Satellite tracking has confirmed that loss of Arctic sea ice is opening up the waterway connecting the Pacific and Atlantic oceans to marine mammals.
A route through the fabled Northwest Passage, providing a valuable shortcut between Europe and Asia, has been the quest of seafarers for centuries.
Despite the effects of global warming and Arctic sea ice shrinking at a rate of 8% per decade, the route is too dangerous for shipping.
But the research shows that the Northwest Passage has already opened up for bowhead whales, which are expert at negotiating ice-bound waters.
Between 2001 and 2010 scientists tagged 180 whales in West Greenland, Alaska and the western Canadian Arctic with satellite tracking transmitters.
The first evidence that bowhead whales were making progress through the Northwest Passage came in 2002. A 12 metre long juvenile from Greenland swam to a western point about a third of the way along the route. Four years later a 14 metre adult male tagged near Point Barrow, Alaska, was tracked east 800 kilometres from the position reached by the Greenland whale.
Then in August last year, two adult males from West Greenland and Alaska entered the Canadian High Arctic sea channels during summer.
Approaching from opposite directions, the whales crossed each other’s paths in the Parry Channel in the Canadian High Arctic.
The scientists, led by Dr Mads Peter Heide-Joergensen, from the Greenland Institute of Natural Resources, discussed the findings today in the Royal Society journal Biology Letters.