The remains of M. robusta were found in 

 the ston^ach of a fur seal collected about 25 

 miles west of the Farallon Islands on 21 May 

 1965. This is the second specimen identified 

 from fur seal stomachs. The first, also taken 

 off California, was obtained in 1961 but not 

 identified until comparative material became 

 available in 1962. 



M . robusta is an important food of sperm 

 whales off central California (Rice, 1963), but 

 because of its large size is probably not regu- 

 larly eaten by fur seals. The cartilaginous end 

 cone of the pens from two whole specimens in 

 our reference collection approximated one- 

 fourth of their dorsal mantle length (DML). 

 The end cone found in 1 965 measured 1 50 mm., 

 indicating a DML of about 600 mnn. A squid of 

 this size cannot be swallowed whole. Frag- 

 ments of flesh were found in addition to the 

 end cone. Beaks or additional parts of the pen 

 were not found. 



Abraliopsis sp. was of minor importance 

 (seven occurrences) in 1965. Two stomachs 

 contained fragments and beaks of 70 and 97 

 squids each. This squid was in stomachs of 

 seals collected in the same general area in 

 1961.'" 



Three gonatids identified in 1965 were: 

 Gonatus fabricii (California 17, Washington 2); 

 G. magister (California 4); and Gonatopsis 

 borealis (California 2). 



Miscellaneous. Unidentified bird feathers 

 were in the stomachs of two fur seals collected 

 off California (the volume of feathers in one 

 was 320 cc.) and in one collected off Wash- 

 ington. Other items were: pebbles (4-6 mm. 

 diam.) in three stomachs; small fragments of 

 wood (largest 1 cm. by 1 cm.) in two stomachs; 

 and a piece of kelp in one stomach. 



Relation of Fur Seals to Commercial 

 Fisheries 



The effect of predation by fur seals on 

 various species of commercially important 

 fishes and cephalopods cannot be determined 

 without adequate knowledge of the distribution 

 and abundance of each prey species, the extent 

 to which these species are utilized by other 

 predators, and the extent to which other 

 predators of the prey species are removed 

 by fur seals. Detailed knowledge of the ocean 

 environment and its influence on fish popula- 

 tions is also needed if the effects of fur seals 

 on commercially important species of fish are 

 to be accurately appraised. Data collected to 

 date indicate that fur seals feed heavily on 

 the most readily available fishes or cepha- 

 lopods. 



To show the degree to which fur seals use 

 con-imercially important fishes off California, 

 the species found in the stomachs may be 

 compared with those that support the fishery. 



'" See footnote 7. 



The 10 leading fish and shellfish in the Cali- 

 fornia commercial fishery, listed in the order 

 of pounds landed in 1963 (California Depart- 

 ment of Fish and Game, 1965), were: Tra- 

 churus symmetricus (jack mackerel); Thunnus 

 alalunga (albacore); Scomber japonicus [ diego ] 

 (Pacific mackerel); Loligo opalescens (squid); 

 all species of Sebastodes and Sebastolobus 

 (rockfish); Microstomus pacificus (Dover sole); 

 Oncorhynchus kisutch and O^, tshawytscha (sal- 

 mon); Sardinops sagax (sardine); Thunnus 

 thynnus (bluefin tuna); and Engraulis mordax 

 (northern anchovy). Four of the ten commer- 

 cially important species were found in fur 

 seal stomachs: jack mackerel (3.3 percent of 

 the total food volume in seal stomachs), squid 

 (24.8 percent), rockfish (11.6 percent), and 

 northern anchovy (15.0 percent). Almost no 

 fishing for these species, however, is done in 

 the offshore waters where fur seals feed. 

 Pacific hake, which formed 36.7 percent of the 

 total food volume in seal stomachs, are of 

 little commercial value in California. 



The most important connmercial fish taken 

 by fur seals collected off Washington were 

 salmon, which occurred in 8 of 147 stomachs. 

 Off Grays Harbor, Wash., fur seals were com- 

 mon in an area where salmon troUers were 

 fishing. 



No valid conclusion about the relation of fur 

 seals to commercial fisheries can be drawn 

 from the data available. Considering the vol- 

 ume and frequency of occurrence of commer- 

 cially important food species in fur seal 

 stomachs examined in 1965, predation by fur 

 seals on commercial species of fish is not a 

 cause for alarm. 



SUMMARY 



The United States has conducted pelagic 

 research on fur seals since 1958 in coopera- 

 tion with Canada, Japan, and the U.S. S.R. under 

 the terms of the Interim Convention on Con- 

 servation of the North Pacific Fur Seals. In 

 1965, observations and collections were made 

 off Washington 2-24 April and off central 

 California 11 April to 23 June, by two char- 

 tered purse seine vessels. 



Seals were widely scattered off Cape Flat- 

 tery, Wash,, in early April, but a concentra- 

 tion was located off Grays Harbor, Wash., in 

 mid-April. Of 147 seals taken off Washington, 

 only 19 were males. In California waters, 

 seals were most numerous off Monterey and 

 near Cordell Bank west of Pt. Reyes; 1 of 269 

 collected were males. 



To study distribution and migration of fur 

 seals off California, transect lines extending 

 10 to 80 miles offshore were established at 

 20-mile intervals between Bodega Head and 

 Pt. Sur. Seals were counted along these lines 

 each month. Seals were most abundant 30 to 

 40 miles offshore, and decreased gradually 

 out to 80 miles. 



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