Science & Data

The Marine Mammal Laboratory conducted aerial surveys to photograph and count Steller sea lion pups (approx. 1 month old) and non-pups (adults and juveniles ≥ 1 year old) on known terrestrial rookery and haulout sites in Alaska in June-July 2019.

Northern fur seal pup estimates

The northern fur seal (Callorhinus ursinus) is harvested commercially by the United States on St. Paul Island of the Pribilof Islands, Alaska, and by the USSR on its Commander and Robben Islands. Japan and Canada, in return for abstention from pelagic sealing, share in these harvests under terms of the Interim Convention on the Conservation of North Pacific Fur Seals. Under this same Convention, all four countries cooperate in an international program of conservation and research on the species.

This report describes field activities of the Aerial Surveys of Arctic Marine Mammals (ASAMM) project conducted during summer and fall (1 July–29 October) 2018, and data and analyses used to summarize field activities. Surveys were based in Utqiaġvik (formerly Barrow), Alaska, and Deadhorse, Alaska, and targeted the northeastern and southcentral Chukchi and western Beaufort seas, between 67°N and 73°N latitude, 140°W and 169°W longitude.

The Marine Mammal Laboratory (MML) conducted aerial- and ship-based surveys to count Steller sea lion pups and non-pups in Summer 2018.

Approximately 30-50% of global anthropogenic CO2 emissions are absorbed by the world’s oceans (Feely et al. 2004, Sabine et al. 2004). Increased CO2 uptake by the oceans is expected to reduce surface ocean pH by 0.3 – 0.5 units over the next century, which would be the largest change in pH to occur in the last 20-200 million years (Feely et al. 2004). Ocean acidification reduces the calcium carbonate (CaCO3) saturation point. Dramatic reductions in calcium carbonate saturation have been observed in the North Pacific since the industrial revolution (Feely et al. 2004).

Steller sea lions (Eumetopias jubatus) use terrestrial sites for reproduction, resting, molting, and other activities. Rookeries are terrestrial sites used for mating, giving birth, and resting. Rookeries are primarily used during breeding season (May-August) but can be occupied at other times of the year as well. Haulouts are terrestrial sites used for resting anytime of the year.

The NOAA Alaska Fisheries Science Center Marine Mammal Laboratory (MML) Alaska Ecosystem Program (AEP) maintains a list of known Steller sea lion terrestrial sites in the United States portion of the sea lion range.

This is a list of all Steller sea lions branded by National Marine Mammal Laboratory (NMFS), Alaska Department of Fish and Game, and Alaska Sea Life Center between 2000 and May 2014. It does not include animals marked before the year 2000 and does not include animals marked in Russian waters. This list also does not include tagging information. Some of the animals on this list may also have been tagged with flipper tags.

This dataset contains counts of adult and juvenile (non-pup) Steller sea lions on rookeries and haulouts in Alaska Aleutian Islands, Bering Sea, and other areas made between that beginning of 1904 and June 18, 2015.