Aerial and Land-Based Surveys of Steller Sea Lions (Eumetopias jubatus) in Alaska, June and July 1996
Sease JL, Strick JM, Merrick RM, Lewis JP. 1999. Aerial and Land-Based Surveys of Steller Sea Lions (Eumetopias jubatus) in Alaska, June and July 1996. NOAA Technical Memorandum. NMFS-AFSC-99. US National Marine Fisheries Service; Alaska Fisheries Science Center. Seattle
The National Marine Fisheries Service and the Alaska Department of Fish and Game conducted aerial and land-based surveys of Steller sea lions (Eumetopias jubatus) during June and July 1996 from Southeast Alaska to the western Aleutian Islands. We counted a total of 41,529 adult and juvenile (non-pup) sea lions at 280 rookery and haul-out sites. Of these sea lions, 30,454 (73.3%) were at 95 trend sites (rookeries and haul-outs) and 22, 562 (54.3%) were at 33 trend rookeries. The 1996 count at the 95 trend sites was a decline of 18.0% since 1991, 12.6% since 1992, and 7.6% since 1994. Overall declines were slightly less for all surveyed sites. The average annual rate of decline from 1991 to 1996 was about 3.7% for trend sites and trend rookeries and 2.1% for all surveyed sites. The western stock of Steller sea lions in Alaska includes animals from the eastern Gulf of Alaska through the western Aleutian Islands. In 1996 we counted 30,622 non-pups at 222 surveyed sites. Of these, 22,223 (72.6%) were on 82 trend sites and 16,358 (53.4%) were on 30 trend rookeries. For the 82 trend sites, the 1996 count represented declines of 27.2% from 1990, 24.5% from 1991, 18.6% from 1992, and 7.9% from 1994. The annual rates of decline were about 5.5% for trend sites and trend rookeries (1990 to 1996) and 3.8% for all surveyed sites (1991 to 1996). In the Kenai Peninsula to Kiska Island index area, a sub-area within the Alaska portion of the western stock, we counted 24,625 non-pup sea lions at 189 surveyed sites. Of these, 17,900 (72.7%) were at 69 trend sites, and 13,905 (56.5%) were at 26 trend rookeries. The 1996 count for the 69 trend sites was a decline of 21.3% from 1990, 17.7% from 1991, 13.4% from 1992, and 4.3% from 1994. The estimated annual rates of decline were 4-5% for trend sites and trend rookeries (1990 to 1996) and 2% for all surveyed sites (1991 to 1996).
- Type
- Published Report
- Authors
- Sease, J; Strick, J; Merrick, R; Lewis, J
- Date of Issue
- 1999-03
- Publisher
- US National Marine Fisheries Service; Alaska Fisheries Science Center
- Units
- ANIA , GLBA , KATM , KEFJ , SITK , WRST
- Keywords
- Eumetopias jubatus, Land-Based Survey, Marine Mammals, marine wildlife, Steller Sea Lion