Miscellaneous 



Four unidentified traces of birds were 

 found. Gastropod or pelecypod fragments oc- 

 curred in seven stomachs. There were 24 

 occurrences of crustaceans; 1 an unidentified 

 fragment, 1 a hermit crab, Pagums sp., which 

 was in a broken gastropod shell, and 22 oc- 

 currences of the parasitic isopod, Rocinela bel- 

 liceps. 



R. belliceps, an ectoparasite of fishes in the 

 families Gadidae and Cottidae, is found 

 throughout the Aleutian area (Murie and Schef- 

 fer, 1959). This isopod was found only in seal 

 stomachs taken in Unimak Pass and closely 

 adjoining parts of western Alaska and the 

 Bering Sea. It was probably attached to fish 

 that were eaten by seals. With its hard exo- 

 skeleton it is relatively resistant to digestive 

 juices. The hermit crab and the isopods were 

 identified by Patsy A. McLaughlin, Oceanog- 

 raphy Department, University of Washington, 

 Seattle, Wash. 



Pebbles ranging in size from 2 to 40 mm. 

 were found in 44 stomachs. The number in a 

 single stomach varied from 1 to over 100, 

 although only 9 stomachs contained more than 

 25 pebbles. Pebbles were found throughout the 

 collection period in stomachs collected in 

 shallow water (less than 100 fathoms) feeding 

 grounds. Pebbles have been recovered from 

 fur seal stomachs during previous investiga- 

 tions, although in 1958, 1959, and 1961 when 

 collections were made mostly in deep water 

 off the coast of California, Oregon, and Wash- 

 ington, pebbles were seldom found (see below). 

 Seal stomachs from Alaska waters contained 

 pebbles more frequently, probably because 

 large numbers of seals were collected in 

 shallow water and because many of the seals 

 taken had been landing on the Pribilof Islands. 



Number of fur seal stomachs 

 containing pebbles 



Relation of fur seals to commercial fish- 

 eries . — In 1962, seal stomachs contained sal- 

 mon, probably more than one species, and 

 Theragra which are fishes that are fished com- 

 mercially in this region. Salmon are apparently 

 subject to some predation as they pass through 

 the feeding grounds of seals in western Alaska 

 and in the Bering Sea. However, salmon was 

 found in only 1 seal stomach of a collection 

 of 440 seals taken in Unimak Pass. They 

 formed 2.6 percent of the total food by volume 

 in 1962. 



Theragra appear in the catch of the Japanese 

 and Soviet trawl fleets. They are used prin- 

 cipally to produce fish meal. They are a major 

 food item of the fur seal in the Bering Sea. 

 The effect of the fur seal upon this fishery 

 is difficult to assess. 



Predators 



The only known predator of the fur seal in 

 northern waters is Orcinus orca (killer whale). 

 Orcinus was observed in Unimak Pass twice 

 each in June, September, and October; in 

 western Alaska it was seen once in August 

 and once in October; and in the Bering Sea 

 one observation was made in August. No 

 predation by Orcinus was observed. 



SUMMARY 



The fifth year of pelagic fur seal research 

 under the terms of the Interim Convention on 

 Conservation of North Pacific Fur Seals was 

 completed in 1962 in waters off Alaska. 



One vessel carried on investigations from 

 May through September in western Alaska, 

 Unimak Pass, and the Bering Sea. A second 

 vessel worked from August to October in the 

 same area. 



An intensive study of seal movements and 

 food habits was made in Unimak Pass and 

 vicinity. Two major feeding areas were found; 

 one centered 10 to 15 miles north of Akun 

 Island and the other about 20 miles southeast 

 of Tigalda Island. 



56 



