Chinook salmon haven't returned naturally to the Boise River for decades, since dams downstream on the Snake River blocked their passage.
But the Idaho Department of Fish and Game will be stocking 300 to 400 Chinook jacks in the Boise River Monday.
The jack salmon are young Chinooks that return to fresh water earlier than other spawning adults.
They're about half the size of typical Chinooks that return to rivers.
These ones will be released from the Glenwood Bridge to Barber Park, at sites Fish and Game commonly uses to release another of the Boise River's fish, the steelhead, whose historical spawning journeys were also interrupted by dams.
The jack salmon being released in the Boise River are among those not required for broodstock at the Rapid River Hatchery downstream.