Running against time: Forecasting Chinook salmon runs on the Yukon River


When Yupik fishermen told Phil Mundy, a young biologist at the time, that the wind blew the salmon into the Yukon River, his Western science mind imagined a literal interpretation. “Perhaps they put their dorsal fins above the water and get a ride from the wind,” he thought. Now retired, he laughs at that idea.

The Yukon River, nearly 3,200 kilometers (2,000 miles) long, spreads from the Bering Sea like spider veins into the interior of Alaska and northwestern Canada. In late spring and early summer, Chinook salmon—commonly known as King salmon for their immense size and rich, oily meat—take on this river in one of the world’s greatest migrations and longest salmon runs. And they do it twice: born in freshwater, they swim out to sea to feed and grow for three to five years, only to return as plump adults to spawn, guard their eggs, and die.

The villages dotting the Yukon rely on these salmon for subsistence and commercial fisheries, and the fish play a big part in their culture and heritage. Mistakes in harvesting decisions, such as whether to open or close a fishery, could mean people upstream go hungry or the salmon population struggles to recover. “It’s very stressful to be in charge of the economic welfare of a few thousand miles of river.

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