2014 Results of Steller Sea Lion Surveys in Alaska

Aerial and ship-based surveys to count Steller sea lion (Eumetopias jubatus) pups (approx. 1 month old) and non-pups (adults and juveniles) on land in Alaska were conducted by the National Marine Mammal Laboratory in June to July 2014. The manned aircraft photographic survey was conducted from 23 June to 9 July, and targeted all known rookeries and haulout sites in the range of the western distinct population segment (DPS) between the Delarof Islands in the Aleutian Islands and the Shumagin Islands in the western Gulf of Alaska (between 179°W and 158°W). Ship-based survey effort, which included the first use of a small uncrewed aircraft to survey Steller sea lions, was conducted from 19 June to 3 July in the western portion of the Aleutian Islands from Attu Island eastward to the Delarof Islands (between 172°E and 179°W).

Aerial surveys to count Steller sea lions are conducted in late June through mid-July starting at least 10 days after the mean birth dates of pups in the survey area (approx. June 10; Pitcher et al. 2001). The primary objective in 2014 was to survey all terrestrial rookeries and haul-out sites along the Aleutian Island chain (western DPS) of Alaska (Figure 1). A NOAA twin Otter aircraft equipped with three high resolution digital cameras (as in 2009–2013; Fritz et al. 2013) surveyed portions of the central Aleutian Islands, and the eastern Aleutian Islands and western Gulf of Alaska. Ship-based effort on board the USFWS RV Tiĝlâx was concentrated in the western and part of the central Aleutian Islands, and included the use of an unoccupied aircraft system (UAS; APH-22 hexacopter).