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As gray whales die along the West Coast, Alaska scientists look for answers beneath blubber

Jun 4, 2019

Veterinary pathologist Kathy Burek slices through the blubber layer on a gray whale that was beached at the end of the Turnagain Arm outside Anchorage. (Photo by Nat Herz/Alaska’s Energy Desk)

Cutting through a 6-inch-thick layer of blubber demands a sharp knife.

But as a veterinary pathologist Kathy Burek prepared to slice into the abdomen of a dead gray whale beached outside Anchorage on May 18, many of her knives were dull. Burek, a veterinary pathologist, had used them two days earlier to collect samples from a different gray whale, 100 miles away. Then, the next whale washed up.

“I didn’t have time. That’s what our problem is right here,” Burek said as she struggled to pull off a slab of blubber.

Federal officials later found a third dead gray whale in Alaska, on Kodiak Island. Those three deaths are among at least 60 along the West Coast this year, according to the National Oceanic and Atmospheric Administration.

Scientists say more deaths are likely in Alaska, since each spring, gray whales swim 5,000 miles from Mexico to their Arctic feeding grounds.

“The level of strandings we’ve seen on the West Coast means Alaska should brace itself for probably some significantly elevated numbers of gray whale strandings,” said John Calambokidis, a research biologist at the Washington-based Cascadia Research Collective.

Burek was hired by NOAA to take samples from the stranded whale outside Anchorage, just off the Seward Highway at the eastern tip of Turnagain Arm. It had been floating in the arm for nearly two weeks, and she wasn’t planning an extensive necropsy – the animal version of an autopsy.

“It’s just not worth the time and effort because once we get inside the abdomen – the kidneys, the liver are just going to be kind of liquefied,” she said.

The whale looked “skinny,” she added. 

Experts say it appears that many of the other gray whales died of starvation. But scientists aren’t sure why.

The overall eastern North Pacific stock of gray whales is healthy and estimated at 27,000, according to NOAA. They rebounded from a similar spike in deaths in 1999 and 2000, and scientists think it’s possible they’ve simply reached what’s called “carrying capacity” – the maximum number of whales that its habitat can sustain.

But researchers also are asking whether recent warming trends in the Arctic and reduced sea ice have affected the whales’ prey.

“We have to really be on top of: Is there any relationship to climate change? And does this link to any other factors that might be affecting other species as well?” Calambokidis said. “Could gray whales be an early warning sign of other things that we need to be watchful for?”

Gray whales were once hunted nearly to extinction by whalers. But the Endangered Species Act protected them, and the eastern North Pacific population rebounded and was removed from the endangered species list in 1994.

Each spring and fall, the whales swim on one of the longest known mammal migrations – between their winter area in Mexico and their summer feeding grounds in the Chukchi, Beaufort and Bering seas in the Arctic. They primarily eat tiny, shrimp-like creatures called amphipods, sucking them off the ocean floor and filtering mud and seawater out through their baleen.

The Arctic is warming at twice the rate of the rest of the world, and temperatures in the Bering Sea last summer were especially high – as much as 9 degrees above normal. In the previous winter, ice levels were the lowest ever recorded.

Chunks of blubber were cut from the whale to allow veterinary pathologist Kathy Burek access to its abdomen. (Photo by Nat Herz/Alaska’s Energy Desk)

NOAA surveys the gray whales’ feeding patterns each summer. Survey results from last year are now getting scrutinized to see whether they can help explain this year’s deaths, said NOAA spokesman Michael Milstein.

“The scientists that do those surveys are going back through their records and trying to understand if there was something unusual about when and where the whales were feeding,” he said.

Milstein said they’ll be doing another survey this year, trying to determine: “Are there more whales that are competing for limited resources? Or, for some reason, is that food less nutritious or not providing them as much energy to sustain them on that long migration?”

NOAA also hopes to gather information from dead whales. The agency is encouraging people to report them as soon as possible, so that scientists can get to them to collect data before the whales start decomposing.

(Editor's note: NOAA asks Alaska residents who see a beached or dead whale to call 877-925-7773.)

Burek wasn’t optimistic about the quality of samples she’d get, but it turned out that the whale was in better shape than she thought.

After cutting and peeling a swath of blubber off one side, Burek cut into the whale’s abdomen, which released periodic spurts of gas and a foul smell. Internal organs slowly slid out of Burek’s incision. 

“Ooh, guess what that is – that’s the kidney!” Burek said, as she sliced into the big red mass. “We got kidney!”

Burek placed tiny chunks into bags and vials – muscle, testicle, even poop. They’ll be tested later, as potential clues for researchers trying to solve the mystery of why whales are dying.