Polar Bears International

Western Hudson Bay Coastal Survey


Every year, Hudson Bay's polar bears are forced ashore by melting ice in summer, where they must live off their fat reserves until freeze-up takes place in the fall.

When the ice breaks up, the bears ride floes ashore to the Hudson Bay coastline, landing in an area from the Ontario border to the south to the Nunavut border to the north. When freeze-up comes again in the fall, they head back onto the sea ice to hunt seals.

Our aerial surveys, in cooperation with Manitoba Conservation, take advantage of these predictable movement patterns to observe a large sample of the Hudson Bay polar bears along the coast in a short period of time—just before the ice forms and again when the ice breaks up in summer. The surveys allow scientists to map the population's distribution patterns and also to provide data on its composition—tracking how many cubs there are, for example.

Why is this important?

The energy reserves of polar bears are at their greatest just after break-up and lowest just before freeze-up. Therefore, annually repeated counts at these times may provide an index to trends in survival and hence the welfare of the Hudson Bay bears. Ultimately, as sea ice continues to disappear from global warming, coastal surveys may provide an important index to polar-bear welfare, range wide.

Our thanks to Banrock Station and the Columbus Zoo & Aquarium for helping to fund this study.