Spawning season arrives for Russian River’s ailing salmon, steelhead

No one can say yet how many Chinook salmon are milling in the Pacific Ocean near the closed mouth of the Russian River waiting to launch their migration up drought-parched waterways to reach favored spawning grounds.

An intricate play of natural forces — including ocean waves, the river’s flow and the weather — will determine the success of the Chinook and coho salmon and steelhead trout, the watershed’s three federally protected fish.

They are coming off subpar years for returning adults and contending with the deepest drought in a century of California record keeping.

Chinook salmon fared the worst, as officials counted just 609 spawning fish in 2020-21 — a 10th as many as the 6,730 in 2012-13, prior to a drought — and well below the 20-year average of more than 3,000 Chinook.

Only 35 Chinook, a few steelhead and possibly two coho had been counted in video recordings at the Sonoma Water fish ladder near Forestville through Oct. 14, about two weeks after waves and tides built a sand barrier over the river’s mouth at Jenner on Sept. 28.

Rain in recent days has given some small replenishment to the drought-starved river and the Jenner estuary, but there’s no way of knowing yet how the fall, winter and spring spawning season will play out.

“The migration picks up slowly until we get some rain,” said David Manning, environmental resources manager for Sonoma Water, the agency that supplies Russian River water to 600,000 Sonoma and Marin county residents. “One storm is not going to solve all the issues in the watershed.”

The California Nevada River Forecast Center predicted as much as 10 inches of rain from Oct. 20-26 at Venado — the watershed’s rain hot spot in the hills west of Healdsburg that feeds Austin and Dry creeks.

The Russian River at Healdsburg measured just 0.4 feet deep (with flow at 44 cubic feet per second) on Saturday and was expected to abruptly swell, cresting at 16.8 feet (27,267 cfs) early Monday and falling to 5.0 feet (2,665 cfs) Tuesday night, the center said. A cubic foot is about 7.5 gallons.

Manning said the river last week was the lowest he could recall in 22 years, far below the typical 100 cfs flow for this time of year and the “lowest flow we’ve ever seen fish migrate.”

If another dry spell sets in, the gains from last week’s rain will be erased, he said.

Don McEnhill, the seasoned head of the Healdsburg-based group Russian Riverkeeper, said last week he had not seen the river “this low for this long” in five decades.

Spawning fish won’t get past the dam site at Healdsburg, and numerous riffles between pools in the river from Wohler Bridge to Alexander Valley have less than an inch of water flowing over gravel and are likely impassible, as well, McEnhill said.

He’s seen salmon “blast through” 2 to 3 inches of water, but this year thinks the fish would be better off remaining in the ocean until the river runs higher, as it is now.

But there won’t be any mass migration until the river mouth opens, and Sonoma Water lacks the means to make that happen with an excavator on the sand at Goat Rock Beach.

A concrete jetty next to the breaking waves bars the excavator’s access, said Jessica Martini-Lamb, a Sonoma Water environmental resources manager.

Meanwhile, the rain-refreshed river is driving the closed Jenner estuary higher and could more than double it to the 9-foot flood level this weekend, she said.

Ocean waves and tides, combined with pressure from a rising estuary, could also breach the sandbar at the river’s mouth, letting water out and fish in. The estuary has closed and opened several times this year, most recently closing on May 10 and reopening on its own eight days later.

“All these conditions are changing constantly,” Martini-Lamb said. “It’s always a challenge for us to predict (what will happen).”

If creek levels fall too low, the fish can spawn in the river’s main stem or in Dry Creek, which has a guaranteed year-round flow of cold water from Lake Sonoma, the region’s main reservoir.

If the river mouth remains closed for a month, fish can “hang around in the ocean” that long, Manning said. “But how long they’ll wait we don’t know.”

You can reach Staff Writer Guy Kovner at 707-521-5457 or guy.kovner@pressdemocrat.com. On Twitter @guykovner.