Biologists with special water-filled, aerated backpacks trudged up a remote creek in Northwest Sonoma County on Tuesday, carrying their precious cargo of hatchery-raised coho salmon to release into the wild.
Within a couple hours, they had put 4,000 juvenile fish into Devil Creek, part of an ongoing program to re-populate the Russian River with the endangered coho.
"They're really beautiful," Ken Leister, an Army Corps of Engineers animal care specialist, said as he used a small net to scoop up and examine batches of writhing fingerlings.
Coho Fingerlings Released
"You get the gold and the green color and some blues," he said, pointing out the subtle hues of the fish before they were placed strategically along a half-mile of the creek.
The coho salmon re-stocking program began a decade ago when scientists took some of the last remaining wild juvenile coho from Russian River tributaries and raised them in special tanks at the hatchery at Warm Springs Dam.
The captured fish were spawned, and their offspring tagged and released into a dozen creeks in northern Sonoma County that flow to the Russian River.
Coho mature in fresh water and go to sea before returning to spawn and die, all in about a three-year life cycle.
In a promising sign of their recovery, the fish have been coming back to the tributaries to reproduce and hatch in the wild.
"It was definitely a good thing to document," said Jeff Jahn, a biologist with the National Marine Fisheries Service. "Last year an estimated 200 Coho returned to the Russian River — a record return in over a decade."
Scientists counted 89 juvenile coho this winter that spawned naturally in Devil Creek, which flows into East Austin Creek and the Russian River.