Spring distribution and habitat use of belugas (Delphinapterus leucas) in the eastern Beaufort Sea

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Asselin, Natalie Claudette
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An understanding of the adaptability of belugas (Delphinapterus leucas) to changing ice-conditions is required to interpret and predict possible changes in habitat selection in response to projected loss of sea ice throughout the circumpolar Arctic. Beluga spring distribution in the eastern Beaufort Sea was described by analyzing observations from aerial surveys conducted from 1975 to 1979. Repeated surveys along the Franklin Bay fast-ice edge in June 2008 were used to study the distribution and behaviour of belugas and bowheads. Despite inter-annual variability in ice extent, belugas consistently selected areas with water depths of 200-500 m, heavy ice concentrations (8/10 to 10/10) and seafloor slope ≥0.5 degrees in spring 1975 to 1979. While predator avoidance may partially explain the observed distribution, foraging success likely has more influence on beluga habitat selection in the spring. In ice-covered offshore regions, belugas may be engaged in under-ice and deep water foraging on Arctic cod (Boreogadus saida). In lighter ice years, belugas may expand their distribution and shift shoreward to take advantage of high prey densities along fast-ice edges. Both belugas and bowheads appeared to be feeding along the Franklin Bay ice edge in June 2008. More research is required to examine and compare possible changes in distribution since the late 1970s and to investigate the factors driving the patterns described.
Delphinapterus leucas, Balaena mysticetus, Sea ice, Arctic, Habitat selection, GIS