California drought threatens coho salmon with extinction Salmon, unable to swim upstream to spawn, at risk of extinction - species stranded in ocean awaiting water surge for migration

Coho salmon are raised at the Warm Springs hatchery in Geyserville as well as one in Santa Cruz. Coho salmon are raised at the Warm Springs hatchery in Geyserville as well as one in Santa Cruz. Photo: Beck Diefenbach, Special To The Chronicle Photo: Beck Diefenbach, Special To The Chronicle Image 1 of / 7 Caption Close California drought threatens coho salmon with extinction 1 / 7 Back to Gallery

The lack of rain this winter could eventually be disastrous for thirsty California, but the drought may have already ravaged some of the most storied salmon runs on the West Coast.

The coho salmon of Central California, which swim up the rivers and creeks during the first winter rains, are stranded in the ocean waiting for the surge of water that signals the beginning of their annual migration, but it may never come.

All the creeks between the Golden Gate and Monterey Bay are blocked by sand bars because of the lack of rain, making it impossible for the masses of salmon to reach their native streams and create the next generation of coho. The endangered coho could go extinct over much of their range if they do not spawn this year, according to biologists.

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

The situation is bad even in the one place fish can get upstream, in West Marin County. Very few coho have been seen in Lagunitas Creek, long considered a bellwether of salmon health in the region, according to Eric Ettlinger, the aquatic ecologist for the Marin Municipal Water District.

Attempt to lure the coho

The dire situation prompted the district to release 29 million gallons of valuable drinking water from Kent Lake early this month in an effort to lure the coho into the watershed, which winds 33 miles through the redwood- and oak-studded San Geronimo Valley on the northwest side of Mount Tamalpais.

Watershed biologists in Marin have counted only 57 coho redds, the word scientists use for the clusters of pink eggs that salmon lay in the gravel. That's "exceptionally low for mid-January," Ettlinger wrote in his weekly spawning update. More than 100 redds were counted last January in Lagunitas Creek, where many thousands of fish once spawned until seven dams were built in the watershed to supply Marin with drinking water.

Lagunitas Creek run

It is still the largest run of wild coho - many of the fish in other areas are raised in hatcheries - and a model for fisheries restoration throughout the state.

"This lack of rainfall is a disaster," said Jonathan Ambrose, a biologist with the National Marine Fisheries Service. "When you have very few individuals left, every fish is precious."

Coho, also known as silver salmon, are born in cold freshwater rivers and streams, where they live for a year before swimming to the ocean. They typically return at age 3 to where they were born to lay eggs and fertilize them. The drying creek beds are also a problem for juvenile salmon.

Steelheads also waiting

"The adults are having trouble getting in and the juveniles that hatched last year are trapped in streams that are drying up," Ambrose said. "Fish need water. If they don't have water, they can't go walk somewhere else. So we are in somewhat of a crisis mode right now, and we don't have a whole lot of options."

Steelhead trout, which are listed as threatened under the Endangered Species Act, are also waiting offshore at the same streams, but they are more resilient - unlike coho, they can often wait a year to spawn. Still, an extended drought could further reduce their population, Lehr said.

"The question is, can they respond once the drought is over?" Lehr said. "Are populations so depressed that they're not able to rebound?"

The Scott Creek hatchery in Santa Cruz may end up being the only hope for coho and steelhead south of San Francisco. Ambrose said the species are being bred at the hatchery in an attempt to keep their genetic line going.

The problem is that almost all salmonid species in California, from chinook to steelhead trout, are under some level of federal or state protection.

"If the drought continues there are going to be dead fish," said Tom Stokely, water policy analyst for the nonprofit California Water Impact Network, which advocates for environmentally sensitive use of California water. "Depending on what the runs are like, it could pale in comparison to anything we've seen in recent history."

Fishermen in jeopardy

A collapse of the fall run of chinook, which is the only viable fishery left in Central California, would put hundreds of commercial fishermen and marine-related businesses out of work. Such a scenario would require drastic measures, such as rescues of fish stranded in dried-up pools in creeks and rivers, Lehr said.

"For our sensitive aquatic fish, it is not looking good," Lehr said. "We are developing contingency plans as we speak, putting the challenge out there that we may have to explore some options that we may not have considered historically. We are facing uncharted waters both literally and figuratively."