Common murres on a ledge. Photo: Brie Drummond//USFWS
You may remember, way back in 2014-2015, when a massive marine heatwave rocked the planet. It was named “The Blob,” and all these years later, researchers are still finding out its effects. One that recently came to light is particularly troubling: the worst single-species die off in modern history, according to biologists.
Four-million murres estimated to be dead in a staggering loss of life triggered by The Blob. Murres, also called the common guillemot, live in the low-Arctic and boreal waters in the North Atlantic and North Pacific. They spend most of their time at sea, but they nest along rocky cliffs.
Researchers studying Alaska’s murre colonies noticed that, when they showed up to monitoring sites in the summer of 2015, that the deafening calls of the murres were notably absent. Generally, those sites are an assault to the senses.
“A common murre colony is a very loud, smelly place, with thousands of black and white seabirds packed shoulder to shoulder on coastal cliffs,” Brie Drummond, a seabird biologist for Alaska Maritime National Wildlife Refuge, told the U.S. Fish and Wildlife Service.
That year, however, only a few birds were to be seen where once there were thousands. Researchers thought that maybe this was a one-off, but they were soon proven wrong.
“At first we thought, the birds didn’t show up to breed, but they’ll be back next year,” Drummond remembered. “The refuge biological team had to adjust our protocols based on the low attendance and breeding failure. Hardly any of the birds had laid eggs.”
As the months progressed, the bodies of the missing murres began to show up. They washed up on beaches all over the area in huge numbers.
“We knew right away this was a big, unprecedented die-off,” said Heather Renner, supervisory biologist, Alaska Maritime National Wildlife Refuge, to the US Fish and Wildlife Service. “We just didn’t know how big.”
So how did The Blob, that stifling hot dome of heat that descended on us in 2014, have anything to do with it? Well, both the Gulf of Alaska and the Eastern Bering Sea were affected by the two-year long phenomenon, and a heat wave that long is bound to disrupt the natural order of things. Common murres rely on small fish that school a few feet below the surface, and those died in vast numbers or dove to deeper, cooler waters to escape The Blob. The murres couldn’t find enough food and eventually died. Just how many, though, wasn’t clear until a few years later.
Most seabirds die at sea, so the numbers on the beaches didn’t represent much. Early loose estimates theorized about a million dead. But as monitoring went on, the true scale has become clear.
“Something that blew us away was the geographic scope,” Drummond explained. “These sites are hundreds, thousands of kilometers apart and it was the same story. Every monitored colony across the Gulf of Alaska and Eastern Bering Sea showed dramatic declines.”
Now, researchers are coming to the understanding that the colonies show no signs of recovering to their previous numbers.
“To put this in perspective,” Renner said, “the common murre die-off was approximately 15 times larger than the number of seabirds killed during the Exxon Valdez oil spill, an environmental disaster of epic proportions.”
