Chinook returning to Cedar River big-time

Chinook salmon are returning to the upper reaches of the Cedar River in record numbers -- albeit a short record.

This fall about 300 fish have returned, compared with 79 chinook four years ago, and the salmon should keep coming until late October.

"We're not done with salmon recovery by any stretch of the imagination, but it's nice to see some success along the way," said Bruce Bachen, a director for scientific and technical services with Seattle Public Utilities.

In 2003, the utility completed an elaborate fish ladder on the Cedar to allow chinook, which are protected by the Endangered Species Act, to pass a dam used to divert drinking water. The $12 million project was part of a habitat conservation plan to help the fish pass the dam as adults and juveniles and to compensate for harm caused by removing water from the river.

The strong returns provide mounting evidence that salmon will recolonize rivers once dams or other blockages are removed. Many environmentalists have argued for the removal of dams on the Snake River to boost lagging salmon runs.

For more than a century, the Landsburg Dam cut the fish off from miles of streams surrounded by woods that are largely off-limits to people. With the fish ladder, chinook, coho and trout are allowed to go upstream into this nearly pristine area. Sockeye raised in a controversial nearby hatchery are blocked from passage. City officials are concerned that if more than 4,500 fish pass, they could foul the city's largest source of drinking water.

Hundreds of scientists and students with government agencies and the University of Washington have been doing research at the site over the past seven years. They're doing genetic analysis to figure out how many of the returning fish are offspring from salmon spawning above the dam and how many are wandering past the dam for the first time. They're looking at how salmon carcasses feed bugs and other fish and decay into fertilizer for algae and shoreline plants. They're also tracking what kinds of restoration work benefits salmon the most.

"It's really a good educational tool," said Peter Kiffney, a National Oceanic and Atmospheric Administration research ecologist. "It's a living laboratory to look at this process (of recolonization)."

Excitement over this year's strong chinook returns is muted by the fact that you can't reliably put a lot of stock in a year or two of strong showings.

"We need to see an upward trend," said Mark Taylor, president of the state chapter of Trout Unlimited, a fishing conservation group. "Any increase is better than the opposite, of course."

Other local chinook returns are up as well. Record numbers of the fish were counted at the Ballard Locks this fall -- mostly hatchery-raised chinook. The Cedar River has the largest population of wild spawning chinook in the Lake Washington basin.

Fish biologists don't know exactly why the chinook numbers are up. The chinook hatch in the rivers and swim to the ocean, returning when they're about 5 years old to spawn and die. Ocean temperatures and food supply are important factors influencing how many return.

Still, some credit likely goes to the fish ladder.

"It's a strong indication that the project is working," Bachen said. "Success will be determined over a long period of time. Everything is playing out consistent with the hopes a lot of us had that the fish would go up there voluntarily and use the habitat ... that is the trend that we're seeing."

It's unclear what conclusions can be drawn regarding the effect of hatchery sockeye on the chinook.

A retired manager from King County's Surface Water Management Division continues to bring court challenges against city plans to rebuild and expand the hatchery because of concerns the sockeye would hamper chinook recovery by competing for food and spawning habitat and introducing disease.

The strong chinook numbers don't vindicate the hatchery; "it's just merely additional evidence that they can coexist," Bachen said.