Since 2019, more than 600 gray whales have washed ashore along the west coast from Mexico to Alaska.
Occasional strandings occur every year. But these numbers are far higher than normal. And some of the whales were abnormally thin.
“We set about … to really try to look at what was going on with their food source,” says Sue Moore of the University of Washington.
She says gray whales do most of their feeding in the Arctic during the summer. They primarily eat small arthropods that live on the ocean floor.
But in some areas, these bottom-dwelling animals are declining, and the mix of species is shifting.
Moore says those changes are partly driven by the changing climate.
Melting sea ice speeds up Arctic ocean currents, which limits the ability of some arthropods to build homes in the sediment. Melting ice also affects the growth of algae, which these creatures need for food.
In some areas, Moore says whales are turning to other sources of food, such as krill.
“But it’s very hard to be definitive about how that could cause a mortality event,” she says.
So she says more research is needed, but it appears that even this large, powerful mammal faces challenges adapting to the warming world.
Reporting credit: Sarah Kennedy/ChavoBart Digital Media