The Marine Mammal Laboratory (MML) conducted aerial surveys to photograph and count Steller sea lion (Eumetopias jubatus) pups (~1 month old) and non-pups (adults and juveniles ≥ 1 year old) hauled out on known terrestrial rookery and haulout sites (AFSC/MML/AEP 2016) in Alaska in June-July 2021. On odd years, MML surveys in the Gulf of Alaska (Southeast Alaska towards the western Gulf of Alaska) portion of the Steller sea lion range in Alaska. On even years, MML surveys the Aleutian Islands regions (and sometimes into the western Gulf of Alaska if sites were missed in the previous year). Surveys scheduled for 2020 were cancelled because of the COVID-19 pandemic. Additionally, there was no ship-based (or uncrewed aircraft system) effort in the Aleutian Islands in 2020 or 2021.

During the summer of 2021 there was a coordinated effort to survey the entire eastern DPS among the MML, Washington Department of Fish and Wildlife, Oregon department of Fish and Wildlife, and Fisheries of Oceans Canada. Once all counts are finalized, information will be shared in a NOAA Fisheries Stock Assessment Report. There was also a collaboration with the Ecosystem Conservation Office of the Aleut Community of St. Paul Island to survey Walrus Island, a rookery in the Pribilof Islands, which will be reported in our next survey memorandum.

The survey team conducted the 2021 survey from 23 June to 8 July from Southeast Alaska (Dixon Entrance, 132°W) through the western Gulf of Alaska (Sanak Islands, 163°W). These Gulf of Alaska surveys have been essential for obtaining status updates during and after anomalous warming events in the North Pacific Ocean reported in 2014-2016, and in 2018- 2019 (Litzow et al. 2020). Subsequently, there were anomalies observed in sea lion counts from 2015 to 2019 in the Gulf of Alaska (Fritz et al. 2016, Sweeney et al. 2016-2019).