The collapse of Central California Coast coho salmon population is imminent, according to a report by the National Marine Fisheries in late December 2009. Numbers of returning coho may be too low to support a viable population.
For the last three years very few nests, or “redds,” have been found in Marin County’s Lagunitas watershed, where 80 percent of Central California’s coho salmon live. The salmon live three years, half in the coastal streams and half in the Pacific, then return at the end of their lives to spawn. The salmon reproduce in three groups, each returning every third year, so that in three years, all three groups have returned and spawned. When, for three years in a row, numbers are drastically low, the entire population is at risk.
Rain was good in early December, and some coho made their way up Lagunitas Creek from Tomales Bay. But since then, few have been sighted.
Paola Bouley, of the Salmon Protection and Watershed Network, says more rain may bring fish up the streams. “We have a one-month window to get some good storms. But basically, we need to increase productivity by improving the habitat in the watershed. We need to install woody debris to slow the streams and provide shelter for the fish. We need to reduce human impact at the streamside and prevent runoff of toxic chemicals. If we can produce more fish, they have a chance at survival. It’s a numbers game. So far this year 44 redds have been counted. Since 2000 the annual average has been 247.”
SPAWN recently received a California Fish and Game grant to increase the amount of woody debris in the streams. The group is also pushing hard at the county level to reduce the pressures of human development in the watershed. There is a county supervisors’ meeting on January 21 to discuss a salmon enhancement plan for the San Geronimo Valley. SPAWN is hoping people will attend and speak out. “The county has the primary jurisdiction over land use,” says Bouley. “They have the power to make things happen in the watershed.”
A concerned human population is the coho’s greatest hope, says National Marine Fisheries Biologist Charlotte Ambrose. “In Marin County you have a community of people who care. We need that across the range. The time is now to find hope, and find out what actions need to be taken.”
NMF is releasing a much-awaited Salmon Recovery Plan at the end of January, with the priority to “increase the probability of survival for every individual,” says Ambrose. “For instance, we’re asking, ‘What can we do for the fish at each life stage? What can we do for adults? What can we do to decrease the likelihood of incidental catch by steelhead fishermen? What are the needs of the fish at each stage of life? What does increasing water release do for each age group?’”
The real story, she says, “is as the population decreases, you have a decreased ability of the individual to survive the pressures of the environment, both natural and human. Fewer survive to spawn, and the decline feeds on itself. The coho are in an extinction vortex.”