The Significance of the North Water Polynya to Arctic Top Predators
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The Significance of the North Water Polynya to Arctic Top Predators Mads Peter Heide-Jørgensen, Louise M. Burt, Rikke Guldborg Hansen, Nynne Hjort Nielsen, Marianne Rasmussen, Sabrina Fossette, Harry Stern
Received: 15 February 2012 / Revised: 26 June 2012 / Accepted: 25 October 2012 / Published online: 28 December 2012
Abstract The North Water polynya (*76N to 79N and 70W to 80W) is known to be an important habitat for several species of marine mammals and sea birds. For millennia, it has provided the basis for subsistence hunting and human presence in the northernmost part of Baffin Bay. The abundance of air-breathing top predators also represents a potential source of nutrient cycling that maintains primary production. In this study, aerial surveys conducted in 2009 and 2010 were used for the first time to map the distribution and estimate the abundance of top predators during spring in the North Water. Belugas (Delphinapterus leucas) were not detected north of 77200 N but were found along the coast of West Greenland and offshore in the middle of the North Water with an abundance estimated at 2245 (95 % CI 1811–2783). Narwhals (Monodon monoceros) were widely distributed on the eastern side of the North Water with an estimate of abundance of 7726 (3761–15 870). Walruses (Odobenus rosmarus) were found across the North Water over both shallow and deep ([500 m) water with an estimated abundance of 1499 (1077–2087). Bearded (Erignathus barbatus) and ringed seals (Phoca hispida) used the large floes of ice in the southeastern part of the North Water for hauling out. Most polar bears (Ursus maritimus) were detected in the southern part of the polynya. The abundances of bearded and ringed seals were 6016 (3322– 10 893) and 9529 (5460–16 632), respectively, and that of polar bears was 60 (12–292). Three sea bird species were distributed along the Greenland coast (eiders, Somateria spp.), in leads and cracks close to the Greenland coast (little
Electronic supplementary material The online version of this article (doi:10.1007/s13280-012-0357-3) contains supplementary material, which is available to authorized users.
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auks, Alle alle) or widely in open water (thick-billed guillemots, Uria lomvia). Keywords North Water Polynya Sea ice conditions Top predators Marine mammals Sea birds
INTRODUCTION Since William Baffin circumnavigated Baffin Bay in 1616, it has been known that there is an open-water area in northern Baffin Bay that does not freeze in winter. This polynya was recognized by Arctic whalemen as the North Water (*76N to 79N and 70W to 80W) and was frequently visited by whaling and exploring expeditions during the nineteenth century (Vaughan 1991). The area was attractive because of its year-round open-water conditions and its abundance of marine mammals, including commercially valuable bowhead whales (Balaena mysticetus). For the same reasons, the area around the North Water had attracted Inuit hunting communities long before its discovery by Europeans. For some 4000 years, the Nor
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