Range 



Fur seals of the genus Callorhinus are restricted to the North Paci- 

 fic Ocean, Bering, Okhotsk, and Japan Seas, They breed in the Bering 

 Sea on St. George, St. Paul, Copper, and Bering Islands, and on Robben 

 Island in the Okhotsk Sea. The seals on the first two are under American 

 jurisdiction while the others are controlled by Soviet Russia. Over 100, 000 

 fur seals have been marked with metal flipper-tags on the Pribilof Islands 

 since 1940. Recovery of these tags at sea and along the coast shows that 

 the main body of the Pribilof herd migrates in winter to the waters off the 

 North American continent, a few individuals swimming as far as 2, 000 

 miles south to the Mexican border. A number migrate to Asian waters, 

 mostly off the northern islands of Japan, Most adult males and some 

 stragglers of other age and sex classes remain in Alaska waters. The 

 majority of the tagged Pribilof seals are captured on the island of their 

 birth. Although immature seals may come ashore at some distance from 

 their rookery of birth, tag returns indicate that as they approach breeding 

 age they tend to return in increasing proportions to the exact place of their 

 birth. 



From studies of tag recoveries, commercial kill statistics, aerial 

 photographs, and sample counts, the total summer population of Pribilof 

 fur seals is placed at about 600, 000 newborn and 1, 300, 000 older animals. 

 Census studies are still in progress and population figures are subject 

 to some revision. 



Breeding habits 



The breeding seals gather on well-worn "rookeries, " where each 

 male recruits a harem of 10 to 100 females; average about 40. The cow 

 gives birth to a single pup in late June or July after a gestation period of 

 approximately 1 year. Mating takes place from 5 to 7 days after the pup 

 is born. The female remains on shore until after mating. She then goes 

 to sea to feed for a period of about 5 days before returning to nurse her 

 pup. Thereafter, her feeding trips last about 8 days and 1 to 2 days are 

 spent ashore with her pup. After a 3-month nursing period the mother 

 puts out to sea for the winter migration and the pup is left to fend for 

 itself. 



Females reach sexual maturity at the age of 3; males at 4 or 5. 

 Some females bear pups at age 4, but males are seldom large and strong 

 enough to participate in breeding-ground activity until 7 or 8 years of age. 



Feeding habits 



Fur seals feed principally in offshore areas. They are known to 

 descend to a depth of 240 feet. Only rarely and at certain places do they 

 approach land during their long winter migration. Stomach analyses indi- 

 cate that, while at sea, they feed principally on squid and small schooling 

 fishes. At certain places along the coasts of southeastern Alaska and 

 British Columbia, fur seals enter straits and bays in the winter and 

 early spring to gorge on herring and capelin. 



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