Climate change could push some cetacean species, including the beluga, north, a new study warns.
Belugas, narwhals and bowhead whales could travel hundreds of kilometers by the end of the century to find not only the water temperature to which they are accustomed, but also the prey on which they feed, say the researchers.
“These animals are really used to rather cold waters, even in summer, and so there we expect much higher temperatures,” said researcher Philippine Chambault, from the Greenland Institute of Natural Resources.
“The models show that eventually, most likely, these species will have to migrate north to escape these water temperatures which will become unfavorable, since they are far too hot for them, as well as for the distribution of their prey, which are also associated with cold water, but also with potential disturbances in their physiology, and therefore their way of managing this higher temperature. »
The researchers integrated satellite tracking data of 227 cetaceans over a 28-year period with two climate scenarios ― the first that sees society doing what is necessary to limit global warming to 2 degrees Celsius by 2100, and the second without such measures to protect the planet.
In both cases, the study published by the journal Science Advances predicts a considerable loss of habitat for the three species in summer, with the exception of the narwhals which swim east of Greenland.
Once all the data has been analyzed, the researchers come to the conclusion that the three species could move, in winter, about 122 kilometers towards the north, and almost double, or 243 kilometers, in summer by the end of end of the century.
Even with thirty years of data, researchers are not yet able to demonstrate that this northward shift has already begun. But other data, which is awaiting publication, would reveal that the narwhals have begun to delay the start date of their annual migration due to warming water.
We cannot conclude, on the basis of this research, that Québec belugas are also at risk of moving north in response to a warming of their environment. It is known, however, that oceanographic conditions in the east, with the influence of the Atlantic Ocean, tend to warm faster.
“We can expect similar reactions, as well as different reactions,” said Ms. Chambault, who admits that there is a “possibility” of seeing this emblematic animal of Quebec eventually leave for colder waters.
Belugas, narwhals and bowhead whales sit at the top of the food chain, and therefore act as indicators of ocean health and marine biodiversity. If they ever feel the need to change neighborhoods, we can suspect that something is wrong.
In fact, studies in recent years have found changes at the lower levels of the food chain.
“Prey and animals are starting to move because, precisely, the environmental conditions that are initially favorable to their development, reproduction and food are changing,” concluded Ms. Chambault.
“We see that these animals are starting to move as well, so it’s not something that we observe only with marine mammals, but indeed, it is starting to affect the whole food chain. »