By Steve Quinn
JUNEAU (Reuters) - Some polar bear clusters have slowly moved to islands north of Canada, which are retaining the Arctic ice for longer, according to a new scientific study that predicts the migration, linked to climate change, would continue.
The study published earlier this month in the journal PLOS ONE was based on DNA taken from nearly 2,800 polar bears in countries where the animals live - the United States, Russia, Canada, Greenland and Norway.
Researchers tracked the shift through genetic similarity in bears among four regions.
Bear clusters from Canada's eastern Arctic area and a marine area off eastern Greenland and Siberia are journeying to the Canadian Archipelago, also known as the Arctic Archipelago, where ice is more abundant, the study found.
The migration has occurred during the last one to three generations of the predators, or between 15 and 45 years, U.S. Geological Survey researcher Elizabeth Peacock, the study's lead author, said in a statement.
The bears are migrating to a region that sits north of the Canadian mainland, close to Nunavut and the Northwest Territories. It is comprised of more than 36,000 islands and covers more than 550,000 square miles (1.4 million square km).
The bears choose this area because that is "where the sea is more resilient to summer melt due to circulation patterns, complex geography and cooler northern latitudes," Peacock said.
The Canadian Archipelago could serve as a future refuge for polar bears, according to the study.
Since 1979, the spatial extent of Arctic sea-ice in autumn has declined by over 9 percent per decade through 2010, the researchers said, adding that recent modeling predicts that nearly ice-free summers will characterize the Arctic before mid-century.
(Editing by Alex Dobuzinskis and Simon Cameron-Moore)