Sea otter counts, perception probability, and measures of available habitat for 20 island groups in the Western Aleutian Islands, 1965

The southwest population of northern sea otters (Enhydra lutris kenyoni) in Alaska was listed under the Endangered Species Act in 2005. A previous estimate of equilibrium density was derived from historical aerial survey data to inform recovery criteria, but research has since demonstrated this estimate may be biased. We used historical data to generate a new estimate of equilibrium density for recovery planning. This dataset includes sea otter counts from aerial surveys from 1965 and associated estimates of habitat from 20 island groups, which were thought to be at carrying capacity in 1965.