Distribution and Relative Abundance of Marine Mammals in the Eastern Chukchi and Western Beaufort Seas, 2015 Annual Report
This report describes field activities of the Aerial Surveys of Arctic Marine Mammals (ASAMM) project conducted during summer and fall (1 July–31 October) 2015 and data analyses used to summarize field activities. Surveys were based in Barrow, Alaska, and Deadhorse, Alaska, and targeted the northeastern and southcentral Chukchi and western Beaufort seas, between 67°N and 72°N latitude and 140°W and 169°W longitude.
Sea ice cover in the study area in 2015 was generally light compared with historical (pre-2007) sea ice cover. In early July, sea ice in the eastern Chukchi Sea remained north of 71.5°N. By late July, sea ice remained in the Hanna Shoal area, but was otherwise absent from the Chukchi Sea study area. Sea ice persisted in most of the western Beaufort Sea through August. From early September through mid-October, sea ice was largely absent from the ASAMM study area although some grounded ice remained nearshore between Camden Bay and Deadhorse. By late
October, new ice was forming in the northern blocks and in shallow nearshore areas in the
western Beaufort Sea study area. The northeastern Chukchi Sea study area remained almost
completely ice free through late October, with sea ice present only in shallow nearshore areas.
A total of 105 survey flights were conducted. The Barrow-based aerial survey team conducted surveys from 2 July through 30 October 2015, and the Deadhorse-based aerial survey team conducted surveys from 19 July through 8 October 2015. Total combined flight time was 521 hours, including 248 hours of transect survey effort. Over 132,000 km were flown, with 54,016 km of effort on transect. Surveys were conducted in the western Beaufort Sea in summer (midJuly through August) for the fourth consecutive year and in block 23 (southcentral Chukchi Sea) for the second consecutive year.