But on the Yukon River, about 500 miles to the north, salmon were alarmingly absent. This summer’s chum run was the lowest on record, with only 153,000 fish counted in the river at the Pilot Station sonar — a stark contrast to the 1.7 million chum running in year’s past. The king salmon runs were also critically low this summer — the third lowest on record. The Yukon’s fall run is also shaping up to be sparse.

The disparity between the fisheries is concerning — a possible bellwether for the chaotic consequences of climate change; competition between wild and hatchery fish; and commercial fishing bycatch.

“This is something we’ve never seen before,” said Sabrina Garcia, a research biologist with the Alaska Department of Fish and Game. “I think that we’re starting to see changes due to climate change, and I think that we’re going to continue to see more changes, but we need more years of data.”

The low runs have had ripple effects for communities along the Yukon River and its tributaries — the Andreafski, Innoko, Anvik, Porcupine, Tanana and Koyukuk Rivers — resulting in a devastating blow to the people relying on salmon as a food staple, as feed for sled dogs and as an integral and enriching cultural tradition spanning millenniums.