About four million common murres were killed by a domino effect of ecosystem changes, and the population is showing no signs of recovery, according to new research.
The first evidence was the feathered bodies washing up on Alaskan beaches. They were common murres, sleek black-and-white seabirds that typically spend months at a time away from land. But in 2015 and 2016, officials tallied 62,000 emaciated corpses from California to Alaska.
Since then, scientists have been piecing together what happened to the birds, along with other species in the northeast Pacific that suddenly died or disappeared. It became clear that the culprit was an record-breaking marine heat wave, a mass of warm water that would come to be known as the Blob. New findings on its effect on murres, published on Thursday in the journal Science, are a stark sign of the perils facing ecosystems in a warming world.
“What we learned was that it was just way worse than we thought,” said Heather Renner, one of the study’s authors and a supervisory wildlife biologist at the Alaska Maritime National Wildlife Refuge.
About half of Alaska’s common murres, some four million birds, died as a result of the marine heat wave, the scientists found. They believe it is the largest documented die-off of a single species of wild birds or mammals. The state is home to about a quarter of the world’s common murres, scientists say.
Murres were the victims of a domino effect of oceanic changes tied to the warm water, according to a growing body of research. It affected marine life from plankton to humpback whales. Critically for the murres, it led to a collapse in the fish they depend on.