Maintenance of Arctic Populations of Mammals

Abstract

Seals roaming freely over the oceans are difficult to observe and are obscure in their ways. At the season of breeding, however, they resort to firm ice or shores and for periods explicit for each population they become attached to specific breeding localities until the pups acquire sufficient capability for independent aquatic life. In these temporarily fixed situations the populations are visible. Exposure at time of breeding, particularly by populations that congregate in numbers, has favored human exploitation leading to near-extinction of some populations. The tenacity of traditional attachments to breeding localities is shown in their persistent exploitation. On the Pribilof Islands the hauling out of fur seals (Callorhinus ursinus) in their established rookeries has worn the hard rock smooth. On some southern coasts the smoothly worn rocks attest that ancient breeding places were long utilized by populations that are now extinct. Erosion of the rocky breeding places demonstrates the persistence of their seasonal use. Northern elephant seals (Mirounga angustirostris) and a northern outpost of southern fur seals (Arctoce-phalus phillippii townsendi) have reconstituted populations from at most only a few survivors of slaughter to occupy again rocks or beaches used by their predecessors off western coasts of Mexico and California.