four polar bears in the Arctic
Eric Regehr
An adult female polar bear and her three two-year-old cubs on the sea ice of the Chukchi Sea.

Polar bears capture the imagination like few other wild animals. Adorable and roly-poly as snow-white cubs, they grow into massive hunting machines, supremely adapted to the harsh landscapes of the Arctic. Iconic the world over, many of us only dream of the chance to see one outside of the zoo.

Polar bears have also become a symbol of an environment that’s changing unfavorably. Images of skinny bears, hungry from a lack of food because of diminished sea ice, have become a rallying cry in conservation to aggressively curtail human-induced climate warming. Many are actively seeking strategies that would, among other things, protect the bears.

But it’s not only the bears that are at risk; people who rely on a healthy population of bears for subsistence harvest are facing new challenges too. For millennia, native people living in the Arctic — including the Iñupiaq of northern Alaska — have have depended on the bear culturally and as a source of food and materials. A key question remains: how do we protect both bears and the traditional practices connected to them, when warming temperatures are already driving immense change?

That’s where UW Applied Physics Laboratory’s Eric Regehr and numerous colleagues, including College of the Environment’s Sarah Converse and Nathan Hostetter, come in. In a recent paper published in Ecological Applications, they provide information on an appropriate level of polar bear harvest that meets cultural needs, while accounting for both climate warming and the health of the Chukchi Sea polar bear population.

“There’s a treaty between Russia and the United States for management of polar bears in the Chukchi Sea,” says Regehr. “A group of bears lives in both countries, and under the treaty we have an obligation to study this resource and manage accordingly. One element to consider is subsistence harvest.”

There are 19 subpopulations of polar bears in the Arctic, all varying in size and health. Initially there was little scientific information on the Chukchi Sea group of bears, so beginning in 2008 Regehr and his team began to study them out on the sea ice. “It’s incredible to fly over the frozen Arctic Ocean for hours, seeing nothing but ice, and then to find a mother polar bear with cubs, or a massive 1,400-pound male,” he says.

reseaercher removing a tranquilizer dart from a bear
Eric Regehr
Eric Regehr removes a tranquilizer dart from a small polar bear on the sea ice of the Chukchi Sea.

From a helicopter, they use tranquilizer darts to immobilize the bears, putting them in a deep sleep for 30 minutes. Scientists then quickly collect data to help estimate polar bear demographics, like survival rates and birth rates. From that and other information, including traditional ecological knowledge shared by native partners, they can build models and calculate how many bears can be removed each year sustainably.

“We couldn’t do any of this without the hard work of the biologists, like Eric, who go out on the ice to monitor these bears,” says Sarah Converse, a study co-author who uses a variety of methods to build ecological models to assist managers with decision making in the face of uncertainty, and complex and conflicting societal values. “The goal with this work was to look at the problem from many different angles. How do we allow for the culturally important subsistence harvest practiced for centuries, while also making sure the population isn’t threatened by it? And we needed to account for a climate we know is changing, even if we don’t understand exactly how things will look in the future.”

Before recognizing that climate change can affect bear populations, there was a standard recipe for harvest; 4.5% of the population could be removed annually. When the climate started warming, however, researchers realized that that number might not be valid anymore.

Two camps emerged about what to do. One thought that with a changing environment, no bears should be hunted; the other thought that the bears likely won’t be affected for years, so continuing with the status quo was fine. The solution lies somewhere in the middle.

Through rigorous data collection and in his role as American chair of the Scientific Working Group that advises the U.S.-Russia Polar Bear Commission — a body made up of representatives from Russia, the United States and native organizations from both countries — Regehr recommended that the sustainable harvest rate for Chukchi Sea polar bears was approximately 2.7%.

“Intellectual input was provided by members of the Science and Traditional Ecological Knowledge Working Group of the U.S. Polar Bear Recovery Team, and members of the Scientific Working Group under the polar bear agreement between the U.S. and Russia,” says Regehr. “We presented the Commission with a range of harvest options from zero to eight percent, pointing out the risks associated with each, and then policymakers can make the choice.”

An important aspect of this work is that it informs, not dictates, how polar bears are managed. The research team’s goal was to provide objective information on how harvest affects the polar bear population, which the Commission could consider along with other factors such as subsistence needs and human safety.

The Commission has since adopted the recommendation of harvest at 2.7%, which allows the bear population to remain healthy and helps native communities continue harvesting the animals as they have for generations. But the question remains, how do we know these recommendations are working, and what do we do if they aren’t?

“Adaptive management — you have to come back and check up on yourself,” says Regehr. “We offer a harvest strategy, illustrate its pros and cons, then we come back in 10 years and reassess. We needed to come up with a management plan now, but it’s equally important to check in periodically and make sure things aren’t getting too off track in case we got something wrong.”

Regehr notes that for now, the Chukchi Sea polar bear population is doing well, where some other subpopulations in the Arctic are not. But 50 years from now, nearly all polar bears will feel the effects of warming, and global action is the only way to address the threat. Regehr and colleagues will continue this work, always looking for ways to strengthen their models and recommendations.

“This paper on harvest has a sister paper from 2018 that presents information on population size and survival. For that paper, we specifically designed an interview survey to bring traditional ecological knowledge into the model phase, which ultimately tells us how many bears are out there. This was important for representation and creating a collaborative and balanced process that pulls from multiple information types to meet the common goals of conserving polar bears as well as the traditional practices connected to them.”