An estimated 200,000 to 300,000 fall-run Chinook salmon were killed early yesterday morning at the Feather River Fish Hatchery – Thermalito Facility due to a pump failure from a faulty wire. More than two million remaining salmon at the facility will be released over the next month as they reach an appropriate size.

Overnight on May 10, 2017, the primary pump supplying well water to the facility failed, drastically reducing the water supply to the hatchery raceways.

California Department of Fish and Wildlife (CDFW) staff first observed stressed fall-run Chinook salmon at 6:30 a.m. along with mortalities in the raceways due to low dissolved oxygen levels. Hatchery staff immediately started supplying supplemental oxygen to the raceways to keep fish alive. CDFW notified the California Department of Water Resources (DWR), which manages the wells, and DWR electricians made immediate repairs to restart the pump motor and resume the flow of water.

Early loss estimates suggest 200,000-300,000 fall-run perished in this event. A rapid response likely saved thousands if not millions more fall-run Chinook at the facility.

The fall-run were reared at the Thermalito Facility after they were evacuated from the main hatchery in February following erosion of the Oroville Dam gated flood control spillway.

More than two million fall-run Chinook at the Thermalito Facility will remain there until they reach an appropriate size for release to the Feather River. Releases begin this week and will continue over the next month. CDFW and DWR staff are developing additional redundancy measures to prevent future pump failures.