b i l i t y  popu-  i n Hecate  limited coast  i s l a n d w i t h e a c h s u c c e e d i n g y e a r and t h a t t h e  Vancouver i s l a n d  Rose  the o c e a n o g r a p h i c  i n t o Hecate  months o f A u g u s t and September  result  I n 1946  o f t h e p o s s i b l e movement o f d o g - f i s h  i s suggested that  population  the  o f f Barkley  coast of Vancouver i s l a n d It  but increased o f f  t h e months o f A u g u s t  decrease i n the r e t u r n per u n i t  indication  availability  strait  f o r t h e sunken g i l l - n e t  1946  the  of  the m i g r a t i o n o f the a v a i l a b l e  The  first  I n 1945  coast  may  of  sudden  strait  in  have b e e n t h e  f r o m t h e west  coast  of  by the s o u t h e r n e n t r a n c e In former years the  dog-fish  by the n o r t h e r n e n t r a n c e around  southern migration  into  Hecate  strait  was  i n d i c a t e d by the f i r s t  otter-trawls, gill-nets The  s o u t h o f Cumshewa i n l e t ,  o f f Skidegate i n l e t  and  success of the d o g - f i s h  parallels  the Canadian p i l c h a r d  Vancouver i s l a n d . upon t h e l a r g e s t  larger fish  and  l a t e r by the  by  sunken  Tlell. fishery  fishery  i n Hecate - s t r a i t o f f t h e west  almost  coast  of  i s dependent  p i l c h a r d s w h i c h make a n o r t h w a r d m i g r a t i o n c o a s t a l waters  the p i l c h a r d s o f f t h e C a l i f o r n i a  succeeding year,  catches of dog-fish  The C a n a d i a n p i l c h a r d f i s h e r y  e a c h summer f r o m t h e C a l i f o r n i a As  large  c o a s t grow o l d e r w i t h  the n o r t h w a r d m i g r a t i o n  go f a r t h e r ,  1958).  (Hart  i s extended.  each  Since  the  t h e y take a l o n g e r time t o r e t u r n t o  C a l i f o r n i a w a t e r s , t h u s t h e y become s u b j e c t e d t o t h e C a n a d i a n fishery. The  success of the dog-fish  n e t s i n Hecate o l d e r age area. west  graphic  increase  are  i n the a v a i l a b i l i t y  strait  i n 1946.  would  i n 1945  i n t o Hecate  strait  younger d o g - f i s h would  the w e s t  strait  gill-  i n t h e p a s t upon t h e this  o f d o g - f i s h o f f the  indicate,,that  the  oceano-  f o r the m i g r a t i o n o f the and t h e f i r s t  As t h e o l d e r  removed f r o m the f i s h e r y  t i o n i n t o Hecate off  depended  c o n d i t i o n s were n o t s u i t a b l e  the f i s h e r y  migrate of  largely  of Vancouver i s l a n d ,  d o g - f i s h i n t o Hecate of  has  c l a s s e s o f d o g - f i s h w h i c h have m i g r a t e d . i n t o  The coast  strait  f i s h e r y f o r t h e sunken  age  t h r e e months  classes of  dog-fish  the tendency f o r the d o g - f i s h  w o u l d become l i m i t e d . be l i m i t e d  i n their  b u t t h e y would  c o a s t o f Vancouver  island.  still  The  to  numbers  range o f m i g r a tend  t o remain  - 56 -  VI. The  ACKNOWLEDGEMENTS  author wishes to express h i s s i n c e r e  thanks to Dr. Station,  and  R.  E.  to Dr.  investigation^for a n a l y s i s o f the  Foerster,  data  d i r e c t o r o f the  J". L . H a r t ,  granting  appreciation  i n charge of the  permission  f r o m the  Pacific  t o use  sunken g i l l - n e t  Biological  otter  the  and  trawl  r e s u l t s of  fishery for  the  -  this  work. Sincerest Hart,  t h a n k s and  f o r h i s suggestions  appreciation and  are  criticisms  extended to Dr.  t h r o u g h o u t the  J.  L.  investi-  gation. For  their  of catch Mr.  Ki  co-operation  statistics,  F.  sincere  H a r d i n g o f the  A s s o c i a t i o n ; Mr.  K.  i n making p o s s i b l e thanks are  Prince  F i s h i n g Company L i m i t e d ; o f the  Dr.  Rupert Fishermen's  Mr. C.  collection  extended t o the  Dybhaven o f the U n i t e d  t i v e A s s o c i a t i o n at Vancouver;  the  R.  Co-operative  Fishermen's  L. Monk o f the E l s e y and  B r i t i s h C o l u m b i a P a c k e r s L i m i t e d ; Mr.  Mr. D.  following:-  co-opera-  Canadian W.  R.  N.  Cole  Tarbuck of  B o r d e n Company L i m i t e d , F a r a l l o n e D i v i s i o n a t V i c t o r i a ; G.  Joliffe  o f Queen C h a r l o t t e  Industries at The  The Pacific  and  t o Western  Mr.  Chemical  Vancouver.  author i s g r a t e f u l f o r the  operation gill-net  City;  the  given  i n the  field  by  the  assistance  and  willing  f i s h e r m e n i n the  co-  sunken  fishery. author i s also indebted  t o M i s s F.  B i o l o g i c a l S t a t i o n f o r t y p i n g the  V.  Collins  manuscript.  of  the  - 57 VII.  A n d e r s o n , A. C.  REFERENCES  1877• R e p o r t o f t h e i n s p e c t o r o f f i s h e r i e s f o r B r i t i s h Columbia, f o r the y e a r o f 1876. N i n t h Ann. R e p t . D e p t . Mar. and F i s h . , S u p p l . No.4, App. No. 21, pp. 339-247, f o r 1876, O t t a w a , I877.  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Vitamin D content of l i v e r o i l of the dog-fish. Can. Chem. Met. March 1929. 1941. The- chemistry and technology of marine animal o i l s with p a r t i c u l a r reference to those of Canada. F i s h . Res. Bd. Can. B u l l .  No. 59, pp. 408-409, 1941.  Carlson, C. B. 1942. Subsurface g i l l - n e t f i s h i n g f o r soup-fin sharks. P a c i f i c Fisherman, V o l . 40, No. 3, PP. 33, 35, February, 1942. Chaddock, R. C. 1925. P r i n c i p l e s and methods of s t a t i s t i c s . Houghton M i f f l i n Co. New York, 1925* Clark, F. N.  1939• Measures of abundance of the sardine,  Sardinops caerulea, i n C a l i f o r n i a waters. C a l i f . Div. F i s h and Game, Fish B u l l . No. 53, 45 pp., f i g s . l-19b, 7 tables, 1939-  Clark, G. H. 1931.  1933.  The C a l i f o r n i a halibut (Paralichthvs c a l i fornicus) and an analysis of the boat catches. C a l i f . Div. Fish and Game, F i s h B u l l . No. 32, 52 pp., 25 f i g s . , 1931. Fluctuations i n the abundance of striped bass (Roccus lineatus) i n C a l i f o r n i a . C a l i f . Div. Fish and Game, F i s h . B u l l . No.39, 18 pp., 7 f i g s . , 1933.  Clemens, W. A. and G. Wilby. 1946. Fishes of the P a c i f i c coast of Canada. F i s h . Res. Bd. Can. B u l l . No. 68, 368 pp., 1946. Craig, J . A. 1930.  Conner, G.  An analysis of the catch s t a t i s t i c s of the striped bass (Roccus l i n e a t u s ) , f i s h e r y of C a l i f o r n i a . C a l i f . Div. Fish and Game, F i s h . B u l l . No. 24, 41 pp., 22 f i g s . , 1930.  1935* Modernizing commercial f i s h e r i e s s t a t i s t i c s . C a l i f . Div. F i s h and Game, Fish B u l l . , No. 44, pp. 11-36, f i g s . 1-9, pp. 11-3-6, 19351937.  Cooper, J . 1874.  Fish and game s t a t i s t i c s . C a l i f . Fish and Game, V o l . 23, No. 2, pp. 113-118, 1937. Remarks on the f i s h e r i e s of B r i t i s h Columbia, by the agent of the department of marine and f i s h e r i e s at V i c t o r i a . Sixth Ann. Rept. Dept. Mar. and F i s h . , F i s h . Branch, App. V, pp. 205-206, f o r 1873, Ottawa, 1874.  - 59 Cunningham, F. H. 1920. Report of chief inspector, western f i s h e r i e s d i v i s i o n ( B r i t i s h Columbia) f o r the year 1919* F i f t y - t h i r d Ann. Rept. F i s h . Br. Dept. Naval Serv. 1919, pp. 42-51, Ottawa, 1920. F i r t h , F. E. and C. B. Carlson. .1944. Preservation and care of f i s h nets. Western F i s h e r i e s , V o l . 28, No. J , pp. 57-38, 40, June Foerster, R, E . 1945. C a l i f o r n i a soupfin shark captured i n B r i t i s h Columbia. F i s h . Res. Bd. Can. Prog. Rep. P a c , No. 64, p. 64, 1945. Hart, J . L. 1938.  A b r i e f account of the l i f e - h i s t o r y of the p i l c h a r d . Rep. B r i t . Columbia F i s h . Dept.  1937, pp. 50-56, 1938.  Lord, J . K. 1866.  The n a t u r a l i s t i n Vancouver island and B r i t i s h Columbia. Vol. 1, 358 pp., London,  1866.  Motherwell, J . A. 1923. Report of chief inspector, western f i s h e r i e s d i v i s i o n ( B r i t i s h Columbia) f o r 1922. F i f t y - s i x t h Ann. Rept. F i s h . Br., Dept. Mar. and F i s h , f o r 1922-23. pp. 42-55, Ottawa,  1925.  Mowat, T. 1887.  1888.  Report.  I893.  Annual report of the f i s h e r i e s of B r i t i s h Columbia f o r the year 1886. Ann. Rept. Dept. F i s h , f o r l886, App. No. 7, pp. 247269, Ottawa, 1887. Annual report of the f i s h e r i e s of B r i t i s h Columbia f o r the year -18.87. Ann. Rept. Dept. F i s h f o r 1887, App. No. 7, pp. 239252, Ottawa, 1888. B r i t i s h Columbia Fishery Commission Report 1892, pp. 1-433, i-xx, Ottawa, 1893.  Report. 1908.  Dominion F i s h e r i e s Commission of B r i t i s h Columbia of 1905-1907, Report and Recommendations, pp. 1-111, Ottawa, 1908.  Report. 1923.  B r i t i s h Columbia Fisheries Commission 1922, Report and Recommendations, pp. 1-35, Ottawa,  1925.  Ripley, W. E. 1946. The soupfin shark and the f i s h e r y . C a l i f . Div. F i s h and Game, F i s h . B u l l . No. 64, pp. 7-37, 1946.  - 60 Rounsefell,  G. A. and G. B. Kelez. 1938. The salmon and salmon f i s h e r i e s of Swiftsure bank, Puget sound, and the Fraser r i v e r . U.S. Bureau F i s h . B u l l . v. 48, No. 27, pp. .693-823, 1938.  Sanford, F. B. and K. Bonham. 1946. Grayfish l i v e r colour r e lated to fin-spine length. Commercial F i s h e r i e s Review, Vol. 8, No. 6, 1946. S i l l i m a n , R. P. and F. N. Clark. 1945. Catch per-unit-ofe f f o r t i n C a l i f o r n i a waters of the sardine (Sardinops caerulea) 1932-1942. C a l i f . Div. F i s h and G me, F i s h . B u l l . No. 62, 76 pp., 22 f i g s . , 1945. a  Swain, L. A. 1944. The.Pacific coast dog-fish and shark l i v e r , o i l industry. F i s h . Res. Bd. Can. Prog. Rep. P a c , No. 58, pp. 3-7, 1944. Taylor, E. G. 1916. Report on the f i s h e r i e s of D i s t r i c t No. 3, B r i t i s h Columbia. Forty-Ninth Ann. Rept. F i s h . Br., Dept. Naval Serv. 1915-16, App.  No. 9, pp. 260-263, Ott awa, 1916.  Tester, A. L. 1945. Catch s t a t i s t i c s ..of the B r i t i s h Columbia herring f i s h e r y to 1943-44. B u l l . F i s h . Res. Bd. Can. No. 67, 47 pp. Thompson, W. F., H. A. Dunlop, and F. H. B e l l . 1931. B i o l o g i c a l s t a t i s t i c s of the P a c i f i c halibut f i s h e r y . (1) Changes i n y i e l d of a standardized unit of gear. Rept. Internat. F i s h . Comm. No. 6, 108 pp., Appendices, 1931. 1934. B i o l o g i c a l s t a t i s t i c s of the P a c i f i c halibut f i s h e r y . (2) E f f e c t of changes i n i n t e n s i t y upon y i e l d and y i e l d per unit of gear. Rept. Internat. F i s h . Comm., No. 8, 49 pp., 1934. Whitehead, S. S. 1930. Analysis of boat catches of white sea bass (Cynoscion n o b i l i s ) at San Pedro, C a l i f o r n i a . C a l i f . Div. Fish and Game, F i s h B u l l . No. 21, 26 pp., 20 f i g s . , 1930. 1931. Fishing methods for the b l u e f i n tuna (Thunnus thynnus) and an analysis of the catches. C a l i f . Div. Fish and Game, F i s h B u l l . No. 33, 32 pp. 22 f i g s . , 1931-  - 61 -  Villi  APPENDIX  fab Is  1  Length Frequency Distributions of Dog-fish oaught by Sunken Gill-nets off Barkley Sound i n June, 1944. Measurements made from 7 different "sets". length (cm.) 60 • ^61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88  HO. O f  Males 1  2 1 2 5 1 4 4 9 3 9 20 26 29 41 48 46 53 35 30 • Total  length (cm.) 89 , 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 480 cf  I>iO. O f  Males 32 24 13 16 10 4 6 2 3 1  length I cm.) J  60 . 61 ' 62 - 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 :  Length (cm.  WO. O f  Female s  89" 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116  1  1 5 1 1  2 1 1 1 1 5 1 1 T o t a l  8 1  2  iMO. O f  ire male s 1 2 2 1 3 5 1 2 1 4 3 2 4 3 7 3 1 1 2 5 2 1 2 1  Table 2  Length Frequency Distributions of Dog-fish Caught by Sunken Gill-nets off Darkley sound i n August 1944. Measurements made from 10 different "sets". Length I cm..) 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 , 80 81 82 83 84 85 86  No. of Males  4 1 2 4 6 5 6 11 14 7 6 16 24 22 31 33 33 47 56 67 71 70 81 58 Total  length (cm.) 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 976 o"  No. of Males 82 65 56 31 24 19 13 5 5 1  length (cm.))  No. of i'emales  58 . 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86  1  1 4 4 6 12 6 8 9 6 6 6 5 7 3 9 4 4 5 4 4 1 7 10 2 Total  Length :(cm.) I 87 88 89 90 91 92 93 94 • .95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 182 9  No. of Females 1 3 1 4 5 3 2 4 3 3 4 3 2 2  2 2 1 1 1 1  Table 3 Length Frequency Distribution of Dog-fish Caught by Sunken Gill-nets in Hecate S t r a i t i n June 1946. Measurements made from 7 different "sets". length (cm.} 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92  NO.  of Males  1 1 2 1 1 1 34 1 1 1 2 1 2 3 2 1 3 1  Total  Length (cm.) 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 33 o*  •No.  of Males  1  length (cm.)  No. of Females  65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92  1 1 3 3 1 3 5 2 6 3 4 3 7 8 4 5 3 8 4 7 6 12 13 15 14 18 Total  length (cm.) 93 94 95 96 97 98 99 100 101 102 103 104 • 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 401 9  No. of Females 15 19 23 19 15 7 13 18 15 9 11 7 8 11 11 10 8 7 .5 2 4 1 1 2 1  Table  4"  Length frequency Distributions of Dog-fish Caught by Sunken Gill-nets off Barkley dound i n June 1945. . Measurements made from 8 different "sets". length (cm. j 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90  HQ. Of  Males 1  1 1 2 1 2 2  4 2 3 8 3 3 10 5 9 3 6 10 6 5 Total  Length (,cm. ) 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118" 119 120 93 o*  JMo. of Males 1 2 1  Length (cm. ) 60 61 62 63 64 65 66 67 68 69 • 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90  No. of jremale s  1 1  1 1 3 1 2 1 1 2 2 1 3 1 2 3 5 1 4 Total  Length (cm.)  No. of Females  91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 .109 110 111 112 113 114 115 116 117 118 119 120  7 5 8 12 10 17 14 14 18 21 18 17 29 21 22 18 13 7 12 8 2 1 5  342  $  2 2 1 1 1  Table 5 Length Frequency Distribution of Dog-fish caught by Otter Trawls off Amphitrite Point (Barkley Sound) i n June and July 1945. length (cm.) 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72  73 74 75  No. of Males 1 5 4 3 6 7 5 8 6 11 8 12 7 9 10 5 8 6 4 5  Total  Length (cm. )  No. of Males  Length (cm. )  76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95  5 5 6 7 8 5 6 6 7 9 6 4 2 1 3 2 2  55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75  214 c?  No. of Females 3 1 2 3 6 6 7 7 8 11 13 14 9 12 . 7 9 7 5 1 • 4  Total  Length (cm. )  No. of Females  76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95  3 3 2 1  165  3 1 2 3 1 1 3 2 1 1 2  9  Table  6a  Daily Landings of Dog-fish and Soup-fin Shark Livers Caught i n Hecate Strait by Sunken Gill-net Boats (from available data). May 1943  May 1944  Weight of Weight of' Soup-fin No. Dog-fish Shark of Livers lb.. Livers l b . Trips 1 2 3 4 5  May 1945  May 1946  Weight of Weight of Weight of Weight of Soup-fin No. Weight of Soup-fin No. Weight, of Soup-fin No. Dog-fish Shark of Dog-fish Shark of Dog-fish Shark of Livers l b . Livers l b . Trips Livers l b . Livers l b . Trips Livers l b . Livers l b . Trips  679  2  a  O  7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 . 31 Total  2,201  600  1 1  1,120  1.720 No. Boats  2 1  3,647 566 456 995 664 163 1,092 390 2,609 793 431 2,638 2,763 2,016 909 166 766 2,136 3,562 3.687 33.329 No. Boats  24  1  57  1  301  2  86 164  1 1  98 742  1 2  408 4,927  1 4  2  2 22 10 i  4 13 10 61 25  3 2 2 2 2 1 4 1' 6 3 3 4 7 5 2 1 3 6 7 5 73  4,158 750 1,620 435 48 6,118 9:, 610 1 12,315 9,010 41,743 3 - 14,250 13.978 114.035 4 No. Boats 69  1 1 4 2 1 9 10 8 6 27 13 8 90  5,891 2 5,519 9.555 2 27.772 No. Boats 20  3 6 7 30  Table  6b  Daily Landings of Dog-fish and Soup-^fin Shark Livers Caught in Hecate S t r a i t by Sunken Gill-net Boats (from Available data)i June 1945 June 1944 June 1943 Weight of Weight of Soupr-f i n No. Dog-fish Shark of Livers l b . Livers l b . Trips 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Total.  2,022  6  1  210  1,021 758 727 368 * 1,571 727  1  2  5 12  2  s  2 1 1 3 3  80 220  1 1  558 1,120 201  15  1 2 1  40  20  10,386 No. Boats £  June 1946  Weight of Weight of Weight of Weight of Soup-fin No. Weight of Soup-fin No. Weight of Soup-fin No. Dog-fish Shark of Dog-fi sh Shark of Dog-fish Shark of Livers l b . Livers l b . Trips Livers l b . Livers l b . Trips Livers l b . Livers l b . Trips 43 5,101 7 5 2 15 27,278 19 17,085 19,843 10 15 21,763 5 14 « 2,214 2 16,581 5 20 3,766 9 6,222 2 4,005 8 20,237 12 19,611 83 20 29,092 13 20 248 1 7,478 37,008 25 34 12,256 12 9 28,442 . 70 21 64,828 24 43 17,007 4 - 10,616 5 15 52,129 5 37 12,873 9 63 9 17,562 22 18 1,343 3 20,248 23,163 38 20 5,040 72 11 1,368 4 8,297 10 22,110 7 22 12,664 5 12 19,764 39 . 11 17,, 225 6 37 28,721 8 15 8,505 28 6 11,827 14 24 4,847 45 8 22,502 43 10 19,860 5 . 26 2,934 4 24,652 65 11 •22,003 154 28 1,450 - 90 3 51,154 153 24 24,179 28 31 17,053 4 9 24,820 138 15 11,284 8 18 21,867 4 18 175 10 18,315 64 38 2,140 8 3 18,119 60 15 24,301 40 23 11,412 112 8 16,326 186 15 16,585 182 16 16,310 . 84 14 19,624 9 16,448 153 35 14,146 44 14 12,187 220 13,668 173 11 25,272 279 28 7,212 11 6 22,188 214 10 57,054 365 33 2,012 60 4 140 15 14,238 86 23 10,285 32 8 16,830 148 10 17,674 177 26 14,622 61 11 16,140 16,545 262 10 24,597 228 38 9,450 33 10 28 28,758 148 29 13,769 70 10 420 50,003 372 21 27,416 407 19 12,366 19 9 30,211 222 11 44,584 355 42 6,996 33 7 10,433 813 27 57.614 328 48 6,741 10 .3 57.363 825 275,629 752 215 3,219 434 780,047 626,404 4,147 No. boats 217 No. Boats 70 No. Boats 92 c  Table 6 c Daily Landings of Dog-fish and Soup-fin Shark L i vets Caught i n Hecate S t r a i t by Sunken Gill-net Boats (from available data).. . July 1943 height of Weight of Soup-fin No. Dog-fish Shark of Livers l b . Livers l b . Trips 198 1 1 2 3 835 1 4 160 1 5 6 7 8 9 56 4 1 10 118 7 1 11 598 81 2 12 1,093 144 4 13 1,326 98 .2 14 1,874 136 3 15 799 43 3 16 '7764 1-9 2 17 "199 1 18 .85 1 19 222 1 20 1,000 3 6 21 66 1 22 353 13 1 23 2,453 41 5 24 403 9 1 25 3,306 118 2 26 96 1 27 403 2 28 29 4,514 276 2 30 627 15 3 31 2,152 .8 3 Total 23,700 1,027 48 No. Boats 10 r -  •  July 1944 July 1945 Weight of Weight of Weight of Soup-fin No. Weight of Soup-fin No. Dog-fish Shark of Dog-fish Shark of Livers l b . Livers l b . Trips Livers l b . Livers l b . Trips . 129 11 18,054 3,116 15 14 18,123 460 13 12,292 81 15 23,813 363 15 23,648 196 24 27,333 674 23 29,753 238 33 7,037 166 10 18,002 509 29 49,946 286 16 48,707 779 37 13,087 276 9 23,056 463 35 15,297 446 14 22,757 688 34 16,497 38 8 37,218 457 29 13,716 23 8 18,678 303 28 28,035 283 16 13,981 296 25 9,467 29 9 15,145 371 18 20,724 349 10 13,777 301 13 2,430 14 5 15,051 472 24 .14,358 88 9 8,603 299 18 23,258 116 16 13,588 179 25 24,369 966 17 24,956 521 34 11,433 34 13 16,224 530 33 24,010 358 26 21,910 673 31 16,508 470 16 24,947 605 13 14,039 1;.109 9 17,239 256 9 11,652 303 7 4,565 465 8 . 6,906 408 12 7,706 164 15 19,501 430 17 2,566 89 12 15,338 308 16 10,192 117 17 11,147 348 10 10,652: 188 7 11,911 1,179 •18 '8,710151 13 ,. 8,607 1,352 9 6,364 98 11 .8,941 739 8 • 9,280 164 9 , 8,834 914 10 1,348 59 7 11,356 1,174 14 : 4,771 68 10 13,?32 488,802 394 9,795 630 505.827 NO. Boats 110 No. Boats 190  July 1946 Weight of Weight of Soup-fin No. Dog-fish Shark of Livers l b . Livers l b . Trips 4,736 3 17 1,227 4 4 11,961 8 50 32 10,140 6 523 4 2 749 16 1 8,666 85 9 12,538 128 8 3,565 25 '-7 1,653 3 3,737 45 4 2,161 26 3 7,445 300 6 615 4 1 13,302 169 7 11,320 102 8 20,583 176 14 1,694 138 3 1,210 5 4 32 2 1,011 2,847 68 5 .3,751 168 6 7,179 86 5 8,976 37 8 8,046 58 7 5,930 81 6 4,964 12 5 3,014 36 3 11,498 88 9 10,821 79 ,. 7 2.449 3 188.311 2,071 j 167 No. Boats 49  Tab la  6d  Dally Landings of Dog-fish and Soup-fin Shark Livers Caught i n Hecate S t r a i t by Sunken Gill-net Boats (from available data). August 1943 Weight of Weight of Soup-fin No. Dog-fish Shark of Livers l b . Livers l b . TripB 1 . 1,056 9 3 2 4,023 240 1 3 4,187 48 2 4 820 1 5 6 2,948 146 3 7, 3,470 766 2 8 1,333 82 . 3 .9 2,340 83 2 10 98 1 11 148 1 12 4,619 27 2 13 1,288 12 2 14 1,388 652 2 15 263 2 16 3,473 6 2 17 450 234 1 18 19 20 21 59 208 1 22 110 23 1,499 6 2 24 125 1 25 4,951 45 3 26 1,240 2,028 2 27 61 16 1 28 29 2,409 513 1 30 1,976 1,025 1 31 Total. 44,224 42 6,256 No. Boats 9  August 1944 Weight of Weight of Soup-fin Dog-fish Shark Livers l b . Livers.lb. 12,658 1,154 '9,043 129 18,018 804 26,188 380 12,426 158 8,544 260 12,584 228 16,153 106 3,660 32 12,969 492 10,089 152 13,614 158 3,000 4,636 243 18,943 318 11,742 65 15,358 153 6,553 110 25,212 177 12,633 ' 165 5,556 141 14,090 111 3,000 4,267 39 7,606 76 2,020 20 1,239 16 10,823 34 4,818 73 3,423 24 .. .5.315 • 39 316,180 5,857 No. Boats 76  No. of ' Trips 18 11 21 18 17 8 12 9 4 13 8 12 1 6 11 8 12 8 15. 10 6 11 1 8 3 7 3 10 9 6 6 292  August 1945 Weight of Weight of Soup-fin No. Dog-fish Shark of Livers l b . Livers l b . Trips 9,656 175 12,814 672 5,599 110 14,740 99 5,124 18 20,898 271 8,294 31 13,415 50 8,703 124 5,344 61 6,084 31 2,169 2 5,758 52 7,678 31 9,416 . 23 7,383 9 4,263 71 • 2,312 6 4,578 27 14,327 107 9,518 143 7,039 15 4,418 52 7,980 '26 2,867 5 11,143 23 349 3 3,450 48 57 658 22 3.329 22 219,363 2.329 No. Boats 91  17 15 7 13 13 17 11 14 12 8 4 8 19 11 12 14 7 8 9 12 10 14 10 12 5 11 3 7 •2 2 .6 313  August 1946 Weight of Weight of Soup-fin No. Dog-fish Shark of Livers l b . Livers l b . Trips 852 4 15,958 21 11 9,649 18 5 19,675 2,709 10,668 3,101 12,592 12,666 4,143 16,977 6,736 1,611 15,841 4,467 4,245 ' 28,378 2,768 13,720  19 4 86 5 3 31 23 2 14 45 5 11 7 8 39  9 4 6 4 7 11 3 6 4 6 11 3 "4 6 4 12  74 1 6,094 3 7 1,471 2 2 2,035 10 3 5,943 37 6 10,500 6 5 5 3 4,644 1,059 3 2 73 . 12.474 8 480 157 231.050 No. Boats 35  Table 6e Daily Landings of Dog-fish and Soup-fin Shark Livers Caught in Hecate Strait  September 1943  by Sunken Gill-net Boats (from available data), September 1944 September 1945  September 1946  Weight of Weight of Weight of Weight of Weight of Soup-fin No. Weight of Soup-fin No.- Weight of Soup-fin No. Weight of Soup-fin No. Of Dog-fish Shark ' of Dogrfish Shark of • Dog-fish Shark of Dog-fish Shark Livers lb.Livers lb. Trips Livers lb.Livers lb.Trips Livers, lb.Livers lb. Tri"ps Livers lb.Livers lb.Trips 72 998 19,699 . 14 1,057 1 2,653 4 4 2 2 1,492 158 -2 9,326 70 10 12,208 - 41 9 1,956 26 4 -3 2,011 2 2,153 28 5 1,943 32 5 4 30 1 2,508 7 3 7,090 33 .. 7 1,279 2 2 5 11,410 61 8 2,303 19 5 7,823 7 6 3,351 868 3 3,673 62 3 7,017 23 11 21,095 14 11 7. 93 - 1 6,409 8 6 779 '4 3,552 15 3 8 1,435 342 2 12,133 19 6. 1,293 41 9 7,257 31 6 9 ' 1,045 2 8,213 29 10 1,803 3 5 14,377 11 11 10 3,618 2,967 4 5,150 23 8 6,234 11 6 18,350 20 14 11 , 3,225 2 7,184 8' 5,804 9 8 1,591 5 12 568 • 1 642 .1 4,188 24 6 6,411 4 13 133 1 7,946 4 2,083 7 3 425 1 14 3,982 491 3 10,564 7 7 9,049 4 1,653 6 7 15 1,737 3 l.LOO 1 2 234 1 16 2,796 6 6 876 2 2,561 4 17 ; 733 3 2,325 5 2 1,745 7 3 23,852 7 24 18 . 2,735 3 1,995 3 7,265 23 7 4,645 5 19 . 1,327 3 4 5,386 2 6 486 1 20 ' 1,628 2 811 3 1,326 3 1,703 32 2 21 80 1 2,809 5 999 2 12 22 1,686 2 605 2 793 1 23 ' 618 7 2 ' 864 2 41 1 1,785 3 24 1,150 2 1,251 2 327 2 • 4,826 7 25 1,395 3 6,821 14 5 1,103 10 5 3,116 7 26 1,274 2 1,597 4 39 1 6,663 18 27 1,512 21 4 859 2 186 2 4,962 7 28 556 47 2 6,338 6 4 1,263 5 5,252 5 4,395 13 3 5,352 24 7 88 1 7,181 6 3 29 30 721 499 2 805 1 1.821 5 3 630 , 6 5 208 177 161.457 128 254 146 82.020 144.697 445 59 42.119 5.425 Total * • f No. Boats 45 No. Boats 64 No. Boats 38 No. Boats 15 :  :  f  .•  Table  6f  Daily Landings of Dog-fish and Soup-fin Shark Livers Caught i n Hecate Strait by Sunken Gill-net Boat3 (from available data). October 1943  October 1944  October 1945 ' •  October 1946 -  Weight of Weight of Weight of Weight o f Weight of Soup-fin No. Weight of Soup-fin No. . 'Weight of, Soup-fin No. Weight of Soup-fin No. Dog-fish • Shark of Dog-fish Shark . Of Dog-fish Shark, < of Dog-fish Shark of Livers l b . Livers l b . Trips Livers l b . Livers l b . Trips. Livers l b . Livers l b . Trips Livers l b . Livers l b . Trips 18 2 - 3,688 3 1,138 -., 3 3,428 11 564 1 2 150 3 4,927 1 1,320 4 1,984 2,042 23 6 748 2 1,202 3 3 13 6 1,956 5 853 2 5 1,877 3 4. • 2,204 5 4,550 3 100 3 1 5 4,009 2,781 10 6 535 1 4,479 . 3 6 482 1 6 65 8 649 2 1,440 4 2 1,065 5,486 Oil 7 4 1,933 4 4,126 • 26 5 6,728 8 2,367 4 2,270 3 4,020 . 7 5 1,842 3 9 414 1 5,371 4 2,121 3 10 863 3 2,941 3 1,938 5 1,361 11 1 12 2,099 24 5' 3,373 3 ; 4,350 2 2,860 3 13 2,348 3 1,419 3 • 1,319 3 14 5 15 1,328 264 1 1,424 6 213 2 3,291 3 2,464 8 4 ." 2,360 5 900 2 16 17 1,047 3 7,358 4 752 1 4,927 9 18 937 5 "1,864 3 1,804 3 144 2 5 2,202 7 4,523 2 1,270 123 660 1 19 602 2 242 . 1 5,587 8 367 2 20 21 101 1 1,085 2 192 2 78 1 22 921 3 640 2 ' 2,541 2 •. 1,934 6 2,832 3 187 2 2,568 3 23 168 1 1,000 2 357 5 24 261 2 766 1 2,007 2 25 3 656 3 93 2 . 1,080 4 26 396 27 330 2 4,615 3 .. 28 ^132 1 385 3 860 7 465 2 2,837 6 84 1 29 30 194 1 5 643 7 4 2,215 3 . 2,396 5 31 ,j 1.213 165 .114 50,696 36.677 310 101 63.664 66 Total 1 41,389 8 63 3 No. Boats 24 No. Boats 38 No. Boats 17 [ No. Boats 19 U  •  1  :  Table. 7 T o t a l Weight ( l b . ) o f D o g - f i s h L i v e r s Landed' e a c h M o n t h by Sunken G i l l - n e t B o a t s f r o m H e c a t e S t r a i t f r o m 1943 t o 1946. The number o f b o a t s l a n d i n g d o g - f i s h l i v e r s e a c h month i s i n d i c a t e d i n b r a c k e t s below the weight.  1943  1944  1945  1946  1,720 (1)  33,329 (25)  114,035  27,772 (20)  10,386 (3)  626,404  780,047  275,629 (70)  July  23,700 (10)'  488,802 (190)  188,311 (49)  August  44,224  505,827 (110) 316,180 (76)  219,363 (91)  231,050 (35)  September  42,119  144,697  (15)  (45)  82,020 (64)  161,457 (38)  41,389  50,696  63,664 (38)  36,677  1,677,133 1,747,93.1 (669) (365)  920,896 (236)  2,613  3,902  May  June  October  (9)  (19)  Total  Weighted Average catch per boat per month.  163,528  (59)  2,772  (92)  (l7)  4,595  (69)  (217)  (24)  Table  8  T o t a l Weight ( l b . ) o f D o g - f i s h L i v e r s landed each Month by Sunken G i l l - n e t B o a t s from Hecate S t r a i t , from 194-3 t o 1946. The number o f . t r i p s per boat p e r month i s i n d i c a t e d i n b r a c k e t s below the w e i g h t . 1944  1945  1946  1,720 (2)  33,329 (73)  114,035 (90)  27,772 (30)  June  10,386 (20).  626,404 (434)  780.047 ($25)  275,629 (215)  July  23,700 (48)  505,827 (394)  488,802 (630)  188,311 (167)  August  44,224 (42)  316,180 ( 292)  219,363 (313)  231,050 (157)  September  42,119 (59)  144,697 (146)  82,020 (128)  161,457 (177)  October  41,389 (101)  50,696 (63)  63,664 (114)  36,677 (66)  163,538 (272)  1,677,133 (1,402)  1,747,931 (2,100)  920.896 (812)  601  1,196  832  1,134  1943 May  Total  Weighted Average catch per t r i p per boat per month  Table 9  Average Catch ( l b . ) per Boat per Month of Dog-fish L i v e r s landed by Sunken G i l l - n e t Boats from Hecate S t r a i t , from 1943 to 1946.  1943  1944  1945  1946  May  1,720  1,333-2  1,652.7  1,388.6  June  2,077.2  6,808.7  3,394.7  3,937.6  July  2,370.  4,598.4  2,572.6  3,843.1  August  4,913-8  4,160.3  2,410.6  6,601.4  September  2,807-9  3,215.5  1,281.6  4,248.9  October  2,178.4  2,982.1  1,675-4  1,528.2  2,771.8.  4,594.9  2,612.7  3,902.1  Weighted average > catch per boat per month  Table 10 Average C a t c h ( l b . ) p e r T r i p p e r Boat p e r Month o f D o g - f i s h L i v e r s l a n d e d by Sunken G i l l - n e t B o a t s from Hecate S t r a i t , from 1943 t o 1946.  1943  1944  • 1945  May-  860.0  456.6  1,267.1  June  319.3  1,443.3  July  493.7  1946 '  925.7  945.5  1,282.0  1,283.8  775.9  1,127.6  1,052.9  1,082,8  700.8  1,471.7  September  713.9  991.1  640.8  .912.2  October  409.8  804.7  558.5  555.7  Weighted average c a t c h per t r i p per boat p e r month  601.2  1,196.2  832.3  August  i  1,134.1  Table 11 Index of t h e Average Catch per Boat per Month of Dog-fish Livers landed by Sunken G i l l - n e t Boats from Hecate S t r a i t , from 1943 to 1946. Determined by the method of l i n k  relatives.  1943  1944  1945  1946  May  1.0  0.77  0.95  0.80  June  1.0  3.28  1.74  1.91  July  1.0  1.94  1.09  1.62  August  1.0  0.85 ' 0.49  1.35  September  1.0  1.14 ; 0.46  1.51  October  1.0  1.37  0.77  0.70  Index for Each Year.  1.0  1.66  0.95  1.4  o  Table  12  Index of the Average Catch per T r i p per Boat per Month of D o g - f i s h L i v e r s landed by Sunken G i l l - n e t Boats from Hecate S t r a i t , from 194-3 t o 194-6 Determined by t h e method of l i n k  relatives.  1943  1944  1945  1946  May  1.0  0.53  1.47  1.07  June  1.0  2.78  1.81  2.46  July  1.0  2.60  I.56  2.26  August  1.0  1.03  0.67  1.41  September  1.0  1.39  0.90  1.28  October  1.0  1.96  1.35  1.34  Index f o r Each Year.  1.0  1-99  I.38  1.88  ~  "  Table 13  Monthly Landings of Dog-fish Livers landed by. the same Sunken Gill-net Boats, Fishing i n adjacent years i n Hecate S t r a i t .  May Weight of Dog-fish Livers (lb.)  June  1943 August September October  July  3,615 18,417  20,389  8,803  Number of boats  2  5  4  3  Average Catch per boat (lb.)  1,808  3,683  5,097  2,934  June  July  May  Number of boats  10  Average Catch per boat (lb.)  1,974  May  56  52  7,835  6,415  June  July  6,162 3  23 4,719  24,776 7  3,539  16,305  Number of Boats  9  53  39  Average Catch per boat (lb.)  2,125  5,478  4,087  65,964 34,005 19 3,472  1944 July August September October  4,136  9,918 7,474  May  5  6,452  14,548  3  3  2,151  4,849  4  2,068  1,984 1,869  June  1945 July'- August September October  18,894 215,960 145,533 60,746  15,157  10,301  7  4  4  10  56  " 4,076  1,889  3,856  2,799 2,641  June  194L6 July August September October  1945 August September October  Weight of Dog-fish 19,129 290,371 159,376 Livers (lb.)  June  2  2,054  1944 August September October  Weight of Dog-fish 19,735 438,750 333,569 108,536 Livers (lb.)  May  15,166  15  10  2,267  1,517  May  52  23  14,586 235,831 168,685 149,424 9 1,621  53 4,450  39  19  4,325 7,864  2,165  2,575  40,668  15,547  15  10  2,711  1,555  T a b l e 14 I n d e x o f t h e C a t c h o f D o g - f i s h L i v e r s l a n d e d b y t h e same Sunken G i l l - n e t B o a t s F i s h i n g i n a d j a c e n t y e a r s , 1943-44, 1944-45, 1 9 4 5 - 4 6 , i n Hecate S t r a i t . D e t e r m i n e d b y t h e method o f l i n k  1943 May  •.  relatives.  1944  I945  0.741  0.709  O.54O '  1946  June  1.0  1.144  O.563  0.457  July  1.0  0.538  0.235  0.249  August  1.0  0.367  0.205  0.464  September  1.0  0.733  0.449  0.537  October  1.0  2.360  1.491  1.-528  Index each year  1.0  0.741  0.367  0.392  Table  15  T o t a l Weight ( l b . ) o f S o u p - f i n Shark L i v e r s l a n d e d each Month by Sunken G i l l - n e t B o a t s from Hecate S t r a i t , from 1 9 4 3 t o 1 9 4 6 . The number of b o a t s l a n d i n g s o u p - f i n s h a r k l i v e r s each month i s i n d i c a t e d i n b r a c k e t s below the w e i g h t .  May June  1943  1944  U)~  61 (25)  40 (5)  '  1945  1946  4 (69)  2 (20)  4,147 (92)  3,219 (217)  752 (70)  July  1,027 (10)  13,732 (110)  9,795 (190)  2,071 (49)  August  6,256 (9)  5,857 (76)  2,329 (91)  480 (35)  September  4,525 (15)  445 (45)  254 (64)  208 (38)  8 (17)  165 (38)  3 (24)  13,058 (59)  24,250 (365)  15,766* (669)  3,516 (236)  225-14  66.44  23.57  14.90  October  Total  Weighted average catch per boat per month  310 • (19)  Table  16  T o t a l Weight ( l b . ) o f S o u p - f i n Shark L i v e r s l a n d e d each Month by Sunken G i l l - n e t B o a t s from Hecate S t r a i t , from 1 9 4 3 to 1 9 4 6 . The number o f t r i p s p e r b o a t p e r month i s i n d i c a t e d i n b r a c k e t s below' t h e w e i g h t  1943 May  "(2) June  1944 61 (72)  (50)  9,795 (630)  2,071 (167)  (42)  5,857 ( 292)  2,329 (315)  (157)  5,425 (59)  (146)  254 (128)  208 (177)  310 (101)  8 (65)  (114)  1,027 (48)  August  6,256  Weighted average per t r i p per boat p e r month  2  12,722 (294)  July  Total  4 .(90)  752 (215)  4,147 (424)  October  1946  (825)  40  (20)  September  1945  445  ' 13,058 (270)  24,250  48.26  17.50  (1,402)  3,219  165  15,766 (2,100)  7.51 '  480  5 (66)  5,516 (812)  4.55  Table  17  rage C a t c h ( l b . ) per Boat per Month o f S o u p - f i n Shark L i v e r s l a n d e d by Sunken G i l l - n e t B o a t s from Hecate S t r a i t , from 194J t o 1946.  1943 May June  8.00  1945  1946  2.44  0.06  0.1  45.07  14.83  10.74  124.84  51.55  42.26  1944  July  102.7  August  693.11  77.06  25.59  13.71  September  361.67  9.89  3.97  5.47  16.31  0.47  4.34  0.12  225.14  66.44  23.57  14.90  October  Weighted average c a t c h per boat per month  T  Table  18  Average Catch, ( l b . ) per T r i p p e r Boat per Month o f S o u p - f i n Shark L i v e r s l a n d e d by Sunken G i l l - n e t B o a t s from Hecate S t r a i t , from 1943 t o l°4o  194?  May  1944  1945  1946  0.84  0.04  3.90  0.07 3.50  June  2.00  July  21.40  9.55 34.85  148.95  20 .06  91-94  August September October  Weighted .average c a t c h per t r i p per boat p e r month  3.07  48.36  12.40  3.05 0.13  1-55 7.44 1.98 1.45  17.30  7.51  4.33  3.08 1.18 0.04  Table  19  Index o f the Average C a t c h per Boat p e r Month o f S o u p - f i n Shark L i v e r s l a n d e d by Sunken G i l l - n e t B o a t s f r o m H e c a t e S t r a i t , f r o m 1943 t o 1 ° 4 6 D e t e r m i n e d b y t h e method  1943  of l i n k  relatives.  1944  1945  1946  0.295  0.25  0.42  May  -  June  1.0  5.63  1.86  1.34  July  1.0  1.22  0.50  0.41  August  1.0  0.11  0.04  0.02  September  1.0  0.03  0.01  0.01  October  1.0  0.03  0.28  0.01  Index f o r each year  1.0  0.295  0.105  0.07  -  —  '  T a b l e 20 Index o f t h e Average C a t c h per T r i p per Boat per Month of S o u p - f i n Shark L i v e r s l a n d e d by Sunken G i l l - n e t B o a t s from Hecate S t r a i t , from 1 9 4 ? t o 1946... Determined by the method of l i n k  1942 May  relatives.  1944  1945  1946  0.337  0.05  0.87  June  1.0  4.77  1.96  1.76  July  1.0  1.63  0.06  0.48  August  1.0  0.13  0.02  0.02  September  1.0  0.03  0.02  0.01  October  1.0  0.04  0.45  0.01  Index.for each y e a r .  1.0  0.337  0.133  0.09  ^  Table . 21 Monthly Landings of Soup-fin Shark Livers landed by the same Sunken u i l l - n e t Boats Fishing i n adjacent iears i n Hecate S t r a i t  May  1943 August September  June  July  Weight of Soup-fin Shark Livers (lb.)  22  724  591  19  14  Number of Boats  2  5  4  3  3  Average Catch per boat (lb.)  11  145  148  6  5  June  July  May Weight of Soup-fin Shark Livers (lb.)  39  Number of Boats  10  56  52  Average Catch per boat (lb.)  4  49  203  May  June  Weight of Soup-fin Shark Livers (lb.) Number of Boats Average Catch per boat (lb.)  2,762 10,530 1,874  July  1,248 3,459  9  1944 August September  October  October  86  8  23  7  4  81  12  2  1945 August September  October  May  -July  1944 August  84 2,056  814  37  5  4  3  411  204  12  . June July  1945 August  1,028 2,250  339  70  2  June  2  •  42  May  September  September  October  3  October  56  52  23  7  4  18  43  15  10  0.5  May  June  July  1946 August  10 —  -  September  304  85  34  2  572  1,848  271  145  53  39  19  15  10  9  53  39  19  15  24  89  16  6  3  0.2  11  47  14  10  October  10  Table 22 Index o f the C a t c h of S o u p - f i n Shark L i v e r s l a n d e d b y t h e same Sunken G i l l - n e t B o a t s F i s h i n g i n A d j a c e n t Y e a r s , 1943-44, 1944-45, 1945-46, i n Hecate S t r a i t . Determined b y the method o f l i n k  1945 May  1944 —  relatives.  1945  1946  '  June  1.0  3.818  1.420  0.650  July  1.0  2.840  0.608  0.325  August  1.0  1.377  0.249  0.222  September  1.0  1.947  1.585  2.704  October  1.0  0.500  0.250  0.70  Index each year  1.0  2.183  0.526  0.291 '  Table  23a  D a i l y Landings o f D o g - f i s h L i v e r s Caught o f f ' B a r k l e y Sound by Sunken G i l l - n e t Boats (from able data) . •May 1944 Weight o f Dog-fish Livers l b . 1 2 • 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31  900 318 1,176 764 871 819 . 1,278 3,032 1,828 880 1,581 1,159 793  Total  19,404  657 224 365 94 202 27 360 1,074 847  155  May 1945  Number of. Trips'  • Weight o f Dog-fish Livers l b .  Number of Trips  4 1 7  126 357 1,418 276 2 2,460 58 20 64  3 3 5 3 1 23 8 5 2  48  1  192 101  4 3  .1,051 1,415 678 607 1,974 1,883 2,504 909 2,526 2,012 1,142 300  8 6 6 5 4 5 7 4 8 6 5 1  22,123  126  04  •  6 1 5 4 5  1 7.' 7 9 11 10 9 10 12 13 11 14 17 11 179  avail-  Table 23b D a i l y Landings o f D o g - f i s h L i v e r s Caught o f f B a r k l e y Sound by Sunken G i l l - n e t Boats .(from a v a i l a b l e d a t a ) . June 1944 Weight o f Dog-fish Livers l b .  1 2 2 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Total  237 555 76 734 . 264 929 176 2,292 2,737 2,471 1,786 2,965 2,660 1,724 1,326 1,846 1,912 1,914 2,123 1,489 587 372 987 390 228 715 889 2,864 2,805 1,556 41,609  June 1 9 4 5  Number of Trips  Weight o f Dog-fish L i v e r s lb.  June 1946  Number of Trips  5 8 2 9 5 5 2 15 20 14 10 15 ? 16 11 .16 17 15 17 17 17 10 14 7 7 11 8 1143 13  4,108 888 1 , 26 25 90 1,186 2,966 2,427 1,462 296 28 110 1,889 102 21 ,, 21 61 01 897 5104 34 1 , 0142 62 106 866 921 873  18 7 6 6 8 12 •8 9 4 1 2 7 1 9 7 7 7 2 7 5 1 10' 9 8...  1,513  1,596  7 9 9 6  352  30,246  192  2  469 441  Weight o f Dog-fish Livers lb.  1,079 4,325 1,566 951 363 1,140 22 ,, 61 21 82 3,707 3,402  4,890 3,180 2,261 1,035 1,373 455 112  5,742  •  Number of Trips  5 11 9 13 6 11 11 11 11 11 10 11 12 9 10 2 1  3,544 664 355 261 604  101 2 5 6  45,749  195  T a b l e 2Sc D a i l y Landings of Dog-fish L i v e r s C a u g h t o f f B a r k l e y Sound b y S u n k e n G i l l - n e t B o a t s (from a v a i l a b l e data) duly Weight o f Dog-fish Livers l b . 1 2 3 4 5 6 7 8 9 10 11 12 13 14 13 16 17 18 , 19 20 ' 21 22 23 24 25 26 27 28 29 '30 31 Total  2,376 639 2,841 736 23 695 767 653 156 326 617 2,988 1,374 819 832 1,148 1,736 2,832 1,454 2,379 2,573 1,523 444 1,173 606 213 1,021 719 421 2,078 3,655 39,817  1944  July  Number of Trips 16 7 29 . 10 1 14 12 8 3 6 12 30 18 13 11 7 x  ?  16 11 18 12 4 15 15 5 17 11 3 14 15 379  Weight o f Dog-fish Livers l b .  1945  July  Number of Trips  369 53 409  4 3 4  571 626  3 3  82<  1  311 392  2 3  607 231 623 602 467 374 1,490  3 3 3 3 3 4 3  451  '2  650 164 74' 240 510  4 3' 2 2 5  9,296  63  Weight o f Dog-fish Livers l b . .  1946 Number of Trips  2,813 1,365 729 1,053 1,351 712 . 98 569 288 934 1,192 436 79  8 3 5 8 6 6 2 7 3 11 7 8 5  803 670 151 1,773 567  14 9 1 16 5  15,583  124  Table Caught  D a i l y Landings o f Dog-fish L i v e r s o f f B a r k l e y Sound b y S u n k e n G i l l - n e t .'Cfrom a v a i l a b l e d a t a ) . August  Weight o f Dog-fish Livers l b .  1 2 3 " 4 5 6 7 8 9 10 11 12 13 14  15. 16 17 18 19 20 21 22 23 24 2  ^  26 27  28 • 29 30 31 Total  23d  1,711 1,090 398 1,311 527 1,025 223 349  1,004 893 452  20 767 595 2,709 600 350 1,437 585  2,204  581 755 3,190 629 1,111  1944  August  Number of Trips  13  14  5 17 8 19  '7 2 13 16 6 1 9 10 32 13 4 19 5 18 6 15 33 16 ^  41  8 15 12 12 .4 1  28,706  368  840  1,232 1,018 535 524  "Weight o f Dog-fish Livers lb.  1945 Number of Trips  122 317 396 603 583 252 470  2 3 4 4 3 3 5  571 64 658 5  4 1 6  378 123 255  3 3 3  63 353 59  3 5 3 • 5  136  4 3 3  442 143  447  1  414  296 63 67 52  2 3 1 3 2  7,332  82  Boats  Table 23e D a i l y Landings o f D o g - f i s h L i v e r s Caught o f f B a r k l e y Sound by Sunken G i l l - n e t B o a t s (from a v a i l a b l e d a t a ) .  September Weight o f Dog-fish Livers l b .  1 2 3  4  5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Total  837 820 2,825 1,159 372 65 151 207 424 477 151 132 96 268 18 o 457 59 76 58  1944 Number of Trips_  8 8 23 16 7 3 2 4 4  6 • 1 2 2 5 3 4  2 2 3  30 102 84  1 2 1  9,030  109  Table  24  T o t a l C a t c h ( l b . ) o f D o g - f i s h L i v e r s landed by Sunken G i l l - n e t B o a t s F i s h i n g o f f B a r k l e y Sound on t h e West C o a s t o f . V a n c o u v e r I s l a n d f r o m 1944 t o 1946. (from a v a i l a b l e data) The number  o f b o a t s f i s h i n g i n e a c h month i s indicated i n brackets.  1946  1944  1945  May  19,404 (20)  22,123 (14)  June  41,609 (3D  30,246 (14)  45,749 (17)  July  39,817 (3D  9,296 (6)  15,583 (13)  August  28,706 (24)  7,332 (6)  9,030 (13)  September.  f  Total  138,366 (119)  68,997 (40)  61,332 (30)  Table  25  Index o f the R e t u r n p e r - U n i t - o f - F i s h i n g E f f o r t f o r D o g - f i L i v e r s l a n d e d b y Sunken G i l l - n e - t B o a t s F i s h i n g o f f B a r k l e y Sound on the West C o a s t o f V a n c o u v e r I s l a n d , f r o m 1944 t o 1946.  1944  1945  May  15.5  25.1  June  16.9  22.5  33-5  July  15.0  21.1  18.0  August  11.1  12.8  September  11.8  1946  

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