Young Salmon Get a Truck Ride to the California Shore

The young Chinook salmonids, called smolts, are just three inches long. They were raised as part of the hatchery's role in mitigating the impacts of the Shasta and Keswick dams on the upper Sacramento River. They are being released into the bay to help rebuild the area's depleted salmon runs.

This was the first time in more than a decade that Coleman employees trucked smolts from the hatchery to San Pablo Bay, a shallow tidal estuary that forms the northern extension of San Francisco Bay in northern California.

"Trucking was challenging at times, but the results will help us better understand how the release location influences the number of salmon available to the ocean fisheries and returning to the Sacramento River and Coleman National Fish Hatchery," said Coleman Manager Scott Hamelberg.

"Although it will likely take several years to gather all the data, we expect the information will help us improve salmon management in the Central Valley," he said.

After a difficult and disappointing first day when one load of fish died due to a failed circulation pump, all of the remaining fish made a successful trip to San Pablo Bay.

They were placed in net pens operated by the Fishery Foundation of California for acclimatization and then released into the bay.

Some the smolts have coded-wire tags attached to their noses to identify them as part of this experiment, which remain in place for the life of the fish. As these smolts are harvested or return as adults to spawn, fisheries biologists will be able to determine the rate of return of these fish.

Salmon spawning in the small, cold California stream where they were spawned. (Photo courtesy NOAA SFSC)

The Coleman National Fish hatchery is located on cold, narrow Battle Creek, one of the many creeks running into the Sacramento River.

The hatchery was constructed in 1942 as part of the mitigation measures to help preserve major runs of Chinook salmon threatened by the loss of natural spawning areas resulting from the construction of Shasta and Keswick dams on the upper Sacramento River.

One of the primary goals of the hatchery is to assure that salmon return to the upper Sacramento River.

The hatchery produces 12 million fall Chinook salmon, one million late-fall Chinook salmon, and 600,000 steelhead trout annually, which then later in their life cycle migrate up the Sacramento River from the Pacific Ocean.

Fall Chinook salmon smolts produced at Coleman are typically released on-site so that they complete the imprinting cycle during their outmigration to the ocean.

Another important goal of the hatchery is to contribute to the ocean sport and commercial fishery. Coleman contributes up to 100,000 Chinook annually to the ocean fisheries as well as thousands of fish for the fisheries in the Sacramento River.

Copyright Environment News Service (ENS) 2008. All rights reserved.