2018 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–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.
Sea ice cover in the Chukchi Sea study area in 2018 was extremely light in August, September, and October. Sea ice cover in the Beaufort Sea study area was heavy in July, August, early September and the latter half of October, and light in late September and early October. When surveys commenced in early July, sea ice remained throughout the Beaufort Sea study area and north of 70.5°N in the Chukchi Sea study area and remained there through mid-July. Sea ice persisted throughout the Alaskan Beaufort Sea in August, but the Chukchi Sea study area was nearly sea ice free by mid-August. Areas completely devoid of sea ice in the Alaskan Beaufort Sea remained limited through mid-September, and the study area was completely ice free for <20 days (from late September through mid-October). By mid-October, new ice was forming nearshore and offshore in the Beaufort Sea study area and this area was effectively covered with >90% new ice by the end of the field season. The Chukchi Sea study area remained ice-free through September and October.
A total of 99 survey flights were conducted. The Utqiaġvik-based aerial survey team conducted surveys from 3 July through 27 October 2018, and the Deadhorse-based aerial survey team conducted surveys from 20 July through 8 October 2018. Total combined flight time was 481.4 hours, including 248.5 hours of transect effort. Nearly 125,000 km were flown, with 54,277 km of effort on transect. Data were also collected during Focal Group Follow (FGF), Field of View (FOV), and Cetacean Aggregation Protocols (CAPs) mode. Images from a camera mounted in the belly of one of the survey aircraft were collected during 32 flights. Surveys were conducted in the western Beaufort Sea in summer (July-August) for the seventh consecutive year and in survey block 23 (southcentral Chukchi Sea) for the fifth consecutive year.