Anglers in Idaho will not be allowed to keep any steelhead starting Friday, but catch-and-release will be permitted.
The Idaho Department of Fish and Game says the decision announced Tuesday is intended to allow enough steelhead to make it to hatcheries to have future generations.
Officials say that through Monday, about 400 steelhead have crossed the Lower Granite Dam in eastern Washington state, about 30 miles downstream from Lewiston in northern Idaho.
Officials say the 10-year average for this time of year is about 6,000 steelhead.
The announcement applies to hatchery fish identified with a clipped adipose fin - the fin on top between the dorsal fin and tail.
Wild steelhead have that fin intact, but Idaho anglers have been required to release those fish unharmed since 1987.