, a researcher at the 91̽��Applied Physics Laboratory, appears in the film doing fieldwork on Wrangel Island, an island off the northeast coast of Russia that is home to the world’s highest concentration of polar bears. He and 91̽��glaciologist will field audience questions after of the film, which focuses on the changing Arctic environment.

91̽��News asked Regehr a few questions about his research studying a population of polar bears that traverse the waters between Alaska and Russia.

When do you typically go to Wrangel Island, and how long do you spend there?

I’ve been leading polar bear research on Wrangel Island since 2016. I typically spend about one month there each fall, although the entire trip takes two months because the island is so remote. Unfortunately, everything has been on hold since early 2022 due to the political situation with Russia.

Who are your usual collaborators? What was it like to have a film crew with you?

The research project is a collaboration between the 91̽��, the UNESCO Natural System of Wrangel Island Reserve, the U.S. government, and others. Having a film crew was fun. The only downside was that it meant keeping track of more people, to make sure they didn’t wander off and bump into a bear.

How did you come up with the technique, shown in the film, that uses a wire enclosure to collect polar bear fur for DNA analysis?

A colleague in Alaska developed the first “hair snare” traps for polar bears, and then engineers here at the 91̽��Applied Physics Laboratory improved the design to make the traps lightweight and collapsible. I came up with the secret polar bear sauce (it’s really old fish, old cheese and walrus blubber) that we put inside the traps as a scent attractant.

What do you wish people knew about polar bears?

Actually, I’m constantly amazed by how much the public knows about polar bears — especially kids. It’s great. But if there was one thing I’d emphasize, it’s that polar bears are directly connected to the people that live and work in the Arctic. Climate warming is rapidly changing things for both bears and humans.

Why is important to study polar bears on Wrangel Island?

The U.S. and Russia share a polar bear population, most of which ends up on Wrangel Island each fall to wait for the sea ice to reform. I’ve tagged a bear in Alaska in April, and then stood 10 feet from that same bear on Wrangel Island in October. Polar bears don’t recognize political boundaries, so it’s critical that the U.S. and Russia work together to conserve these awesome animals.

Previously, Regehr also worked on the BBC series , narrated by David Attenborough, where he appears in episode 6. That series is available on Amazon Prime and Google TV.

For more information, contact Regehr at eregehr@uw.edu.

Not all polar bears are in the same dire situation due to retreating sea ice, at least not right now. Off the western coast of Alaska, the Chukchi Sea is rich in marine life, but the number of polar bears in the area had never been counted. The first formal study of this population suggests that it’s been healthy and relatively abundant in recent years, numbering about 3,000 animals.

The by researchers at the 91̽�� and federal agencies is published Nov. 14 in , an open-access journal from the Nature Publishing Group.

“This work represents a decade of research that gives us a first estimate of the abundance and status of the Chukchi Sea subpopulation,” said first author , a researcher with the UW’s Polar Science Center who started the project as a biologist in Alaska with the U.S. Fish and Wildlife Service. “Despite having about one month less time on preferred sea ice habitats to hunt compared with 25 years ago, we found that the Chukchi Sea subpopulation was doing well from 2008 to 2016.

“Sea-ice loss due to climate change remains the primary threat to the species but, as this study shows, there is variation in when and where the effects of sea-ice loss appear. Some subpopulations are already declining while others are still doing OK.”

Of the world’s 19 subpopulations of polar bears, the U.S. shares two with neighboring countries. The other U.S. subpopulation — the , whose territory overlaps with Canada — is showing signs of stress.

“The southern Beaufort Sea subpopulation is well-studied, and a growing body of evidence suggests it’s doing poorly due to sea-ice loss,” Regehr said.

Polar bears were listed as threatened under the U.S. Endangered Species Act in 2008 due to the threat of , which the animals depend on for hunting, breeding and traveling. But the new study suggests that such effects are not yet visible for bears in the remote waters that separate Alaska from Chukotka, Russia.

“It’s a very rich area. Most of the Chukchi Sea is shallow, with nutrient-rich waters coming up from the Pacific. This translates into high biological productivity and, importantly for the polar bears, a lot of seals,” Regehr said.

Previous studies by the State of Alaska show that ringed and bearded seals have maintained good nutritional condition and reproduction in the Chukchi Sea region, Regehr said.

“Just flying around, it’s night and day in terms of how many seals and other animals you see,” Regehr said. “The Chukchi Sea is super productive and the Beaufort Sea is less so.”

The area also has an abundance of whale traffic, and when carcasses wash up on shore the polar bears can , when the sea ice melts and a portion of the Chukchi Sea subpopulation waits on land for the ocean to refreeze.

Recent ecological observations had suggested that Chukchi Sea bears are doing well. A study led by co-author , at the U.S. Geological Survey, showed the top predators have similar amounts of body fat as 25 years ago, a good indicator of their overall health.

The current study is the first assessment of the subpopulation size using modern methods. It estimates just under 3,000 animals, with generally good reproductive rates and cub survival.

As a federal wildlife biologist based in Alaska until 2017, Regehr and colleagues gathered the data by tagging roughly 60 polar bears in most years from 2008 to 2016. He flew by helicopter over the area just north of Alaska’s Seward Peninsula, looking for tracks on the sea ice. The helicopter then would follow tracks in the snow to locate the bear and use a tranquilizer dart to sedate the animal. Over about an hour, researchers would weigh the bear, collect biological samples, apply individual tags and, in some cases, attach a GPS transmitter.

All the data were incorporated into a new model designed to estimate population size for large carnivores that are highly mobile and whose territory spans a large region. The authors made the model publicly available in the hope that it will be used on other populations or species.

“Polar bears can travel thousands of miles in a year. But with the GPS tags, we can see when a bear leaves our study area but is still alive, because it’s moving. This information is key because there are bears that we see once and never see again, and to get a good population estimate you need to know if these animals died or just moved to a new area,” Regehr said.

For the first time, the model also considered collected by the North Slope Borough of Alaska from Native hunters and community members who have generations of experience with polar bears.

“It was important to bring our science together with the observations and expertise of people who live in polar bear country year-round and understand the animals in different ways,” Regehr said.

A joint U.S.-Russia commission is responsible for management and conservation of the Chukchi Sea subpopulation. In response to the new assessment, the commission raised the sustainable level of subsistence harvest, which is nutritionally and culturally important to Native people in Alaska and Chukotka.

“These polar bears move back and forth between the U.S. and Russia, so it’s very much a shared resource,” said Regehr, a longtime scientific advisor to that commission.

As part of his current research at the UW, Regehr spends about two months each year working with Russian scientists on Wrangel Island in the Arctic Ocean, where hundreds of Chukchi Sea polar bears spend their summers.

“These findings are good news for now, but it doesn’t mean that bears in the Chukchi Sea won’t be affected by ice loss eventually,” Regehr said. “Polar bears need ice to hunt seals, and the ice is projected to decline until the underlying problem of climate change is addressed.”

Co-authors are at the U.S. Geological Survey; and with the U.S. Fish and Wildlife Service in Alaska; and , a 91̽��associate professor and leader of the U.S. Geological Survey’s Washington Cooperative Fish and Wildlife Research Unit.

The research was funded by the U.S. Fish and Wildlife Service, the U.S. Geological Survey, the UW, the U.S. Air Force, the State of Alaska, the Bureau of Ocean and Energy Management, the Bureau of Land Management and the National Fish and Wildlife Foundation.

###

For more information, contact Regehr at 206-685-3512 or eregehr@uw.edu.

Research from the 91̽��, the U.S. Fish and Wildlife Service and the U.S. Geological Survey investigates what these changes could mean for subsistence harvest of polar bears — a practice that has cultural, nutritional and economic importance to many Northern communities.

An open-access published this month in the Journal of Applied Ecology addresses this question using an improved model of how polar bear populations function.

“A big question in polar bear conservation is: How will habitat loss and harvest interact to affect the status of polar bear populations?” said lead author , a researcher with the UW’s Applied Physics Laboratory who did the work as a biologist with the U.S. Fish and Wildlife Service.

The authors identify ways to maintain subsistence harvest without compounding the negative effects of habitat loss, as long as there is accurate population data and the harvest is responsive to changes in the environment.

“A key takeaway is that, under many conditions, it is possible to identify a rate of harvest — the fraction of a population to be removed each year — that doesn’t drive down the population or accelerate any potential population declines due to habitat loss,” Regehr said.

Currently there are about 26,000 polar bears divided into 19 subpopulations across the Arctic, two of which occur partially in Alaska. The species was listed as threatened throughout its range under the U.S. Endangered Species Act in 2008 due to observed and projected loss of sea-ice habitat due to climate change.

“The current status of the 19 subpopulations in relation to climate change is variable. Some are declining or exhibiting signs of stress,” Regehr said. “Because of regional variation in environmental conditions and ecology, some subpopulations are stable or may be increasing.”

But the sea ice trend is clear. A recent UW-led study showed all 19 subpopulations are , and that from 1979 to 2014 polar bears lost an average of seven weeks on the sea ice. This trend toward shorter ice-covered periods is expected to continue, and in the long term is anticipated to negatively affect polar bears throughout most of their range.

In the new study, researchers combined the polar bear population model with projections for future sea ice extent provided by co-author in the UW’s Applied Physics Laboratory. Results show that, with the right approach, subsistence harvest can likely continue without putting subpopulations at additional risk.

“When habitat loss causes crowding, there are generally negative effects on animals such as lower nutritional condition, reproduction and survival,” Regehr said. “If a well-designed harvest can reduce this crowding, there’s more ecological space for animals to feed, and as a result more cubs can be born.”

The study finds that as climate shifts it becomes increasingly important to monitor each subpopulation regularly, through scientific studies and collection of local knowledge, and adjust harvest accordingly. This strategy, known as “state-dependent management,” is becoming popular for other wildlife species that live in changing ecosystems.

“If environmental conditions are changing fast, it’s important to have more frequent population assessments, so you don’t go for a long time with a harvest that used to be OK but eventually becomes unsustainable,” Regehr said. “In the absence of good information about a subpopulation, you generally have to take a more conservative approach.”

Regehr has spent the past 15 years studying polar bears for the U.S. Department of the Interior. For the past eight years he has led research on the Chukchi Sea subpopulation, which is shared between the U.S. and Russia. Regehr is also the American co-chair of the scientific advisory group under a treaty between the two countries intended to conserve this shared subpopulation. He will continue to study polar bears and wildlife management in his new position as a researcher with the UW’s .

The research was funded by the U.S. Fish and Wildlife Service, the U.S. Geological Survey and NASA. Other co-authors are at the U.S. Fish and Wildlife Service; and and at the U.S. Geological Survey.

###

For more information, contact Regehr at eregehr@uw.edu or Runge at mrunge@usgs.gov. Regehr is in Greenland until mid- April but can be reached by email.

NASA grants: NNX13AN28G, NNX11A063G