Drought and poor water conditions at Lake Sonoma prompted the California Department of Fish and Wildlife to move young coho salmon from Warm Springs Fish Hatchery in Geyserville to a conservation facility in Petaluma, in order to avoid heat stress.

The rising temperatures also increase the risk of pathogen outbreaks, officials said.

“We all have a vested interest in seeing coho salmon remain healthy,” said Stacy Sherman, acting regional manager with the state office. “In addition to being endangered, coho are an indicator species and a sign of the health of the watershed. When they’re in danger action needs to be taken.”

The relocation of more than 4,000 salmon moved by truck in recent weeks was made possible by a successful public-private partnership led by the U.S. Army Corps of Engineers, which operates the Warm Springs Fish Hatchery. The California Department of Fish and Wildlife contributed pathogen testing and logistical support.

The student-operated conservation facility, located at Casa Grande High School in Petaluma, is maintained by United Anglers of Casa Grande Inc. Also joining the relocation effort was the National Marine Fisheries Service, Monterey Bay Salmon and Trout Project, Sonoma Water and Jackson Family Wines which provided funding for the effort.

The fish will be returned to the hatchery once conditions return to normal at Lake Sonoma.