2025 Results Of Steller Sea Lion Surveys In Alaska
September 24, 2025
The Alaska Fisheries Science Center’s Marine Mammal Laboratory conducts annual crewed aircraft and vessel surveys to known terrestrial Steller sea lion rookery and haulout sites in Alaska to collect visual counts and high-resolution imagery.
In 2025, Marine Mammal Laboratory focused efforts on the western distinct population segment in Alaska, where the vessel-based team surveyed in the western and central Aleutian Islands regions. The crewed aircraft team did not conduct surveys this year.
The vessel-based survey collected counts in-person or with an uncrewed aircraft system from 22 sites, totaling 2,013 non-pups and 919 pups.
We used agTrend (R package) to model all raw count data through 2025 to estimate modeled counts (as an index of abundance) and annual rates of change since 2010. The estimated model count for the western DPS of Alaska was 38,911 non-pups and 12,762 pups. This year, the non-pup 15-year trend changed from increasing to "stable," or no growth, while pup counts increased from 2010 to 2025.