298 



[Reprinted by the U.S. Department of Health, Education, and Welfare. Public Health 



Service] 



Residues in Fish, Wildlife, and Estuaries— Organochlorine Pesticides in 



Fur Seals 



(By Raymond E. Anas ^ and Alfred J. Wilson, Jr.'' 



ABSTRACT 



(Samples of liver and brain tissue from 30 northern fur seals (Callorhinus 

 ursinus) and 7 fur seal fetuses that were collected on the Pribilof Islands, 

 Alaska, in 1968 and off the Washington coast in 1969, were analyzed for organo- 

 chlorine pesticides. These compounds were found in all of the fur seals and in 

 three of the fetuses. Polychlorinated biphenyls (PCB) were not detected. Of 

 30 samples of liver tissue from the seals, all contained DDE ; 21. DDD ; 24, 

 DDT ; and 3 contained dieldrin. Of the 30 brain samples, all contained DDE : 

 5, DDD ; 4. DDT ; and none contained dieldrin. DDE was present in liver tissue 

 from three of the fetuses and in brain tissue from two. ) 



introduction 



Pesticides are widespread in the oceans. Organochlorine pesticides have been 

 found in the tissues of marine mammals in Antarctica (1, 4), Scotland (2), 

 Canada (2), and the United States (A. J. Wilson, Bureau of Commercial Fish- 

 cries, unpublished data.) This report records the amounts of DDE, DDD, DDT, 

 and dieldrin found in the tissues of northern fur sea's, Callorhinus ursinus, col- 

 lected on the Pribilof Islands, Alaska, and off the Washington coast. 



Thousands of fur seals are taken each year by the United States on the Pribilof 

 Islands. Alaska. The skins are used for fur garments, and the carcasses, minus 

 the blubber, are ground and fed to mink. The liver and meat are eaten by residents 

 of the Pribilof Islands. The U.S.S.R. takes seals on the Commander and Robben 

 Islands, and some seals are taken at sea in research by Canada. Japan, the 

 U.S.S.R.. and the United States. Fur seals migrate to the Bering Sea (to return 

 to the Pribilof and Commander Islands) and the Okhotsk Sea (to return to 

 Robben Island) during summer and autumn; they migrate as far south as Cali- 

 fornia and Japan in winter and spring. Fur seals feed principally on small fishes 

 and squids. Killer whales and sharks are probable predators. 



SAMPLING procedures 



Samples of liver and brain tissues were collected from fur seals in July 1968 

 on the Pribilof Islands, and in February and March 1969 off the Washington 

 coast. Samples of blubber were not collected, but the concentrations of pesticides 

 are usually greater in the blubber than in other tissues (2). Brain and liver 

 tissue samples weighing about lOg each were collected from each of 30 seals and 

 7 fetuses. Tissues were kept frozen from the time of collection until analysis. 

 Seventeen of the seals were animals of known age that had been tagged previously 

 as pups. The ages of the 13 other seals were determined by counting layers of 

 dentine in upper canine teeth. The fetuses were in their fourth month. 



1 Bureau of Commercial Fisheries, Marine Mammal Biological Laboratory, Seattle. Wash 

 98115. 



2 Bureau of Commercial Fisheries, Biological Field Station, Gulf Breeze. Fla. 32561. 



