Lower Granite Dam counts say one thing, but catching says another: Fall Chinook report

Trapping during this early part of the season allows the team to collect a fair number of large fall Chinook, many of which are natural-origin fish. This strategy also means that the high trap rate does not trap as many steelhead because they tend to arrive slightly later than fall Chinook at Lower Granite Dam.

Unfortunately, river conditions are warm in the Columbia River, and both fall Chinook and steelhead timing to Lower Granite Dam are later than expected. There were also fewer larger fish than expected. With a later run timing and fewer big fish being trapped, extending the high trap rate was necessary to ensure enough adults are collected to meet broodstock goals.

As of the end of trapping on Sept. 9, a total of 2,532 adult fall Chinook have been collected for broodstock at Lower Granite Dam, and 2,129 adults and jacks were returned to the river. The broodstock goal is approximately 4,000 adult fish that are at least 28 inches in length.

Collection of broodstock fish will continue at Lower Granite Dam and during the season, further adjustments might still occur, such as modifying the trap rate or size criteria if the expected return to Lower Granite Dam changes. A lower trap rate is needed to reduce the amount of fish being trapped and handled when more fish are expected to arrive. With numbers of fall Chinook and steelhead starting to bump up at Ice Harbor Dam, the trap rate was lowered to 16% on Sept. 9 so more fish should be coming your way.

If you have any questions regarding the fall Chinook salmon program and the trapping that occurs at Lower Granite Dam, feel free to contact Fish and Game Fisheries Biologist Marika Dobos ([email protected]), the Regional Manager Joe DuPont ([email protected]), or other staff at the Lewiston Regional Office by email, or call (208) 750-5010.