First young coho in Walker Creek since 2008

10/24/2013

At least one effort to restore the salmon population in West Marin is proceeding swimmingly, according to researchers with Marin Municipal Water District, who announced the sighting of 71 juvenile coho salmon in Walker Creek, a tributary to Tomales Bay, this month.

It was the first sighting in the creek since 2008, said Gregory Andrew, a MMWD biologist. “We don’t know if all the fish are from the one [nest] we found last year or if there were more. But it is very exciting to have found any juveniles at all.”

The coho were seen in 10 pools throughout several sections of the creek spanning approximately two miles downstream of Marshall-Petaluma Road. Some were found near the single redd, or nest of eggs, that was recorded during last year’s surveys. And one coho was observed in Frink Canyon, a nearby tributary. 

Beginning in November, the salmon swim upstream from the ocean to West Marin’s creeks to spawn before the end of their life cycle. The spawning period coincides with the rainy season and lasts for three to four months. 

The offspring, like the ones documented this month, live in the creek for about a year and a half before migrating to the ocean. 

In the early 90’s there were no coho in the creek, which flows 18 miles from its origin before draining into Tomales Bay and the Pacific. Surveyors have concluded that the juvenile coho found this year had not been released as part of a restoration program that began in 2003, in which the California Department of Fish and Wildlife began releasing coho. 

Instead, they might be the offspring of the program, or they might also have hatched from truly wild California salmon, said Manfred Kittle, the coho salmon recovery coordinator at the state wildlife department. 

The team has collected small pieces of fin tissue that will be used in genetic analysis at the National Marine Fisheries Service’s lab in Santa Cruz to determine the origin. 

The burgeoning population has benefited from more than $1 million in creek restoration projects funded by the Marin Resources Conservation District to restore streambeds. 

The local ranching community has embraced the efforts by fencing off livestock and restoring vegetation and shading along stream banks. 

“To have a habitat in Walker Creek is pretty great news, considering that statewide populations are struggling,” said Nancy Scolari, the executive director of the conservation district. “Just seeing they are able to survive there is quite an accomplishment for us. It shows all this work wasn’t for naught.”