Chinook salmon are coming up the Russian River to spawn in near-record numbers, signaling what may be one of the best returns of the threatened fish in a decade.
"I am optimistic, but ever cautious," said Dave Manning, a principal environmental specialist for the Sonoma County Water Agency. "Until the season is over, it is difficult to say how this will stack up, but it will be above average."
The return to the place of their birth indicates conditions for the chinook, which as a threatened species was one step away from extinction, are generally improving in the Russian River system.
It also means there were favorable conditions in the Pacific Ocean three years ago, when the juvenile salmon left the Russian River for the ocean.
"There is something compelling about salmon, they bring a bit of the wild into our backyards every time they return," Manning said. "Their journey is amazing for any species, the rigors of their environments, their instincts to survive and return to where they have spawned."
Chinook are native to the Russian River and genetically distinct from the chinook that are found in the Sacramento, Klamath, Eel and other rivers.
Water Agency biologists follow the fish throughout their life cycle.
As juveniles, biologists catch them in nets as they are preparing to leave the Russian River at Jenner in the spring.
Since mid-September, the first chinook adults have been photographed as they move through the Water Agency's fish ladders at Forestville.
On Wednesday, biologists began their annual survey of spawning chinook, using kayaks to float along the Russian River between Crocker and Washington School roads in Cloverdale looking for activity.
"We didn't see any salmon. I was a little disappointed but not surprised. it is still early in the salmon run window," said Water Agency biologist Dave Cook.
The biologists were looking for redds, the shallow nest that a female salmon will dig in the gravel with her tail and fill with eggs, fertilized by a male salmon, and then die.
Knowing where and when the spawning ritual begins helps the Water Agency manage water releases from Lakes Mendocino and Sonoma, which are vital for spawning.
"The peak spawning is two to three weeks out," Cook said. "If we get some rain in the next two or three weeks, that will be cue. Now they are just holding."
As of Monday, 2,175 chinook have been photographed moving through the Water Agency's fish ladders, where the agency has a rubber dam erected to form a pool for its water pumping system.
The only year in which more fish have passed through by this time in the spawning run was in 2002, when 2,363 fish were seen and the total run for the season was 5,474, the second highest in 12 years of record-keeping.
The highest count in the 12 years the agency has been photographing the fish was in 2003, when 6,103 were recorded. The low was 2008, when 1,125 were seen.
Chinook usually enter the Russian River after a two-year stay in the ocean, where they feed primarily on krill. The spawning run starts in mid-September and peaks from mid-October to mid-November.
Bill Sydeman of Petaluma, president of the Farallon Institute for Ecological Research, said the return this year is not a surprise.