The Idaho Department of Fish and Game may expand spring chinook fishing on the Clearwater River and its tributaries to seven days per week if the run continues to outpace the preseason forecast.

The forecast called for about 8,000 adult hatchery spring chinook to return to the Clearwater, allowing for a four-day-a-week season and a modest harvest share of about 1,360 adult chinook. Chinook that are surplus to hatchery spawning quotas are available for harvest and split evenly between tribal and nontribal anglers. Joe DuPont, regional fisheries manager for the Idaho Department of Fish and Game at Lewiston, said in his weekly spring chinook fishery update that the projected harvest share now sits at 3,789 — meaning each angler group can catch that many fish.

Harvest shares are projected using detections of hatchery fish as they swim past Bonneville Dam on the Columbia River. They can fluctuate up and down, depending on the run performance.

DuPont wrote in his update that if the number of hatchery chinook bound for the Clearwater River continues to project a much healthier harvest share than what was originally forecasted, the department may ask the Idaho Fish and Game Commission to expand fishing to seven days.

However, the number of fish passing Bonneville Dam has declined recently. It peaked at nearly 6,000 on May 3 and dropped to about 3,000 a day by Wednesday.

“We need these counts to pick back up or at least stabilize for a few more days for us to achieve or exceed our preseason forecast,” DuPont wrote in his update. “The tangle net test fishery near the mouth of Columbia River has shown steady catch rates for the past two weeks which gives me hope this will occur.”

The projected harvest share for chinook bound for the Rapid River Hatchery near Riggins has not fared so well. It started at about 2,500 and is now at 1,854. The harvest share on the Snake River and Hells Canyon is projected to be 684.

There is still time for the shares to change.

“It is important to realize these harvest shares assumed that the run has an average run timing (about 60% complete). However, if the actual run timing is later than average, then the harvest share will go up, and if the run timing is earlier than average our harvest share will drop,” DuPont said.

His full update is available at bit.ly/4b94axL.

Barker may be contacted at ebarker@lmtribune.com or at (208) 848-2273.