northward in the summer to the Gulf of Alaska; it 

 ranges the western North Pacific Ocean, from 

 Japan northward to the Kurile Islands (National 

 Marine Fisheries Service 1978). During pelagic 

 fur seal research voyages off California (1958-66) 

 and Washington (1958-72), 767 pods of dolphin 

 totalling 8,803 animals were sighted^ (297 pods, 

 5,555 dolphin, and 490 pods, 3,248 dolphin, respec- 

 tively). Dolphin pod size ranged from 1 to 1,000 + 

 animals. The dolphin reported here were collected 

 from pods ranging from 4 to 300 animals. 



The Dall's porpoise ranges the North Pacific 

 Ocean from northern Baja California and Japan in 

 the south to the Bering and Okhotsk Seas, moving 

 into the southern portion of its range during 

 winter. The porpoise usually occur in smaller 

 groups than do the dolphin. During pelagic fur 

 seal research cruises off California and Washing- 

 ton, 868 pods totalling 3,575 porpoise were sighted 

 (657 pods, 2,845 porpoise, and 211 pods, 730 por- 

 poises, respectively). Porpoise pods generally con- 

 tained fewer than 20 animals. The porpoise re- 

 ported here came from pods of three to five ani- 

 mals. Sightings and collections of dolphin and 

 porpoise were obtained during 388 d at sea off 

 California in 1958-66 and 368 d at sea off Wash- 

 ington in 1958-72. 



The northern fur seal ranges across the subarc- 

 tic waters of the North Pacific Ocean and numbers 

 about 1.8 million animals (Lander and Kajimura 

 1976). Most seal are found near their breeding 

 islands in the Bering and Okhotsk Seas from July 

 into early November except for the very small San 

 Miguel Island, Calif., population that numbers 

 about 2,000 animals. In the eastern North Pacific 

 Ocean few adult males are found south of the Gulf 

 of Alaska. Mature females and immature males 

 and females begin to appear in coastal waters be- 

 tween British Columbia and central California in 

 late November and early December, the pups 

 slightly later in January or February. The move- 

 ment is generally southward along the continen- 

 tal shelf and slope in January into March with 

 some animals ranging south to about lat. 32° N; 

 however, most of the wintering population can be 

 found between about lat. 35° and 49° N. Some 

 northward migration out of this region may begin 

 as early as March. Most wintering seal are found 



from over the continental shelf seaward as much 

 as several hundred miles (Fiscus 1978). 



Northern fur seal are most frequently observed 

 alone rather than in company with other seal of 

 their species; however, concentrations do occur in 

 areas of abundant food supply. In 1966 (January- 

 March) off California when most of the dolphin 

 and porpoise were collected, 1,441 groups of seal 

 were observed, of which 31% were single animals; 

 22% were in groups of 2; 16.9% in groups of 3; 

 10.5% in groups of 4; and 10.2% in groups of 5-20 

 (Marine Mammal Biological Laboratory 1969). 



In 1967-68 (November-February) off Washing- 

 ton, when most of the dolphin and porpoise were 

 collected, 669 groups of seal contained 40.8% 

 single animals; 24.9%, groups of 2; 13.6%, groups 

 of 3; 9.3%, groups of 4; and 14%, groups of 5-9 

 (Marine Mammal Biological Laboratory 1970). 



There are no reliable estimates of the numbers 

 of Pacific white-sided dolphin and Dall's porpoise 

 that inhabit the eastern Pacific offshore waters 

 from California to Washington; however, these two 

 species are the most frequently sighted cetaceans 

 in these waters.The northern fur seal is the only 

 pinniped regularly inhabiting this region. It is a 

 seasonal visitor, from December through May; as 

 many as 500,000 may be here during the peak of 

 the wintering period (Fiscus 1979). 



Methods 



Hand harpoons or shotguns were used to collect 

 the Pacific white-sided dolphin and Dall's porpoise 

 as they rode the bow wave of the research vessel or 

 dory. Northern fur seal were collected from the 

 vessel or dory with shotguns. The dolphin and 

 porpoise were taken off California, 1-130 km sea- 

 ward of the continental shelf; those from Washing- 

 ton waters were taken near or over the continental 

 shelf. 



Standard measurements and weights of each 

 cetacean and seal were recorded (American Soci- 

 ety of Mammalogists, Committee on Marine 

 Mammals 1961, 1967). Reproductive tracts, skulls, 

 stomachs, and tissue samples were collected. 

 Stomachs were tied with string at the esophagus 

 and pyloris and then injected with and preserved 

 in 10% Formalin^ for laboratory examination. The 

 contents of each stomach were gently washed and 

 drained in a small mesh sieve. The stomach rugae 



'NMFS, Natl. Mar. Mammal Lab. 1958-74. Birds and 

 mammals observed at sea. Unpubl. data listing, various pagi- 

 nation. Natl. Mar. Mammal Lab., Natl. Mar. Fish. Serv., NOAA, 

 7600 Sand Point Way NE., Seattle, WA 98115. 



^Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



953 



