The Pribilofs are a cluster of volcanic islands in the Bering Sea, 200 miles off the west coast of Alaska and 500 miles from Siberia. They are named for Gavriil Pribilof, a Russian explorer, who encountered them in 1786, triggering a wholesale slaughter of their northern fur seal colonies and the displacement of native Aleuts, who had occupied the islands for at least 7000 years. As the threat of extinction developed, fur seal hunting restrictions were imposed by an International accord in 1911, a year before the Alaska Territory was annexed by the United States; a full ban on the hunting of northern fur seals was passed in 1966, though resident Aleuts may kill them for sustinence.
In addition to the seals, the Pribilof islands are known for their large colonies of sea birds, including Pacific species of puffins, murres, auklets, cormorants and kittiwakes; birders also visit these outposts to view a wide variety of migrants from the Siberian mainland. The Aleut communities of St. Paul and St. George (on their respective islands) are sustained by rich crab and halibut fisheries. Other island residents, well adapted to the harsh climate, include Arctic fox and caribou.
The wealth of marine life on the Pribilofs is primarily due to their position along the North American continental shelf, where upwelling, deep ocean currents produce nutrient-rich waters. But these volcanic islands do not lie along a tectonic plate margin; in fact, the southern edge of the North American plate lies along the Aleutian chain, 250 miles to the south, and its western edge is in eastern Siberia. The islands, like the volcanoes of Yellowstone and northern Arizona, developed over a hotspot beneath the plate; in the case of the Pribilofs, this process occurred throughout the Pleistocene (beginning about 2 million years ago) and has continued through most of the Holocene, ending just 3000 years ago.
