Standing on a stone bridge overlooking Lagunitas Creek in west Marin County, giddy onlookers observed a male coho salmon swimming upstream toward a nesting area guarded by a female.
Naturalist Catie Clune explained that male coho have a mere 20 seconds to fertilize hundreds of eggs laid by females. It’s a delicate, acutely time-sensitive task crucial for the survival of one of Northern California’s iconic species — and one most people have never witnessed.
Yes, you read that right, 20 seconds.
“This is amazing,” said Larry Martin, a retired food and wine professional from Forestville. “I’ve pretty much lived here my whole life and never seen a salmon spawning in a creek.”
This year’s salmon spawning season so far appears to be a mixed bag, with some locations, such as Lagunitas Creek, showing robust activity, and others, including the Russian River in Sonoma County, falling short of expectations.
Officials with the Sonoma County Water Agency observed about 1,200 to 1,500 chinook salmon in the Russian River this winter, roughly half the historical average of 3,200, according to Gregg Horton, a principal environmental specialist for the organization.
He said it’s too soon to say whether this portends a longer-term trend. Also unknown is why the numbers dipped this year.
“Having said that, it wasn’t the lowest return we’ve had,” Horton said. “You don’t want to make too much noise about one year just because there is variability, and these populations have a way of dealing with that.”
Lagunitas Creek is an important barometer for the health of Central California Coast coho, which were listed as an endangered species in 2005 and are considered to be among eight species most at-risk for extinction without concerted conservation efforts.
About 500 adult coho salmon typically arrive in Lagunitas Creek from mid-December through mid-January, producing about 10,000 smolt that venture through Tomales Bay to the ocean.
Ecologists reported seeing robust numbers of the fish after Thanksgiving storms swelled the creek, including one pool brimming with 28 adult coho. There also were promising observations of chinook and pink salmon.
At Lagunitas Creek on a recent Saturday morning, the crimson-colored coho appeared plentiful, much to the delight of more than two dozen people who’d signed up for a guided tour led by naturalists with SPAWN, which operates under the Turtle Island Restoration Network. Female coho produce as many as 3,500 eggs, but on average only about 10 to 20 percent hatch. Depending on the species, salmon live for two to seven years at sea, where food is more plentiful. The overwhelming majority that survive life in saltwater return to the same watershed where they were born, a fascinating phenomena Clune said is the result of the fish being drawn to their native home through their sense of smell.
“They know their best chance (of survival) is the stream they were born in,” Clune said.
Returning salmon instinctively swim as far upstream as they can make it because flows tend to be lessened there. That in turn diminishes the chances of fertilized eggs being swept away.
Salmon are crucial to forest health. As the bodies of the fish break down, a number of nutrients are siphoned into streamside vegetation, spurring growth at an accelerated rate and maintaining nature’s balance. At Samuel P. Taylor park, the lush forest of redwoods, oaks, ferns and other trees and plants growing alongside the meandering creek reflect this healthy symbiosis.