Distribution and relative abundance of bowhead whales and other marine mammals in the western Beaufort Sea, 2021

Aerial line-transect surveys for bowhead whales (Balaena mysticetus) and other marine mammals were conducted in the western Beaufort and eastern Chukchi seas from 23 September to 10 October 2021. The primary survey area ranged from Utqiaġvik to Prudhoe Bay, Alaska (157°-148°W, shore to 72°N). Surveys were conducted on a total of 11 days, mainly in the primary survey area due to survey priorities, weather, and logistical limitations. A total of 138 sightings of 200 bowhead whales were documented during the survey period. Sightings occurred from 146.0°W to 157.1°W, though 90% of whales were sighted west of 150°W. Most sightings (150 whales, 75%) were located over the inner continental shelf (≤ 50 m), 48 whales were sighted over the outer continental shelf (51-200 m), and two whales were sighted in the 201-2,000 m depth zone.