Biologists Track Endangered Fish

May 20, 2008

Release from: Bob Norberg
The Press Democrat

Biologists are making daily counts of young salmon and steelhead migrating the Russian River to the ocean to find out how well the attempt to restore the fisheries is going.

"It's important, it gives us indices of how salmon and steelhead production is doing," said Sean White, a Sonoma County Water Agency biologist. "Some of the fish are wild fish. Some are part of a coho-recovery program happening at the hatchery. It gives us an understanding of when smolt are in the river."

It is the only program counting chinook in California's coastal rivers, and in the past few years, it also has seen a return of coho, White said. Both are on the federal endangered species list.

The count occurs in the Russian River just below the agency's rubber dam downstream of the Wohler Bridge, where biologists have moored two rotary-screw fish traps.

The traps turn in the slow current of dark green water, the blades drawing the small fish into a holding tank.

Every morning, biologists scoop out the fish, which measure 1 to 4 inches, to count, measure and for some, to clip a fin.

The smolt run will last until mid June.

"During the season, we will touch 30,000 fish," White said.

It is estimated the traps will catch about 10 percent of the fish swimming downstream, representing roughly 250,000 smolt, White said.

The number of smolt is an indication of the survival rate for the young fish, as well as how many adults returned to spawn in the fall.

"There are so many stages in the life, you can have a poor return, a fantastic survival and smolt production, or a large return and then a flood that wipes out the smolt production," White said.

The Water Agency has run the fish-counting program since 1999.

"This year has been a solid year, we have had a fair number of chinook every day. We have been seeing coho from the recovery program almost every day," White said. "The first five years, we didn't get any coho."

Coho have been raised since 2001 at the Warm Springs hatchery through a UC Davis and state Department of Fish and Game program. The smolt are then planted in Russian River tributaries, where the adults return to spawn.

White said it is in only the past few years they have seen any coho smolt.

"One day, we got five or six, and for us it felt like an avalanche," White said.

They have been seeing 50 to 100 chinook smolt daily, considered a large number, with occasionally a spurt of 1,000.

That follows a year in which biologists only counted 1,900 chinook adults going upstream to spawn. In a normal year, biologists will count 4,000 heading upstream.