Coho (silver) salmon spawn in the Bay Area

Ken Jones

Staff member

Nearly extinct salmon spawn in the Bay Area for the first time in 18 years
Amanda Bartlett, SFGATE, Jan 9, 2022

At first, barely visible beneath the rippling waters of Montezuma Creek in Forest Knolls, the bright red tail of a coho salmon suddenly emerged, splashing along the surface as it swam upstream.

The recent sighting by Salmon Protection and Watershed Network (SPAWN) biologist Ayano Hayes was a milestone for the Bay Area, marking the first time the endangered fish has been spotted in the small tributary of the San Geronimo Valley in Marin County since 2004.

“This is extremely exciting and is the result of big storms that have let coho salmon maneuver through culverts under roads that are a barrier to migration under lower flows,” said Hayes in a statement.

The biologist also discovered salmon in Arroyo Creek, Woodacre Creek and Larsen Creek, where they had not been seen since 2006.

The species has experienced a “serious decline” since the mid-20th century, according to the California Department of Fish and Wildlife, due to threats such as loss of habitat, overexploitation (which occurs when more fish are harvested beyond the species’ capacity to repopulate), interaction with hatchery-raised fish and climatic factors such as lack of precipitation. In recent years, the coho salmon that typically spawned in creeks between the Golden Gate and Monterey Bay were blocked by sand bars because of the drought. They faced extinction over most of their range.

"It may already be too late," Stafford Lehr, chief of fisheries for the California Department of Fish and Wildlife, told the Chronicle in 2014. "The Central Coast coho could be gone south of the Golden Gate."

Spawning season typically happens in December and January, and though thousands of coho salmon once made their way to the Bay Area, only “a couple hundred” now return each year, according to SPAWN.

Even those numbers are encouraging, however.

“Endangered coho salmon are on the brink of extinction, yet one of the largest populations left in California occur within 35 minutes of the Golden Gate Bridge,” wrote SPAWN in a statement.

The organization attributes this year’s success in part to the removal of a dam on the former San Geronimo Valley golf course in 2021, allowing salmon to more easily migrate into the upper watershed; Chinook salmon were recently documented in Woodacre Creek for the first time ever.

Preston Brown, SPAWN’s Director of Conservation, also noted the concentration of rainfall in recent months, which “has to be just right to allow fish to jump into and swim through artificial culverts that concentrate flow and increase velocity.”

And though recovery is slow, biologists are optimistic. “We can bring back the salmon of Marin from the brink of extinction if we care enough to protect and restore habitat,” said Todd Steiner, the founder and executive director of SPAWN. “We have the know-how and the state and federal agencies have offered the resources. It boils down to our local elected officials having the courage to enact the regulations that will protect the habitat the fish need to survive for our children and grandchildren.”