PELAGIC FUR SEAL INVESTIGATIONS, 

 ALASKA WATERS, 1962 



by 



Clifford H. Fiscus, Gary A. Baines, 

 and Ford Wilke 



ABSTRACT 



A fifth year of pelagic fur seal research under the terms of the Interim Conven- 

 tion on Conservation of North Pacific Fur Seals was conducted in Unimak Pass, 

 Alaska, and vicinity, from May to October 1962. Unimak Pass is an important route 

 for seals passing between the Pacific Ocean and the Bering Sea. Major feeding areas 

 are located 10 to 15 miles north of Akun Island and 20 miles southeast of Tigalda 

 Island. They are utilized by concentrations of seals from late July to October. Of 

 1,486 seals collected, 91 percent were females and 9 percent were males. The 

 proportion of pregnant females ranged from 63 percent in June to 15 percent in 

 mid-July and almost none thereafter. Post partum females formed about 50 percent 

 of seals taken from August to October, and nonpregnant mature females formed 

 10 percent of the total. Immature females predominated in the feeding area off 

 Tigalda Island. Seal movements through Unimak Pass were not correlated with 

 stomach contents or tide direction. Tagged seals, including one with a Soviet 

 tag, made up 3.4 percent of the total. From 1958 to 1962 the pregnancy rate of 

 all females was 72.3 percent and the rate for females 6 to 26 years of age was ■ 

 83.8 percent. 



Female fetuses were more numerous than males, and pregnancies in the left 

 uterine horn were more frequent than were those in the right horn. Twin seals were 

 smaller than an average normal fetus. Major food species of fur seals by area 

 were: Western Alaska — squids, Mallotus villosus, and Ammodytes hexaptems; Unimak 

 Pass-- WoZ/o^us and Pleurogrammus monoptery-gius; Bering Sea — Theragra chalcogrammus, 

 Mallotus, and squids. Mallotus, Theragra, and squids have been the leading food of fur 

 seals in this region since the first investigations in 1896. Mallotus formed over 50 

 percent of the food volume. Of the food fishes taken commercially near Unimak 

 Pass, only salmon and Theragra had been eaten by seals. 



INTRODUCTION these years were concentrated primarily where 



T .u A inco /ii 1 ■ t. seals were abundant. 

 In the 4 years, 1958-61, pelagic research 



on fur seals as specified by the Interim Con- 



_, . . . , . _, ... ^ Note: Clifford H. Fiscus, If j7(//i:/efiio/ot;js«r/^esearc/i;, 



vention on Conservation of North Pacific Fur ^, . □,. ^ „■,,,■, n , . ,r ,, . a c^r-A 



Gary A, Baines, W ddUfe Biologist (General), and Ford 



Seals carried U.S. investigators into the entire wilke.ir,W/,7e Biologist (Research), Bureau of Com- 

 north-to-south range of the northern fur seal mercial Fisheries Marine Mammal Biological Labora- 



in the eastern Pacific. Collecting efforts in tory, U.S. Fish and WildlifeService, Seattle, Washington. 



