“It’s been a phenomenon for probably a third year in a row,” Tony Child, Thanet Coast project manager, told LiveScience. He estimated about 25,000 of the dead velvet swimming crabs (Necora puber) were in piles this year, where birds are now ferociously feeding on their carcasses. [Image of beaches littered with dead crabs]

Last year, about 40,000 of the crabs washed ashore on the Thanet Coast, which is a long coastline of chalk reefs in Kent, England. This year, more starfish also washed ashore…

In the past, environmental scientists ran tests to check for disease or other physiological problems with the crabs, coming up empty-handed. But Child said every year the die-offs have occurred after there was snow on the beaches. The meltwater causes temperatures near shore to drop, and Child said the deaths must be linked to hypothermia.