The Nez Perce Tribe’s hatchery supplementation program — and to some extent Mother Nature — can be credited for this year’s fall chinook salmon count at Lower Granite Dam, which is expected to set a record with a return of 10,000 adult fish.

On Monday, 604 fall chinook were counted at the dam, located 20 miles northwest of Lewiston, Idaho, on the Snake River. That’s higher than the total fall season counts in six individual years since the dam was built in 1975.