Which Pacific salmon species has the longest freshwater migration, up the Yukon River?

Chinook salmon make the longest freshwater migration of any Pacific salmon species, traveling up the Yukon River. Some reach spawning grounds upstream of Whitehorse, Yukon, more than 3,000 kilometres from the river’s mouth in the Bering Sea.

This journey begins after adult salmon leave the ocean and enter freshwater, where they stop feeding and depend on stored energy. Chinook are the largest Pacific salmon species, and their substantial fat reserves help power them through strong currents, rapids, and long stretches of river.

The Yukon route crosses Alaska and Canada and includes the Whitehorse Rapids area. A fish ladder around the hydroelectric dam at Schwatka Lake allows salmon to continue upstream toward spawning habitat. The effort is the final stage of a life cycle that began when the fish hatched in freshwater and migrated downstream to the sea.

Pink, coho, and sockeye salmon also undertake major migrations, but they do not match the Yukon Chinook’s freshwater distance. Chinook are also called king salmon, a name reflecting their size and importance in fisheries.