Range of Beluga Whale |
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Beluga whales are found around the North Pole in arctic and sub-arctic waters. Beluga migrate considerable distances between summering and wintering locations. Distinct stocks of Beluga can be identified geographically based on summering location. There are 7 stocks in Canada (Beaufort Sea, Baffin Bay, southeast Baffin Island west Hudson Bay, east Hudson Bay, Ungava Bay and the St. Lawrence River) and 4 in Alaska (Cook Inlet, Bristol Bay, Norton Sound, and eastern Chukchi Sea). |
The Beaufort Sea |
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Hudson Bay |
Hudson Strait and Baffin Island |
Alaskan Habitat |
Wintering sites are less well defined as harsh weather conditions limit observation of Beluga during the winter. Radio tracking data indicates that all the North American beluga congregate into 5 wintering areas; Bering Sea, Hudson Strait, Baffin bay, Cook Inlet, and the St. Lawrence River. |
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| Differential Habitat Use | ||
Belugas show differences in habitat selection based on differences in energy requirements and survival strategies between individuals. These differences are due to age, size, sex and reproductive stage (Kingsley, 1993). Rather than segregating based on age or sex alone, the Beluga show differential habitat preferences based on a combination of age and sex. A study examining the beluga population that summers in the Beaufort Sea found three distinct habitats used by three types of belugas. Older and larger males spent the majority of their time in areas of heavy ice cover, while females with young offspring and some slightly older males spent most of their time in shallow open water. Medium sized males and females with older offspring were found to prefer habitats of medium ice cover near the edges. This habitat use demonstrates a mix of predation risk and forage based habitat selection strategies. The older males with higher energy requirements due to their size enjoy the high energy containing prey found in the ice (Goetz et al., 2007) |
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| Use of Warm Water Estuaries | ||
At the beginning of the summer thousands of Beluga congregate in shallow warm water estuaries (10-18°C). Belugas continue to congregate in these areas despite hunting pressure from aboriginal peoples. The reason behind this congregation is not fully understood. Originally it was thought that this was a reaction to movement of prey into the warmer waters but the lack of food in the stomachs of whales killed by hunters does not support this hypothesis. It is possible that the warmer waters are necessary for calving (birthing), however few full term fetuses have been observed in harvested females, and neonates have been observed in colder off-shore waters. The most commonly accepted hypothesis is that the warm water is necessary for skin repair. When the whales first enter the estuaries their skin is cracked and yellow from the extreme cold of the winter, and by rubbing against the gravel in the shallow estuaries their skin molts. The warm water thus allows the whales to shed their skin and lowers their thermal energy requirement allowing them to promote efficient epidermal re-growth before the next winter season.(Watts et al., 1990) The Warm water is also beneficial to newborn calves as they are born without the heavy layer of blubber that would be necessary to survive prolonged periods in the colder open water (Robeck et al., 2005). |
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