ECOLOGY AND BIOLOGY OF THE PACIFIC WALRUS 



27 



Table 1. Composition of samples of Pacific walruses from the St. Lawrence, 

 Pribilof, and Bristol Bay wintering concentrations in March and April 1971- 

 76, as determined from shipboard observations and interpretation of aerial 

 photographs. 



Life stage 











Immature 



Subadult 



Wintering 







Number 



(both 



and adult 



area and 







of 



sexes) 



Males 



Females 



data type^ 



Month 



Year 



animals 



(%) 



(%) 



(%) 



St. Lawrence (S) 



March 



1972 



907 



28 



10 



62 



St. Lawrence (S) 



April 



1971 



332 



39 



4 



57 



St. Lawrence (A) 



April 



1972 



1171 



39 



3 



57 



Pribilof (S) 



April 



1971 



255 



2 



94b 



3 



Pribilof (S) 



March- 



1976 



73 



15 



74b 



11 





April 













Bristol Bay (A) 



April 



1972 



621 



38 



6 



56 



^Data types: (A) = aerial photos; (S) shipboard observations. 

 bMore than 75% subadults; all others more than 90% adults. 



sighted there in April 1976 but was present in April 1979 (G. A. Fedoseev, 

 personal communication). Its composition has not been determined. I suspect 

 that it is derived from a small concentration that winters southwest of Cape 

 Navarin, along the Koryak coast. 



Animals from the St. Lawrence concentration seem to be the first to reach 

 Bering Strait in late April (Fig. 7). At the same time, those from the Pribilof and 

 Navarin areas apparently stream northwestward toward the Gulf of Anadyr, 

 while many of those from Bristol Bay begin to move northward along the 

 Alaskan coast. 



In May (Fig. 8), most of the St. Lawrence concentration seems to pass through 

 Bering Strait, into the Chukchi Sea. Probably, this is the first wave of migrants 

 that was noticed by Brooks (1954), as well as by K. W. Kenyon and J.J. Burns 

 (personal communication), at Little Diomede Island. Apparently, some of these 

 animals advance northeastward along the eastern Chukchi flaw, toward 

 Barrow, while the rest make their way northwestward, toward Wrangell Island. 

 Meanwhile, much of the Bristol Bay concentration seems to reach eastern St, 

 Lawrence Island and Norton Sound. These animals apparently move northward 

 through Bering Strait mainly in June as the second wave of migrants observed at 

 Diomede by Brooks (1954) and others. Large herds also appear in June in the 

 northern part of the Gulf of Anadyr (Fig. 9), but it is not entirely clear from 

 whence they come. This is Belopol'skii's (1939) Kresta group, which he thought 

 moved into that area only from the east. Probably, it also includes those that 

 move up from the Navarin and, perhaps, Pribilof areas. 



Large herds occasionally have been sighted in June near Point Hope 

 (W. Berry, personal communication), as well as near Cape Serdtse Kamen, 

 northeastern Chukotka, and in Long Strait (Nikulin 1941). To the south, some 

 males from the Bristol Bay concentration remain in the vicinity of Round Island 

 (Miller 1975a), and large herds have been sighted on the Koryak coast, especially 



