A record number of Chinook and Coho salmon are moving up the Russian River to spawn, an indication of rich ocean conditions necessary for those fish to survive, fisheries biologists said.

It may also be an indication that the millions of dollars being spent on habitat restoration to keep those fish from extinction may also be working.

There have been 6,348 Chinook salmon photographed as of Wednesday moving through the fish ladders at the Sonoma County Water Agency's dam at Forestville, which is inflated during low river flows to create a pool for the agency's water pumping system.

The number surpasses the record 6,103 seen in 2003 and is the third year that the numbers for that fish, which is on the threatened list, has increased, said Dave Manning, principal environmental specialist for the Water Agency.

"The good news is we officially have a record number of Chinook returning to the river. We have been getting a ton of fish returning the past few days," Manning said. "We are definitely over that old record total number and we will probably beat it by quite some margin."

The Water Agency has also counted 44 Coho salmon, which are an endangered species, moving through the Russian River near Austin Creek, even though it is still very early in that run.

Those salmon were tagged at the Warm Springs fish hatchery, where they are raised, before being released. The tags are read by an array of antennas at several spots of the Russian River and some of the tributaries.

"The numbers we are seeing are encouraging. The trend is again this year showing it is in the right direction," said Gregg Horton, a senior environmental specialist for the Water Agency. "It sounds like small numbers of fish, but 10 years ago there was less than a dozen. We have seen a dramatic rise."

Chinook and Coho salmon are both native to the Russian River, which they leave as juveniles to return two to three years later to spawn.

The Water Agency is spending $1 million a year to monitor both species of salmon and steelhead, which are also a threatened species.

In the ocean, the fish feed on krill and small crustaceans, which for the past few years have been in abundance.

Still, the survival rate of salmon is only between 1 percent and 5 percent, one of the reasons perhaps that the female lays 3,000 to 5,000 eggs.

"They have a challenging lifecycle," Manning said. "They face perils in the river and at sea. It is why salmon produce so many offspring."

For Chinook salmon, which spawn mainly in the Russian River, the Water Agency has reduced the overall flows by 44 percent and keeps a reserve of water in Lake Mendocino to release during the fall spawning run.

Coho salmon, which were on the verge of extinction, take much more work. Last year, there were 380 Coho estimated to be in the Russian River and its tributaries.

A breeding program at the Don Clausen Hatchery at Warm Springs Dam has been operating since 2001, with about 150,000 young Coho released each year.

About 20 percent of those fish now have tags that can be read by Water Agency antennas.

The Water Agency, local resource conservation districts and other agencies and landowners are also spending between $36 million and $48 million to improve habitat on Dry Creek and other Russian River tributaries over a dozen years.

Coho like cold water and rocks, logs and eddies to get out of the flow of the stream.

"Coho are the biggest challenge. But one of their biggest requirements, abundant cold water, we already have in Dry Creek from Lake Sonoma," Manning said. "It is meeting the velocity and the depth and the cover that will be our challenge. Dry Creek represents so much potential habitat."