March 30, 2022 — During a typical fall, almost a million chum salmon pour into Alaska’s Yukon River, a torrent of wild fish that has sustained the economy and Indigenous culture in the far north for generations. Last year, that run collapsed, with salmon trickling upstream at a 10th of normal levels, forcing the state to airlift frozen fish from other regions to feed the population.
About 400 miles to the south, in Bristol Bay, the world’s largest sockeye salmon fishery set a record last year, with more than 66 million salmon returning to the rivers in the watershed. That total is expected to be broken again this year.
Salmon in the Pacific Ocean face dramatically different fates from one river system to the next. As the planet warms, driven by the burning of fossil fuels, scientists say changes in ocean conditions are helping drive these wild swings and collapses of key stocks. These North Pacific fish account for most of the world’s wild-caught salmon, and their survival has implications for economies and cultures around the Pacific Rim.
During her three decades as a government scientist, as climate change has intensified, Laurie Weitkamp has watched these fluctuations in salmon numbers become bigger and the models that predict how many salmon will return from sea become more unreliable.
“Salmon will go out, in what we think is a really good ocean, and then it collapses,” said Weitkamp, a fisheries biologist with the National Oceanographic and Atmospheric Administration based in Oregon. “They don’t come back.”