Northern Sea Lion Decline in the Eastern Aleutian Islands
Braham HW, Everitt RD, Rugh DJ. 1980. Northern Sea Lion Decline in the Eastern Aleutian Islands. The Journal of Wildlife Management. 44(1):25-33
From June 1975 through June 1977, 6 aerial surveys were conducted along the eastern Aleutian Islands and north coast of the Alaska Peninsula to assess the distribution and abundance of northern sea lions (Eumetopias jubatus). Site-specific counts of sea lions on rookeries and haulout places were compared to counts made in 1957, 1960, 1965, and 1968. Analysis of total counts from sites replicated among survey years since 1957 indicated that a significant population decline occurred. The 1977 population estimate was below 25,000, whereas in the late 1950's and early 1960's the population exceeded 50,000. The 1977 population level was 44.9-54.7% of the 1957 estimate, and it appeared that the population decline has been greatest since 1968. No cause for the decline was apparent, but several contributing factors are discussed.
- Type
- Journal Article
- Authors
- Braham, Howard; Everitt, Robert; Rugh, David
- Units
- ANIA , KATM , WRST
- Keywords
- Alaska, Aleutian Islands, Eumetopias jubatus, Marine, Marine Mammals, Northern sea lions, Population, Wildlife