The principal breeding grounds of the northern fur seal (Callorhinus ursinus) occur on the Pribilof Islands in the eastern Bering Sea. These islands were discovered in 1786 by the crew of the St. George, a Russian ship under the command of Gerasim Gavrilovich Pribilof. Breeding colonies occur in various other locations in the Pacific Ocean and Bering Sea; among the newest is a rapidly growing rookery on Bogoslof Island (first colonized about 1980; see reference 1123) just north of the Aleutian island chain. The first fur seal to be seen by a European was sighted in 1741 (by Georg Wilhelm Steller, Aug. 10, south of Kodiak Island; reference 1579). Since that time, especially in this century, the northern fur seal (sometimes called the Alaska fur seal) has been the subject of both intensive and extensive biological studies, more so than most other wild living large mammals. At the same time, these animals have helped promote a growing awareness of marine mammal issues by the general public. Fur seals have been the focus of wildlife conservation through public concern, as an economic resource, and as an indicator of the health of the ecosystems in which it occurs. As a result, there is a large volume of formal and informal literature on fur seals – from scientific investigations to more popularized accounts of the fur seal's extraordinary life history. The importance of the resulting scientific information is emphasized by a population that has been declining for the past two decades – a change with implications regarding past and present anthropogenic activities.