Posted by: The ocean update | December 1, 2015

New travel habits of gray whales are the result of climate change, study finds (North hemisphere)

The melting sea ice in Arctic has opened up new passageways to the Atlantic for such species as the gray whale. Photo by Junko Kimura/Getty Images

The melting sea ice in Arctic has opened up new passageways to the Atlantic for such species as the gray whale. Photo by Junko Kimura/Getty Images

December 1st, 2015 (Don Hawkins). Gray whales are drifting from their Arctic habitat to discover new horizons, and that is not a good thing, according to a new paper just published in the journal Global Change Biology. While world leaders converge in Paris to discuss the potentially catastrophic effects climate change promises to have on the global economy, this new study argues that a more subtle effect of climate change could wreak havoc on food webs around the globe.

Calling it a “perplexing–yet apparently increasing–trend,” the Washington Post reported yesterday that this paper argues that the melting sea ice caused by climate change is transforming the Arctic into the new hub for “faunal exchange” between the Pacific and Atlantic ocean basins. As the ice melts, new passageways open up, allowing historically ice-locked species to traverse new territories. Consequently, these territories suddenly find themselves hosting new predators.

As the Washington Post article explains, the sea ice has heretofore prevented mammals like gray and bowhead whales from swimming through the arctic. The ice has also deterred far-reaching travel of birds such as gannets and auks that are specific to the region. Even though they can obviously fly over the ice, their movement has always been stunted by the fact they cannot swoop down to catch fish in a frozen part of the ocean.

When predators journey into new territory, it can dramatically disrupt the existing food web in that area. Many traditional predators may find themselves in the unfamiliar role of prey, the authors argue. To support their contention, they cite a recent expansion of killer whales into the iceless regions of Canada’s Hudson Bay. The new surroundings introduced the killer whales to new cuisine, as they preyed on such Arctic whale species as beluga, narwhal, and bowhead, as well as several seal species.

Although the paper only focuses on 10 to 20 species, some who are genetically predisposed to movement, the authors of this paper argue that the scientific community must be prepared for the ecological changes caused by the new travel habits of these species. For example, they contend that these new patterns could cause radical shifts in food webs across the globe.

Even the Northwest Passage, an Arctic shipping route that is still obstructed by sea ice, will eventually be opened up for wildlife migration, the authors contend. Larry Crowder, the science director for Stanford’s Center for Ocean Solutions, for one, insists these changes are significant : “If there hasn’t been a gray whale in the Atlantic in 200 years and now there is one, that’s a change. They [the researchers] certainly didn’t overreach.”

Citation : McKeon, C. S., Weber, M. X., Alter, S. E., Seavy, N. E., Crandall, E. D., Barshis, D. J., Fechter-Leggett, E. D. and Oleson, K. L. L. (2015), Melting barriers to faunal exchange across ocean basins. Global Change Biology. doi : 10.1111/gcb.13116

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