The Significance of the North Water Polynya to Arctic Top Predators

Abstract

The North Water polynya (*76°N to 79°N and 70°W to 80°W) 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 77°20 0 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 auks, Alle alle) or widely in open water (thick-billed guillemots, Uria lomvia).

Seasonal Trends in Acoustic Detection of Marine Mammals in Baffin Bay and Melville Bay, Northwest Greenland + Supplementary Appendix 1 (See Article Tools)

“…It is generally assumed that most beluga whales overwintering in the North Water polynya move toward the southwest to the mouth of Lancaster Sound in April and early May (Koski et al, 2002) in order to summer in the Canadian Arctic Archipelago . Even though beluga whales are seen occasionally in spring and summer on the Greenland side of the North Water polynya (Heide-Jørgensen et al, 2013a), it is most probable that the beluga whales detected in the present study during spring 2014 were en route to the Canadian summering grounds in the High Arctic.…”

“…4B). During a spring survey, Heide-Jørgensen et al (2013a) detected bearded seals on ice floes and along the ice edge, primarily over shallow water in the eastern part of the North Water polynya. Also of interest, stations BB10 and BB6 were located in deep waters (1000 m and 575 m, respectively), suggesting that the bearded seal distribution in Baffin Bay is not limited to shallow areas, as previously reported (Kovacs et al, 2011).…”

“…The spring bloom of primary productivity triggered by retreating sea ice attracts high densities of prey species in the lower trophic level, including forage fish and zooplankton that many marine mammal species follow into the region (Laidre et al, 2010;Heide-Jørgensen et al, 2013a). Little is known about the year-round occurrence of marine mammals, particularly in winter when environmental conditions make traditional monitoring methods challenging.…”

“…Little is known about the year-round occurrence of marine mammals, particularly in winter when environmental conditions make traditional monitoring methods challenging. Thus far, research in the region has been limited to visual surveys, which can take place only from spring to late fall (Finley and Renaud, 1980;Heide-Jørgensen et al, 2013a), and studies using satellite transmitters on a few individuals from a population (Dietz and Heide-Jørgensen, 1995;Teilmann et al, 1999;HeideJørgensen et al, 2003aHeideJørgensen et al, , 2006. More detailed information on marine mammal occurrence in and around Baffin Bay, south of the North Water polynya, is required to adequately manage the risks to marine mammals from offshore oil and gas exploration.…”

Biodiversity and Species Change in the Arctic Ocean: A View Through the Lens of Nares Strait

“…Generally, arctic photosynthetic planktonic productivity is thought to follow retreating ice edges, and as surface nutrients are drawn down chlorophyll concentrations and phytoplankton productivity become non-detectable (Renaut et al, 2018). In contrast, the North Water Polynya has a much longer productive season, supporting large populations of migrant and resident marine mammal and bird populations (Heide-Jørgensen et al, 2013). The massive annual production of the North Water is linked to regional hydrography, which is influenced by cyclonic circulation.…”