Pelagic Fur Seal Investigations 

 Alaska, 1963 



Clifford H. Fiscus, Gary A. Baines, 

 Hiroshi Kajimura 



ABSTRACT 



The sixth year of pelagic fur seal research under the terms of the Interim 

 Convention on Conservation of North Pacific Fur Seals was conducted in the Bering 

 Sea from July to September 1963. Seals were found scattered through the area 

 between the Strait of Juan de Fuca and Unimak Pass, but most were seen within 75 

 to 100 miles of land. Much of the collection was made north of Unalaska Island. The 

 principal movement of seals in the Bering Sea in late summer and early fall is 

 between the Pribilof Islands and the feeding grounds. Most animals appeared to 

 travel from 60 to 90 miles offshore from the islands to feed. Groups of one to three 

 seals accounted for 90.3 percent of all seals seen in 1 963. Of 1,355 seals collected in 

 1963, 111 were males and 1,244 females. Post partum females -were predominant 

 in the collection. The first adult males that appeared to have held harems in 1963 

 were seen on 31 July near Akun Island. Most of 25 males accompanying females were 

 observed within 20 miles of the Pribilof Islands. Of 43 tagged seals collected in 1963, 

 8 were males and 35 females. Mean lengths of nonpregnant, pregnant, and post 

 partum females were compared. Pregnant females were longer than nonpregnant or 

 post partum females. Females in ages 8 through 1 3 had the highest pregnancy rates. 

 The youngest pregnant females collected were 4 year s old. The fish and cephalopods 

 eaten ranged from 5 to 45 cm. inlength. Small prey usually are eaten below the sea 

 surface, and larger prey brought to the sea surface and swallowed in chunks. Sur- 

 face water temperature appears to have no direct effect on distribution. Fur seals 

 are primarily night and early morning feeders. Squids were the major food in 1963 

 in the Bering Sea, followed by capelin, walleye pollock, and deepsea smelt. A deepsea 

 smelt, the Greenland halibut, and a lanternfish were found for the first time in fur 

 seal stomachs. Salnnon were found in 14 fur seal stomachs, herring in 15, and 

 walleye pollock in 47. These three species are fished commercially in the Bering 

 Sea. 



INTRODUCTION were carried out from 1 July to 5 September. 

 Behavior, feeding patterns, and reproductive 



This report furnishes information on the condition of females were also studied. 

 sixth year of pelagic research on fur seals To observe the distribution and movement 



conducted by the United States as specified of fur seals in the North Pacific during their 



by the Interim Convention on Conservation of spring migration, the research vessels sailed 



North Pacific Fur Seals. directly to Unimak Pass from the Strait of 



From 1958 to 1961, investigations were Juan de Fuca. 

 made of fur seals from the southern to the 



TnTensYve 'st^^udy^ ^L' concentrated' in^u'^m^k METHODS. EQUIPMENT. AND PERSONNEL 



Pass and vicinity. Operations in 1963 were 



confined to the Bering Sea, where investiga- Methods and Equipment 



tions of distribution, abundance, and food 



habits of fur seals on their summer range Vessel and boat requirements and operations 



described in the 1962 report (Fiscus, Baines, 



Note.-ChffordH. Fiscus, Wildlife Biologist (Research), ^^^ ^^^1^^^ 19^4, ^^^^ duplicated in 1963. 



Gary A. Baines, Wildlife Biologist (General), and Hiroshi ^wo purse seine vessels, the M/V Harmony ' 



Kajimura, Fisheries Biologist (Research), Bureau of Com- 



mercial Fisheries Marine Mammal Biological Laboratory, » M/V Harmony: registered length 70. 5 feet, 61 net tons, 



U.S. Fish and Wildlife Service, Seattle, Wash. 220 horsepower, cruising speed 9 knots. 



