Bowhead whale mortality event in Nunavut, Canada – Autumn, 2020

Resumen

Cetacean mortality events in the Arctic often go underreported compared with events in more highly populated regions. Here, we report a mortality event involving the death of 11 bowhead whales around the Gulf of Boothia, Canada. The whales were discovered between October 2020–April 2021. Reports of 11 dead bowhead whales within six months in one area raised concerns among local hunters and community members. Due to the remoteness of these strandings and challenges with access, complete necropsies were not performed, but local Inuit collected tissue samples from eight of the whales. Possible reasons for these deaths include unusual weather events, nutritional stress/starvation, metabolic abnormalities, infectious disease, anthropogenic impacts (such as vessel collisions) and killer whale predation. To determine the most likely cause of these strandings, demographic, temporal, environmental, epidemiological, pathologic and contaminant analyses were performed. Results were compared with published accounts and historical data where appropriate. Killer whale sightings by local Inuit both before and during the stranding events confirmed the presence of these predators in close proximity to the carcass locations, with predation marks observed in several carcasses. We conclude that this was the most probable direct contributing factor to the mortality event. Indirect contributing factors might also include reduced ice coverage as a result of climate change and nutritional stress. Further monitoring of this population is required to assess health from both a scientific and an Indigenous perspective.