Most of the world’s northern fur seals gather to breed on just a few small islands in the Bering Sea. From this base, the seals fan out over the North Pacific Ocean, some swimming as far as Japan and southern California before heading back to the rookeries. Severely overhunted in the past for its valuable pelt, the northern fur seal, Callorhinus ursinus, recovered only after the sealing nations placed limits on the cull. The population again declined during the 1970s and 1980s, in part because so many seals became entangled and drowned in enormous drift nets set by the international fishing fleet. Since 1993, when the use of these nets was outlawed, fur seal numbers seem to have stabilized.