Growth of the Northern Fur Seal Colony on Bogoslof Island, Alaska

Northern fur seal, Callorhinus ursinus, pups were first observed on Bogoslof Island, southeast Bering Sea, in 1980. By 1988 the population had grown at a rate of 57%/yr to over 400 individuals, including 80+ pups, 159 adult females, 22 territorial males, and 188 subadult males. Some animals originated from rookeries of the Commander Islands, whereas others are probably from the Pribilof Islands. In 1983 and 1985 over 50% of the females were estimated to be >6 years of age, based on vibrissae color. The rookery is in the same location where solitary male fur seals were seen in 1976 and 1979 and is adjacent to a large northern sea lion rookery.Key words: Bogoslof Island, northern fur seal, Callorhinus ursinus, northern sea lion, breeding colony