CHAPTER 15 



Marine Mammals 



Carl Abegglen, Alton Y. Roppel, and Dale W. Rice 



Fur Seals 



Distribution. Seven species of fur seals belonging to the genera Callo- 

 rhinus or Ardocephalus are currently recognized. Members of the genus 

 Arctocepha'us are more abundant in the southern hemisphere, where they 

 support industries in South Africa, Southwest Africa, and Uruguay. The 

 northern fur seal, the only species in the genus Callorhinus, breeds on the 

 Pribilof Islands, the Commander Islands, and Robben Island (USSR), 

 and in small numbers in the northern Kurile Islands. Fur seals are taken 

 for commercial use on the Pribilof, Commander, and Robben Islands. 



More than 80 per cent of the northern fur seals resort to the Pribilof 

 Islands in the Bering Sea each summer to reproduce. The Pribilof fur 

 seals are known to winter 10 to 100 miles or more offshore from the 

 Bering Sea to lower California and off the coast of northern Japan where 

 they intermingle with seals from Asian islands. 



Sealing Operations. Because fur seals are polygamous and because 

 equal numbers of males and females are born, most of the males can be 

 utilized without detrimental effect on the herd. Until recent years, the 

 only females taken were killed inadvertently because of the difficulty in 

 identifying the sexes. However, the need for taking females as a vital part 

 of maintaining a productive herd is now recognized. Table 15.1 shows the 

 kill, by sex, on the Pribilof Islands since 1911. 



During the summer months, the young males congregate on areas, 

 known as hauling grounds, adjacent to the rookeries. From late June to 



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