Habitat use and habitat selection by spotted seals (Phoca largha) in the Bering Sea

摘要

Twelve spotted seals (Phoca largha) equipped with satellite-linked tags were tracked in the Bering Sea for 46-272 days during August-June 1991-1994. Alaskan seals were mostly near shore during August-October and 100-200 km offshore in January-June, and were broadly distributed in the region north of the 200-m isobath. Russian seals were located primarily near shore and within 100 km of the 200-m isobath during all months. During August-October, all seals were usually more than 200 km south of the sea-ice edge. In January-June, seals were mostly 0-200 km north of the sea-ice edge, often in areas with extensive ice coverage (7/10-9/10). We tested for habitat selection by determining how frequently a randomly moving seal would have been located in each habitat and comparing that with observed habitat use. Russian seals selected for nearshore and shallow-water areas in September-October and for near shore, within 25 km of the 200-m isobath, and the ice front during November-April. Alaskan seals selected for near shore areas in September-December; for offshore, shallow water, and the ice front in January-February; and for shallow water and pack ice in March-April. Biological processes associated with the highly productive "Green Belt" may have influenced the habitat use of Russian seals, but this did not appear to have been the case with Alaskan seals. [References: 36]