249 dogfish stomachs examined, 188 contained 

 food, and all of the stomachs having food con- 

 tained some eulachon. Salmonoids were found 

 in two stomachs. 



Dominant food items in stomachs of dog- 

 fish taken from the west coast of Vancouver 

 Island, British Columbia, included shrimp, 

 herring, flatfish, and sand lance (Ammodytes 

 tobianus); whereas dogfish collected from 

 Hecate Strait contained large amounts of 

 flatfish, herring, squid, octopus, and shrimp. 

 The investigators (Chatwin and Forrester, 

 1953) concluded that dogfish are "opportunists, 

 rather than discriminating predators." There 

 is no evidence to suggest that dogfish mate- 

 rially affect salmon stocks by predation. 



Migrations 



Movements of dogfish have been studied and 

 reported by Holland (1957), Kauffman (1955), 

 and Bonham, Sanford, Clegg, and Bucher 

 (1949). Tagging studies have indicated that 

 the offshore dogfish population or populations 

 may be highly migratory. Some rather long 

 migrations have been noted. One fish, tagged 

 in Willapa Harbor, Wash., was recovered off 

 the northeast corner of Honshu Island, Japan. 

 Migrations between California and British 

 Columbia have also been noted. 



Dogfish within Puget Sound show less ten- 

 dency to migrate, and Puget Sound stocks 

 are apparently somewhat independent from 

 coastal and offshore stocks. Nevertheless, 

 some movement of dogfish may occur between 

 ocean areas and Puget Sound. 



and as a machine lubricant and grease for 

 skidways on logging roads. Before cheap 

 petroleum products became available, dogfish 

 oils brought as much as 40 cents a gallon 

 in the Puget Sound area. Barraclough (1953) 

 reports that large quantities of dogfish oil 

 were used for lubrication and lighting in saw- 

 mills at Burrard Inlet and in coal mines at 

 Nanaimo and Departure Bay, British Columbia. 

 Lighthouses in British Columbia also burned 

 dogfish oil. Clemens and Wilby (1946) state 

 that a reduction plant in Skidegate Inlet, 

 British Columbia, was producing dogfish oil 

 in 1880. 



Attempts to use dogfish as human or chicken 

 food have been largely unsuccessful in North 

 America. A program designed to encourage 

 human consumption of dogfish in the United 

 States was approved as a wartime measure 

 on June 21, 1916. Congress appropriated 

 $25,000 for the purpose, and 4 million pounds 

 of dogfish were landed in 1917. But the 

 market, which disappeared as the more tradi- 

 tional food fish became available again after 

 World War I, has never been revived. Experi- 

 mental attempts to can dogfish have not met 

 with success owing, in part, to the in-the-can 

 breakdown of dogfish urea into ammonia and 

 carbon dioxide. Reduction of dogfish carcasses 

 to provide meal for chicken feeds has also 

 been attempted, intermittently, without much 

 success, although limited quantities of car- 

 casses are still reduced for chicken feeds 

 and fertilizer. Properties of meals, and the 

 suitability of meals as chicken feeds, are 

 described in a bulletin published by the State 

 College of Washington (Rhian, Carver, Harri- 

 son, and Hamm, 1942), 



HISTORY OF THE FISHERY 



The North American Fishery in 

 the Pacific 



Along the shores of the eastern Pacific, dog- 

 fish were first exploited by Indians who ex- 

 tracted clear oils from dogfish livers by heat 

 and pressure (Lord, 1866). Oils so obtained 

 were used primarily for dressing animal 

 skins, flavoring food, finishing wood, and 

 preparing paint. Early white settlers in the 

 Pacific Northwest used the oil also in lamps 



Early tests (based on total nitrogen) indi- 

 cated that dogfish flesh might have a high 

 protein content, but later tests (based on pro- 

 tein nitrogen) proved that the protein content 

 (and therefore the nutritive value) of the 

 edible portions of the dogfish is less than 

 that of teleost (bony) fishes. Dogfish tissues 

 contain a high percentage of nonprotein nitro- 

 gen, much of which is in the form of urea 

 plus trimethylamine. 



The use of shark livers as a source of 

 vitamin A was responsible for the large-scale 



