Bowhead whale carcasses in the eastern Chukchi and western Beaufort seas, 2009-2019
Amy L. Willoughby, Raphaela Stimmelmayr, Amelia A. Brower, Janet T. Clarke and Megan C. Ferguson
International Whaling Commission
Bowhead whale (Balaena mysticetus) carcass data and imagery provide insight into the health of the species. The Aerial Surveys of Arctic Marine Mammals (ASAMM) project surveys large areas bowhead whale habitat annually from July to October. ASAMM offers a long time series of consistent information on floating and beach-cast bowhead whale carcasses detected during standardized line-transect surveys. A total of 44 bowhead whale carcasses were documented July–October, from 2009 to 2019. Thirty-one carcasses (70%) were found floating and 13 were beach-cast (30%). Carcasses were distributed across the eastern Chukchi (EC) and western Beaufort (WB) sea study areas from 141°W to 169°W and 69°N to 72°N. Highest percentage of carcasses were observed in 2019 (25%), followed by 2015 (23%) and 2016 and 2013 (14% each year). More bowhead whale carcasses were seen in the EC study area; September had the highest number of bowhead whale carcass sightings in both EC and WB study areas; and September had the most survey effort and highest bowhead whale carcass sighting rates. Bowhead whale carcasses having injuries consistent with killer whale predation were photo-documented in one carcass each in 2010 and 2017, two carcasses in 2012, three carcasses each in 2013 and 2015, four carcasses each in 2016 and 2018, and six carcasses in 2019. Prior to 2010, evidence of killer whale predation on bowhead whales was not recorded in the ASAMM database or carcass imagery. Four carcasses, one each in 2013 and 2018 and two in 2015 were whales that were struck and lost during aboriginal subsistence hunting activity; this is based on timing, proximity to known struck and lost whales, and image review of those carcasses.