Gray Whales Could Become Winners in the Great Arctic Thaw
This species vanished from the Atlantic Ocean nearly 300 years ago. But its numbers are rebounding in the eastern North Pacific. Combine that with a thawing Arctic, and the chances of the gray whales taking increasingly ice-free northern sea routes back to the other side of the world are improving, according to new research published this week in the journal Molecular Ecology.
“For a few decades now, marine mammalogists have been observing that gray whales in the eastern Pacific have been changing their feeding grounds in the Arctic,” said study lead author Elizabeth Alter, a professor of biology at the Graduate Center and York College of the City University of New York.
The whales have moved farther north and are staying longer in their Arctic feeding grounds. “Both those things increase the chances that some whales may eventually take a wrong turn and end up in the Atlantic,” she said.
In studying the DNA of gray whale fossils, the researchers found that prehistoric gray whales of the Atlantic and Pacific were all but identical genetically. That meant that individuals moved between the two oceans during periods when sea ice decreased and sea levels rose—in other words, conditions just like those we’ve created in present times by burning fossil fuels.
The fossil record also suggests that Atlantic gray whale populations were in decline long before hunters killed the last of them in the 18th century, Alter said.
Don’t plan to watch gray whales migrate past the Statue of Liberty anytime soon. It would be “remarkable” if they began breeding again in the Atlantic, said study coauthor Howard Rosenbaum, director of the Wildlife Conservation Society’s “Ocean Giants” program.
One reason is that gray whales are creatures of habit, he said, and the habits of most contemporary gray whales form along the eastern North Pacific. “Some of these behaviors are…transmitted from one generation to the next. You have to have some major learning of the migration routes and see it sustained over time,” he said. “So you’re probably talking more than just the Adam and Eve of gray whales in the Atlantic.”
The genetic record suggested that these kinds of movements happened over thousands or tens of thousands of years, Alter added.
Also, from a gray whale’s point of view the old neighborhood has really gone downhill.
“The North Atlantic is a very different place now from when gray whales were last there,” Alter said, with human activities including cargo shipping and commercial fishing transforming the coastal waters that they prefer. “Given how much human pressure there is on the North Atlantic right now,” she said, “would they be able to establish themselves?”
The sighting of a gray whale off the coast of Israel in 2010, however, and another off the coast of Namibia in 2013, suggest that a few of the great creatures are already making commuter runs between the Pacific and Atlantic basins.