2016 Aerial Surveys of Arctic Marine Mammals
This report describes field activities of the Aerial Surveys of Arctic Marine Mammals (ASAMM) project conducted during summer and fall (1 July–31 October) 2016, and data and 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 72N latitude and 140°W and 169°W longitude. Between 19 July and 20 August, surveys extended up to 111 km north of the usual ASAMM study area to collect information specific to the Eastern Chukchi Sea (ECS) stock of belugas.
Sea ice cover in the study area in 2016 was generally light compared with historical (pre-2007) sea ice cover. When surveys commenced in early July, sea ice remained north of 70°N, and persisted though early August. By late August, sea ice remained near Hanna Shoal, but was otherwise absent from the study area. The remnant sea ice near Hanna Shoal shifted location through late September, moving closer to Point Barrow and into the westernmost Beaufort Sea, and was completely absent by mid-October. By late October, new ice was forming in shallow nearshore areas in the study area.
A total of 108 survey flights were conducted. The Barrow-based aerial survey team conducted surveys from 2 July through 26 October 2016, and the Deadhorse-based aerial survey team conducted surveys from 19 July through 10 October 2016. Total combined flight time was 536.7 hours, including 265.5 hours of transect effort. Over 135,000 km were flown, with 59,291 km of effort on transect. Surveys were conducted in the western Beaufort Sea in summer (mid-July through August) for the fifth consecutive year and in survey block 23 (southcentral Chukchi Sea) for the third consecutive year.
There were 4,286 sightings of 37,430 marine mammals observed during all (transect, search, and circling) survey modes.
- 950 sightings of 1,859 bowhead whales (Balaena mysticetus),
- 445 sightings of 1,130 gray whales (Eschrichtius robustus),
- 13 sightings of 26 humpback whales (Megaptera novaeangliae),
- 12 sightings of 17 fin whales (Balaenoptera physalus),
- 14 sightings of 16 minke whales (Balaenoptera acutorostrata),
- 364 sightings of 1,841 belugas (Delphinapterus leucas),
- 5 sightings of 30 killer whales (Orcinus orca),
- 10 sightings of 16 harbor porpoises (Phocoena phocoena),
- 36 sightings of 43 unidentified cetaceans,
- 817 sightings of 27,755 Pacific walruses (Odobenus rosmarus divergens),
- 21 sightings of 21 bearded seals (Erignathus barbatus),
- 1 sighting of 1 ribbon seal (Histriophoca fasciata),
- 1,509 sightings of 4,361 unidentified pinnipeds, and
- 89 sightings of 314 polar bears (Ursus maritimus).