Dozens of grey whales have been found dead along the West Coast in recent weeks and some scientists believe the cause lies in the heated-up Arctic waters off Alaska.

Fifty-eight grey whales have been found stranded and dead so far this year in sites stretching from California to Alaska, according to the U.S. National Oceanic and Atmospheric Administration (NOAA).

The latest discovery announced on Wednesday by NOAA was a dead grey whale in Turnagain Arm, a narrow glacier-fed channel off Anchorage where grey whales rarely venture.

“They’re moving north from their wintering grounds in Mexico and appear to be running out of steam,” Michael Milstein, a spokesman for NOAA’s Fisheries Service, said on Thursday.