Fur Seal Investigations, 1967 



by 



Bureau of Commercial Fisheries 



MARINE MAMMAL BIOLOGICAL LABORATORY 



Sand Point Naval Air Station 



Seattle, Wash. 98115 



ABSTRACT 



Totals of 55,720 male northern fur seals ( Callorhinus ursinus ) and 10,471 

 females were killed on the Pribilof Islands in 1967. The predicted kill of males was 

 56,200. Counts of dead seals on the rookeries included 17,426 pups, 155 adult males, 

 and 185 adult females. Counts of live adult males were 8,876 harem and 5,707 idle. 



Major causes of death among 232 pups were malnutrition, liver damage -multiple 

 hemorrhage-perinatal complex, hookworm disease, and infections. 



Thirty-four percent of 1,255 females age 4 and older had given birth to pups„ 



The mean weights of pups from four rookeries differed significantly. 



Seals tagged included 12,472 pups, 835 yearlings, and 1,200 of ages 2 to 4; 115 

 pups were marked by freeze branding. A total of 5,435 seals tagged on the Pribilof 

 Islands were recovered there in 1967 as were 31 seals tagged by the U.S.S.R. on 

 the Commander Islands or on Robben Island. 



An estimated 377,000 pups were born on the Pribilof Islands in 1965 and 

 385,000 in 1967. The estimate of yearling males in 1963 from the 1962 year class 

 was 79,000; in 1965 the estimate of yearlings from the 1964 year class was 

 129,000. The predicted kill of 2- to 5 -year -old males on the Pribilof Islands in 1968 

 is 49,500. 



An artificial formula supplemented with selenium, vitamin E, methionine, and 

 glycerin, was superior to an unsupplemented formula for maintaining fur seal pups in 

 captivity. 



During pelagic fur seal investigations, seals were most commonly seen within 

 111 km. (60 nautical miles) of land in January and February, and most were col- 

 lected off Cape Flattery and westward to La Perouse Bank. Of 835 fur seals sighted 

 off Washington, 131 were collected 27 were wounded and lost, and 21 were killed and 

 lost. Of 118 female seals collected, 57 percent were gravid; the youngest were three 

 primiparous and one multiparous 5-year-olds. 



Salmonidae ( Oncorhynchus spp.) and Pacific herring (Clupea harengus pallasi ) 

 were the principal species eaten by seals off Washington. Shrimp were found for the 

 first time in fur seal stomachs. 



We saw 32 seals and collected 1 during studies of distribution in the Bering Sea 

 and in waters near the eastern Aleutian Islands from 20 November to 4 December 

 1966. 



One of us observed Japanese pelagic fur seal research in April and May 1967. 



We saw two fur seals off northern California in September and none off Wash- 

 ington and Oregon in August and September 1967. 



On the basis of gastrointestinal contents and parasites, 9 of 20 pups had fed on 

 marine organisms while still on the Pribilof Islands. 



INTRODUCTION 



The problems of managing an international intended to supply information needed by the 

 resource have collectively been the strongest North Pacific Fur Seal Commission for man- 

 influence in establishing and maintaining a agement of fur seals have continued since 1956 

 sustained research program for the northern on the Pribilof Islands and since 1958 at 

 fur seal (Callorhinus ursinus). Investigations sea. 



