Decline in Abundance of the Northern Sea Lion, Eumetopias jubatus, in Alaska, 1956-86
Merrick RL, Loughlin TR, Calkins DG. 1987. Decline in Abundance of the Northern Sea Lion, Eumetopias jubatus, in Alaska, 1956-86. U.S. Fishery Bulletin. 85(2):351-365
Aerial, ship, and onshore surveys were conducted to assess the abundance of northern sea lions, Eumetopias jubatus , in southwestern Alaska, from the central Gulf of Alaska through the central Aleutian Islands, during June-July of 1984-86. Counts of northern sea lions from these surveys were compared with counts made in 1956-62 and 1975-79. These data indicated that the number of adults and juveniles onshore declined 52% from 140,000 animals in 1956-60 to 68,000 in 1985--an annual rate of decline of at least 2.7%. Numbers have declined throughout the region, with the greatest declines in the eastern Aleutian Islands (79%) and the least in the central Aleutian Islands (8%). This was not due to emigration because significant increases have not been noted elsewhere.
- Type
- Journal Article
- Authors
- Merrick, R; Loughlin, T; Calkins, D
- Units
- ANIA , GLBA , KATM , KEFJ , SITK , WRST
- Keywords
- Animal Communities (Wildlife), Coastal/Marine Systems, declining population (sea lion), Eumetopias jubatus, Gulf Of Alaska, Marine, Marine Mammals, northern sea lion, Population Decline, Wildlife