This week, the brown bears that live in Katmai National Park are facing off in an annual tournament-style competition to determine which bear best exemplifies the essence of fatness. Since 2014, Fat Bear Week has celebrated the park’s ursine residents with a beloved online contest.
But, Fat Bear Week is also about the salmon that make the bears so fat. And scientists are still scratching their heads about why those salmon are doing so well while other runs are crashing.
The event kicked off Wednesday, with matchups between bears 335 and 164, and between 856 and 747. This year, Fat Bear Week seems to be getting more attention than ever, with national and international coverage in the New York Times and BBC. Last year, more than 800,000 votes were cast, as the competition — like other virtual events — saw increased participation during the pandemic.
Behind the corpulent brown bears, the salmon are the secret heroes of Fat Bear Week. Promotional materials for the event herald the fat bears as a testament to the richness of the Bristol Bay area — home to record-setting salmon runs, in, “a wild region that is home to more brown bears than people and the largest, healthiest runs of sockeye salmon left on the planet.”
But biologists like Vanessa von Biela with the Alaska Science Center study how, while the Bristol Bay salmon continue to be a success story, salmon runs around the rest of the state‚ including on the Kenai Peninsula, are in decline.
Von Biela studies the impact of environmental factors, like temperature, on salmon. She said record warm and dry weather in summer 2019 coincided with widespread mortality for pacific salmon, including many that were on their way back to their home rivers to spawn.
Von Biela said throughout her 15-year career as a fish biologist, the tide has changed on how experts regard the impact of warmer waters on salmon. She said researchers once viewed warmer waters as a benefit to salmon, but now, those temperature increases have gone too far.
“A ton of research papers showed that when things got a little bit warmer, that was better, the salmon had more food, the water temperatures more more at an ideal range for them, both in the ocean and the freshwater,” she said. “But now, some places have hit tipping points.”
Bristol Bay was less impacted by the warm conditions in 2019. And scientists there generally observed less salmon mortality in the area.
Von Biela said scientists are still trying to figure out why that’s the case. She said it could be related to the deepness of the area’s lakes, which create a variety of water temperatures.
Other scientists credit the region’s intact habitat — or even said that for now, warmer temperatures are in fact benefiting the salmon.
In the meantime, salmon in the Gulf of Alaska and other warming waters are able to move to new areas to adapt. For example, when glaciers retreat, salmon take advantage of new habitats.
“But now, we’re seeing that pace maybe change to be a lot faster,” von Biela said. “And so that makes it hard for the places where people are really connected to salmon, because sometimes that means we’re looking at links being broken in some places where people are connected to salmon, given that the climate is changing so rapidly.”
Von Biela and other scientists are still trying to get to the bottom of the declines impacting fisheries around the state. But she said for now, Bristol Bay’s runs continue to stick out as a salmon success.
The daily matchups for Fat Bear Week continue through tomorrow, Oct. 11, when the ultimate fat bear will be crowned. You can view the Brooks Falls brown bears — often eating salmon — on the live cams at explore.com. You can vote at fatbearweek.org from 8 a.m. to 5 p.m. each day until then.
