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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 AVAILABILITY OF THE DOG-FISH (Squalus s u c k l e y i G i r a r d ) AND THE SOUP-FIN SHARK (Ga l e o r h i n u s galeus Linnaeus) IN BRITISH COLUMBIA WATERS FROM 1943 TO 1946. B Y W. Edward B a r r a c l o u g h A T h e s i s submitted i n P a r t i a l F u l f i l m e n t o f The Requirements f o r t h e Degree o f MASTER OF ARTS i n the Department of ZOOLOGY THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1948 TABLE OF CONTENTS Page I . INTRODUCTION 1 A. The Problem 2 B. ' 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 3 1. The D o g - f i s h (Squalus s u c k l e y i ) 3 2. The S o u p - f i n Shark (Galeorhinus g a l e u s ) . . . . . . 4 I I . HISTORY OF THE DOG-FISH FISHERY IN BRITISH COLUMBIA... 3 A. P r o d u c t i o n of O i l From the L i v e r s of the D o g - f i s h . 5 B. D e s t r u c t i o n of F i s h i n g Gear and Food F i s h by the D o g - f i s h 7 C. I n t r o d u c t i o n of O r i e n t a l s to the D o g - f i s h F i s h e r y . 9 D. V a l u a t i o n of the D o g - f i s h and D o g - f i s h L i v e r s 9 E . P r e s e n t Uses of D o g - f i s h L i v e r O i l and Body O i l . . . 10 I I I . THE SUNKEN GILL-NET FISHERY IN BRITISH COLUMBIA 12 A. The E a r l y Sunken G i l l - n e t F i s h e r y 12 B. The Modern Sunken G i l l - n e t F i s h e r y 13 1. D e s c r i p t i o n of Gear and F i s h i n g Methods 13 a. Boats 13 t (1) Small Boats 13 (2) Large Boats 13 b. Drum and R o l l e r s 1 4 c. Nets 15 d. G l a s s B a l l F l o a t s 16 e. Lead Line 18 f . Buoy L i n e s , Buoys', and Anchors..-. 18 2. F i s h i n g Methods 18 3. Care of the Nets 20 C. Other S p e c i e s of F i s h Caught by Sunken G i l l - n e t s . . 20 1. In Hecate S t r a i t 20 2. E a s t Coast of Vancouver I s l a n d 21 3. West Coast of Vancouver I s l a n d 22 D. S e l e c t i v i t y of the Sunken G i l l - n e t 2 4 Length Frequency D i s t r i b u t i o n of D o g - f i s h Caught by Sunken G i l l - n e t s and by O t t e r Trawls 2 4 IV. TOTAL CATCH STATISTICS OF THE DOG-FISH AND SOUP-FIN SHARK IN BRITISH COLUMBIA ' 26 V. DESCRIPTION AND ANALYSIS OF THE AVAILABILITY OF THE DOG-FISH AND SOUP-FIN SHARK 29 A. S e l e c t i o n and Source of Data 29 Page B. E s t i m a t i n g Changes i n the A v a i l a b i l i t y and Abundance of F i s h P o p u l a t i o n s 30 C. Meaning of A v a i l a b i l i t y and Abundance 32 D. A n a l y s i s o f the Catch Records 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 Boats F i s h i n g i n Hecate S t r a i t 33 1. The T o t a l Landings o f L i v e r s by Sunken G i l l - n e t Boats3 3 2. The Average Catch per Boat per Month 34 3.- The Average Catch per T r i p per Boat per Month 35 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 35 5 . The Index o f the Average Catch per Boat per Month and the Index o f the Average Catch per T r i p per Boat per Month as Determined by the Method of L i n k R e l a t i v e s . 37 6 . Comparison of the Average Catch per Boat per.Month f o r t h e Same Sunken G i l l - n e t Boats F i s h i n g i n Adjacent Years 38 7 . The Index o f the T o t a l Landings o f D o g - f i s h L i v e r s made by the Same Sunken G i l l - n e t Boats F i s h i n g i n Adjacent Years, a s Determined by the Method of L i n k R e l a t i v e s , 40 E . A n a l y s i s of the Catch Records of S o u p - f i n Shark L i v e r s Landed 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 . 42 1. The T o t a l Landings o f L i v e r s by Sunken Gi l l - n e t Boats 42 2. The Average Catch per Boat per Month 43 3 . The Average Catch per T r i p per Boat per Month 43 4 . The Average Catch per Boat per Month and the Aver-age Catch per T r i p per Boat per Month f o r Each Year as a Whole 43 5 . The Index of the Average Catch per Boat per Month and the Average Catch per T r i p per Boat per Month, as Determined by the Method o f L i n k R e l a t i v e s 44 6 . Comparison of the Average Catch per Boat per Month f o r the Same Sunken G i l l - n e t - B o a t s F i s h i n g i n Ad-jacent Years 44 7 . The Index of the T o t a l Landings o f S o u p - f i n Shark L i v e r s made by the Same Sunken G i l l - n e t Boats Page Fishing in 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 Strait 46 G. Analysis of the Catch Records of Dog-fish Livers, landed by Sunken Gill-net Boats Fishing off Barkley'.. Sound on the West Coast of Vancouver Island, f rom 1944 to 1946., 51 1. The Total Landings of Dog-fish Livers by Sunken Gill-net Boats 52 2. Catch per Unit of Effort 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 Strait 53 VI. ACKNOWLEDGEMENTS 56 VII. REFERENCES * ; 57 VIII. APPENDIX 61 ABSTRACT As the requirements f o r v i t a m i n ttAw i n c r e a s e d d u r i n g World War I I , the l i v e r s from the P a c i f i c c oast d o g - f i s h (Squalua s u c k l e y i ) and the s o u p - f i n shark (Galeorhinus galeua) became one of the p r i n c i p a l sources of v i t a m i n " A " . Under the pressure of a h i g h and i n c r e a s i n g f i s h i n g i n t e n s i t y , the c a t c h of these two sharks i n B r i t i s h Columbia has dropped g r e a t l y d u r i n g the years f o l l o w i n g 1944. Changes i n the a v a i l a b i l i t y o r r e l a t i v e abundance of the d o g - f i s h and s o u p - f i n shark caught in.Hecate s t r a i t and the d o g - f i s h caught o f f B a r k l e y sound on the west coast of Vancouver i s l a n d were determined from the a n a l y s i s of t h e - i n d i v i d u a l t a l l y s l i p s or f i s h r e c e i p t s of each fishermen's l a n d i n g of the l i v e r s from these two sharks caught by sunken g i l l - n e t s . Methods employed i n the a n a l y s i s of the data to determine the a v a i l a b i l i t y , i n c l u d e d the a n a l y s i s of the t o t a l l a n d i n g s of the l i v e r s from eaeh area under i n v e s t i g a t i o n ; the average boat catches per month; and average boat catches per t r i p p e r month. The method of l i n k r e l a t i v e s i s used i n the a n a l y s i s and the c a t c h per u n i t of e f f o r t o f f B a r k l e y sound i s determined. The a v a i l a b i l i t y or r e l a t i v e abundance of the d o g - f i s h i n Hecate s t r a i t was found to d e c l i n e from 1943 to 1945 w i t h a s l i g h t i n c r e a s e d u r i n g 1946. The a v a i l a b i l i t y of the s o u p - f i n shark was found to d e c l i n e g r e a t l y from 1944 to 1946. In the year 1946, the s o u p - f i n shark f i s h e r y i n Hecate s t r a i t was almost a f a i l u r e . The d e c l i n e i n the a v a i l a b i l i t y of the d o g - f i s h and the drop i n the average v i t a m i n *A n per gram of l i v e r o i l i s c l o s e l y r e l a t e d to the removal or p o s s i b l e d e p l e t i o n of the o l d e r age c l a s s e s from the p o p u l a t i o n . On the west coast of Vancouver i s l a n d , o f f B a r k l e y sound the index of r e t u r n per u n i t of e f f o r t (one sunken g i l l - n e t 75 fathoms l o n g f i s h i n g over a p e r i o d of 24 hours) i n d i c a t e d t h a t the a v a i l a b i l i t y of the d o g - f i s h has i n c r e a s e d i n each year s i n c e 1944. The sunken g i l l - n e t s (7 i n c h s t r e t c h e d mesh) were found t o s e l e c t ; d o g - f i s h g r e a t e r than 76 cm. i n l e n g t h . Small d o g - f i s h of no commercial v a l u e ( l e s s than 76 cm.) tend to pass through the meshes. I. INTRODUCTION The production of o i l from the livers of the dog-fish (Squalus suckleyi Girard) was one of the earliest fishing ac-t i v i t i e s carried on in Br i t i s h Columbia. This o i l was used mainly for lighting and lubricating purposes. With the dis-covery of vitamin "A M in the livers of the dog-fish, a very significant and important use for these livers was disclosed. The vitamin "A" content of the soup-fin shark (Galeorhinus  galeus Linnaeus) was found to be even greater than that in the livers of the dog-fish. As the demands and requirements for vitamin "A" increased during World War II, the Pacific coast dog-fish and soup-fin shark livers became one of the principal sources. For the past few years the soup-fin shark has been the major source in the production of vitamin "A" supply in the United States (Ripley 1946). The catch, however, dropped so seriously in American waters that the soup-fin shark was re-placed by the dog-fish. In British Columbia there has been a f a i r l y intensive fishery for the soup-fin shark during recent .years. At the same time; the intensity of the dog-fish fishery has increased greatly u n t i l i t now ranks with the important fisheries in British Columbia. As a result of the high and increasing f i s h -ing intensity, the catch of the dog-fish and soup-fin shark has dropped greatly in the years following 1944. - 2 -I t has seemed u n l i k e l y tha;t a s u f f i c i e n t and s t a b l e s t o c k c o u l d be maintained at t h i s h i g h l e v e l o f e x p l o i t a t i o n but adequate i n f o r m a t i o n c o n cerning the stook has been l a c k i n g . The abundance of any stock which i s e x p l o i t e d by man, must be known before the r a t e o f e x p l o i t a t i o n may be determined. The maximum r a t e of e x p l o i t a t i o n or the optimum y i e l d must a l s o be determined so t h a t a s t a b l e and p r o d u c t i v e p o p u l a t i o n may be maintained f o r f u t u r e u t i l i z a t i o n . A. The Problem An i n v e s t i g a t i o n was undertaken t o determine the changes i n the a v a i l a b i l i t y o r r e l a t i v e abundance of the d o g - f i s h and s o u p - f i n shark caught i n Hecate s t r a i t and o f f B a r k l e y sound on the west coast o f Vancouver i s l a n d . Changes i n the a v a i l a b i l i t y were determined from the a n a l y s i s of i n d i v i d u a l , t a l l y s l i p s or f i s h r e c e i p t s of each fisherman's l a n d i n g of the l i v e r s o f these two sharks caught by sunken g i l l - n e t b oats and r e c o r d e d by the i n d u s t r y . The a n a l y s i s o f these d a t a to determine the a v a i l a b i l i t y , i n c l u d e : 1 . the t o t a l c a t c h of l i v e r s from each area under i n v e s t i g a t i o n ; 2. the average c a t c h per boat per month; 3. the average c a t c h per t r i p per boat per month; 4. the average c a t c h per boat per month and the average c a t c h per t r i p per boat per month f o r each year as a whole; 5. the index of the average c a t c h per boat per month, and the index of the average c a t c h per t r i p per - 3 -boat per month, as determined by the method of l i n k r e l a t i v e s ; 6. comparison of the average catch per boat per month for 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 catch of the same sunken g i l l -net boats f i s h i n g i n adjacent years as determined by the method of l i n k r e l a t i v e s ; 8. the catch p e r - u n i t - o f - f i s h i n g e f f o r t . A knowledge of the h i s t o r y of the f i s h e r y and a detailed description of the e a r l y and modern sunken-gill-net f i s h i n g methods are pertinent to an understanding of the problem. B. Description and D i s t r i b u t i o n of Each Species. 1. The Dog-fish (Squalus- sucklevi) The dog-fish ( F i g . 1) i s a member of the family Squalidae, which includes another member i n B r i t i s h Columbia waters, the sleeper shark (Somniosus microcephalus). Dog-fish a t t a i n a size of s l i g h t l y over f i v e f e e t . The head i s flattened dorso-v e n t r a l l y and-the mouth i s ventral i n p o s i t i o n . I t has f i v e g i l l openings anterior to the pectoral f i n s , and a large s p i -racle close behind the eye. The two d o r s a l f i n s are each pre-ceded by a large spine. There i s no anal f i n . Small placoid scales cover the gray to l i g h t brown dorsal surface and the d i r t y white ventral surface. Girard was the f i r s t to describe the dog-fish i n 1854 and according to Clemens and Wilby (1946) i t was f i r s t recorded '•'Fig; 1 Sketch o f D o g - f i s h . Squalus s u c k l e y l ( G i r a r d ) F i g . 2 Sketch of S o u p - f i n shark. G a l e o r h i n u s gale us (Linnaeui - 4 -i n B r i t i s h Columbia by J . K. Lord i n 1866 as Ac a n t h i u s s u c k l e y i . The words g r a y - f i s h and d o g - f i s h are synonomous, bot h to the commercial fisherman and to the i n d u s t r y . The range 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 northwestern A l a s k a . 2. The S o u p - f i n Shark ( G a l e o r h i n u s galeus) T h i s shark i s one of the two members o f the f a m i l y Car-c h a r i n i d a e found i n B r i t i s h Columbia. The other member i s the blue shark (Prionace g l a u c a ) . The s o u p - f i n shark ( F i g . 2) a t t a i n s a s i z e of s l i g h t l y over s i x f e e t . I t s head i s depressed and the snout extends w e l l beyond the v e n t r a l mouth opening. The f i f t h and l a s t g i l l opening i s l o c a t e d above the shortened p e c t o r a l f i n l a n d the s p i r a c l e , s i t u a t e d behind the eye, i s s m a l l . An a n a l f i n i s p r e s e n t . No s p i n e s precede the two d o r -s a l f i n s . The caudal f i n i s c o n s i d e r a b l y s h o r t e r than the r e s t of the body and i s deeply notched, forming a l a r g e l o b u l e ' o n the upper lobe o f the f i n . There are no l a t e r a l k e e l s on the caudal peduncle. S m a l l p l a c o i d s c a l e s cover the s u r f a c e o f the body. The c o l o u r i s dark gray to dark blue on the 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 on the v e n t r a l s u r f a c e . The 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&, and, a c c o r d i n g to Clemens and Wilby (1946) was f i r s t r ecorded from B r i t i s h Columbia i n 1 8 9 1 . P u b l i c a t i o n s from C a l i f o r n i a s t i l l l i s t and r e f e r t o t h i s s p e c i e s as Gal e o r h i n u s  zvopterus ( R i p l e y 1946). The range i s from southern C a l i f o r n i a t o northwestern A l a s k a . II. HISTORY OF THE DOG-FISH FISHERY IN BRITISH COLUMBIA A. Production of O i l from the Livers of the Dog-fish. O i l extracted from the livers of the dog-fish ranks as one of the earliest products of the fishing industry in Brit i s h Columbia. Lord (1866) noted that the Pacific coast Indians extracted the clear o i l from the fatty livers by heat and pressure for their domestic uses. A few years later the production of dog-fish"liver 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 for two men to commence operations to fish dog-fish, as follows: Boat, with oars and s a i l . $60.00 Try-pot $18.00 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 six cents per gallon. A net, for catching herring for bait, cost from $150 to $200 and was used in common by many - fishermen in the same neighbourhood. The annual yield to the fisherman was estimated at from 40 to 150 barrels of o i l . Each barrel contained approximately 30 to 40 gallons of o i l . This o i l was valued at forty cents a gallon in Victoria. Large quantities of oi l , were consumed for lubricating - 6 -and lighting purposes in the extensive saw-mills at Burrard inl e t , in the coal-mines at Nanaimo and Departure hay and by numerous steamers and sailing vessels frequenting these waters (Anderson 1877). Two of the light stations on this 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 light and, besides, was cheaper than any other o i l that could be imported during this period (Cooper 1874). During the spring of 1877 an establishment employing white fishermen was formed on the Queen Charlotte islands for collecting dog-fish o i l (Anderson 1878), but two years later the Skidegate O i l Company largely employed Indian labour secured from the villages around them (Anderson I 8 8 0 J . The livers of the dog-fish (theonly part of the shark processed i n 1879) were f i r s t steamed in large vessels, in which the o i l collected at the., top. After separation, the o i l was again subjected in another vessel to a certain degree of heat, thus dissipating very minute water ^a r t i c l e s . This refined o i l was sealed i n five gallon cans, two of which were packed in a case for shipment to ready markets (Anderson 1880). The quality of dog-fish o i l could not be excelled for lubricating purposes at this time. In A p r i l 1881 the best quality liver o i l was used on the "H.M.S. Rocket" as a lub-ricating o i l for the engines, and i t was found that, the dog-fi 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 called then, were not used as a source of o i l - 7 -to any great extent. In 1880 two qualities of o i l were pro-cured from the dog-fish at the refinery on the Queen Charlotte islands; one o i l of superior quality was refined from the livers 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 in a very primitive fashion. After cleaning the f i s h , they would cut them into pieces, b o i l them in vats, place them in large tubs, and the squaws would press the- o i l out by tramping with their feet. This made a very inferior o i l which was mostly used for dressing skins, and for greasing skidways on logging roads (Mowat 1888). At this time British Columbia was not permitted to share the privileges 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 in the United States (Anderson 1884). Since the ex-port market of o i l was very limited, commercial fishing for the dog-fish almost ceased and, as a result, a reduction occurred in the number of gallons of o i l produced (see Table I I ) . B. Destruction of Fishing Gear and Food Fish by the Dog-fish With the reduction in fishing effort, dog-fish appeared to increase in numbers in coastwise waters, and became a source of great annoyance to fishermen in other branches of the fishing industry. It was claimed that the dog-fish would - 8 -not o n l y out the f i s h l i n e s but would a l s o e a t the f i s h on the hooks, l e a v i n g o n l y the heads (Mowat 1887). I n s p i t e o f these claims by the fishermen, the B r i t i s h Columbia F i s h e r y Commis-s i o n (1893) recommended t h a t the system p r e v a i l i n g along the coast of k i l l i n g vast numbers of d o g - f i s h , f o r the use o f the l i v e r s f o r o i l purposes o n l y , should be d i s c o n t i n u e d u n l e s s the b o d i e s of the d o g - f i s h could be u t i l i z e d i n the same manner. To h e l p a l l e v i a t e some of the complaints from many fishermen who de p l o r e d the d o g - f i s h a s a pest because i t de-s t r o y e d v a l u a b l e food f i s h , the Dominion F i s h e r i e s Commission of B r i t i s h Columbia (1908) recommended t h a t the d o g - f i s h c a r -casses be marketed as a f r e s h f i s h . T h i s product has appeared on the market at v a r i o u s times under such trade names as " w h i t e f i s h " , "ocean w h i t e f i s h " , and " f l a k e " . T a y l o r (1916) r e p o r t e d t h a t the d o g - f i s h had become a more s e r i o u s menace to the f i s h e r i e s than the h a i r s e a l and the s e a - l i o n . One of the reasons t h a t the d o g - f i s h had i n -creased t h e i r numbers was pro b a b l y due t o replacement o f dog-f i s h l i v e r o i l f o r l i g h t i n g purposes by c a l c i u m c a r b i d e . I t was not u n t i l the years 1916-18 that the d o g - f i s h on the P a c i f i c coast were caught i n l a r g e q u a n t i t i e s f o r export t o the f r e s h f i s h market. The name " g r a y - f i s h " was g i v e n t o the d o g - f i s h marketed as f r e s h f i s h and n e a r l y the whole c a t c h was exported t o the U n i t e d S t a t e s . T h i s market disappeared a f t e r the c e s s a t i o n o f h o s t i l i t i e s o f World War I . Although great numbers of whole d o g - f i s h were u t i l i z e d as c a t t l e and chicken f o o d (Cunningham 1920), the d o g - f i s h continued t o work havoc w i t h the fishermen's n e t s . The B r i t i s h - 9 -Columbia F i s h e r i e s Commission of 1922 ( 1 9 2 3 ) s t r o n g l y recom-mended, t h e r e f o r e , t h a t the u t i l i z a t i o n of t h i s pest by reduc-t i o n p l a n t s be encouraged i n some way,, e i t h e r by f i n a n c i a l or other a s s i s t a n c e , and t h a t t h e r e be no r e s t r i c t i o n whatsoever p l a c e d on the c a t c h i n g of d o g - f i s h . The Commission a l s o r e -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 a bounty should be p a i d f o r the c a t c h i n g o f such f i s h i f n e c e s s a r y . Motherwell ( 1 9 2 3 ) c o n s i d e r e d t h a t the Fordney-McCumber t a r i f f hindered the market of d o g - f i s h p r o d u c t s from the Canadian e s t a b l i s h m e n t s , s i n c e the t a r i f f a f f o r d e d p r o t e c t i o n t o American fishermen. The t a r i f f thus l i m i t e d the Canadian fishermen i n attempting to r i d the waters o f t h i s p e s t . C. I n t r o d u c t i o n of O r i e n t a l s to the D o g - f i s h F i s h e r y D u r i n g 1923 the number of l i c e n c e s p r e v i o u s l y i s s u e d t o O r i e n t a l s was reduced c o n s i d e r a b l y i n the salmon and cod f i s h e r i e s . S i n c e no r e s t r i c t i o n was p l a c e d on t h e number of hook and l i n e d o g - f i s h l i c e n c e s g i v e n to O r i e n t a l s , many Japa-nese turned t o t h i s i n d u s t r y . Thus, there was a g r a d u a l i n -crease i n the number of O r i e n t a l fishermen (see Table I ) . A t the same time the low p r i c e o f $ 3 to $4 per ton f o r d o g - f i s h d i s c o u r a g e d many white fishermen from e n t e r i n g t h i s f i s h e r y . D. V a l u a t i o n of the D o g - f i s h and D o g - f i s h l i v e r s . I t was not u n t i l 1938 t h a t the number o f fishermen en-gaged i n the d o g - f i s h f i s h e r y i n c r e a s e d s u b s t a n t i a l l y . I n t h i s year 488 l i c e n c e s were o p e r a t i n g , as oompared t o o n l y 1 6 1 Table I L i s t of Dog-fish l i c e n c e s Issued and Operating i n B r i t i s h Columbia from 1922 to 1 9 4 6 . White Indian Others* Cancelled T o t a l 1922 . 1 1923 25 3 54 82 1924 143 1923 166 1926 177 1927 237 1928 219 11 191 421 1929 149 35 238 3 422 1930 90 2 228 320 1931 32 213 245 1932 9 123 2 134 1933 9 65 74 1934 31 1 120 152 1935 23 1 88 112 1936 ' 43 81 124 1937 56 11 94 161 1938 169 20 299 488 1939 P 12 258 365 1940 164 2 ' 239 1 406 1941 357 121 419 1 898 1942 1 , 0 2 6 1 ,807 208 1 1 ,235 1943 242 2,049 1944 2,745 320 ]_** 3 , 0 6 6 1945 2 , 0 3 1 135 4 * * 2,170 1946 1 , 4 0 5 Mostly Japanese fishermen. B r i t i s h subjects of Chinese o r i g i n . - l o -i n the p r e v i o u s y e a r (see Table I ) . The number of l i c e n c e s i s s u e d continued to i n c r e a s e as the p r i c e of the l i v e r s and the whole f i s h continued to r i s e . L i v e r s rose from 6 cents per l b . i n 1937, to 16 cents i n 1942, t o 23 cents i n 1943, and to 34 cents per l b . i n 1944. The p r i c e o f whole d o g - f i s h i n c r e a s e d from |6 per t o n i n 1937, t o $8 i n 1940 and to $70 per ton i n 1943. The d o g - f i s h l i v e r s are bought "on t e s t " at p r e s e n t , t h a t i s the l i v e r s are t e s t e d f o r the potency of v i t a m i n "A" before the f i s h i n g i n d u s t r y pays f o r the l i v e r s from the f i s h e r -men. E . Present Uses o f D o g - f i s h L i v e r O i l and Body O i l . Although Broeklesby (1927) determined the v i t a m i n "A" content of the l i v e r o i l i n 1927 and the v i t a m i n "D" content i n 1929 (Broeklesby 1929), i t was not u n t i l World War I I t h a t t h i s d i s c o v e r y became very important when new sources o f v i t a -min "A" were needed. The l i v e r s of the d o g - f i s h became i n c r e a s -i n g l y important as a new source o f v i t a m i n "A" i n 1943 when the d o g - f i s h , w i t h a market value of 2 .7 m i l l i o n d o l l a r s , stood i n t h i r d p l a c e among B r i t i s h Columbia f i s h and seventh i n the Canadian l i s t . The d o g - f i s h l i v e r o i l i s used e x t e n s i v e l y as a b l e n d i n g o i l i n the p r e p a r a t i o n of p o u l t r y o i l s . I n 1932, a t the P a c i f i c F i s h e r i e s E x p e r i m e n t a l S t a t i o n , a m e d i c i n a l o i l " T h a l a t t o l " was developed. T h i s o i l c o n t a i n s the n e c e s s a r y v i t a m i n "A" and v i t a m i n "D" from high-grade d o g - f i s h l i v e r o i l and p i l c h a r d o i l . For a number of years t h i s m e d i c i n a l o i l has been s u p p l i e d - 11 -to the Dominion Indian Department for distribution to i t s wards in British Columbia, Saskatchewan, and the Northwest Territories (Swain 1944). Brocklesby (1941) relates that both the l i v e r o i l and body o i l s can be used in the leather trades and also in i n -secticide sprays for codling-moth control and for tree band-ing. He also mentions that the body o i l and the lower grades of liver o i l and mixed o i l s of the dog-fish, have been used in steel tempering and in the manufacture of sheep and cattle 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. THE SUNKEN GILL-NET FISHERY IN BRITISH COLUMBIA A. The Early Sunken Gill-net Fishery. In the early 1920*8 representations were made to the De-partment of Fisheries by the Japanese and other fishermen for the use of old sockeye nets to capture the dog-fish. These discarded linen nets were the f i r s t sunken gill - n e t s to be used in capturing dog-fish. A number of graycod and red snappers were also tangled in the nets. These nets were in continuous operation throughout the year in 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 this year the f i r s t restrictions were imposed and, thereby, fishing for dog-fish was prohibited in an area around Pylades Channel (Fig. 3)« Further legislation prohibi-ted fishermen from catching dog-fish with sunken gill-nets from the 1st of November in eaoh year to the 31st of Maroh in the following year.** Fishermen using sunken gill-nets were not numerous in comparison with those fishing with the conventional long-line gear, which could be operated throughout the year without any restrictions. In early 1942, when the cotton sunken gill-net was introduoed into British Columbia and the power drum on the gill-net boats used for l i f t i n g such nets from the * (Order in Council, Ap r i l 28, 1939), Special Fishery Regula-tions for the'Province of Bri t i s h Columbia, 1939« ** (Order in Council, September 25, 1940), Special Fishery Regulations for the Province of British Columbia, 1941. Fig* 3 Prohibited area for sunken gill-nets in the Strait of Georgia, 1939. - 13 -sea bottom was perfeoted, the sunken gill-net fishery became an important part of B r i t i s h Columbia's fishing industry. B. The Modern Sunken Gill-net 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 in catching"dog-fish and soup-f i n shark. They range from the small salmon gill-net boats to the larger vessels used in the salmon purse-seine, the trawling and the halibut fisheries. Despite the diversity in sizes, the boats may be grouped into two size classes whioh may for purposes of description be called small and large. ( 1 ) Small Boats The small boats are essentially the salmon gill-net boats equipped with a rotating drum for l i f t i n g their nets. The boats range from 28 feet to 34 feet i n length, 7 feet to 9 feet in beam and 3 tons to 6 tons in weight. Gaso-line marine engines of various designs and manufacture, rang-ing from 7 to 115 horse-power, supply the motive power. There i s sleeping accommodation for 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 typical small sunken gill-net boat i s shown i n Fig. 4 . ( 2 ) Large Boats The larger vessels range in length from 45 to 55 feet, with beams from 10 to 16 feet, and tonnages F i g . 4 A t y p i c a l small sunken g i l l - n e t boat. F i g . 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 diesel engines with horse-power ratings of 60 to 165. Sleeping accommodation for a crew of four to six men i s provided for by tiered bunks below the deck in the bow. Usually the captain sleeps in the pilot 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 (Fig. 8 ) . b. Drum and Rollers. The drums are constructed of wood of a size suitable to the individual boat. They range from 3 to 4 feet i n diameter and about 4 feet along the axis. Some of the larger drums are constructed of steel but these drums are not in com-mon use among the fishing f l e e t . The wooden drum in use today i s shown in Fig. 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 for the gill-net 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 rotating drum and remove the dog-fish from the net as the latter 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 (Fig. 6) whioh prevents the net from becoming entangled'in the propeller. . It also acts^as a guide in keeping the net in the correct plane when the net i s wound on the drum. F i g . 6 The "V" r o l l e r on the s t e r n of a s m a l l sunken g i l l - n e t boat. F i g . 7 A d o g - f i s h coming over the bow r o l l e r o f a l a r g e r sunken g i l l - n e t boat i n Hecate s t r a i t . - 15 -Some of the larger boats are equipped with bow ro l l e r s (Fig. 7), whioh enable the vessels to l i f t the nets in rougher seas. These are not power driven as were the bow ro l l e r s of the Columbia river gill-net and "diver-net" boats (Anon 1951)• c. Nets The sunken gill-net 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 invariably 7 inches at the present time, but both 6 1/2 and 7 inoh mesh nets were used by some fisher-men in 1943 and 1944. Each net i s about 50 fathoms long although some of the f i r s t nets constructed in Bri t i s h Columbia were as long as 75 fathoms. The depth of the net i s 25 meshes or about 14 feet. Webbing i s marketed to the wholesale dealer in bales con-taining 910 fathoms of white cotton web, weighing about 273 pounds. The wholesale merchant treats the white web with a solution of "tanbark" referred to as "cutch" whioh protects the web from bacterial 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 for long periods of time without risk of bacterial decay or overheating. Many fishermen treat the web with "cutch" or "tanbark" extracts from one of several oriental woods. Similar extracts are made from oak bark, hemlock bark, japonica, or quebracho (Firth and Carlson 1944). Specifications of the dog-fish web are as follows: - 16 -Twine Size Mesh Size Depth in Meshes Length of Bale  inches 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 lb. per bale in 194-5, 62 1/2 cents in 194-6, and fl.10 per lb. per bale in 194-7. Some fishermen carry a few fathoms of the larger mesh size webbing for catching soup-fin sharks. Specifications of the soup-fin shark web are as follows: Twine Size Mesh Size Depth:in Meshes . Length of Bale  inches fathoms 21 thread 10 24 500 24 thread 10 22 500 Nets are hung on the "cork line" of 1/2 or 5/8 inch manllla or s i s a l rope. Proper fullness of the web i s important in the nets. Too much or too l i t t l e web may affect the wearing qua-l i t y , as well as the efficiency 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 fa. stretched measurement w i l l be only 50 fa. long when hung on the "cork line" (Fig. 10). The nets are hung with cotton hanging twine, usually 56 thread, but running to 54 thread or heavier, depending on the preference of individual fishermen. d. Glass B a l l Floats. The glass b a l l floats most oommonly used on sunken gill-nets are 4 1/2 inches in diameter although 5 and 6 inch glass balls 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 floating 23 oz. and the 6-inch diameter doubling this buoyancy to 46 oz. (Anon. 1943). Spacing of the glass balls along the "cork-line" varies somewhat with preference of the fisherman. Usually they are placed about 1 1/2 fathoms apart for the 4 1/2 inch size (Fig. 10). The glass balls are "trapped" in "covers" (Fig. 11) made of tarred seine web of 1-ineh mesh. Sometimes this i s done by lacing pieces of tarred web of the proper dimensions into a par-t i a l sack and, when the glass b a l l i s inserted, the pouch i s then completed with close lacing. Another method, which i s widely used, i s the knitting of web about the glass b a l l i n diamond-shaped meshes or in square meshes of beeket twine. Before the glass b a l l float was f u l l y developed on thi s continent, a suitable float for submerged fishing presented a problem. The float must be able to withstand high water pres-sure without breaking or becoming water-logged and must be easily handled. Cedar floats treated with hot paraffin, coal tar, pine tar, or linseed o i l were used in some experiments with "diver set-nets" (Anon. 1942)in catching soup-fin sharks off the Columbia river and in the submerged gill-net fishery in Alaska for king crabs (Carlson 1942). A satisfactory float was found to be the empty "stubby" beer bottle, with a buoyancy of approximately 7 ounces when sealed with standard lacquered metal caps with cork disk inner lining. It was during the summer of 1940 that J". T. Barnaby, U. S. Fish and Wildlife Service, constructed a submerged tangle net in which the Fig. 8 The captain on the bridge i s scouting for his marker pole, indicating position of the sunken gi l l - n e t in Hecate s t r a i t . Fig. 9 A marker pole and buoy "Scotchman" i n Hecate s t r a i t . - 18 -"stubby" beer bottles were f i r s t used as floats (Carlson 1942). e. Lead Line. The lead weights on the "lead line" keep the net in place on the sea bottom while the glass floats keep i t upright in the water. The lead line i s 1/2-inch or 5/8-inch rope with 4 oz. lead weights strung along the rope and the weight-ing Is such that the buoyancy of the glass b a l l floats 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 line (Figs. 10 and 11). f. Buoy Lines. Buoys, and Anchors. An anchor bridle from 4 to 6 fathoms long i s formed at the end of the "string" of nets from the "cork line" and the "lead line". These, when joined, form an "eye" or a small loop. 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. The dory anchor weighing from 45 to 75 pounds holds the net on the sea 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 (Fig. 10). 2. Fishing Methods. From three to five nets are joined into one "string" or a "gang" (Whitehead 1930) of nets, and fished as one unit of 150 to 250 fathoms in length. In s e t t i n g ^ net (Fig. 10), a marker pole (Fig. 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 direction of the tide, while the net i s payed out from the rotating drum. Another marker pole and / R E D BUOY K E G RED C A N V A S F L A G -14'-16' B A M B O O P O L E DIAGRAM OF A SUNKEN GILL-NET SET TO CATCH DOG-FISH 12 S E I N E C O R K S S A S H WEIGHTS F i g . 10 - 19 -buoy Is attached to the other end of the net. A "string" of nets i s usually l e f t in the water from 12 to 24 hours. Upon returning to the fishing grounds the fisherman l i f t s the marker and buoy into the boat and fastens the buoy line to a loop of rope on the axle of the drum. The buoy line and the net are now l i f t e d from the sea bottom by the rotating drum. The speed of the rotating drum i s governed by the clutch mounted nearby. It may take from 1 to 2 hours to l i f t a "string" of nets, depending on the weather and the number of dog-fish caught in the net. A ^string" of nets i s reset on the same grounds i f a good catch has been made, otherwise grounds are sought where better fishing has been reported-.- The dog-fish and other spe-cies of fish (see Fig. 11 and Fig. 13) are picked out of the net as they come over the stern r o l l e r in the small boats or the bow r o l l e r in the large boats. Fig. 7, shows a dog-fish coming over the bow r o l l e r of one of the larger boats and in Figs. 11 and 13, the fisherman i s removing the dog-fish from the net on the same boat. After fishing operations the boats enter sheltered bays where the livers are removed from the dog-fish into 40 pound capacity tins. The carcasses are thrown over-board. They are not discarded on the fishing grounds as the Canadian fisherman believe the latter w i l l become fouled, thus preventing further catches. The-American otter trawl fleet, however, operating in Hecate st r a i t , discard a l l the carcasses on the fishing grounds. International fishing regulations prohibit these vessels from trawling'within three miles of the shoreline but they are per-mitted to seek the shelter of a Canadian port during a storm. M g . 11 _ Fig. 12 " P i c k i n g " a $ d o g - f i s h from the g i l l - n e t . Note the female d o g - f i s h on deck and the rock s o l e caught i n the mesh. Winding the sunken g i l l - n e t on the drum o f a l a r g e 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 island, off Barkley sound, the boats return to the fishing camp every evening to market the dog-fish livers and other fresh f i s h caught• The fishing camps in Skidegate inlet at Queen Charlotte City are shown in Fig. 14. The camp i s a large scow with a store and an ice-house for freezing the livers and fresh f i s h . 3. Care of the Nets. Eaoh week the nets are mended and cleaned i n a solu-tion of copper sulphate to prolong their usefulness. Generally, 25 to 40 pounds of copper sulphate (bluestone) are dissolved in about 29 gallons of water (Firth and Carlson 1944). Exact proportions are seldom used, the strength being determined by the colour of the solution. The bluestone i s placed i n a bur-¥ lap sack and worked through the water in a large- wooden tank, then the nets are immersed in the solution. After bluestoning, the nets must be washed in 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 Fig. 14, contains bluestone tanks and drying racks for the nets. C. Other Species of Fish Caught by Sunken Gill-nets. 1. In Hecate Strait . Although the 7-inoh mesh net was designed to cap-ture dog-fish, other species of fis h are taken on the gear. A number of soles are taken but these along with gray cod, F i g . 13 " P i c k i n g " d o g - f i s h from the sunken g i l l - n e t of a large boat i n Hecate s t r a i t . F i g . 14 Two f i s h i n g camps i n Skidegate i n l e t , queen Ch a r l o t t e i s l a n d s . Note bluestone tanks on a scow i n the center background. - 21 -skate, halibut and others are usually returned to the sea because there i s not a ready market for them in this area. Oc-casionally a few lingcod and blackcod are caught an are marketed along with their 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 "strings" or a total of 25 sunken gill- n e t s . The nets were set in 14 fathoms, off Skidegate bar in Hecate st r a i t . butter sole (Isopsetta isolepis) 166 sand sole (Psettichthys melanostictus) .... 125 rock sole (Lepidopsetta bilineata) 38 gray cod (Gadus macrocephalus) 13 halibut (Hippoglossua 3tenolepis) 1 dog-fish female 457 male 57 Other sets were observed on different boats fishing in this area and similar catches were recorded. 2. East Ooast of Vancouver Island. I The sunken gill-net proved to be very effective in capturing large numbers of lingcod (Ophidon elongatus) in the strait of Georgia, when set on the lingcod reefs. On June 9, 1942*, fishermen using gill-nets, set-nets, and sunken g i l l -nets were prohibited from marketing lingcod caught by such gear. * * (Order in Council, June 9, 1942, P.O. 4877), Special Fishery Regulations for the Province of Br i t i s h Columbia, 1942. - 22 -Gn May 26, 1944, a special set was made on a lingcod reef, 300 fa. east of Pinnacle point near Departure bay. The "string" of nets, 300 fa. long with a mesh size of 6 l / 2 inches, had been set in 50 fa. 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. It was estimated that nearly 2,000 pounds of lingcod (averaging 15 lbs. each) were taken from this sunken gi l l - n e t . It i s evident that i f this fishery were intensified, these sunken gill-nets could deplete in a short time many of the lingcod banks in the gulf of Georgia. By the Order in Council of July 7, 1944**, sunken g i l l -nets were prohibited from operating in a l l the coastal waters of British Columbia after December 16, 1944. This order was later amended on Ap r i l 16, 1945*** to apply only to the gulf of Georgia and certain other fishing l o c a l i t i e s . • 3» West Coast of Vancouver Island. On the mud bottom of the waters off Barkley sound lingcod and sable-fish or black cod (Anoplopoma fimbria) are ** (Order in Council July 7, 1944, P.O. 5207), Special Fishery Regulations^jfor the Province of British Columbia, 1944. *** (Order in Council A p r i l 16, 1945, P.O. 2649; O.C. February 28, 1946, P.O. 736; O.C. A p r i l 18, 1946, P.C. 1525), Spe-c i a l Fishery Regulations for the Province of B r i t i s h Columbia, 1946. - 23 -caught in the sunken gill-nets along with dog-fish in s u f f i -cient quantity to be readily marketed. Nets set in certain areas may have lingcod and black cod tangled in the web one day and when set in the same area on other occasions neither species may be caught. The following species and their numbers were recorded from 10 different sets made by boats fishing off Barkley sound in June, 1944: Hag-fish (Folistotrema stoutii) 2 . Dog-fish (Squalus suckleyi) .. 1,028* Big skate (Raja binoculata) 1 Rat-fish (Hydrolagus c o l l i e i ) 175** Spring salmon (Oncorhynchus tahawytscha) .. 6 Gray cod (Gadus macrocephalua) 77777777 1 Bocaccio (Sebastodes paueispinis) 5 Yellow-tailed rock-fish (Sebastodes flavidus) .... 3 Sebastodes spp 3 Lingcod (Ophiodon elongatus) 62 Sable-fish (Black cod) (Anoplopoma fimbria) 4 Long-jaw flounder (Atheresthea stomias) T 245** Halibut (Hippoglossua stenolepls) .. .7 2 B r i l l (Eopsetta jordani) ......7* 52 Crabs (Cancer magiste'rT 1 * This i s an estimated number, based upon counted random samples of dog-fish livers of known weights and the total weight of a l l the dog-fish li v e r s . ** This number i s in part estimated. The following species of fis h were recorded from different landings in Barkley sound; soup-fin shark (Galeorhinus galeus), green sturgeon (Aoipenser medirostrls), pilchard (Sardinops  oaerulea), herring (Clupea p a l l a s i l ) , eoho salmon (Oncorhynchus  kisutch), hake (Merluccius productus), red-striped rock-fish (Sebastodes proriger), flat-head sole (Hippoglossoides elas-sodon), rock sole (Lepidopsetta bilineata), lemon sole (Paro-phrys vetulus), wolf-eel (Anarrhichthya ocellatus) -, wry-mouth - 24 -(Delolepis giganteus). It was observed off Barkley sound that the hag-fish (Polistotrema stoutii) w i l l eat the livers from the dog-fish when the nets are l e f t in the water for more than 12 hours. Thef writer has removed as many as four hag-fish from the body cavity of a single dog-fish. D. Selectivity of the Sunken Gill-net. i The sunken gill - n e t has not only proven an effective 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. Male dog-fish less than 76 om. 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 this size. Length-Frequency Distribution of Dog-fish Caught by  Sunken Gill-nets and by Otter Trawls Figures 15 and 16 illustrate the length-frequenoy d i s t r i -butions of dog-fish caught in sunken gill-nets off Barkley sound during the months of June and August respectively, in 1944. During these two months a greater percentage of males than females was taken. Fig. 17 illustrates the length-fre-quency distribution pf dog-fish caught by sunken gill-nets in Hecate strait during June 1946. A greater percentage of fe-male dog-fish were caught by the sunken gill-nets during this period in Hecate s t r a i t . Figures 18 and 19 illustrate the w LENGTH FREQUENCY DISTRIBUTION OF DOG-FISH CAUGHT BY SUNKEN G I L L - N E T S OFF BARKLEY SOUND IN JUNE 1 9 4 4 MEASUREMENTS MADE FROM 7 DIFFERENT "SETS" FEMALES eo 85 L E N G T H CM. 100 105 110 118 Fig. 15 LENGTH FRENQUENCY DISTRIBUTION OF DOG-FISH CAUGHT BY SUNKEN G I L L 7 N E T S OFF BARKLEY SOUND IN AUGUST 1 9 4 4 M E A S U R E M E N T S M A D E F R O M 10 D I F F E R E N T " S E T S " i i ' T i 100 105 110 116 120 i i i i i i i i i i i i i — i — r 3 0 S S S O as 7 0 7 S 8 0 8 8 9 0 9 S 1 0 0 108 110 118 ' 1 2 0 L E N G T H CM. Fig.- 16 LENGTH FREQUENCY DISTRIBUTION OF DOG-FISH CAUGHT BY SUNKEN G I L L - N E T S IN H E C A T E S T R A I T IN JUNE 1 9 4 6 MEASUREMENTS MADE FROM 7 DIFFERENT "SET" 6 9 7 0 7 6 SO S S 9 b 9 5 1 0 0 105 110 115 1 2 0 L E N G T H CM. J Fig. 17 - 25 -length-frequency d i s t r i b u t i o n s of dog-fish caught by sunken g i l l - n e t s and otter trawls respectively o f f the west coast of Vancouver i s l a n d . The dog-fish caught by the sunken g i l l - n e t s ( F i g . 18) were caught o f f Barkley sound while those caught by the otter trawls ( F i g . 19) were taken only 10 miles northward, o f f F lorencia i s l a n d and Amphitrite point. Figures 15, 16, 17, and 18 show that the sunken g i l l - n e t s tend to select the larger dog-fish over 76 cm. which have l i v e r of s i g n i f i c a n t commercial value while, F i g . 19 i l l u s t r a t e s the large number of otter trawl caught dog-fish that are less than 76 cm. which are of no appreciable value. I t i s evident that the otter trawl does not se l e c t the dog-fish when f i s h i n g on the sea bottom and thus also catches large i n d i v i d u a l s when they are present on the trawling grounds. LENGTH FREQUENCY DISTRIBUTION OF DOG-FISH CAUGHT BY SUNKEN GILL-NETS OFF BARKLEY SOUND IN JUNE 1945 M E A S U R E M E N T S MADE F R O M 8 Dl F F E R E N T S " S E T S " Fig." 18 LENGTH FREQUENCY DISTRIBUTION OF DOG-FISH CAUGHT BY OTTER- TRAWLS OFF AMPHITRITE POINT C BARKLEY SOUND) IN JUNE AND JULY 1945 MEASUREMENTS MADE FROM 8 DIFFERENT "DRAGS' I 5 o z UJ a I 5 I 0 i i r 55 60 65 7 0 75 60 65 90 95 100 105 110 Fig. 19 - 26 -IV. TOTAL CATCH STATISTICS OF THE DOG-FISH AND SOUP-FIN SHARK IN BRITISH COLUMBIA Total .catch stat i s t i c s are of value wherever a mass of data exists- and wherever those facts can he expressed quanti-tatively in a form suitable for analysis. Catch s t a t i s t i c s of a commercial fishery help to constitute a s c i e n t i f i c back-ground for fishery 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 units, varies from year to year and the quantitative units form a means of expressing the economic condition of the fishery. Total catch s t a t i s t i c s may indicate the changes, i f any, in the abundance of f i s h on the grounds, but usually are too involved to reveal the existing state of abundance of a commercially exploited fishery popu-lation. The annual production and value of dog-fish liver o i l and body o i l from I876 to 1945 are given in Table II. From 1879 to 1887 a record was kept of the production of refined dog-fish liver o i l . Separate catch stat i s t i c s for the production of li 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 liver o i l in British Columbia was f i r s t centered on the Queen Charlotte islands at Skidegate, where production of liver 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 in the total amount of dog-fish l i v e r and body o i l produced. The amount of dog-fish liver and body o i l produced i n Table I I Production of Dog-fish Liver o i l and Body o i l from 1876 to 1945. Dog-fish Liver and Body O i l Refined Dog-fish l i v e r O i l Gallons Value Gallons Value 1876 50 ,124 25 ,024.00 1877 115 ,495 46 ,198.00 1878 150 ,516 60 ,206.40 1879 104 ,475 41 ,790.00 1880 119 ,362 47 ,744.80 1881 142 ,240' 56 ,896.00 1882 196 ,407 78 ,562.80 1883 217 ,419 86 ,967.60 1884 10 ,000 3 ,500.00 1885 22 ,200 5 ,550.00 1886 25 ,000 10 ,000.00 1887 40 000 16 000.00 1888 64 345 32 ,172.50 .1889 141 ,420 70 ,710.00 1890 162 ,264 81 ,132.00 1891 249 ,500 124 ,750.00 1892 259 554 129. .046.20 1893 172 250 68 900.00 1894 143 000 57 ,200.00 1895 135 ,000 54 ,000.00 1896 61 500 24, 600.00 1897 . 95 500 28 650.00 1898 124 525 37 357.00 1899 145 ,200 43 560.00 1900 128 100 35 227.50 1901 152 ,100 45 ,630.00 1902 161 ,950 56 ,682.50 1903 223 ,550 78 ,242.50 1904 192 ,750 67 462.50 1905 175, 990 61 596.50 1906 125 265 43, 842.00 1907 116, 640 40 474.00 1908 142 480 56, 646.00 1909 209, 950 64 122.50 1910 77 240 26 767.00 1911 •75 550 24 262.00 1912 85, 826 29 075.00 1913 144 ,050 46 690.00 1914 41 249 12 481.00 1915 33 ,565 12 363.00 1916 7 505 1917 44 820 23, 892.00 1918 ,53 383. 53 383.00 1919 54 954 35 097.00 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 Table II Dog-fish Liver and Body Oil Gallons Value | 1920 55,669 31,155.00 1921 44,700 7,110.00 1922 75,461 22,655.00 1923 180,318 64,696.00 1924 241,376 88,855.00 1925 354,853 1926 217,150 1927 375,130 138,180.00 1928 411,208 119,120.00 1929 459,575 122,513.00 1930 114,558 22,229.00 1931 170,271 19,362.00 1932 35,147 4,629.00 1933 117,600 13,170.00 1934 203,930 25,205.00 1935 122,380 23,744.00 1936 164,643 34,745.00 1937 124,464 28,074.00 1938 113,360 18,802.00 1939 130,044 38,177.00 Dog-fish Body Oil Gallons Value . # 1940 95,484 20,997.00 1941 71,582 29,569.00 Dog-fish Body Oil lb. Value # 1942 433,667 31,135 1943 334,696 16,756 1944 163,103 8,263 Refined Dog-fish Liver Oil. Gallons V a l u e $ Dog-fish Liver Oil Gallons Value $ 84,405.00 64,269 212,175 531,355.00 Dog-fish Liver Oil lb. Value i 2,802,277 1945 1,178,242.00 3,509,213 2,028,875.00 4,909,808 3,661,131.00 2,337,267.00 3,880,433 Dog-fish Body Oil Dog-fish Body Oil Gallons* Gallons* 1942 390,300 • 2,538,863 1943 301,226 3,179,347 1944 146 793 4,4481286 1945 3;515,663 * Sp. gr. of Dog-fish Liver Oil at 25°C. - 0.906 - 27 -British Columbia was relatively constant from 1877 to 1940, with the exception of minor fluctuations. A drop in production of o i l ensued following the outbreak of World War I. With the f'boom" years which followed (1927 to 1929) an increase in ef-fort, indicated by the increase in the number of licences, re-sulted in a decided inorease in total production (Table I I ) . During the decade that followed the output returned to i t s former level of production. Un t i l 1941 the demand for dog-fish l i v e r and body o i l never attained a magnitude of importance. During this year the need for vitamin "A", which i s stored in the l i v e r of the dog-fish, became very apparent and the dog-fish assumed a de-gree of importance with a resulting sudden influx of fishermen to this fishery (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 liver o i l and body o i l pro-duced was recorded in pounds. These figures 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-fi s h the remainder after processing i s marketed as meal and f e r t i l i z e r (Table III). The production of body o i l ceased after 1944. Since the dog-fish were caught only for their livers after this year the carcasses were discarded. Some fresh dog-fish have been marketed in certain 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 in Br i t i s h Columbia from 1916 to 1944 i s presented in Table IV. Table I I I 'Production of Dog-fish Hfeal and F e r t i l i z e r from 1892 to 1944. Dog-fish Meal and Fe r t i l i z e r Tons Value | 1892 15 375.00 1893 15 375.00 1894 30 600.00 1895 15 375.00 1896 50 1,000.00 1897 1898 200 6,000.00 1899 550 16,500.00 1900 200 6,000.00 1901 300 9,000.00 1902 150 4,500.00 1903 1,060 31,800.00 1904 ' 607 18,210.00 1905 872 26,160.00 1906 140 3,570.00 1907 1,294 32,362.50 1908 84 2,352.00 1909 . 487 13,636.00 1910 266 ,700.00 1911 1912 150 5,097.00 1913 1,649 59,254.00 1914 1,244 .47,432.00 1915 953 36,477.00 1916 1917 1,220 70,164.00 1918 1,802 18,198.00 Dog-fish Meal and f e r t i l i z e r Tons Value 4 1919 1,800 --"• 19^756.00 1920 466 39,147.00 1921 489 27,010.00 1922 911 48,926.00 1923 , .-r 823 . 43,447.00 1924 1,709 94,303.00 1925 2,468 1926 1,752 1927 2,512 145,449.00 1928 3,658 1929 3,626 173,254.00 1930 899 45,165.00 1931 1,010 34,869.00 1932 264 7,018.00 1933 786 23,580.00 1934 1,135 39,510.00 1935 768 22,924.00 1936 1,065 34,906.00 1937 833 26,740.00 1938 1,262 42,807.00 1939 925 36,322.00 1940 1,285 63,210.00 1941 1,051 69,062.00 1942 914 60,872.00 1943 708 41,857.00 1944 330 21,136.00 Table I V Quantity of Dog-fish (whole fishj uaught and Landed in Brit i s h Columbia from 1916 to 1944 Weight Landed cwt. Value # Marketed Fresh cwt. Value $ 1916 5,460 1,911 5,460 1,911* 1917 11,200 4,480 11,200 4,480* 1918 59,194 29,607 59,194 29,607* 1919 50,920 17,822 1920 15,000 4,550 1921 52,560 12,998 1922 40,240 10,085 1923 48,640 12,812 1924 74,000 23,150 1925 74,040 22,212 1926 78,380 23,514 1927 112,700 39,445 1928 230,557 . 80,694 1929 259,540 90,839 1930 98,680 30,372 1931 112,348 22,929 1932 28,020 4,203 1933 79,609 13,789 1934 117,020 21,921 1935 76,800 15,360 1936 116,140 26,309 340 68 1937 113,220 32,428 3,920 1,274 1938 159,690 27,087 45,951 2,310 1939 114,816 23,888 1940 141,350 57,236 1941 142,999 100,965 5,843 13,117 1942 100,540 12,055 1943 78,924 9,865 1944 24,339 25,606 * Exported to the United States - 28 -Fig. 20 illustrates the total landings of dog-fish livers for British Columbia from 1937 to 1946. The value of the livers and the average price per pound paid to the fishermen i s given in Table V. The catch of the dog-fish dropped greatly in the years following 1944 as indicated by the quantity of livers landed, (Fig. 20). This drop in total catch indicated that the high fishing intensity was possibly exploiting the dog-fish beyond the limits of a stable and productive level. Although the soup-fin shark i s not nearly as abundant as the dog-fish in British Columbia waters, i t s livers provide a substantial part of the vitamin MA" supply. The vitamin "A" content of the- soup-fin shark livers i s even greater than that in the livers of the dog-fish. Fig. 21 illustrates the total landings of soup-fin shark livers in Br i t i s h Columbia from 1940 to 1946. There was a marked drop in the landings of livers during the years 1945 and 1946. The value of the soup-fin shark livers and the mar-keted value of the liver o i l i s given in Table VI. F i g . 20 Table V Quantity and value of Dog-fish Livers Landed in B r i t i s h Columbia from 1937 to 1946. Weight Landed lb. value $ Average Price £ to Fishermen per lb. 1937 178,900* 1 0 , 7 0 2 ; 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 livers exported. ** A l l livers exported with the exception of a small pro-portion used by local chemical and fishery companies in experimental vrork. *** Figure estimated from vitamin o i l Production plus quantity exported. • ° Marketed values of livers only. F i g . 21 Table VI Quantity of Soup^-fin Shark Livers Landed in British Columbia with Marketed values of the Livers and Liver O i l . height Landed lb. Value § Liver Oil Marketed Landed Marketed lb. value 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 - 29 -V. DESCRIPTION AND ANALYSIS OF THE AVAILABILITY OF THE DOG-FISH AND SOUP-FIN SHARK A. S e l e c t i o n and Source of Data. Before an a n a l y s i s of the a v a i l a b i l i t y o f the d o g - f i s h and s o u p - f i n shark may be accomplished, adequate c a t c h s t a t i s t i c s must be a v a i l a b l e . F o r a n a l y s e s i t i s n e c e s s a r y to know the i n d i v i d u a l l a n d i n g s o f l i v e r s from a l l , or n e a r l y a l l the f i s h e r -men, and the l o c a l i t y o f each c a t c h . I n B r i t i s h Columbia, n e i t h e r the Dominion nor the P r o v i n c i a l F i s h e r i e s Department c o l l e c t c a t c h s t a t i s t i c s t h a t are adequate f o r an a n a l y s i s o f the a v a i l a b i l i t y and abundance o f commercially important f i s h e s caught i n these waters. I n the S t a t e o f C a l i f o r n i a , the D i v i s i o n of F i s h and Game have f o r many years had a c l e a r e r p i c t u r e of the f i s h e r y p r o -blems because o f the nature of the r e c o r d e d d a t a . I n 1931 (Conner 1937) the c o l l e c t i o n of complete and i n f o r m a t i v e b i o -l o g i c a l s t a t i s t i c s was i n a u g u r a t e d . The C a l i f o r n i a D i v i s i o n o f F i s h and Game have what i s known as the "pink t i c k e t " system o f c o l l e c t i n g s t a t i s t i c s . F i s h r e c e i p t s , or t a l l y s l i p s are made In t r i p l i c a t e , on forms s u p p l i e d by the D i v i s i o n of F i s h and Game. One copy c o v e r i n g each sale goes to the fisherman, one to the f i s h buyer, and the t h i r d or "pink t i c k e t " t o the D i v i s i o n . The D i v i s i o n then t r a n s f e r s the data from t h e r e -c e i p t or "pink t i c k e t " t o s p e c i a l cards which are s o r t e d and recorded i n almost any d e s i r a b l e form, by e l e c t r i c a l l y operated H o l l e r i t h t a b u l a t i n g machines (Conner 1935)* - 3 0 -F o r the a n a l y s i s i n t h i s study i t t h e r e f o r e became neces-s a r y to c o l l e c t such d a t a from the f i s h i n g i n d u s t r y and t o t a -b u l a t e , i t . The data were c o l l e c t e d from the i n d i v i d u a l t a l l y s l i p s , or f i s h r e c e i p t s , of the d o g - f i s h and s o u p - f i n shark l i v e r l a n d i n g s from a l l - p a r t s of the B r i t i s h Columbia c o a s t , where-ever r e c o r d s were t o be found. I t i s not e s s e n t i a l t o have a complete r e c o r d of e v e r y l a n d i n g made from e a c h area under study. In u n d e r t a k i n g an a n a l y s i s of a v a i l a b i l i t y , complete-ness i n da t a adds t o the accuracy o f the i n v e s t i g a t i o n . Each t a l l y s l i p or f i s h r e c e i p t i n d i c a t e s the date, p l a c e o f s a l e , the d e a l e r ' s name, the fisherman's name, the name o f the boat, weight and value o f the d o g - f i s h and s o u p - f i n shark l i v e r s landed, as w e l l as the weights of the v a r i e t i e s o f f r e s h f i s h • i landed. The da t a on these r e c e i p t s were then compiled on spec-i a l forms, l i s t i n g the fisherman's name and boat, and the l o -c a l i t y where the f i s h were caught. B. E s t i m a t i n g Changes i n the A v a i l a b i l i t y and Abundance o f  F i s h P o p u l a t i o n s . E x p l o i t a t i o n o f any v i r g i n f i s h e r y tends t o change the abundance of the f i s h p o p u l a t i o n on which i t depends. E f f e c -t i v e f i s h e r i e s a d m i n i s t r a t i o n depends upon knowledge o f the ex-t e n t o f the e x p l o i t a t i o n and i t s course. I n g e n e r a l , d i r e c t measures of f i s h p o p u l a t i o n s 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 can be obtained from a n a l y s e s o f f i s h e r i e s s t a t i s t i c s " . As a r u l e , such s t a t i s t i c s are most u s e f u l when they i n c l u d e d e t a i l e d accounts of the amount of f i s h i n g e f f o r t and l o c a l i t i e s - 31 -fished. In most fisheries, total catch i s too involved with the amount of fishing effort to r e f l e c t well the changes in the abundance of fish on the grounds. Knowledge of fishing costs i s useful in interpreting fishery production figures. In order to obtain fishery statistics in the most useful form, pilot house record books have been used in the herring (Tester 1945), the pilchard, and the halibut fisheries on the pacific coast.. Some fishermen on sunken gill-net boats keep pilot house record books of their own. As a rule, calculations of return per unit of fishing effort 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 effort that Is used, vary from year to year, catch per unit of effort may not be used directly to indicate the relative abundance or availability, without considering the actual amount of effort used in suc-cessive years. Conclusions can be distorted by cumulative and unassessable changes i n the quality of the effort. The theore-t i c a l relationship of catch per unit effort to abundance and rate of exploitation has been discussed by Ricker (1940). The return per-unit-of-effort-•- has been used in the h a l i -but investigations (Thompson, Dunlop, and B e l l 1 9 3 1 , Thompson and Bell 1934), and in the study of the depletion of the black cod by Bell and Gharrett (194$). The index used in these stud-ies was the "catch per-skate".- The "catch per-seine-day" has been used by Tester (1945) in the herring fishery; the catch "per-boat-week", the "catch per-boat-per-night", by Silliman and Clark ( 1 9 4 5 ) , and "catch per-lunar month" (Clark 1939) in the pilchard fishery investigation. Rousefell and Kelez - 32 -(1938) use the " c a t c h per-seven-day p e r i o d per boat o f 3 0 - 3 9 net tons as i n index of the a v a i l a b i l i t y f o r the salmon f i s h e r y . C. Meaning of A v a i l a b i l i t y and Abundance. In t h i s study o f the d o g - f i s h and s o u p - f i n shark, " a v a i l -a b i l i t y " w i l l r e f e r , t o the r e l a t i v e amount of the d o g - f i s h and s o u p - f i n shark i n the waters of B r i t i s h Columbia s u b j e c t e d to the sunken g i l l - n e t f i s h e r y . A v a i l a b i l i t y i n t h i s sense does not mean abundance. The d o g - f i s h and s o u p - f i n sharks may be abundant, t h a t i s , the a c t u a l numbers of these sharks may be i n g r e a t q u a n t i t i e s i n the waters but they may not be a v a i l -able t o t h e sunken g i l l - n e t s . A v a i l a b i l i t y , t h e r e f o r e , i s a r e l a t i v e term a p p l y i n g o n l y t o t h a t p a r t o f the t o t a l popula-t i o n w i t h i n the h o r i z o n t a l and v e r t i c a l range of the sunken g i l l - n e t s and moving around a c t i v e l y enough to become emmeshed i n them. T n the a n a l y s i s of c a t c h s t a t i s t i c s from Hecate s t r a i t , the u n i t o f e f f o r t i s the average boat c a t c h per month o f dog-f i s h and s o u p - f i n shark l i v e r s , independent of the number of nets f i s h e d . Should there be a d e c l i n e i n the average c a t c h per boat from year t o . y e a r , even though there i s an i n c r e a s e i n the number of nets f i s h e d per boat, i t w i l l c e r t a i n l y i n -d i c a t e a d e c l i n e i n the a v a i l a b i l i t y of the d o g - f i s h and soup-f i n shark. On the west coast o f Vancouver i s l a n d , o f f B a r k l e y sound more d e t a i l e d i n f o r m a t i o n of the e f f o r t expended by the f i s h e r -men i n c a t c h i n g the d o g - f i s h was a v a i l a b l e f o r the p e r i o d of - 33 -time under investigation. In this area catch per sunken g i l l -net (75 fathoms,) per day (24 hours) w i l l be used i n determining the availability of the dog-fish. D. Analysis of the Catch Records of Dog-fish Livers Landed  by Sunken Gill-net Boats Fishing in Hecate Strait. 1. The Total Landings of Livers by Sunken Gill-net Boats. In Hecate strait (Fig. 22), the sunken gill-net f i s h -ery commences in May and usually terminates at the end of October. Fig. 23 i l l u s t r a t e s the decided increase In total catch from 1943 to 1944. In 1946 the total catch was only half the amount landed in 1944. About 24 per cent of a l l the dog-fish livers ' landed in British Columbia in 1944 was caught by sunken g i l l -net boats fishing in Hecate s t r a i t from May u n t i l October. Dur-ing the same months in 1945 and 1 9 4 6 , sunken gill-net boats i n Hecate st r a i t caught 30 per cent and 32 per cent respectively of the total catch landed in Bri t i s h Columbia. During.1945 there was nearly double the number of sunken gill-net boats f i s h -ing in Hecate strait (Table 7) as there was in 1944, but the total weight of livers landed by the boats was slightly lower in 1945 than in 1944. Poor weather conditions during the summer months of 1945 hindered the fishing effort of some of the small-er boats, thus contributing to the smaller catch. Fig. 24 illustrates the total catch.of dog-fish livers for each month from 1943 to 1 9 4 6 . The largest catches were made during.the months of June and July in 1944 and 1 9 4 5 . In 1946 the months of greatest total eatches were in June and GRAHAM ISLAND MORESBY ISLAND PACIFIC OCEAN QUEEN CHARLOTTE SOUND F i g . -22 The shaded area i n d i c a t e s the g e n e r a l f i s h i n g grounds f o r the sunken g i l l - n e t s i n Hecate s t r a i t . F i g . 23 TOTAL. WEIGHT OF DOG-FISH LIVERS LANDED EACH MONTH BY SUNKEN GILL-NET BOATS FISHING IN HECATE STRAIT FROM 1943 TO 1 9 4 6 MAY J U N E J U L Y AUGUST SEPTEMBER OCTOBER Fig. 24 - 34 -- August. 2. The Average Catch per Boat per Month. When the average c a t c h per month i s used as an index of a v a i l a b i l i t y , changes i n the number of f i s h i n g days per t r i p are d i s c o n t i n u e d . For example:- two boats f i s h e d twenty days i n a month, and each boat caught the same amount of f i s h each day. One boat lands i t s c a t c h e v e r y day, and the o t h e r boat every f i f t h day. The c a t c h per t r i p of the boat t h a t landed i t s c a t c h every f i v e days i s f o u r times g r e a t e r than the boat t h a t landed i t s c a t c h every day but the c a t c h at the end o f the month i s the same f o r each boat. The d a t a from both the l a r g e and s m a l l boats are used, because the number of days per t r i p made by eaoh c l a s s of boat i s d i s c o u n t e d . The average c a t c h per boat per month and the average ca t c h per boat per t r i p per month both give i n d i c e s of a v a i l -a b i l i t y . Both, of these two methods of a n a l y s i s o f c a t c h s t a t i -s t i c s have been used i n . a v a i l a b i l i t y s t u d i e s of the white sea bass (Cynosoion n o b i l i s ) of C a l i f o r n i a (Whitehead 1930); the s t r i p e d bass (Roccus l i n e a t u s ) of C a l i f o r n i a ( C r a i g 1930), C l a r k 1933); the b l u e f i n tuna (Thunnus thynnus),(Whitehead 1931); and the C a l i f o r n i a h a l i b u t ( P a r a l i c h t h y s c a l i f o r n i c u s ) ( C l a r k 1931)'. F i g . 25 i l l u s t r a t e s the average c a t c h per boat per month f o r the years 1943 to 1946. T h i s method of a n a l y s i s i n d i c a t e s the d o g - f i s h were most a v a i l a b l e d u r i n g the month of August i n 1943 and 1946. In 1944 and 1945 the d o g - f i s h were most a v a i l a b l e d u r i n g the month of June. The year 1945 shows a 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 O F D O G - F I S H L I V E R S L A N D E D B Y S U N K E N G I L L - N E T B O A T S FISHING IN H E C A T E S T R A I T F R O M 1943 TO 1946 . . 1943 e o 1944 ., • 1945 , ^ 1946 >• z -> o 0 . 1 -< 3 3 3 U l O s -> -> < in o F i g . 25 - 35 -decided drop in the av a i l a b i l i t y from 1944, while in the year 1946 the- ava i l a b i l i t y increased over the previous year. The sources of error in this graph are discussed later in the text. 3. The Average Catch -per Trip per Boat per Month. The average catch per trip per boat i s determined by dividing the monthly catch of a l l the—boats by the number of trips that a l l the boats made in each particular 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 of the longer trips in each successive year. It i s seen (Table VII) that there has been a general drop in the average number of trips per month since 1 9 4 3 , except during the months of June in 1944, and the months of August and September in 1946. Like the other method (Fig. 23) of analysis Fig. 26 i n d i -cates the ava i l a b i l i t y of the dog-fish to be greatest during the month of August in 1943 and 1946. The year 1945 shows a decided drop in the availability compared with 1944. 4. The Average Catch per Boat per Month and the Average  Catch per Trip per Boat per Month for Bach Year as a  Whole. Fig. 27 illustrates the weighted average catch per boat per month and the weighted average catch per trip per boat per month. The average catch i s weighted by the different number of boats fishing each month and the changes in the number of trips made for 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 Strait 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 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 O F D O G - F I S H L I V E R S L A N D E D B Y S U N K E N G I L L - N E T B O A T S FISHING IN H E C A T E S T R A I T F R O M 1943 TO 1 9 4 6 • • 1943 • • 1944 1 f 1945 . o 1946 15 14 13 12 in a 1 1 z 3 o I o u. 9 o 8 in ° 7 LiJ . <r a 6 Z ' « 4 \ -3 -2 -0 ' 1 1 1 1 1 1-MAY JUNE JULY AUG. SEPT. OCT. _ A _ . - 36 -per trip per boat dropped only slightly. These two graphs indicate lower ava i l a b i l i t y during the years 1943 and 1945 and an increase in the availability during 1946. The graphs in Fig. 27 give a somewhat distorted picture of the actual conditions. Consider the following situation:-A limited population in a certain locality is..being fished with a fixed, amount of gear. If the number of boats and gear i s doubled, the total catch would not double because of competi-tion among the increased gear. It i s probable that each boat in operation would catch less f i s h than i f only the smaller number were operating. Such a situation occurred in Hecate strait from 1943 to 1945. During 1946 the number of sunken gill-net boats fishing in Hecate strait was much less than in 1945 (Table 7 ) . There are many cumulative factors which would tend to increase the average boat catch in 1946. Some of these factors may be discussed. The general drop in the average number of trips per month since 1943 could indicate a greater amount of effort expended by the fishermen before a landing of dog-fish livers 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 fi s h in bad weather in 1946. This would increase their 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 rising value of the dog-fish and soup-fin shark livers would tend to keep the fishermen on the fishing grounds for longer periods* r 3 7 -5• The Index of the Average Catoh per Boat per Month and  the Index of the Average Catch per Trip per Boat per  Month as Determined by the Method of Link Relatives. Link relatives are determined by comparing the catch in one month, with the catch in the same month in the previous year, or in each successive year. In the analysis presented here, the year 194-3, was used as the base year. Each month of this year was compared with the same months in each of the successive years. Chaddock ( 1 9 2 5 ) describes this method of analysis in detail, and i t has been used in the analysis of boat catches in the California halibut fishery (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 in the successive years 1 9 4 3 to 1 9 4 6 ; the relative 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 third relative i s 6 + 1 2 » 0 . 5 0 , and the fourth relative for the year 1 9 4 6 would be 3 * 6 « 0 . 5 0 . These relatives must now be linked together by what i s termed the chain relative. The f i r s t year of the series, 1 9 4 3 , i s the base year, and i s there-fore 1 0 0 percent. The chain relative for 1944 would be 1 0 0 multiplied by I . 5 0 « 1 5 0 percent; the chain relative for 1945 would be 1 5 0 x 0 . 5 0 = 7 5 percent; and the chain relative for 1 9 4 6 would be 0 . 7 5 x 0 . 5 = 3 7 1 / 2 percent. The chain relative for the years 1944 to 1 9 4 6 would then be 1 . 5 , 0 . 7 5 , and O . 3 7 5 . In Figs. 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 in Hecate strait was greatest in 1944 for the months of June, July, and October. In the month of May, 1 9 4 5 , I N D E X OF T H E A V E R A G E C A T C H P E R B O A T PER M O N T H O F D O G - F I S H L I V E R S L A N D E D B Y 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 H E C A T E S T R A I T F R O M ? [ 9 4 3 T O 1 9 4 6 DETERMINED BY THE METHOD OF LINK RELATIVES M A Y A U G U S T J U L Y O C T O B E R 200 I 50 -100 50 0 20 0 I 50 100 50 0 to CD lO CT> ro O) <J> If) <7> 10 on f i g . 28 INDEX OF THE AVERAGE CATCH PER TRIP PER BOAT PER MONTH OF DOG-FISH LIVERS LANDED BY SUNKEN GILL-NET BOATS FISHING IN HECATE. STRAIT FROM 1 9 4 3 TO 1946 DETERMINED BY THE METHOD OF LINK RELATIVES 150 100 50 0 300r-250 200 h 150 Z U 100 LU a. 300,— 250 200-150 100 50 0 CT) MAY JUNE JULY CT) ID ff> 200|— 150 -100 - • 50-250p 200 — 150 -100 — 50-0 — 10 CT) ro CT) AUGUST OCTOBER fl-fl-CT) fl-CT) 10 fl-CT) Fig., 29 - 38 -the availability index rises when compared with May. 1944, indicating a possible early movement of dog-fish in Hecate strait for that year. The index remained high during June but f e l l very sharply for the rest of the year, depicting the poor catches which were made by the sunken gill-net 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 for the months of June, July, August, and September. The,index of the average catch per boat per month and the average, catch per tr i p per boat per month increased abruptly during the months of August and September. This agrees with increased in the average catch per boat per month and the average catch per tri p per boat per month for this year, 1946, as shown in Figs. 25 and 26. When the years as a whole are compared with each other (Fig. 3 0 ) , the index also shows that the availability was greatest in 1944 and that the year 1946, shows a definite i n -crease in availability over the previous year. Less competi-tion between gear and improved weather conditions would probably increase the yield of the boat catches during some of the months in 1946 when compared with 1945. 6. Comparison of the Average Catch per Boat per Month  for the Same Sunken Gill-net Boats Fishing' in Ad-jacent Years. This method of estimating availability has been em-ployed in various fishery investigations. It makes some INDEX OF T H E AVERAGE CATCH OF DOG-FISH LIVERS LANDED BY, SUNKEN G I L L - N E T BOATS FISHING IN HECATE STRAIT FROM 1 9 4 3 TO 1 9 4 6 DETERMINED BY THE METHOD OF LINK RELATIVES INDEX OF THE INDEX OF THE AVERAGE CATCH PER BOAT PER MONTH AVERAGE CATCH PER TRIP PER BOAT PER MONTH 2 0 0 2 0 0 I— A 1 1 5 0 r-Z UJ o 1 50 t— Z UJ o rr 1 0 0 \/ — or 100 — / 3d UJ a -5 0 5 0 -0 1 1 1 1 o 1 I - l | : 1943 <fr lO to * * * 0) CT) 01 to <? \n * * CT) CT) CT) CT) F i g . . 50 - 39 -allowance for the increase in the fishing effort (the increase in the average number of nets per boat) that occurs in each successive year. Information obtained from a number of fisher-men along the coast revealed that the number of nets each sunken gill-net boat used increased gradually in each successive year from 1943 to 1946. It has been roughly estimated that the number.of nets per boat i n 1946 has doubled since 1943. This means that the effort expended by each fisherman in 1946 was much greater than in 1 9 4 3 . The boats fishing in 1943 were compared with the same boats fishing in 1944; boats fishing in 1944 were compared with the same boats fishing in 1 9 4 3 , and the same comparison was made for the years 1 9 4 5 - 4 6 . The increase in 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 fishing in adjacent years, tends to equalize the effect of the increase, or decrease, in the number of nets per boat from 1943 to 1 9 4 6 . However, the increasing number of nets over the fleet w i l l produce a cumu-lative error no less than by other methods. In Fig. 31 the average catch of dog-fish livers per boat per month landed by the same boats fishing in the years 1943-4 4 , indicates the comparitively high av a i l a b i l i t y i n 1 9 4 3 , when the fishery with sunken gill-nets in Hecate strait 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 (Fig. 32) a v a i l a b i l i t y 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 OF DOG-FISH L I V E R S L A N D E D B Y T H E S A M E 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 IN A D J A C E N T Y E A R S 1 9 4 3 - 4 4 IN H E C A T E S T R A I T a 5 1943 o o 1944 < y-o o F i g . . 31 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 OF D O G - F I S H L I V E R S L A N D E D B Y T H E S A M E 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 IN" A D J A C E N T Y E A R S 1 9 4 4 - 4 5 I N H E C A T E S T R A I T -o 19 44 -o 194.5 3 o >-< 3 <a Q. 3 ui < tt o o F i g . , 32 - 40 -i s g r e a t e s t i n the e a r l i e r year, 1944. F i g . 32 a l s o shows t h a t the a v a i l a b i l i t y i n 1945 was g r e a t e s t i n the month of June and then f a l l s o f f s h a r p l y i n the f o l l o w i n g months. Du r i n g 1946 the number of boats f i s h i n g f o r d o g - f i s h i n Hecate s t r a i t was reduced by almost t w o - t h i r d s the number f i s h -i n g i n 1945. T h i s would i n d i c a t e t hat the average c a t c h per boat in . 1946 could exceed the average boat catch i n 1945. T h i s s i t u a t i o n o c c u r r e d d u r i n g the months of June, J u l y , August, and September ( F i g . 2 5 ) . F i g . 33 i l l u s t r a t e s the average c a t c h per boat per month f o r the same boats f i s h i n g i n the years 1945-46. The boat c a t c h i n c r e a s e d a b r u p t l y i n the month of August, 1946, but the average boat catches f o r the other months almost p a r a l l e l e d the catches made i n the p r e v i o u s y e a r . T h i s sudden i n c r e a s e i n the a v a i l a b i l i t y of the d o g - f i s h i n August, 1946, i s p r o b a b l y c l o s e l y r e l a t e d with the v a r i e d mass movements of d o g - f i s h i n Hecate s t r a i t . The abrupt i n c r e a s e i n a v a i l a b i l i t y d u r i n g August, 1946 as shown i n F i g . 33 i s a l s o i n d i c a t e d i n F i g s . 25 and 26. 7. The Index o f the T o t a l Landings of D o g - f i s h L i v e r s  Made by the Same Sunken G i l l - n e t Boats F i s h i n g i n  Adjacent Years as Determined by the Method of L i n k  R e l a t i v e s . The i n d e x c a l c u l a t e d from the t o t a l c a t c h per month from the same boats f i s h i n g i n adjacent y e a r s , and the index c a l c u l a t e d from t h e average c a t c h per boat per month from the same boats f i s h i n g i n adjacent years would be i d e n t i c a l . Only 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 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 S A M E 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 IN A D J A C E N T Y E A R S 1 9 4 5 - 4 6 IN H E C A T E S T R A I T < o - 9 1945 •-e 1946 o o. i \ i \ i \ < z o o - 41 -the same number of boats are compared in each month between two successive years. It would simply mean dividing the total catch of any month in 194J and the total catch of the same month in 1944 by a common denominator. The index of the total landings of dog-fish livers each month made by the same sunken gill-net boats fishing in ad-jacent years (Fig. 34), differs in many details from the i n -dex of the average catch per boat per month (Fig. 2 8 ) , and the average catch per tr i p per hoat per month (Fig. 2 9 ) . The i n -dices in Fig. 34 give a clearer picture of the av a i l a b i l i t y in 1943, when the sunken gill-net fishery commenced in Hecate s t r a i t . It would seem probable that the abundance, Or the total number of dog-fish must have been greater in 1943 than during the following years, when enormous numbers of this spe-cies were- taken from the B r i t i s h Columbia waters. Fig. 34 shows that the availability of dog-fish in Hecate strait varies from year to year, and does not always follow the same course at the same time each year. The abundance i s represented in part by the relative abundance or a v a i l a b i l i t y calculated from the analyses of boat catches. Although very large numbers of dog-fish were removed from Hecate strait in 1944 and 1943, Figures 2 8 , 2 9 , and 34 indicate an increase i n availability, during the months of August and September in 1946-. When the total landings of dog-fish livers from the same sunken gill-net boats fishing in adjacent years are linked to-gether by the method of chain relatives, a more accurate and clearer picture of the av a i l a b i l i t y of the dog-fish i n Hecate st r a i t , from 1943 to 1946, i s demonstrated (Fig. 33). The •f-INDEX OF THE CATCH OF DOG-FISH LIVERS LANDED BY THE SAME SUNKEN GILL-NET BOATS FISHING IN THE ADJACENT YEARS 1 9 4 3 - 4 4 , 1 9 4 4 - 4 5 , 1 9 4 5 - 4 6 , IN HECATE STRAIT DETERMINED BY THE METHOD OF LINK RELATIVES 150 100 50 O M A Y 150 -100 — « 50 -0 -AUGUST JUNE SEPTEMBER UJ o or u 0. Fig.- 34 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 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 100 UJ o or LU Q. 50 0 1 1 1 1 L ro <fr m t£> <fr <tf- ^ * oi ot Oi oi Fig. .35 - 42 -index of the av a i l a b i l i t y (Fig. 33) drops from the year 1 9 4 3 to 1943, and then increases slightly in 1946. E. Analysis of the Catoh Records of Soup-fin Shark Livers Landed by Sunken Gill-net Boats Fishing in Hecate Strait. The catch stati s t i c s of the soup-fin shark are analysed by the same methods employed in the analysis of the dog-fish s t a t i s t i c s . 1. The Total Landings of Livers by Sunken Gill-net Boats. The total landings of soup-fin shark livers for each year are graphed in Fig. 3 6 . The total landings for the year 1944 represent the absolute minimum, since some of the records from one company were missing for that year. In spite of th i s , 1944 represents the year of the greatest landings of soup-fin shark livers from Hecate s t r a i t . The year 1944 also represented the year of the greatest landings of soup-fin shark livers for the Province. In the years 1943 and 1944 about 40 per cent of a l l the soup-fin shark livers landed in B r i t i s h Columbia were caught by sunken gill-net boats fishing from May to October inclusive, in Hecate s t r a i t . The sunken gill-net boats landed 43 per cent and 40 per cent of the total landings for the Pro-vince in the years 1943 and 1946 respectively. Table VTII l i s t s the total weights of soup-fin shark livers landed each month by sunken gi l l - n e t boats fishing in Hecate str a i t from 1943 to 1946. The months of the greatest landings in the year 1943 were August and September. July was the peak F i g . . 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 landed each Month by Sunken G i l l - n e t Boats from Hecate S t r a i t , from 1943 to 1946. 1 9 4 3 1944 1 9 4 5 1 9 4 6 May 6 1 4 • .2 June 40 4,147 3 , 2 1 9 7 5 2 J u l y 1 , 0 2 7 1 3 , 7 3 2 9 , 7 9 5 2 , 0 7 1 August 6 , 2 5 6 5 , 8 5 7 2 , 3 2 9 4 8 0 September 4,525 4 4 5 254 2 0 8 October 3 1 0 8 1 6 5 3 T o t a l 1 3 , 0 5 8 2 4 , 2 5 0 1 5 , 7 6 6 3 , 5 1 6 Weighted average c a t c h per boat per month 225.14 6 6 . 4 4 2 3 . 5 7 1 4 . 9 0 - 43 -month in each of the three years, 1944, 1943, and 1 9 4 6 . ' 2. The Average Catch per Boat per Month. Fig. 37 illustrates the average catch per boat de-creasing from 1943 to 1 9 4 6 . Although more soup-fin shark livers were landed in the year 1944, the avai l a b i l i t y dropped considerably below the previous year for a short period during the months of August and September. The graph indicates the month of August as the month of greatest availability for 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 Trip per Boat per Month. The average catch per t r i p per boat per month (Fig. 38) almost follows the same representative pattern as depicted in Fig. 3 7 . In the year 1 9 4 3 , Fig. 38 shows the av a i l a b i l i t y was greatest in the month of August, whereas Fig. 37 shows that the availability was greatest in the month of July. This d i f -ference i s only very slight when the small amount of livers landed i s considered. 4 . The Average Catch per Boat per Month and the Average  Catch per Trip per Boat per Month for Each Year as a  Whole. Fig. 39 illustrates the continued drop in the avail-a b i l i t y of the soup-fin shark from 1943 to 1946. The avail-a b i l i t y calculated from the average catch per boat per month AVERAGE CATCH PER BOAT PER MONTH OF SOUP-FIN SHARK LIVERS LANDED BY SUNKEN GILL-NET BOATS " FISHING IN HECATE STRAIT FROM 1943 TO 1946 1943 — o 1944 » 1945 o 1946 3 o-a. a a. a < z ID < O o Fig. 37 AVERAGE CATCH PER TRIP PER BOAT PER MONTH OF SOUP-FIN SHARK LIVERS LANDED BY SUNKEN GILL-NET BOATS FISHING IN HECATE STRAIT FROM 1943 TO 1 9 4 6 a z •D o 1 60 1 5 0 140 130 120 — 1 i 0 — 100 >> — 90 80 70 60 — 50 — 40 — 30 — 2 0 — 1 0 0 — • • 1943 0 o 1944 1 • 1945 e o 1946 (9 < a. i n in F i g . 38 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 ava 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 av a i l a b i l i t y (Figures 40 and 41) are very similar. Both of these figures demonstrate the sudden increase in the availability for June 1944 and the Increase in the availability for July 1944, when compared with July 1943. In the years 1945 and 1946 the avail-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 for each year as a whole (Fig. 42) indicates a decided drop in avail-a b i l i t y from 1943 to 1946. 6. Comparison of the Average Catch per Boat per month for the Same sunken Gill-net Boats Fishing in Adjacent Years. This method of analysis demonstrates that the average catch per boat per month increased sharply for a l l months in 1944 when compared with the months in 1943 (Fig. 43). This re-sult, illustrated in Fig. 43, i s partly the reverse of the re-sults i l l u s t r a t i n g the average catch per boat per month (Fig. 37) and the average catch per t r i p per boat per month (Fig. 38). INDEX OF THE AVERAGE CATCH PER BOAT PER MONTH OF SOUP-FIN SHARK LIVERS LANDED BY SUNKEN GILL-NET BOATS FISHING IN HECATE STRAIT FROM 1943 TO 1 9 4 6 DETERMINED BY THE METHOD OF LINK RELATIVES JULY Tig, 40 INDEX OF THE AVERAGE CATCH PER TRIP PER BOAT PER MONTH OF SOUP-FIN SHARK LIVERS LANDED BY SUNKEN GILL-NET BOATS FISHING IN HECATE STRAIT FROM 1943 TO 1946 DETERMINED BY THE METHOD OF LI^ K RELATIVES CO % "> * l*> ^ - l O m * i * ' * 0 » c " i O > < 3 > o> <J> <f> 0"> Fig.- 41 I N D E X OF T H E AVERAGE CATCH OF S O U P - F I N SHARK L IVERS LANDED BY S U N K E N G I L L - N E T B O A T S F ISHING IN HECATE STRAIT FROM 1 9 4 3 TO 1 9 4 6 DETERMINED BY THE METHOD OF LINK RELATIVES INDEX OF THE INDEX OF THE AVERAGE CATCH PER BOAT PER MONTH AVERAGE CATCH PER TRIP PER BOAT PER MONTH 1 0 0 1 0 0 £ 7 5 UJ UJ 0 0 or or _ UJ 5 0 — UJ 5 0 \ — 0. 0. 2 5 /-\ -1 2 5 -0 ro lO (0 U >fr lO <0 *t ^- <t * 0) 05 0) 0) 0> 0) o> Fig._ .42 A V E R A G E CATCH 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 T H E S A M E S U N K E N G I L L - N E T B O A T S FISHING IN A D J A C E N T Y E A R S IN H E C A T E STRAIT Y E A R S 1943 - 4 4 — 1943 4 0 0 ;\ — 1944 3 0 0 — / V / \ / \ / \ 2 0 0 — / / ; / / \ \ \ \ \ \ / / 0. \ \ \ 1 0 0 — / / / / / / \ — . \ CO § o Z> -\ \ \ \ \\ e> o O Q. Y E A R S 1944 - 4 5 r — 1944 — 1945 i - 2 0 0 i C3 — — UJ 5 1 0 0 — / / / / 0 |, Y E A R S 1 9 4 5 -- 4 6 — 1945 1 0 0 — 1946 0 MAY — JUNE — JULY — AUG. — SEPT. — OCT. — F i g . 4J - 45 -Figures 37 and 38 picture the availability to be greater for the months of July and August in 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 fishing i n these adjacent years f a l l s steadily 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 Gill-net Boats Fishing  in Adjacent Years, as Determined by the Method of Re- latives . The indices graphed i n Fig. 44 check f a i r l y closely for a l l months, except September, with the indices graphed in Figures 40 and 41. Figures 40 and 41 illustrate the picture for a l l the boats fishing in Hecate strait while Fig. 44 i l l u - . strates the picture of the availability for the same boats fishing in adjacent years. Fig. 44 indicates an increase i n the availability of the soup-fin .shark in September 1946 when compared with September 1945; and an increase i n a v a i l a b i l i t y in September 1945 when compared with September 1943* Fig. 45 illustrates the average catch of soup-fin shark livers, per month for each year as a whole, landed by the same boats fishing in adjacent years in Hecate st r a i t . The index rises abruptly In 1944, when compared with the base year 1943• The index of av a i l a b i l i t y f a l l s just as abruptly in 1945 and reaches a low index in 1946. I N D E X OF T H E 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 BY T H E S A M E S U N K E N G I L L - N E T BOATS F ISHING IN T H E A D J A C E N T Y E A R S 1 9 4 3 - 4 4 , 1 9 4 4 - 4 5 , 1 9 4 5 - 4 6 , IN H E C A T E S T R A I T DETERMINED BY THE METHOD OF LINK RELATIVES J U N E A U G U S T 400r— 200 100 U l O or U l 0-200 to J U L Y 01 300 200 — 100 to at S E P T E M B E R Fig. ,44 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 THE M E T H O D OF L I N K R E L A T I V E S 2 50 2 00 L A J t -Z LO ° 150 [ A j cr LU CL 100 50 0 '- 1 1 1 1 : 1944 1945 1946 F i g . 4$ - 46 -F. Summary, D i s c u s s i o n , and C o n c l u s i o n s of the R e s u l t s o f  the A n a l y s i s o f the Data from Hecate S t r a i t . A number of methods of a n a l y s i n g ' t h e c a t c h r e c o r d s of the d o g - f i s h and s o u p - f i n shark l i v e r s landed by sunken g i l l - n e t boats i n Hecate s t r a i t has been p r e s e n t e d . The methods of ana-l y s i s of the a v a i l a b i l i t y have been t r e a t e d i n order of com-p l e x i t y , from the g e n e r a l v a r i a t i o n s of the i n c r e a s e and de-crease i n t o t a l c a t c h s t a t i s t i c s , to the more s e a r c h i n g and v a l i d methods of e s t i m a t i n g a v a i l a b i l i t y . The g r a p h i c a l i l l u -s t r a t i o n s have been used to r e p l a c e wordy d e s c r i p t i o n s of d i s -c u s s i n g a v a i l a b i l i t y by each method of a n a l y s i s . From i n f o r m a t i o n gathered i n the f i e l d and by d e t a i l e d s u r -veys of the p r e c i s e area of capture of the d o g - f i s h by i n d i v i -d u a l boats d u r i n g each month, i t was found t h a t the d o g - f i s h migrates i n t o Hecate s t r a i t from the n o r t h each year. E v i -dence of t h i s i s shown by changes i n the p e r i o d s of a v a i l a b i -l i t y f o r the d i f f e r e n t months i n each y e a r . When the vdog-fish reach and e n t e r Hecate s t r a i t they are p a r t l y r e s t r i c t e d i n t h e i r d i r e c t i o n of movements by the b a r r i e r s on b o t h s i d e s o f the s t r a i t . The d o g - f i s h become bunched, and tend to t r a v e l i n v ery l a r g e s c h o o l s , thus i n c r e a s i n g t h e i r v u l n e r a b i l i t y t o 'capture by f i s h i n g gear. In t h e l a t e summer of 1 9 4 3 , the f i r s t year when s u n k e n - g i l l - n e t s were used i n Hecate s t r a i t , the fishermen's boat catches were large, and the d i s t a n c e the f i s h e r -men t r a v e l l e d t o s e t t h e i r n ets was not g r e a t . These fishermen were probably f i s h i n g o n l y a s m a l l p a r t of the a c t u a l popula-t i o n of the d o g - f i s h i n Hecate s t r a i t at t h a t time, or of the 4 - 47 -population which had been in Hecate s t r a i t . In the year 1944, an intensified fishery occurred as a result of the large catches of dog-fish during the later summer months in 1943. Large num-bers of American trawlers entered Hecate strait in 1944 and the total landings of dog-fish and soup-fin shark livers was the largest in the history of British Columbia. The large catches raise doubts as to what quantity of dog-fish and soup-fin shark can be taken from the fishery and yet leave a sufficient number of the specier-s to propagate. In the year 1945, a v a i l a b i l i t y of the dog-fish and soup-fin shark dropped so abruptly that many fishermen considered the fishery in that year almost a failure. The number of sunken gill-nets used in 1945 almost doubled the number that was used i n 1944. The dog-fish enter-ing Hecate strait in 1945 were not only confronted by an ex-temely large barrier of sunken gill-nets but an increased num-ber of otter-trawls. This increase in the number of boats re-duced the average catch per boat when compared with the previous year. Undoubtedly the increased competition between gear and the poor weather conditions during the summer months in 1945 were two detrimental factors influencing the catch. In 1946 the number of fishermen entering the fishery in Hecate strait declined. The dog-fish which entered the strait in 1946 were not subjected to the intensive fishery that occur-red i n the previous years. The availability increased slightly in 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 gill-net - 48 -boats, i t i s now evident that the fishable population of dog-fi s h which enters Hecate strait should only be subjected to a fishery" by a limited number of boats and gear. This i s an eco-nomic conclusion, not a biological one. The analyses of the catch records'indicate a definite decline in abundance of the dog-fish in Hecate strait but i t i s not possible to state that this constitutes depletion. The problem needs at least one more season of investigation. A definite decision i s there-fore reserved because of the influence of two important factors which have not been studied sufficiently to give conclusive results. These two factors are:-1. the changes i n the total amount of effort. 2. the .influence of hydrographic conditions. In addition to the decline in ava i l a b i l i t y of dog-fish and the total landings-of livers from Hecate strait from 1944 to 1946 there has been a noticeable decline in the vitamin "A" po-tency of the dog-fish livers from 1944 to 1947. The average vitamin "A" potency (in USP units per gram of liv e r oil) of livers from dog-fish caught in the same area in Hecate strait by sunken gill-nets has declined with each succeeding year since 1944. The decline in the vitamin "A" potency of the livers has been of great concern to the fishermen and the f i s h -ing industry. It means that the total poundage of livers from dog-fish caught i n Hecate> strait in 1947 would represent a lower stock of vitamin "A" for the same weight of livers re-covered from dog-fish caught by the same gear and in the same area as in 1944. The decline in potency of vitamin "A" i s indicated in - 49 -Table IX. The average number of USP u n i t s per gram of l i v e r o i l were t e s t e d from l i v e r s removed from d o g - f i s h 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 (shaded area F i g . 22). L i v e r s t e s t e d f o r v i t a m i n "A" i n t a b l e IX were landed from the b e g i n n i n g of May u n t i l the end of October i n each y e a r . T h i s d e c l i n e i n potency of v i t a -min "A" i s b o t h an economic problem and a b i o l o g i c a l one. The economic problem i s p a r t i c u l a r l y conoerned w i t h the d e c l i n e i n the potency of v i t a m i n "A" per pound of l i v e r landed. The b i o -l o g i c a l problem i s concerned w i t h the r e l a t i o n s h i p between the d e c l i n e i n the a v a i l a b i l i t y of the d o g - f i s h i n Hecate s t r a i t and the d e c l i n e i n potency of v i t a m i n "A" i n the l i v e r s . What has brought about t h i s d e c l i n e i n average potency of l i v e r s from Hecate s t r a i t ? C e r t a i n f a c t s c o n c e r n i n g the r e l a t i o n s h i p between the v i t a m i n "A" c o n c e n t r a t i o n per l i v e r and the p h y s i c a l c h a r a c t e r -i s t i c s of the d o g - f i s h are w e l l known. Vi t a m i n "A" c o n c e n t r a t i o n of the l i v e r o i l and percentage o f o i l i n the l i v e r are p o s i t i v e l y c o r r e l a t e d with the l e n g t h . There i s a l s o a c l o s e a s s o c i a t i o n w i t h sexual m a t u r i t y of the d o g - f i s h and the v i t a m i n "A" con-c e n t r a t i o n of the l i v e r s . L i v e r s from immature d o g - f i s h c o n t a i n o n l y a s m a l l percentage of v i t a m i n "A" found i n the l i v e r s o f the l a r g e r f i s h . F i s h w i t h dark l i v e r s appear t o mature e a r l i e r than d o g - f i s h of the same s i z e and sex w i t h l i g h t , c o l o u r e d l i v e r s . I t i s known t h a t the darker l i v e r s g e n e r a l l y average high e r i n v i t a m i n "A" c o n c e n t r a t i o n than the l i g h t e r c o l o u r e d l i v e r s and t h a t the l a r g e s t male and female d o g - f i s h have l i v e r s darker i n c o l o u r than the s m a l l e r f i s h of e i t h e r sex. F u r t h e r , Table I X The average number of USP u n i t s per gram of l i v e r , o i l d e t e r -mined from the l i v e r s of the d o g - f i s h taken 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 rom 1944 to 1947. Average number o f USP T o t a l poundage o f u n i t s per gram of d o g - f i s h l i v e r s l i v e r o i l * ana lysed 1944 14 ,648 148 , 191 1945 1 3 , 1 8 3 514 ,000 1946 9 , 7 8 4 4 4 6 , 4 4 8 1947 9 , 0 7 5 5 7 2 , 4 8 6 These f i g u r e s , were determined from 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 separate 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 . \ - 5 0 -there i s a s e a s o n a l v a r i a t i o n i n the l i v e r potency as f o r ex-a m p l e — d o g - f i s h of the same s i z e and sex, have l i v e r s which produce a g r e a t e r l i v e r potency i n the w i n t e r than i n the sum-mer. In g e n e r a l i t has been found t h a t f o r d o g - f i s h of the same sex, l a r g e f i s h , as compared w i t h s m a l l f i s h , have a greate r a t i o of l i v e r weight t o body weight; darker l i v e r s ; more o i l per l i v e r ; l i v e r and l i v e r o i l o f a hi g h e r potency; more v i t a -min "A" per l i v e r . Since- the l a r g e r d o g - f i s h c o n t a i n a h i g h e r c o n c e n t r a t i o n of v i t a m i n "A" than the s m a l l e r d o g - f i s h , the d e c l i n e i n v i t a -min "A" of l i v e r s removed from d o g - f i s h caught i n Hecate s t r a i t by sunken g i l l - n e t s could be a t t r i b u t e d t o the removal of the l a r g e r d o g - f i s h or the movement of these l a r g e r f i s h from the grounds. T h i s would suggest t h a t the d e c l i n e i n a v a i l a b i l i t y o f d o g - f i s h caught i n sunken g i l l - n e t s i n Hecate s t r a i t i s c l o s e l y r e l a t e d to 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 and Bonham (1946) i n d i c a t e t h a t age i s p r o b a b l y the determining f a c t o r i n v i t a m i n "A" p r o d u c t i o n i n the l i v e r independent of the l e n g t h of the d o g - f i s h . They found t h a t w i t h i n a l e n g t h frequency category t h a t there was an i n v e r s e r e l a -t i o n s h i p between l i v e r c o l o u r and the average p o s t e r i o r spine l e n g t h of the d o g - f i s h . I t was assumed that f o r f i s h o f the same s i z e and sex t h a t the d o g - f i s h w i t h the darker l i v e r s are p r o b a b l y the o l d e r s i n c e t h e i r b l u n t s p i n e s would have been s u b j e c t e d t o wear f o r a longer t i m e . T h e i r o b s e r v a t i o n s showed t h a t the d i f f e r e n c e i n the l e n g t h of the spine was most n o t i c e -able among the l a r g e r f i s h , where specimens of the same s i z e - 51 -might have differed considerably in rate of growth. This would indicate that the darkest livers with the highest vitamin "A" concentration are found in the dog-fish which grow the slowest. A question arises. Why was the drop in the av a i l a b i l i t y of the soup-fin shark more pronounced than the drop in the avail-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 gill-nets than the dog-fish. or 2. The soup-fin shark has been subjected to an intense fishery in the United States for a number of years. Thus when the intensity of fishing for this species suddenly increased over the whole of the migratory range, the avai l a b i l i t y of the soup-fin shark would suddenly drop in the l o c a l i t i e s which represent the limits of i t s migratory range. Foerster (1945) re-ported the- possible movement of soup-fin sharks from California to British Columbia when a female soup-f i n shark tagged in California waters was captured inside Bajo' reef, Nootka sound, on the west coast of Vancouver island. G. Analysis of the Catoh Records of Dog-fish Livers. Landed  by Sunken Gill-net Boats Fishing off Barkley Sound on the  West Coast of Vancouver Island, from 1944 to 1946. - 52 -1. The T o t a l Landings o f D o g - f i s h L i v e r s by Sunken G i l l -net Boats. The histogram ( F i g . 47) i l l u s t r a t e s the t o t a l c a t c h 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 f i s h i n g o f f B a r k l e y sound ( F i g . 46), from 1944 to 1946. Catch s t a t i s t i c s f o r 1943 were not a v a i l a b l e . The l a r g e s t c a t c h o f d o g - f i s h l i v e r s was made i n 1944. F i g . 48 i l l u s t r a t e s 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 each month from 1944 to 1946. The g r e a t e s t l a n d i n g s o f dog-f i s h l i v e r s were made i n the month o f June i n each y e a r . 2. Catch per U n i t o f E f f o r t . The f i s h e r y f o r d o g - f i s h o f f B a r k l e y sound d i f f e r s from t h a t i n Hecate s t r a i t , i n t h a t each b o a t ' s c a t c h i s landed every day. The f i s h i n g companies have camps on the out e r i s -lands o f B a r k l e y sound, and at Bamfie l d , U c l u e l e t , and K i l d o n a n ( F i g . 46). The f i s h i n g grounds a r e o n l y about 1 hour to 2 hours t r a v e l l i n g time from the f i s h i n g camps. In the computation of 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 a " u n i t " must be e s t a b l i s h e d and the amount o f f i s h i n g ' t i m e must be i n c l u d e d i n the c a l c u l a t i o n of t h i s u n i t . F o r t h i s survey the " u n i t of e f f o r t " i s d e f i n e d a s one sunken g i l l - n e t (75 f a -thoms) f i s h i n g over a p e r i o d of 24 hours. The number of u n i t s of 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 fisherman's d a i l y c a t c h , and the in d e x of r e t u r n per u n i t o f f i s h i n g e f f o r t f o r each fisherman's c a t c h was determined by d i v i d i n g the d a i l y c a t c h by the number of u n i t s of f i s h i n g e f f o r t . There was a F i g * 4 6 The shaded area i n d i c a t e s the g e n e r a l f i s h i n g grounds f o r the sunken g i l l - n e t s o f f B a r k l e y sound, on the west coast of Vancouver i s l a n d . TOTAL WEIGHT OF DOG-FISH LIVERS EACH YEAR AND EACH MONTH, LANDED BY SUNKEN GILL-NET BOATS FISHING OFF BARKLEY SOUND, ON THE WEST COAST OF VANCOUVER ISLAND FROM 1944 TO 1945 I 946 Fig. 47 Fig. 48 - 53 -slight increase in the actual number of nets per boat each year but the length of the,net was found to decrease slightly each year, according to each fisherman's individual preference. This index of return per unit of fishing effort forms a basis for 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 availability of the dog-fish. In the month of June, the index of return per unit of fishing effort for the dog-fish i s greatest for the years 1944 and 1946 (Fig. 49). Fig. 49 also illustrates that the avail-a b i l i t y of the dog-fish has increased in each succeeding year since 1944. There may be a slight error in the index of re-turn per unit of fishing effort for 1946, since no allowance i s made for the improvement in handling the gear. 3. Average Catch per Boat per Month. The average catch per boat per month i s much lower off Barkley sound when compared with the average catch per boat per month in Hecate strait (Tables X and 9) but the average catch per boat per month off Barkley sound increased from 1944 to 1946. This i s just the reverse of the situation 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 factors could i n i t i a t e a movement of dog-fish off the British ) ! I N D E X OF THE R E T U R N P E R - U N I T - O F - EFFORT FOR D O G - F I S H L I V E R S LANDED BY S U N K E N G I L L - N E T B O A T S F ISHING O F F B A R K L E Y SOUND ON T H E W E S T C O A S T OF V A N C O U V E R I S L A N D FROM 1 9 4 4 - 1 9 4 6 1944 1 945 3 5 1946 V 3 0 \ \ \ \ \ \ \ 2 5 -\ ^ \ \ -2 0 X UJ o z - 15 -* \ -— N ^ \ N \ \ -10 — 5 0 1 1 1 1 1 = MAY JUNE J ULY AUGUST SEPT. I j F i g - 4-9 Table X Average Catch (lb.) per Boat per Month of Dog-fish Livers landed by Sunken Gill-net Boats fishing off Barkley Sound on the West Coast of Vancouver Island, from 1944 to 1946 1944 1945 1946 ' May 9 7 0 . 2 1 , 5 8 0 . 2 June 1,342.2 2 , 1 6 0 . 4 2 , 6 9 1 . 1 July 1,284.4 1,549.3 1 , 1 9 8 . 7 August 1 , 1 9 6 . 1 1 , 2 2 2 . 0 ;September 6 9 4 . 6 Weighted average catch per boat per month .1,164.4 1 , 7 2 4 . 9 2,044.4 - 54 -Columbia coast a r e : -1. a m i g r a t i o n i n search of f o o d . 2. a m i g r a t i o n induced by sexual c o n d i t i o n s . Both o f these f a c t o r s are governed by hydrogfaphic c o n d i -t i o n s which c o n t r o l the d i r e c t i o n , speed, and s e a s o n a l f l u c t u a -t i o n s of t h e i r movements. In 1944 the -abundance of the d o g - f i s h was h i g h enough to m a i n t a i n a s u c c e s s f u l f i s h e r y , both o f f the west c o a s t o f Vancouver i s l a n d and i n Hecate s t r a i t . In 1945 the a v a i l a b i l i t y of d o g - f i s h dropped g r e a t l y i n Hecate s t r a i t but i n c r e a s e d o f f the west coast of Vancouver i s l a n d . I n 1946 the oceanographic c o n d i t i o n s were such t h a t the m i g r a t i o n of the a v a i l a b l e popu-l a t i o n of d o g - f i s h f o r the sunken g i l l - n e t f i s h e r y i n Hecate s t r a i t d i d not occur u n t i l the months of August and September. The decrease i n the r e t u r n per u n i t of e f f o r t f o r d o g - f i s h , i n the month of J u l y 1946 o f f B a r k l e y sound ( F i g . 49) may be the f i r s t i n d i c a t i o n of the p o s s i b l e movement of d o g - f i s h from the west coast of Vancouver i s l a n d i n t o Hecate s t r a i t . I t i s suggested that the g r e a t e r numbers o f the l i m i t e d p o p u l a t i o n of d o g - f i s h tended t o remain o f f the west coast o f Vancouver i s l a n d w i t h each succeeding year and that the sudden i n c r e a s e i n the a v a i l a b i l i t y o f d o g - f i s h i n Hecate s t r a i t i n the months of August and September i n 1 9 4 6 , may have been the r e s u l t of the movement of the d o g - f i s h from the west coast o f Vancouver i s l a n d i n t o Hecate s t r a i t by the southern entrance and not by the n o r t h e r n e n t r a n c e . In former years the d o g - f i s h have migrated i n t o Hecate s t r a i t by the n o r t h e r n entrance around Rose s p i t . Evidence o f t h i s southern m i g r a t i o n i n t o Hecate s t r a i t was i n d i c a t e d by the f i r s t l a r g e catches of d o g - f i s h by o t t e r - t r a w l s , south of Cumshewa i n l e t , and l a t e r by the sunken g i l l - n e t s o f f Skidegate i n l e t and T l e l l . The success of the d o g - f i s h f i s h e r y i n Hecate - s t r a i t almost p a r a l l e l s the Canadian p i l c h a r d f i s h e r y o f f the west coast of Vancouver i s l a n d . The Canadian p i l c h a r d f i s h e r y i s dependent upon the l a r g e s t p i l c h a r d s which make a northward m i g r a t i o n each summer from the C a l i f o r n i a c o a s t a l waters (Hart 1958). As the p i l c h a r d s o f f the C a l i f o r n i a coast grow o l d e r w i t h each succeeding year, the northward m i g r a t i o n i s extended. Since the l a r g e r f i s h go f a r t h e r , they 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 waters, thus they become s u b j e c t e d t o the Canadian f i s h e r y . The success of the d o g - f i s h f i s h e r y f o r the sunken g i l l -n e t s i n Hecate s t r a i t has l a r g e l y depended i n the past upon the o l d e r age c l a s s e s o f d o g - f i s h which have m i g r a t e d . i n t o t h i s area. The i n c r e a s e i n the a v a i l a b i l i t y o f d o g - f i s h o f f the west coast of Vancouver i s l a n d , would indicate,,that the oceano-g r a p h i c conditions were not s u i t a b l e f o r the m i g r a t i o n o f the d o g - f i s h i n t o Hecate s t r a i t i n 1945 and the f i r s t t h r e e months of the f i s h e r y i n 1946. As the o l d e r age c l a s s e s of d o g - f i s h are removed from the f i s h e r y the tendency f o r the d o g - f i s h to migrate i n t o Hecate s t r a i t would become l i m i t e d . The numbers of younger d o g - f i s h would be l i m i t e d i n t h e i r range of migra-t i o n i n t o Hecate s t r a i t but they would s t i l l tend t o remain o f f the west co a s t of Vancouver i s l a n d . - 56 -VI. ACKNOWLEDGEMENTS The author wishes to express h i s s i n c e r e a p p r e c i a t i o n and thanks to Dr. R. E . F o e r s t e r , d i r e c t o r of the P a c i f i c B i o l o g i c a l S t a t i o n , and to Dr. J". L. H a r t , i n charge of the o t t e r t r a w l i n v e s t i g a t i o n ^ f o r g r a n t i n g p e r m i s s i o n to use the r e s u l t s of the -a n a l y s i s o f the d a t a from the sunken g i l l - n e t f i s h e r y f o r t h i s work. S i n c e r e s t thanks and a p p r e c i a t i o n are extended to Dr. J . L. Hart, f o r h i s suggestions and c r i t i c i s m s throughout the i n v e s t i -g a t i o n . For t h e i r c o - o p e r a t i o n i n making p o s s i b l e the c o l l e c t i o n of c a t c h s t a t i s t i c s , s i n c e r e thanks are extended t o the f o l l o w i n g : -Mr. Ki F. Harding of the P r i n c e Rupert Fishermen's Co-operative A s s o c i a t i o n ; Mr. K. Dybhaven of the U n i t e d Fishermen's co-opera-t i v e A s s o c i a t i o n at Vancouver; Mr. L. Monk of the Canadian F i s h i n g Company L i m i t e d ; Dr. C. R. E l s e y and Mr. W. N. Tarbuck of the B r i t i s h Columbia Packers L i m i t e d ; Mr. D. R. Cole of the Borden 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 at V i c t o r i a ; Mr. G. J o l i f f e of Queen C h a r l o t t e C i t y ; and t o Western Chemical I n d u s t r i e s a t Vancouver. The author i s g r a t e f u l f o r the a s s i s t a n c e and w i l l i n g co-o p e r a t i o n g i v e n i n the f i e l d by the fishermen i n the sunken g i l l - n e t f i s h e r y . The author i s a l s o indebted to M i s s F. V. C o l l i n s of the P a c i f i c 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 manuscript. - 57 -V I I . REFERENCES Anderson, A. C. 1877• Report o f the i n s p e c t o r of f i s h e r i e s f o r B r i t i s h Columbia, f o r the year o f 1876. N i n t h Ann. Rept. Dept. Mar. and F i s h . , S u p p l . No.4, App. No. 21, pp. 339-247, f o r 1876, Ottawa, I877. I878. Report of the 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 year 1877./ Tenth Ann. Rep. Dept. Mar. and F i s h . , S u p p l . No.5. App. No. 17, Rep. F i s h . O f f i c e r s , 1877, pp. 287-293- Ottawa, 1878. 1880. Report of the i n s p e c t o r of f i s h e r i e s f o r B r i t i s h Columbia f o r the year 1879. T w e l f t h Ann;. Rept. Dept. Mar. and F i s h . , S u p p l . No.2, Rept. F i s h . O f f i c e r s , App. No. 17, pp. 280-292, f o r 1879, Ottawa, 1880. 1882. Report of the 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 year l88 l . F o u r t e e n t h Ann. Rept. Dept. Mar. and F i s h . , S u p p l . No. 2 F i s h Statements, f o r l88 l , App. No. 6, pp. 202-220, Ottawa, 1882. 1884. Report of the i n s p e c t o r of f i s h e r i e s f o r B r i t i s h Columbia, f o r the year 1883. S i x t e e n t h Ann. Rept. Dept. Mar. and F i s h . , S u p p l . No.2, Rept. F i s h . Can. f o r 1883, App. No.7, pp. 190-199, Ottawa, 1884. Anon. 1931. Power a p p l i e d t o l i f t i n g g i l l n e t s . P a c i f i c Fisherman, V o l . 29, No. 5, pp. 37-38, A p r i l , 1931. Anon. 1940. T r e a t i n g f i s h i n g n e ts and l i n e s . Western f i s h e r -i e s , V o l . 20, No.2, p. 6l, June 1940. Anon. 1942. D i v e r s e t n e t s used i n shark f i s h i n g . P a c i f i c Fisherman, V o l . 40, No.4, p. 39, March, 1942. B e l l , H. F. and J . T. G h a r r e t t . 1945- The P a c i f i c coast b l a c k -cod, Anoplopoma f i m b r i a . Copeia, No. 2, June 30, pp. 94-103, 1945. B r o c k l e s b y , H. N. 1927. D e t e r m i n a t i o n of v i t a m i n A content i n l i v e r o i l of the d o g - f i s h Squalus s u o k l i i . Can. Chem. Met., Sept. 1927H - 58 -1929. Vitamin D content of liv 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 particular reference to those of Canada. Fish. Res. Bd. Can. Bull. No. 59, pp. 408-409, 1941. Carlson, C. B. 1942. Subsurface gill-net fishing for soup-fin sharks. Pacific Fisherman, Vol. 40, No. 3, PP. 33, 35, February, 1942. Chaddock, R. C. 1925. Principles and methods of st 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 California waters. Ca l i f . Div. Fish and Game, Fish Bu l l . No. 53, 45 pp., f i g s . l-19b, 7 tables, 1939-Clark, G. H. 1931. The California halibut (Paralichthvs c a l i -fornicus) and an analysis of the boat catches. C a l i f . Div. Fish and Game, Fish B u l l . No. 32, 52 pp., 25 figs., 1931. 1933. Fluctuations in the abundance of striped bass (Roccus lineatus) in California. C a l i f . Div. Fish and Game, Fish. B u l l . No.39, 18 pp., 7 f i g s . , 1933. Clemens, W. A. and G. Wilby. 1946. Fishes of the Pacific coast of Canada. Fish. Res. Bd. Can. Bu l l . No. 68, 368 pp., 1946. Craig, J . A. 1930. An analysis of the catch statistics of the striped bass (Roccus lineatus), fishery of California. C a l i f . Div. Fish and Game, Fish. B u l l . No. 24, 41 pp., 22 f i g s . , 1930. Conner, G. 1935* Modernizing commercial fisheries s t a t i s t i c s . C a l i f . Div. Fish and Game, Fish Bull., No. 44, pp. 11-36, f i g s . 1-9, pp. 11-3-6, 1935-1937. Fish and game st a t i s t i c s . C a l i f . Fish and Game, Vol. 23, No. 2, pp. 113-118, 1937. Cooper, J . 1874. Remarks on the fisheries of British Columbia, by the agent of the department of marine and fisheries at Victoria. Sixth Ann. Rept. Dept. Mar. and Fish., Fish. Branch, App. V, pp. 205-206, for 1873, Ottawa, 1874. - 59 -Cunningham, F. H. 1920. Report of chief inspector, western fisheries division (British Columbia) for the year 1919* Fifty - t h i r d Ann. Rept. Fish. Br. Dept. Naval Serv. 1919, pp. 42-51, Ottawa, 1920. Firth, F. E. Foerster, R, and C. B. Carlson. .1944. Preservation and care of f i s h nets. Western Fisheries, Vol. 28, No. J, pp. 57-38, 40, June E. 1945. California soupfin shark captured in British Columbia. Fish. Res. Bd. Can. Prog. Rep. P a c , No. 64, p. 64, 1945. Hart, J. L. 1938. A brief account of the life-history of the pilchard. Rep. B r i t . Columbia Fish. Dept. 1937, pp. 50-56, 1938. Lord, J. K. 1866. The naturalist in Vancouver island and British Columbia. Vol. 1, 358 pp., London, 1866. Motherwell, J. A. 1923. Report of chief inspector, western f i s h -eries division (British Columbia) for 1922. Fifty-sixth Ann. Rept. Fish. Br., Dept. Mar. and Fish, for 1922-23. pp. 42-55, Ottawa, 1925. Annual report of the fisheries of Bri t i s h Columbia for the year 1886. Ann. Rept. Dept. Fish, for l886, App. No. 7, pp. 247-269, Ottawa, 1887. Annual report of the fisheries of Bri t i s h Columbia for the year -18.87. Ann. Rept. Dept. Fish for 1887, App. No. 7, pp. 239-252, Ottawa, 1888. British Columbia Fishery Commission Report 1892, pp. 1-433, i-xx, Ottawa, 1893. Dominion Fisheries Commission of Bri t i s h Columbia of 1905-1907, Report and Recommen-dations, pp. 1-111, Ottawa, 1908. British Columbia Fisheries Commission 1922, Report and Recommendations, pp. 1-35, Ottawa, 1925. Mowat, T. 1887. 1888. Report. I893. Report. 1908. Report. 1923. Ripley, W. E. 1946. The soupfin shark and the fishery. C a l i f . Div. Fish and Game, Fish. B u l l . No. 64, pp. 7-37, 1946. - 60 -Rounsefell, G. A. and G. B. Kelez. 1938. The salmon and salmon fisheries of Swiftsure bank, Puget sound, and the Fraser river. U.S. Bureau Fish. B u l l . v. 48, No. 27, pp. .693-823, 1938. Sanford, F. B. and K. Bonham. 1946. Grayfish liver colour re-lated to fin-spine length. Commercial Fish-eries Review, Vol. 8, No. 6, 1946. Silliman, R. P. and F. N. Clark. 1945. Catch per-unit-of-effort i n California waters of the sardine (Sardinops caerulea) 1932-1942. Ca l i f . Div. Fish and Game, Fish. B u l l . No. 62, 76 pp., 22 f i g s . , 1945. Swain, L. A. 1944. The.Pacific coast dog-fish and shark liver , o i l industry. Fish. Res. Bd. Can. Prog. Rep. P ac, No. 58, pp. 3-7, 1944. Taylor, E. G. 1916. Report on the fisheries of District No. 3, B r i t i s h Columbia. Forty-Ninth Ann. Rept. Fish. Br., Dept. Naval Serv. 1915-16, App. No. 9, pp. 260-263, Ott awa, 1916. Tester, A. L. 1945. Catch statistics ..of the British Columbia herring fishery to 1943-44. B u l l . Fish. Res. Bd. Can. No. 67, 47 pp. Thompson, W. F., H. A. Dunlop, and F. H. B e l l . 1931. Biologi-cal s t a t i s t i c s of the Pacific halibut fishery. (1) Changes in yield of a standar-dized unit of gear. Rept. Internat. Fish. Comm. No. 6, 108 pp., Appendices, 1931. 1934. Biological statistics of the Pacific halibut fishery. (2) Effect of changes in intensity upon yield and yield per unit of gear. Rept. Internat. Fish. Comm., No. 8, 49 pp., 1934. Whitehead, S. S. 1930. Analysis of boat catches of white sea bass (Cynoscion nobilis) at San Pedro, C a l i -fornia. Ca l i f . Div. Fish and Game, Fish Bu l l . No. 21, 26 pp., 20 f i g s . , 1930. 1931. Fishing methods for the bluefin tuna (Thunnus thynnus) and an analysis of the catches. C a l i f . Div. Fish and Game, Fish B u l l . No. 33, 32 pp. 22 figs., 1931-- 61 -V i l l i APPENDIX fab Is 1 Length Frequency Distributions of Dog-fish oaught by Sunken Gill-nets off Barkley Sound in June, 1944. Measurements made from 7 different "sets". length H O . length I>iO. length W O . Length i M O . (cm.) O f (cm.) O f I cm.) O f (cm. O f Males Males J Female s ire male s 60 1 89 32 60 1 89" • ^ 61 , 90 24 . 61 90 1 62 91 13 ' 62 91 63 92 16 - 63 92 2 64 93 10 64 93 2 65 94 4 65 94 1 66 95 6 66 95 3 67 96 2 67 96 5 68 97 3 68 1 97 1 69 98 69 98 2 70 2 99 1 70 5 99 1 71 1 100 71 1 100 4 72 2 101 72 1 101 3 73 5 102 73 102 2 74 1 103 74 103 4 75 4 104 75 104 3 76 4 105 76 105 7 77 9 106 77 2 106 3 78 3 107 78 1 107 1 79 9 108 79 108 1 80 20 109 80 1 109 2 81 26 110 81 110 5 82 29 111 82 1 111 83 41 112 83 1 112 2 84 48 113 84 5 113 1 85 46 114 85: 1 114 2 86 53 115 86 115 1 87 35 116 87 1 116 88 30 • 88 Total 480 cf T o t a l 8 1 2 Table 2 Length Frequency Distributions of Dog-fish Caught by Sunken Gill-nets off Darkley sound in August 1944. Measurements made from 10 different "sets". Length No. length No. length No. Length No. I cm..) of (cm.) of (cm.)) of :(cm.) of Males Males i'emales I Females 58 87 82 58 . 1 87 1 59 88 65 59 88 3 60 89 56 60 89 1 61 90 31 - 61 90 4 62 91 24 62 1 91 5 63 4 92 19 63 92 3 64 1 93 13 64 4 93 2 65 2 94 5 65 4 94 • 4 66 4 95 5 66 6 .95 3 67 6 96 67 12 96 3 68 5 97 1 68 6 97 4 69 6 98 69 8 98 3 70 11 99 70 9 99 71 14 100 71 6 100 2 72 7 101 72 6 101 73 6 102 73 6 102 74 16 103 74 5 103 2 75 24 104 75 7 104 76 22 105 76 3 105 77 31 106 77 9 106 78 33 107 78 4 107 2 79 33 108 79 4 108 2 , 80 47 109 80 5 109 81 56 110 81 4 110 82 67 111 82 4 111 1 83 71 112 83 1 112 84 70 113 84 7 113 1 85 81 114 85 10 114 86 58 115 86 2 115 116 1 1 Total 976 o" Total 182 9 Table 3 Length Frequency Distribution of Dog-fish Caught by Sunken Gill-nets in Hecate Strait in June 1946. Measurements made from 7 different "sets". length NO. Length •No. length No. length No. (cm.} of (cm.) of (cm.) of (cm.) of Males Males Females Females 65 93 65 1 93 15 66 94 66 94 19 67 95 67 95 23 68 96 68 1 96 19 69 97 1 69 3 97 15 70 1 98 70 3 98 7 71 1 99 71 1 99 13 72 100 72 3 100 18 73 101 73 5 101 15 74 2 102 74 2 102 9 75 1 103 75 6 103 11 76 1 104 76 3 104 • 7 77 1 105 77 4 105 8 78 3 - 106 78 3 106 11 79 4 107 79 7 107 11 80 1 108 80 8 108 10 81 1 109 81 4 109 8 82 1 110 82 5 110 7 83 2 111 83 3 111 .5 84 1 112 84 8 112 2 85 2 113 85 4 113 4 86 3 114 86 7 114 1 87 2 115 87 6 115 1 88 1 116 88 12 116 89 3 117 89 13 117 2 90 118 90 15 118 91 1 119 91 14 119 1 92 120 92 18 120 Total 33 o* Total 401 9 Table 4" Length frequency Distributions of Dog-fish Caught by Sunken Gill-nets off Barkley dound in June 1945. . Measurements made from 8 different "sets". length HQ. Length JMo. Length No. Length No. (cm. j O f (,cm. ) of (cm. ) of (cm.) of Males Males jremale s Females 60 1 91 60 91 7 61 92 1 61 92 5 62 93 2 62 1 93 8 63 94 1 63 94 12 64 95 64 1 95 10 65 96 65 96 17 66 97 66 97 14 67 98 67 98 14 68 1 99 68 1 99 18 69 1 100 69 • 100 21 70 101 70 1 101 18 71 2 102 71 3 102 17 72 103 72 103 29 73 104 73 1 104 21 74 1 105 74 2 105 22 75 2 106 75 106 18 76 2 107 76 1 107 13 77 4 108 77 1 108 7 78 2 109 78 2 .109 12 79 3 110 79 110 8 80 8 111 80 2 111 2 81 3 112 81 112 1 82 3 113 82 1 113 5 83 10 114 83 3 114 84 5 115 84 1 115 2 85 9 116 85 2 116 2 86 3 117 86 117 87 6 118" 87 3 118 1 88 10 119 88 5 119 1 89 6 120 89 1 120 1 90 5 90 4 Total 93 o* Total 342 $ Table 5 Length Frequency Distribution of Dog-fish caught by Otter Trawls off Amphitrite Point (Barkley Sound) in June and July 1945. length No. Length No. Length No. Length No. (cm.) of (cm. ) of (cm. ) of (cm. ) of Males Males Females Females 55 76 5 55 76 3 56 1 77 5 56 3 77 3 57 5 78 6 57 1 78 2 58 4 79 7 58 2 79 1 59 3 80 8 59 3 80 60 6 81 5 60 6 81 3 61 7 82 6 61 6 82 1 62 5 83 6 62 7 83 2 63 8 84 7 63 7 84 3 64 6 85 9 64 8 85 1 65 11 86 6 65 11 86 1 66 8 87 4 66 13 87 67 12 88 2 67 14 88 3 68 7 89 1 68 9 89 2 69 9 90 3 69 12 . 90 1 70 10 91 2 70 7 91 1 71 5 92 2 71 9 92 72 8 93 72 7 93 2 73 6 94 73 5 94 74 4 95 74 1 • 95 75 5 75 4 Total 214 c? Total 165 9 Table 6a Daily Landings of Dog-fish and Soup-fin Shark Livers Caught in Hecate Strait by Sunken Gill-net Boats (from available data). May 1943 May 1944 May 1945 May 1946 Weight of' Dog-fish Livers lb.. Weight of Soup-fin Shark Livers lb. No. of Trips Weight of Dog-fish Livers lb. Weight of Soup-fin Shark Livers lb. No. of Trips Weight of Dog-fish Livers lb. Weight of Soup-fin Shark Livers lb. No. of Trips Weight, of Dog-fish Livers l b . Weight of Soup-fin Shark Livers lb. No. of Trips 1 2 3 4 5 a 679 2 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 . 31 600 1,120 1 1 2,201 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 2 22 10 i 4 13 10 2 3 2 2 2 2 1 4 1' 6 3 3 4 7 5 2 1 3 6 7 5 4,158 750 1,620 435 48 6,118 9:, 610 12,315 9,010 41,743 - 14,250 13.978 1 3 1 1 4 2 1 9 10 8 6 27 13 8 24 57 301 86 164 98 742 408 4,927 5,891 5,519 9.555 2 1 1 2 1 1 1 2 1 4 3 6 7 Total 1.720 2 33.329 61 73 114.035 4 90 27.772 2 30 No. Boats 1 No. Boats 25 No. Boats 69 No. Boats 20 Table 6b Daily Landings of Dog-fish and Soup-^fin Shark Livers Caught in Hecate Strait by Sunken Gill-net Boats (from Available data)i June 1943 June 1944 June 1945 June 1946 Weight of Weight of Weight of Weight of Weight of Soupr-f in 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-fi sh Shark of Dog-fish Shark of Livers lb. Livers lb. Trips Livers lb. Livers lb. Trips Livers lb. Livers lb. Trips Livers l b . Livers lb. Trips 1 17,085 2 15 27,278 19 43 5,101 7 5 2 19,843 10 15 21,763 5 14 « 2,214 2 3 2,022 6 1 16,581 5 20 3,766 9 6,222 2 4 4,005 8 20,237 12 5 19,611 83 20 29,092 13 20 248 1 6 210 1 7,478 37,008 25 34 12,256 12 9 7 28,442 . 70 21 64,828 24 43 17,007 4 8 - 10,616 5 15 52,129 5 37 12,873 9 9 20,248 63 9 17,562 22 18 1,343 3 10 1,021 2 s 23,163 38 20 5,040 72 11 1,368 4 11 758 2 2 8,297 10 22,110 7 22 12,664 5 12 12 727 1 19,764 39 . 11 17,, 225 6 37 28,721 c8 15 13 8,505 28 6 11,827 14 24 4,847 45 8 14 368 * 1 22,502 43 10 19,860 5 . 26 2,934 4 15 1,571 5 3 24,652 65 11 •22,003 154 28 1,450 - 90 3 16 727 12 3 51,154 153 24 24,179 28 31 17,053 4 9 17 24,820 138 15 11,284 8 18 21,867 4 18 18 18,119 175 10 18,315 64 38 2,140 8 3 19 16,326 60 15 24,301 40 23 11,412 112 8 20 80 1 19,624 186 15 16,585 182 16 16,310 . 84 14 21 220 1 12,187 220 9 16,448 153 35 14,146 44 14 22 13,668 173 11 25,272 279 28 7,212 11 6 23 22,188 214 10 57,054 365 33 2,012 60 4 24 558 1 16,830 140 15 14,238 86 23 10,285 32 8 25 1,120 2 16,140 148 10 17,674 177 26 14,622 61 11 26 201 15 1 16,545 262 10 24,597 228 38 9,450 33 10 27 50,003 420 28 28,758 148 29 13,769 70 10 28 30,211 372 21 27,416 407 19 12,366 19 9 29 10,433 222 11 44,584 355 42 6,996 33 7 30 57.363 813 27 57.614 328 48 6,741 10 .3 Total. 10,386 40 20 626,404 4,147 434 780,047 3,219 825 275,629 752 215 No. Boats £ No. Boats 92 No. boats 217 No. Boats 70 Table 6 c Daily Landings of Dog-fish and Soup-fin Shark Li vets Caught in Hecate Strait by Sunken Gill-net Boats (from available data).. . July 1943 July 1944 July 1945 July 1946 height 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. Dog-fish Shark of Dog-fish Shark of Dog-fish Shark of Dog-fish Shark of Livers lb. Livers l b . Trips Livers lb. Livers lb. Trips Livers lb. Livers lb. Trips Livers lb. Livers lb. Trips 1 198 1 18,054 . 129 11 3,116 15 14 4,736 17 3 2 18,123 460 13 12,292 81 15 1,227 4 4 3 835 1 23,813 363 15 23,648 196 24 11,961 50 8 4 160 1 27,333 674 23 29,753 238 33 10,140 32 6 5 7,037 166 10 18,002 509 29 523 4 2 6 49,946 286 16 48,707 779 37 749 16 1 7 - 13,087 276 9 23,056 463 35 8,666 85 9 8 15,297 446 14 22,757 688 34 12,538 128 8 9 56 4 1 16,497 38 8 37,218 457 29 3,565 25 '-7 10 118 7 1 13,716 23 8 18,678 303 28 1,653 3 11 598 81 2 28,035 283 16 13,981 296 25 3,737 45 4 12 1,093 144 4 9,467 29 9 15,145 371 18 2,161 26 3 13 1,326 98 .2 20,724 349 10 13,777 301 13 7,445 300 6 14 1,874 136 3 2,430 14 5 15,051 472 24 615 4 1 15 799 43 3 .14,358 88 9 8,603 299 18 13,302 169 7 16 '7764 1-9 2 23,258 116 16 13,588 179 25 11,320 102 8 17 "199 1 24,369 966 17 24,956 521 34 20,583 176 14 18 .85 1 11,433 34 13 16,224 530 33 1,694 138 3 19 222 • 1 24,010 358 26 21,910 673 31 1,210 5 4 20 1,000 6 3 16,508 470 16 24,947 605 13 1,011 32 2 21 66 1 14,039 1;.109 9 17,239 256 9 2,847 68 5 22 353 13 1 11,652 303 7 4,565 465 8 .3,751 168 6 23 2,453 41 5 . 6,906 408 12 7,706 164 15 7,179 86 5 24 403 9 1 19,501 430 17 2,566 89 12 8,976 37 8 25 3,306 118 2 15,338 308 16 10,192 117 17 8,046 58 7 26 96 1 11,147 348 10 10,652: 188 7 5,930 81 6 27 403 2 11,911 1,179 •18 '8,710- 151 13 4,964 12 5 28 ,. 8,607 1,352 9 6,364 98 11 3,014 36 3 29 4,514 276 2 .8,941 739 8 • 9,280 164 9 11,498 88 9 30 627 15 3 , 8,834 914 10 1,348 59 7 10,821 79 ,. 7 31 2,152 .8 3 11,356 1,174 14 : 4,771 68 10 2.449 3 Total 23,700 1,027 48 505.827 13,?32 394 488,802 9,795 630 188.311 2,071 j 167 No. Boats 10 r NO. Boats 110 No. Boats 190 No. Boats 49 Tab la 6d Dally Landings of Dog-fish and Soup-fin Shark Livers Caught in Hecate Strait by Sunken Gill-net Boats (from available data). August 1943 August 1944 August 1945 August 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. Dog-fish Shark of Dog-fish Shark of ' Dog-fish Shark of Dog-fish Shark of Livers lb. Livers lb. TripB Livers lb. Livers.lb. Trips Livers l b . Livers lb. Trips Livers l b . Livers lb. Trips 1 . 1,056 9 3 12,658 1,154 18 9,656 175 17 852 4 2 4,023 240 1 '9,043 129 11 12,814 672 15 15,958 21 11 3 4,187 48 2 18,018 804 21 5,599 110 7 9,649 18 5 4 820 1 26,188 380 18 14,740 99 13 5 12,426 158 17 5,124 18 13 19,675 19 9 6 2,948 146 3 8,544 260 8 20,898 271 17 2,709 4 4 7, 3,470 766 2 12,584 228 12 8,294 31 11 10,668 86 6 8 1,333 82 . 3 16,153 106 9 13,415 50 14 3,101 5 4 .9 2,340 83 2 3,660 32 4 8,703 124 12 12,592 3 7 10 98 1 12,969 492 13 5,344 61 8 12,666 31 11 11 148 1 10,089 152 8 6,084 31 4 4,143 23 3 12 4,619 27 2 13,614 158 12 2,169 2 8 16,977 2 6 13 1,288 12 2 3,000 1 5,758 52 19 6,736 4 14 1,388 652 2 4,636 243 6 7,678 31 11 1,611 14 6 15 263 2 18,943 318 11 9,416 . 23 12 15,841 45 11 16 3,473 6 2 11,742 65 8 7,383 9 14 4,467 5 3 17 450 234 1 15,358 153 12 4,263 71 • 7 4,245 ' 11 "4 18 6,553 110 8 2,312 6 8 28,378 2,768 7 6 19 25,212 177 15. 4,578 27 9 8 4 20 12,633 ' 165 10 14,327 107 12 13,720 39 12 21 59 208 1 5,556 141 6 9,518 143 10 22 110 14,090 111 11 7,039 15 14 23 1,499 6 2 3,000 1 4,418 52 10 74 1 24 125 1 4,267 39 8 7,980 '26 12 6,094 3 7 25 4,951 45 3 7,606 76 3 2,867 5 5 1,471 - 2 2 26 1,240 2,028 2 2,020 20 7 11,143 23 11 2,035 10 3 27 61 16 1 1,239 16 3 349 3 3 5,943 37 6 28 10,823 34 10 3,450 48 7 10,500 6 5 29 2,409 513 1 4,818 73 9 57 • 2 4,644 5 3 30 1,976 1,025 1 3,423 24 6 658 22 2 1,059 3 2 31 .. .5.315 • 39 6 3.329 22 . 6 12.474 73 . 8 Total. 44,224 6,256 42 316,180 5,857 292 219,363 2.329 313 231.050 480 157 No. Boats 9 No. Boats 76 No. Boats 91 No. Boats 35 Table 6e Daily Landings of Dog-fish and Soup-fin Shark Livers Caught in Hecate Strait by Sunken Gill-net Boats (from available data),  September 1943 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. Dog-fish Shark ' of Dogrfish Shark of • Dog-fish Shark of Dog-fish Shark Of Livers lb. Livers lb. Trips Livers lb. Livers lb. Trips Livers, lb. Livers lb. Tri"ps Livers lb. Livers lb. Trips 1 2,653 4 19,699 72 . 14 998 4 1,057 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 22 1,686 12 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 29 4,395 13 3 5,352 24 7 88 1 7,181 6 3 30 721 499 2 805 1 1.821 5 3f630 , 6 5 Total 42.119 5.425 59 144.697 445 146 82.020 254 128 161.457 208 177 .• * • f No. Boats 15 No. Boats 45 No. Boats 64 No. Boats 38 Table 6f Daily Landings of Dog-fish and Soup-fin Shark Livers Caught in 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 of 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 lb. Trips Livers lb. Livers lb. Trips. Livers lb. Livers lb. Trips Livers l b . Livers lb. Trips 1 564 18 2 - 3,688 3 1,138 -., 3 - 3,428 11 2 1,984 150 3 4,927 1 1,320 4 3 2,042 23 6 748 2 1,202 3 4. • 2,204 13 6 1,956 5 853 2 5 1,877 3 5 4,009 5 4,550 3 100 3 1 6 2,781 10 6 535 - 1 4,479 . 3 6 482 1 7 5,486 65 8 649 2 1,440 4 2 1,065 Oil U4 8 1,933 4 4,126 • 26 5 6,728 9 2,367 4 2,270 3 4,020 . 7 5 1,842 3 10 414 1 5,371 4 2,121 3 11 863 3 2,941 3 1,938 5 1,361 1 12 2,099 24 5' 3,373 3 ; 4,350 2 2,860 3 13 2,348 3 1,419 3 • 14 1,319 3 15 1,328 5 264 1 1,424 6 213 2 16 3,291 3 2,464 8 4 ." 2,360 5 900 2 17 1,047 3 7,358 • 4 752 1 4,927 9 18 937 5 "1,864 3 1,804 3 144 2 19 2,202 7 4,523 2 1,270 123 5 660 1 20 602 2 242 . 1 5,587 8 367 2 21 101 1 1,085 2 192 2 78 1 22 921 3 640 2 ' 2,541 2 •. 23 1,934 6 2,832 3 187 2 2,568 3 24 168 1 1,000 2 357 5 25 261 2 766 1 2,007 2 26 396 3 656 3 93 2 . 1,080 4 27 330 2 4,615 3 .  28 ^132 1 385 3 860 - 7 465 2 29 2,837 6 84 1 30 194 7 1 643 5 31 , j 1.213 4 2,215 3 . 2,396 5 Total 1 1 41,389 310 101 50,696 8 63 63.664 165 .114 36.677 3 66 : [ No. Boats 19 No. Boats 17 No. Boats 38 No. Boats 24 Table. 7 T o t a l Weight ( l b . ) of 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 Boats from Hecate S t r a i t from 1943 to 1946. The number of boats l a n d i n g d o g - f i s h 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 weight. 1943 1944 1945 1946 May 1,720 (1) 33,329 (25) 114,035 (69) 27,772 (20) June 10,386 (3) 626,404 (92) 780,047 (217) 275,629 (70) J u l y 23,700 (10)' 505,827 (110) 488,802 (190) 188,311 (49) August 44,224 (9) 316,180 (76) 219,363 (91) 231,050 (35) September 42,119 (15) 144,697 (45) 82,020 (64) 161,457 (38) October 41,389 (19) 50,696 ( l 7 ) 63,664 (38) 36,677 (24) T o t a l 163,528 (59) 1,677,133 (365) 1,747,93.1 (669) 920,896 (236) Weighted Average catch per boat per month. 2,772 4,595 2,613 3,902 Table 8 T o t a l Weight ( l b . ) of Dog-fish L i v e r s landed each Month by Sunken G i l l - n e t Boats from Hecate S t r a i t , from 194-3 to 1946. The number o f . t r i p s per boat per month i s i n d i c a t e d i n brackets below the weight. 1 9 4 3 1 9 4 4 1 9 4 5 1 9 4 6 May 1 , 7 2 0 ( 2 ) 3 3 , 3 2 9 ( 7 3 ) 114 , 0 3 5 ( 9 0 ) 2 7 , 7 7 2 ( 3 0 ) June 1 0 , 3 8 6 (20). 626,404 ( 4 3 4 ) 780.047 ( $ 2 5 ) 2 7 5 , 6 2 9 ( 2 1 5 ) J u l y 2 3 , 7 0 0 ( 4 8 ) 5 0 5 , 8 2 7 ( 3 9 4 ) 4 8 8 , 8 0 2 ( 6 3 0 ) 1 8 8 , 3 1 1 ( 1 6 7 ) August 44,224 (42) 3 1 6 , 1 8 0 ( 2 9 2 ) 2 1 9 , 3 6 3 ( 3 1 3 ) 2 3 1 , 0 5 0 ( 1 5 7 ) September 42 , 1 1 9 ( 5 9 ) 144 , 6 9 7 (146) 8 2 , 0 2 0 ( 1 2 8 ) 1 6 1 , 4 5 7 ( 1 7 7 ) October 41 , 3 8 9 ( 1 0 1 ) 5 0 , 6 9 6 ( 6 3 ) 6 3 , 6 6 4 (114) 36,677 (66) T o t a l 1 6 3 , 5 3 8 ( 2 7 2 ) 1 , 6 7 7 , 1 3 3 (1,402) 1 , 7 4 7 , 9 3 1 ( 2 , 1 0 0 ) 9 2 0 . 8 9 6 ( 8 1 2 ) Weighted Average catch per t r i p per boat per month 6 0 1 1 , 1 9 6 8 3 2 1,134 Table 9 Average Catch (lb.) 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. 1943 1944 1 9 4 5 1 9 4 6 May 1 , 7 2 0 1 , 3 3 3 - 2 1 , 6 5 2 . 7 1 , 3 8 8 . 6 June 2 , 0 7 7 . 2 6 , 8 0 8 . 7 3 , 3 9 4 . 7 3 , 9 3 7 . 6 July 2 , 3 7 0 . 4 , 5 9 8 . 4 2 , 5 7 2 . 6 3 , 8 4 3 . 1 August 4 , 9 1 3 - 8 4 , 1 6 0 . 3 2,410 .6 6 , 6 0 1 . 4 September 2 , 8 0 7 - 9 3 , 2 1 5 . 5 1 , 2 8 1 . 6 4,248 .9 October 2 , 1 7 8 . 4 2 , 9 8 2 . 1 1 , 6 7 5 - 4 1 , 5 2 8 . 2 Weighted average > catch per boat per month 2 , 7 7 1 . 8 . 4,594 .9 2 , 6 1 2 . 7 3 , 9 0 2 . 1 Table 10 Average Catch ( l b . ) per T r i p 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. 1 9 4 3 1944 • 1 9 4 5 1 9 4 6 May- 8 6 0 . 0 4 5 6 . 6 1 , 2 6 7 . 1 ' 9 2 5 . 7 June 3 1 9 . 3 1 , 4 4 3.3 i 9 4 5 . 5 1 , 2 8 2 . 0 J u l y 4 9 3 . 7 1 , 2 8 3 . 8 7 7 5 . 9 1 , 1 2 7 . 6 August 1 , 0 5 2.9 1 , 0 8 2 , 8 7 0 0 . 8 1 , 4 7 1 . 7 September 713.9 991.1 6 4 0 . 8 .912.2 October 409.8 8 0 4 . 7 5 5 8 . 5 5 5 5 . 7 Weighted average catch per t r i p per boat per month 601.2 1 , 1 9 6 . 2 8 3 2 . 3 1,134.1 Table 11 Index of the Average Catch per Boat per Month of Dog-fish Livers landed by Sunken Gill-net Boats from Hecate Strait, from 1943 to 1946. Determined by the method of link 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 Trip 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 194-3 to 194-6 Determined by the method of l i n k r e l a t i v e s . 1943 1944 1945 1946 May 1 . 0 0.53 1.47 1 . 0 7 June 1 . 0 2 . 7 8 1 . 8 1 2.46 July 1 . 0 2 . 6 0 I . 5 6 2 . 2 6 August 1 . 0 1 . 0 3 0.67 1.41 September 1 . 0 1 . 3 9 0 . 9 0 1 . 2 8 October 1 . 0 1 . 9 6 1.35 1.34 Index f o r 1 . 0 1 - 9 9 I . 3 8 1 . 8 8 Each Year. ~ " Table 13 Monthly Landings of Dog-fish Livers landed by. the same Sunken Gill-net Boats, Fishing in adjacent years in Hecate Strait. 1943 1944 May June July August September October May June July August September October Weight of Dog-fish Livers (lb.) 3,615 18,417 20,389 8,803 6,162 4,136 9,918 7,474 6,452 14,548 Number of boats 2 5 4 3 3 2 5 4 3 3 Average Catch per boat (lb.) 1,808 3,683 5,097 2,934 2,054 2,068 1,984 1,869 2,151 4,849 1944 1945 Weight of Dog-fish Livers (lb.) May June July August September October May June July'- August September October 19,735 438,750 333,569 108,536 24,776 16,305 18,894 215,960 145,533 60,746 15,157 10,301 Number of boats 10 56 52 23 7 4 10 56 52 23 7 4 Average Catch per boat (lb.) 1,974 7,835 6,415 4,719 3,539 " 4,076 1,889 3,856 2,799 2,641 2,165 2,575 Weight of Dog-fish Livers (lb.) 1945 194 L6 May June July August September October May June July August September October 19,129 290,371 159,376 65,964 34,005 15,166 14,586 235,831 168,685 149,424 40,668 15,547 Number of Boats 9 53 39 19 15 10 9 53 39 19 15 10 Average Catch per boat (lb.) 2,125 5,478 4,087 3,472 2,267 1,517 1,621 4,450 4,325 7,864 2,711 1,555 Table 14 Index of the Catch of D o g - f i s h L i v e r s landed by the same Sunken G i l l - n e t Boats F i s h i n g i n adjacent y e a r s , 1 9 4 3 - 4 4 , 1 9 4 4 - 4 5 , 1 9 4 5 - 4 6 , i n Hecate S t r a i t . Determined by the method of l i n k r e l a t i v e s . 1943 1944 I 9 4 5 1946 May •. 0 . 7 4 1 0 . 7 0 9 O.54O ' June 1.0 1 .144 O .563 0 . 4 5 7 J u l y 1 . 0 0 . 5 3 8 0 . 2 3 5 0 . 2 4 9 August 1.0 0 . 3 6 7 0 . 2 0 5 0 . 4 6 4 September 1.0 0 . 7 3 3 0 . 4 4 9 0 . 5 3 7 October 1 . 0 2 . 3 6 0 1.491 1.-528 Index each 1.0 0 . 7 4 1 0 .367 0 . 3 9 2 year Table 15 T o t a l Weight ( l b . ) of Soup-fin Shark L i v e r s landed each Month by Sunken G i l l - n e t Boats from Hecate S t r a i t , from 1 9 4 3 to 1 9 4 6 . The number of boats l a n d i n g s o u p - f i n shark l i v e r s each month i s i n d i c a t e d i n brackets below the weight. 1 9 4 3 1944 ' 1 9 4 5 1 9 4 6 May U ) ~ 6 1 ( 2 5 ) 4 ( 6 9 ) 2 ( 2 0 ) June 40 (5) 4,147 ( 9 2 ) 3 , 2 1 9 ( 2 1 7 ) 7 5 2 (70) J u l y 1 , 0 2 7 ( 1 0 ) 1 3 , 7 3 2 ( 1 1 0 ) 9 , 7 9 5 ( 1 9 0 ) 2,071 ( 4 9 ) August 6 , 2 5 6 (9) 5 , 8 5 7 ( 7 6 ) 2 , 3 2 9 ( 9 1 ) 4 8 0 ( 3 5 ) September 4 , 5 2 5 ( 1 5 ) 4 4 5 ( 4 5 ) 254 ( 6 4 ) 2 0 8 ( 3 8 ) October 3 1 0 • ( 1 9 ) 8 ( 1 7 ) 1 6 5 ( 3 8 ) 3 (24) T o t a l 1 3 , 0 5 8 ( 5 9 ) 2 4 , 2 5 0 ( 3 6 5 ) 1 5 , 7 6 6 * (669) 3 , 5 1 6 (236) Weighted average catch per boat per month 225-14 6 6 . 4 4 2 3 . 5 7 1 4 . 9 0 Table 16 T o t a l Weight ( l b . ) of S o u p - f i n Shark L i v e r s landed each Month by Sunken G i l l - n e t Boats from Hecate S t r a i t , from 1 9 4 3 to 1 9 4 6 . The number of t r i p s per boat per month i s i n d i c a t e d i n br a c k e t s below' the weight 1 9 4 3 1 9 4 4 1 9 4 5 1 9 4 6 May " ( 2 ) 6 1 (72) 4 .(90) 2 ( 5 0 ) June 40 ( 2 0 ) 4,147 (424) 3,219 ( 8 2 5 ) 7 5 2 ( 2 1 5 ) J u l y 1 , 0 2 7 ( 4 8 ) 12,722 (294) 9 , 7 9 5 ( 6 3 0 ) 2 , 0 7 1 ( 1 6 7 ) August 6 , 2 5 6 (42) 5 , 8 5 7 ( 2 9 2 ) 2 , 3 2 9 ( 3 1 5 ) 480 ( 1 5 7 ) September 5 , 4 2 5 ( 5 9 ) 4 4 5 (146) 2 5 4 ( 1 2 8 ) 2 0 8 ( 1 7 7 ) October 3 1 0 ( 1 0 1 ) 8 ( 6 5 ) 1 6 5 (114) 5 ( 6 6 ) T o t a l ' 1 3 , 0 5 8 ( 2 7 0 ) 2 4 , 2 5 0 (1,402) 1 5 , 7 6 6 ( 2 , 1 0 0 ) 5 , 5 1 6 ( 8 1 2 ) Weighted average per t r i p per boat per month 4 8 . 2 6 1 7 . 5 0 7 . 5 1 ' 4 . 5 5 Table 17 rage Catch ( l b . ) per Boat per Month of Soup-fin Shark 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 194J to 1946. 1943 1944 1945 1946 May 2 . 4 4 0 . 0 6 0 . 1 June 8 . 0 0 4 5 . 0 7 14 . 8 3 1 0 . 7 4 J u l y 1 0 2 . 7 124 .84 5 1 . 5 5 42 . 2 6 August 6 9 3 . 1 1 7 7 . 0 6 2 5 . 5 9 1 3 . 7 1 September 3 6 1 . 6 7 9 . 8 9 3.97 5 . 4 7 October 1 6 . 3 1 0 . 4 7 4 . 3 4 0 . 1 2 Weighted average catch per boat per month 2 2 5 . 1 4 6 6 . 4 4 2 3 . 5 7 14.90 T Table 18 Average Catch, ( l b . ) per T r i p per Boat per Month of Soup-fin Shark 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 l°4o 194? 1944 1945 1946 May 0.84 0.04 0.07 June 2.00 9.55 3.90 3.50 J u l y 21.40 34.85 1-55 12.40 August 148.95 20 .06 7.44 3.08 September 91-94 3.05 1.98 1.18 October 3.07 0.13 1.45 0.04 Weighted .average catch per t r i p per boat per month 48.36 17.30 7.51 4.33 Table 19 Index of the Average Catch per Boat per Month of S o u p - f i n Shark 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 1 ° 4 6 Determined by the method of l i n k r e l a t i v e s . 1943 1944 1945 1946 May - - — ' 0 . 2 9 5 0 . 2 5 0.42 June 1 .0 5 . 6 3 1 .86 1 .34 J u l y 1 . 0 1 .22 0 . 5 0 0.41 August 1 .0 0 . 1 1 0.04 0 . 0 2 September 1 . 0 0 . 0 3 0 . 0 1 0 . 0 1 October 1.0 0 . 0 3 0 . 2 8 0 . 0 1 Index f o r each year 1 .0 0 . 2 9 5 0 . 1 0 5 0 . 0 7 Table 20 Index of the Average Catch per T r i p per Boat per Month of Soup-fin Shark 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 1 9 4 ? to 1946... Determined by the method of l i n k r e l a t i v e s . 1942 1944 1 9 4 5 1 9 4 6 May 0 . 3 3 7 0 . 0 5 0 . 8 7 June 1 . 0 4 . 7 7 1 . 9 6 1 . 7 6 J u l y 1 . 0 1 . 6 3 0 . 0 6 0 . 4 8 August 1 . 0 0 . 1 3 0 . 0 2 0 . 0 2 September 1 . 0 0 . 0 3 0 . 0 2 0 . 0 1 October 1 . 0 0.04 0 . 4 5 0 . 0 1 Index.for each year. 1 . 0 0 . 3 3 7 0 . 1 3 3 ^ 0 . 0 9 Table . 21 Monthly Landings of Soup-fin Shark Livers landed by the same Sunken uill-net Boats Fishing in adjacent iears i n Hecate Strait 1943 1944 May June July August September October May June -July August September October Weight of Soup-fin Shark Livers (lb.) 22 724 591 19 14 84 2,056 814 37 Number of Boats 2 5 4 3 3 • 2 5 4 3 3 Average Catch per boat (lb.) 11 145 148 6 5 42 411 204 12 1944 1945 May June July August September October May . June July August September October Weight of Soup-fin Shark Livers (lb.) 39 2,762 10,530 1,874 86 8 1,028 2,250 339 70 2 Number of Boats 10 56 52 23 7 4 10 56 52 23 7 4 Average Catch per boat (lb.) 4 49 203 81 12 2 — - 18 43 15 10 0.5 1945 1946 May June July August September October May June July August September October Weight of Soup-fin Shark Livers (lb.) 1,248 3,459 304 85 34 2 572 1,848 271 145 Number of Boats 9 53 39 19 15 10 9 53 39 19 15 10 Average Catch per boat (lb.) 24 89 16 6 3 0.2 11 47 14 10 Table 22 Index of the Catch of Soup-fin Shark L i v e r s landed by the same Sunken G i l l - n e t Boats F i s h i n g i n Adjacent Years, 1943-44, 1944-45, 1945-46, i n Hecate S t r a i t . Determined by the method of l i n k r e l a t i v e s . 1945 1944 1945 1946 May — ' June 1.0 3.818 1.420 0.650 J u l y 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 Daily Landings of Dog-fish Livers Caught off'Barkley Sound by Sunken Gi l l - n e t Boats (from a v a i l -able data) . •May 1944 May 1945 Weight of Number • Weight of Number Dog-fish of. Dog-fish of Livers l b . Tr i p s ' Livers l b . Tr i p s 1 6 5 7 4 1 2 6 3 2 224 1 357 3 • 3 3 6 5 7 1,418 5 4 94 04 2 7 6 3 5 202 6 2 1 6 27 1 2 , 4 6 0 2 3 7 3 6 0 5 5 8 8 8 1,074 4 20 5 9 847 • 5 64 2 1 0 11 12 13 48 1 14 1 5 1 9 2 4 1 6 1 5 5 1 101 3 17 1 8 . 1 , 0 5 1 8 19 9 0 0 7 . ' 1,415 6 20 3 1 8 7 6 7 8 6 21 1 , 1 7 6 9 6 0 7 5 22 764 11 1,974 4 2 3 8 7 1 1 0 1 , 8 8 3 5 24 819 9 2,504 7 2 5 . 1,278 1 0 9 0 9 4 2 6 3,032 1 2 2 , 5 2 6 8 2 7 1 , 8 2 8 1 3 2,012 6 28 880 1 1 1,142 5 29 1 , 5 8 1 14 3 0 0 1 3 0 1 , 1 5 9 1 7 3 1 793 11 Total 19,404 179 22 , 1 2 3 1 2 6 Table 23b D a i l y Landings of Dog-fish 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 June 1 9 4 5 June 1946 • Weight of Number Weight of Number Weight of Number Dog-fish of Dog-fish of Dog-fish of L i v e r s l b . T r i p s L i v e r s lb. T r i p s L i v e r s lb. T r i p s 1 2 3 7 5 4 , 1 0 8 1 8 2 5 5 5 8 8 8 8 7 2 7 6 2 6 5 0 6 1 , 0 7 9 4 , 3 2 5 5 4 7 3 4 . 9 1 , 2 2 9 1 , 1 8 6 6 1 1 5 2 6 4 5 8 1 , 5 6 6 9 6 9 2 9 5 2 , 9 6 6 1 2 9 5 1 1 3 7 1 7 6 2 2,427 •8 3 6 3 6 8 2 , 2 9 2 1 5 1 , 4 6 2 9 1,140 1 1 9 2 , 7 3 7 2 0 2 9 6 4 2 , 6 2 8 1 1 1 0 2,471 14 28 1 2 , 1 1 2 3 , 7 0 7 1 1 1 1 1 , 7 8 6 1 0 1 1 0 2 1 1 1 2 2 , 9 6 5 1 5 1 , 8 8 9 7 3,402 1 1 1 3 2 , 6 6 0 2? 1 0 2 1 4 , 8 9 0 1 0 14 1,724 1 6 2 , 1 1 1 9 3 , 1 8 0 1 1 1 5 1 , 3 2 6 1 1 1 , 2 6 0 8 9 7 7 1 6 1 , 8 4 6 . 1 6 7 2 , 2 6 1 1 2 1 7 1 , 9 1 2 1 7 5 3 4 7 1 , 0 3 5 1 , 3 7 3 9 1 8 1,914 1 5 104 2 1 0 19 2 , 1 2 3 1 7 1 , 0 6 2 7 4 5 5 2 2 0 1 , 4 8 9 1 7 142 5 1 1 2 1 2 1 5 8 7 1 7 1 0 6 1 2 2 3 7 2 1 0 8 6 6 1 0 ' 5,742 2 3 9 8 7 14 9 2 1 9 3 , 5 4 4 1 0 24 3 9 0 7 8 7 3 8... 6 6 4 1 2 5 2 2 8 7 3 5 5 2 2 6 7 1 5 1 1 2 6 1 5 2 7 8 8 9 8 1 , 5 1 3 7 2 8 2 , 8 6 4 1 3 1,596 9 6 0 4 6 2 9 2 , 8 0 5 14 469 9 3 0 1 , 5 5 6 1 3 441 6 T o t a l 4 1 , 6 0 9 3 5 2 3 0 , 2 4 6 1 9 2 4 5 , 7 4 9 1 9 5 Table 2Sc D a i l y Landings of 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 data) duly 1944 J u l y 1945 J u l y 1946 Weight o f Number Weight of Number Weight of Number D o g - f i s h of D o g - f i s h of D o g - f i s h of L i v e r s l b . T r i p s L i v e r s l b . T r i p s L i v e r s l b . T r i p s 1 2 ,376 16 369 4 2 , 8 1 3 8 2 639 7 53 3 . 1 ,365 3 3 2,841 29 409 4 729 5 4 736 . 10 1 ,053 8 5 23 1 571 3 1 ,351 6 6 695 14 626 3 712 6 7 767 12 . 98 2 8 653 8 82< 1 569 7 9 156 3 288 3 10 326 6 934 11 11 617 12 1 ,192 7 12 2 ,988 30 436 8 13 1 ,374 18 311 2 79 5 14 819 13 392 3 13 832 11 803 14 16 1,148 7 607 3 670 9 17 1 ,736 x? 231 3 151 1 18 2 , 8 3 2 1 , 4 5 4 16 623 3 1 ,773 16 , 19 11 602 3 567 5 20 2 ,379 467 3 ' 21 2 , 5 7 3 18 374 4 22 1 ,523 12 1 , 4 9 0 3 23 444 4 24 1,173 15 451 '2 25 606 15 26 213 5 650 4 27 1 , 0 2 1 719 17 164 3' 28 11 74 ' 2 29 421 3 240 2 '30 2 ,078 14 510 5 31 3 , 6 5 5 15 T o t a l 3 9 , 8 1 7 379 9 , 2 9 6 63 1 5 , 5 8 3 124 Table 23d D a i l y Landings of D o g - f i s h L i v e r s Caught o f f Barkley Sound by Sunken G i l l - n e t Boats .'Cfrom a v a i l a b l e d a t a ) . August 1944 August 1945 Weight of Number "Weight of Number D o g - f i s h of D o g - f i s h of L i v e r s l b . T r i p s L i v e r s l b . T r i p s 1 1 ,711 13 122 2 2 1 , 0 9 0 14 317 3 3 398 5 396 4 " 4 1,311 17 603 4 5 527 8 583 3 6 1 , 0 2 5 223 19 252 3 7 ' 7 470 5 8 349 2 9 1,004 13 571 4 10 8 9 3 16 64 1 11 452 6 658 6 12 20 1 5 1 13 767 9 14 595 10 378 3 15. 2 , 7 0 9 32 123 3 16 600 13 255 3 17 350 4 18 1 ,437 19 63 3 19 585 5 353 5 20 2,204 581 18 59 3 21 6 442 • 5 22 755 15 23 3 , 1 9 0 33 136 4 24 629 16 143 3 2 ^ 1,111 840 ^ 447 3 26 8 27 1 ,232 15 414 2 28 1,018 12 296 3 • 29 535 12 63 1 30 524 .4 67 3 31 41 1 52 2 T o t a l 2 8 , 7 0 6 368 7 , 3 3 2 82 Table 23e D a i l y Landings of Dog-fish L i v e r s Caught o f f Bar 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 ) . September 1944 Weight of Number Dog-fish of L i v e r s l b . T r i p s _ 1 837 8 2 820 8 3 2,825 23 4 1,159 16 5 372 7 6 65 3 7 151 2 8 207 4 9 424 4 10 477 6 11 151 • 1 12 132 2 13 96 2 14 268 5 15 18 o 3 16 457 4 17 59 2 18 19 76 2 20 58 3 21 22 23 24 25 26 27 30 1 28 102 2 29 84 1 30 T o t a l 9,030 109 Table 24 T o t a l Catch ( l b . ) 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 F i s h i n g o f f B a r k l e y Sound on the West Coast of . Vancouver I s l a n d from 1944 to 1946. (from a v a i l a b l e data) The number of boats f i s h i n g i n each month i s i n d i c a t e d i n b r a c k e t s . 1944 1945 1946 May 19,404 (20) 2 2 , 1 2 3 (14) June 41 , 6 0 9 ( 3 D 3 0 , 2 4 6 (14) 45 ,749 (17) J u l y 3 9 , 8 1 7 ( 3 D 9 , 2 9 6 (6) 1 5 , 5 8 3 (13) August 2 8 , 7 0 6 (24) 7 , 3 3 2 (6) September. 9 , 0 3 0 (13) f T o t a l 1 3 8 , 3 6 6 (119) 6 8 , 9 9 7 (40) 6 1 , 3 3 2 (30) Table 25 Index of the Return 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 landed by Sunken G i l l - n e - t Boats F i s h i n g o f f B a r k l e y Sound on the West Coast of Vancouver I s l a n d , from 1944 to 1946. 1944 1945 1946 May 1 5 . 5 25.1 June 16.9 22 .5 33-5 J u l y 1 5 . 0 21.1 1 8 . 0 August 11.1 12.8 September 11.8 

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