Surveys of Steller sea lions (Eumetopias jubatus) in Alaska, June-July 2016-2025 : An update on the status and trend and comparisons of new analytical methods

From 2016 to 2025, the Alaska Fisheries Science Center’s Marine Mammal Laboratory (MML) conducted annual count surveys of Steller sea lions (Eumetopias jubatus) in June/July in Alaska. MML surveyed the endangered western distinct population segment (DPS) and Southeast Alaska (eastern DPS). Data collection included aerial imagery (crewed and uncrewed aircraft platforms), visual counts (ship, skiff, and crewed aircraft platforms), and land-based visual counts. Imagery was processed and counted via our traditional methods, and a new hybrid count workflow was introduced for counting 2024 imagery, which integrated artificial intelligence detection and classification. We used agTrend to model all raw count data to 2025 to produce estimated counts (an index of abundance)—and annual rates of change for 15- and 30-year periods. However, we restricted reporting to data through 2024; 2025 estimates were excluded due to high uncertainty from limited survey coverage, specifically the lack of count data east of Samalga Pass.