A coho salmon fry is shown in this undated photo. Nine species of salmon in the Northwest are being added to the endangered species list in a move that sends the restrictions deeper into urban areas and could change the way people fertilize their lawns, dig construction sites and wash their cars. (AP Photo/ho)

Dec 1 (Reuters) - California's three-year drought threatens to wipe out the last of the Muir Woods coho salmon that make their way each year from the Pacific Ocean to spawn in a freshwater creek running through the redwoods near San Francisco, state officials said on Monday.

As the annual salmon migration reaches its peak in streams through the northern part of the state, those in Redwood Creek, the southernmost home for returning coho salmon, are on the verge of local extinction, officials said. About 100 juvenile salmon found trapped in the drought-lowered creek are now being raised at a local hatchery.

"We just have to wait and see how the fish mature in the hatchery and what the environmental conditions look like next winter," said Manfred Kittel, the California Department of Fish and Wildlife's regional coho salmon recovery coordinator. "The plan theoretically is to put them back in the creek hoping there is enough water to support them."

The coho, also called silver salmon, once thrived in Redwood Creek in Marin County and provided sustenance for both the Miwok Indians and grizzly bears.

But a search last winter found no coho salmon eggs and there was no sign of any baby salmon over the summer, Kittel said. The young salmon sent to the hatchery will stay there for the next 15 months.

Each winter, 3-year-old fish swim from the ocean to their birthplace in Muir Woods, a protected area that includes many redwoods, along with other stream systems in the state to lay their eggs.

Last month, the state said salmon migration in the American River watershed near Sacramento was slower than usual amid dry weather and warmer temperatures.

The threat to the Redwood Creek coho mirrors problems for salmon throughout the Western United States, where their numbers have dropped dramatically.

The Redwood Creek salmon also face the problem of the popularity of Muir Woods National Monument, established in 1908 by President Theodore Roosevelt. Traffic jams are common on the small road leading to the monument.

"This is a very important signal and we can't afford to ignore it," said Kristin Shannon, chair of a local watchdog group. "The Park Service needs to follow their higher mission, which is to protect the woods and the salmon for the next generation." (Reporting by Michael Fleeman in Los Angeles; Editing by Sharon Bernstein and Peter Cooney)