Polynyas

Winds, currents, salinity and water temperatures combine in some areas of the Arctic to produce areas where there is no ice, or comparatively thin ice, during the winter (see Figure 1.1). These polynyas recur year after year in the same places, although the exact boundaries vary with the particular conditions prevalent each year. Extensive polynyas are found in northern Baffin Bay (the North Water Polynya) and near Cape Bathurst in the eastern Beaufort Sea. Some polynyas normally form for short periods in the early spring.

Polynyas are places where whales, walruses, and certain seals can survive in winter. During this time their presence in other areas of the Canadian Arctic is restricted for lack of places to breathe because of thick ice cover on the sea. The survival of animals over-wintering in polynyas is dependent on the water remaining open, as they have no way of escape.

Birds which migrate into the Arctic in spring often use polynyas as their first feeding areas. Many large bird colonies are located near these important food sources.

The influence of these areas of open water on surrounding lands and seas is still poorly understood. Recent studies suggest that aquatic productivity is considerably higher downstream from polynyas, making these areas excellent habitat for some species of seal.

Figure 1.1