Bowhead whaleBalaena mysticetusseasonal selection of sea ice

• Published in: Marine ecology. Progress series (Halstenbek) Vol. 411; pp. 285 - 297
• Main Authors: Ferguson, Steven H., Dueck, Larry, Loseto, Lisa L., Luque, Sebastián P.
• Format: Journal Article
• Language: English
• Published: Inter-Research 29-07-2010
• Subjects: Aquatic habitats; Habitat conservation; Habitat selection; Sea ice; Sea water; Seas; Seasons; Summer; Whales; Winter
• ISSN: 0171-8630; 1616-1599

Highly mobile large-bodied organisms are adapted to seasonal variation associated with polar environments. We used satellite tracking data from 27 bowhead whalesBalaena mysticetusof the Eastern Canada-West Greenland population to test for movement and habitat selection of the highly variable sea ice landscape that encompasses near-complete coverage in winter to near-complete absence in summer. We demarcated 2 bowhead whale seasons based on movement behaviour identified from inflection points of polynomial regression analysis of movement rate: winter (28 December to 15 March, 16.6 ± 2.65 kmd–1) and summer (27 June to 27 December, 31.9 ± 1.05 km d–1). Resource selection functions were used to evaluate bowhead whale seasonal selection of sea ice landscape (coverage, thickness, and floe size). Movement and habitat use differed between Nunavut tagging sites likely as a consequence of sexual and reproductive segregation. Whales selected relatively low ice coverage, thin ice, and small floe areas in winter close to the maximum ice extent, presumably to reduce risk of ice entrapment while remaining within ice. In contrast, whales selected high ice coverage, thick ice, and large floe size areas in summer, presumably to reduce risk of killer whale predation while providing enriched feeding opportunities. Our results indicate that this large-bodied animal can moderate use of the large-scale fluctuations in seasonal sea ice typical of polar environments.