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Old walrus bones dug up in Alaska's Arctic could shed new light on Point Lay haulouts

  • Author: Kamala Kelkar
  • Updated: September 28, 2016
  • Published October 3, 2015

At a lab in Barrow, University of Alaska Fairbanks researchers are sawing into old Pacific walrus bones unearthed at a site on the Arctic coast.

They're hoping to find DNA, stress hormones and isotopes of carbon and nitrogen, which could tell them about everything from population sizes to the walruses' shifting diet.

This evidence will help managers determine how resilient the animal can be in the face of a changing climate -- which is already affecting the Chukchi Sea ice they used to haul out on during late summer and early fall.

It's unclear exactly how old the bones are, says Barrow-based UAF archaeologist Anne Jensen, who dug up hundreds of them in the 1990s near Point Franklin, between Wainwright and Barrow. She remembers elders from Wainwright warning her that it could be difficult to camp at the dig site because of the pungent smell of walruses.

"It seems like walruses were hauled out on shore in that general area," she said.

Now Jensen is using that research to study past North Slope walrus haulouts. She's among a group of scientists who were awarded $1.7 million from the National Science Foundation to put the late-summer haulouts into context.

In recent years, as sea ice has retreated farther during late summer and early fall, walruses that previously spent that time of year resting on Chukchi Sea ice near Hanna Shoal have instead been hauling out near Point Lay. This year, some 35,000 hauled out there.

The sheer volume of animals can be dangerous. In 2011, about 50 animals, mostly calves and adolescents, were found trampled to death. This year, another 30 were found dead, though a cause has yet to be determined.

"There's this whole thing about, 'Oh my God, the walruses are hauling out at Point Lay and they're all going to die,'" she said.

But walrus remains from as far south as Bristol Bay, combined with oral histories from Natives, portray a resilient animal that has adapted to dramatic changes in the past. The project's lead scientist, Nicole Misarti, said that walruses have seen changes in sea ice in the past 2,000 years and have bounced back from commercial hunting in Alaska during the late 1800s. The key to their research, Misarti said, is figuring out how.

"We know they're resilient because they're still here," she said. "If we can understand how they were resilient and what they did … the aim is that we will be able to ... highlight patterns from the past that can be used by management."

In a lab at the Barrow Arctic Research Center last week, Ph.D. student Casey Clark and a UAF undergraduate used tiny mechanical saws to cut quarter-sized squares out of bones from Jensen's Point Franklin collection. It sounded and smelled like a dentist's office as the blade gnawed and plumes of bone dust passed through the air. Each sample is being tested for DNA to estimate population sizes, for hormones that indicate stress levels or for isotopes that could identify eating habits. Combining the results might help the scientists establish how walruses behaved during previous periods of Arctic warming.

While the UAF team hopes to use their research to illuminate walrus behavior on a timeline dating back 2,000 years, USGS researchers are working on observations from the present.

Federal biologists are comparing how much energy walruses use when there is sea ice and when there is not. They have tracked more than 500 walruses since 2008 with radio tags. USGS wildlife biologist Tony Fischbach says their work reveals that when walruses are on ice, they are primarily resting.

"When they work from shore, they mull around and do these long foraging trips," Fischbach said. "It turns out they spend a tiny fraction of the time resting."

The next step is comparing that to a walrus "energy budget" that USGS compiled from ultrasounds and other data. Those figures will be combined with sea ice trends to make population projections.

Fischbach said he hopes to publish the results by January, in time to be incorporated into decisions about whether the species should be labeled as threatened or endangered. Meanwhile, the UAF scientists plan to work for a few more years.

Both approaches have the support of the U.S. Fish and Wildlife Service, the agency in charge of protecting the animals, because the science could help future planning.

"It all depends on what the results are for both of those studies. Obviously there are different scales in time as well as their geographic extent. They would have usefulness for different purposes," said James MacCracken, the biologist leading Fish and Wildlife's walrus program.

"Let's see what they come up with."