More than 5,000 people turned out Saturday for the Lake Sonoma Steelhead Festival, where many attendees got an up-close look at the mating habits of the threatened trout during its spawning season.

The annual event, put on by the Friends of Lake Sonoma, gives the public a chance to learn more about the fish and the efforts of various government agencies to bulk up its population at the Don Clausen Fish Hatchery at Warm Springs Dam. The nonprofit group has played a vital role since federal budget cuts affected operations at the visitor center, which is managed by the U.S. Army Corps of Engineers. Friends of Lake Sonoma assumed staffing for the tours last year.

Typically, most visitors to the hatchery are elementary school students, with about 4,000 children visiting the facility on annual basis.

The event, complete with food trucks, a wine tent and a karaoke singer, helps educate a broader swath of the public, said Jane Young, executive director for the group.

The ultimate goal of the project, said Joel Miller, supervisory ranger for Lake Sonoma, is to relieve pressure on the hatchery through the restoration of 6 miles of Dry Creek habitat, which is scheduled to be completed in five years.

The steelhead trout and the endangered coho salmon need those pockets of calm water along the Russian River watershed to survive and spawn.

“We are cautiously optimistic,” Miller said. “Instead of spawning the fish here in the hatchery, the fish will naturally reproduce and spend the first year of their lives in Dry Creek.”

Steelhead trout typically spawn from December to April in California, looking for cool and highly oxygenated water, according to the state Department of Fish and Wildlife.

A small creek near the hatchery gave visitors an opportunity to see the female fish create spots in the spawning gravel where they lay eggs, which are later fertilized by male fish. Some females may deposit as many as 5,000 eggs.

The fish spend up to the first three years of their lives in freshwater streams before migrating to the ocean, where they continue to grow. They can spend from one to four growing seasons in the ocean, according to Fish and Wildlife. They later return to the freshwater to spawn, using their sense of smell and taste to identify the water of the Russian River.

“For the most part, (Lake Sonoma) releases water that is ideal for the survival of those fish,” Miller said.

The hatchery produces up to 500,000 steelhead smolts, or young fish, annually. Last year, 240,000 coho were harvested.

You can reach Staff Writer Bill Swindell at 521-5223 or bill.swindell@pressdemocrat.com. On Twitter @BillSwindell.

EDITOR’S NOTE: A previous version of this story incorrectly noted the goal of the Dry Creek habitat restoration project was to put the hatchery out of business, based upon a comment from the supervisory ranger for Lake Sonoma. An official with the U.S. Army Corps of Engineers later clarified that the hatchery’s future is not specifically tied to the restoration of the 6 miles of habitat.