The melting Arctic is allowing previously separated whale populations to interact, satellite tracking data has shown.
The Northwest Passage between the Atlantic and Pacific has garnered increasing attention as climate change leads to record retreats of sea ice. Shipping goods through this shorter route between Asia and Europe could save millions. It appears that whales have also seized on the possibilities.
Previously, a grey whale sighted off Israel and Spain has been suggested as evidence of mixing between the Pacific and Atlantic. Now a team working in the Arctic have actually observed population overlaps via this sea route.
Mads Peter Heide-Jørgensen, of the Greenland Institute of Natural Resources in Nuuk, and his colleagues put satellite tags on two whales in 2010 (tag attachment pictured).
One of these whales came from the Bering-Chukchi-Beaufort population off Alaska and the other from the Baffin Bay-Davis Strait population near eastern Canada. In September 2010, the whales crossed paths in Parry Channel in the Canadian Arctic Archipelago and for more than two weeks in that month they were within two days’ swimming of each other.
“The documented movements of bowhead whales in the Northwest Passage are perhaps an early sign that other marine organisms have begun exchanges between the Pacific and the Atlantic Oceans across the Arctic,” write the paper authors. “Some of these exchanges may be harder to detect than bowhead whales, but the ecological impacts could be more significant should the ice-free Arctic become a dispersion corridor between the two oceans.”
Taking a conservative estimate of the level of sea ice cover that would allow whales to meet amid the ice, the researchers suggest that the Parry Channel was open to bowheads in 1998, 1999, 2007, 2008 and 2010.
Image: © Mads Peter Heide-Jørgensen