Strong start to the marine salmon spawning season

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  • An environmental team searches for salmon at Lagunitas Creek in Samuel P. Taylor State Park on November 18, 2021. Left to right: Eric Ettlinger, Marin Municipal Water District biologist, Emily Cox, Kalvin Joe and Cat Major. Salmon are returning to Marin County streams with recent storms. (Douglas Zimmerman / Marin Independent Journal Special)

  • Salmon swim under a bridge along Lagunitas Creek in Samuel P. Taylor State Park, November 18, 2021 (Douglas Zimmerman / Special to the Marin Independent Journal)

  • Emily Cox and other Americorps members search for salmon in Lagunitas Creek in Samuel P. Taylor State Park, November 18, 2021 (Douglas Zimmerman / Special to the Marin Independent Journal)

  • Kalvin Joe, center, an Americorps member, joins a team searching for salmon along Lagunitas Creek in Samuel P. Taylor State Park on November 18, 2021 (Douglas Zimmerman / Special to the Marin Independent Journal)

  • Eric Ettlinger, Marin Municipal Water District biologist, searches for salmon in Lagunitas Creek in Samuel P. Taylor State Park on November 18, 2021 (Douglas Zimmerman / Special to the Marin Independent Journal)

  • Salmon swim in Lagunitas Creek in Samuel P. Taylor State Park, November 18, 2021 (Douglas Zimmerman / Special to the Marin Independent Journal)

Marine biologists say early storms gave the annual salmon spawning season a good start, including unprecedented sightings of fish in some creeks.

Streams and streams that were dry after two years of drought were suddenly depleted for spawners after a historic storm in late October that dumped 26 inches of rain on Mount Tamalpais, plus a weaker storm about a week later.

“It was so crazy that we went from starvation to feast when it came to salmon,” said Michael Reichmuth, National Park Service biologist.

In Redwood Creek, where conservationists are working to revive struggling salmon runs, researchers such as Reichmuth have documented the first sightings of adult chinook salmon in the creek since monitoring began 20 years ago. Where researchers would be lucky enough to find a few dozen spawning coho salmon in the creek over the past two winters, Reichmuth and his team found nearly 70 chinook salmon in a single day.

“This is a big change considering that a month earlier we were rescuing juvenile salmon and removing them from drying ponds,” Reichmuth said.

Several other streams first saw chinook spawners, including Olema Creek, Woodacre Creek, and Pine Gulch Creek. Central Coast Chinook Salmon are listed as Threatened under the Federal Endangered Species Act.

“It’s encouraging to see the fish persist, and so far the flows have helped increase the fish,” said Preston Brown, conservation director for the Olema-based Salmon Protection and Watershed Network. “I’m just happy that we can celebrate successes when we have them. Hope this year is a success.

On the county’s main salmon stronghold at Lagunitas Creek, Marin Municipal Water District biologist Eric Ettlinger found four species of salmon in a single day, including coho, chinook, and the rarer species of rose and chum. Ettlinger said it was a first.

“Very few things are as exciting to a fisheries biologist as an unprecedented diversity of fish,” Ettlinger said.

This unusual gathering has led to some strange interactions, Ettlinger noted, including a “very confused male pink salmon trying to breed with a female coho.”

“The female seemed to have spawned before, and these species cannot interbreed anyway,” Ettlinger said.

Recent showers have brought other benefits to local streams and streams. The rapid flows washed away the algae that had accumulated during two years of drought. Several large willows have been knocked down in the streams, which will help provide various benefits to young and older fish, including habitat, food sources, and shelter from predators.

“It really rejuvenated Lagunitas Creek in many ways and created a great habitat for young fish and also for adults to come,” Ettlinger said.

Storms can also have the opposite effect, Reichmuth said. While high flow rates can help scour the creek bed and create deep pools essential for both spawning and young salmon, they can also blow up existing pools.

“So far it seems there are more wins than losses,” Reichmuth said.

Now, researchers are awaiting the return of the county’s endangered coho salmon spawners. Although some coho salmon have been found in local streams so far, most spawners arrive in December.

Lagunitas Creek, which rises from its sources on Mount Tamalpais and empties into Tomales Bay, is home to the largest remaining population of coho salmon from the northern end of Monterey Bay to Mendocino County. Federally listed as endangered, coho salmon have declined primarily due to habitat loss caused by land use changes and development that have caused streams to be filled with sediment and blockage. tributaries by dams.

A federal recovery target aims to restore the size of the runs to more than 1,600 salmon roe nests, or nests, for three consecutive years. But in more than 25 years of surveillance, counts have never reached half that amount.

Although this salmon season has had an encouraging start, more rain will be needed when the coho arrive to allow them to return to their spawning grounds. And there’s no guarantee Marin will see another big storm this winter.

“We’ve already seen where you get those first storms and the tap goes off,” Reichmuth said.

The drought will also impact spawners in Lagunitas Creek this year. The Marin Municipal Water District, which dammed Lagunitas Creek to create the reservoir system serving two-thirds of the county’s residents, is releasing less water into the stream for fish in order to preserve its reservoir’s supply.

This emergency authorization granted by the state forces the district to considerably increase its monitoring of the streams. Although the district is authorized to reduce releases from dams, it is not authorized to harm endangered or threatened salmon. If fish passage is restricted or the salmon eggs are about to be exposed to air, the district will need to release more water.

Coho salmon have a three-year life cycle. After hatching, young salmon grow in freshwater for about a year and a half to fatten and grow before swimming out to the ocean as smolts. After about a year and a half, the salmon return to the same creek where they were born to spawn and then die.

In Redwood Creek, young coho salmon face the new experience of sharing water with the newcomer, larger chinook baby salmon.

“There is very little habitat for them and little food. I wonder how the competition is going to go later,” Reichmuth said.


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