This story originally appeared in High Country News and is part of the Climate Desk collaboration.
Every June, Serena Fitka goes home to her Yup’ik community of St. Mary’s, Alaska, near the confluence of the Yukon and Andreafsky rivers in the southwest part of the state. Usually, she helps her family fish for salmon and preserve it in the smokehouse for the leaner winter months. But this year, that didn’t happen: This year, there were no salmon to catch.
“I could feel the loss,” she said. “I didn’t know what to fill my days with, and I could sense it was like that for everyone along the Yukon River.”
There are five kinds of salmon in Alaska: Chinook, sockeye, chum, coho, and pink. Chum is the most harvested fish on the Yukon, but both chum and chinook are crucial to the lives and culture of the roughly 50 communities around Alaska who rely on the river and its tributaries for subsistence.
Around the state, chinook counts have been declining for a decade, but this year’s run is the lowest ever recorded. Chum counts took a nosedive in 2021, and this year’s count is the second-lowest on record; as a result, state and federal fishery managers have closed chum fishing on the Yukon. This will affect more than 2,500 households in the region that rely on chum to feed their families. “That annual harvest is gone,” said Holly Carroll, a Yukon River subsistence fishery manager for the U.S. Fish and Wildlife Service. Scientists haven’t figured out why chum and chinook runs have been so poor in parts of western Alaska, but many theorize that warming ocean conditions are impacting the salmon early on in their life cycles—and some local subsistence fishers believe that commercial fishing operations in other parts of the state could be contributing as well.
Warmer waters have caused a downturn in chinook and chum numbers across the Pacific, and those changes are hurting salmon in the Yukon as well. In one study of chum, researchers found that the fish were eating things outside their usual diet, like jellyfish, and, because of that, likely didn’t have enough energy stored in their bodies to survive the winter. “That’s associated with these marine heat waves that we’ve seen in the Bering Sea as well as the Gulf of Alaska,” said Katie Howard, a fisheries scientist with the Alaska Department of Fish and Game Salmon Ocean Ecology Program. During marine heat waves, chum eat prey that is easier to catch, but often less calorically dense. Drought in the spawning grounds of Interior Alaska and Canada could also contribute to lower numbers of chinook, since it leads to lower water levels and makes the water warmer.
Meanwhile, nearly 400 miles south in Bristol Bay, a warming climate might actually be helping salmon runs instead, said Jordan Head, a state biologist working in the region. Bristol Bay fishers have harvested over 57 million sockeye this year, breaking the all-time record of 44 million fish set in 1995. The region has seen over 74 million sockeye return so far this season, the largest number in the fishery’s history. With the warmer temperatures, the lakes are frozen for less time, and the juvenile sockeye may have been able to grow larger and be more competitive as they enter the ocean, thereby increasing their odds of survival. But as the Bering Sea continues to warm, it too could see the same salmon declines as the Yukon.