The California Department of Fish and Wildlife has pulled the plug on plans to release a quarter-million hatchery-born Chinook salmon into Bodega Bay after several North Bay conservation groups demanded the agency first conduct a full environmental review.
The decision to cancel the project came just weeks before the planned release, providing what commercial and recreational fishing interests hoped would be a boost to fishery stocks when the juvenile smolts matured in three years.
But limited experience with ocean releases, and available data on survival, migration and spawning habits of trucked hatchery fish raised concerns about how they might mix or out-compete endangered fish naturally occurring in the Russian River and Lagunitas Creek once the introduced fish reached spawning age.
The fish were to have been transported directly from the Mokelumne River Hatchery in San Joaquin County to Bodega Bay, bypassing the usual downstream voyage from native freshwater habitat to the ocean.
That plan would have left them subject to straying randomly upstream, a Marin County salmon restoration group wrote to state wildlife officials as part of its insistence on a full and public environmental review.
“We have already documented adult Chinook from Half Moon Bay releases straying into Lagunitas Creek,” said the letter from the Lagunitas Creek Technical Advisory Committee, an independent consortium of about two dozen local, state and federal natural resource and wildlife agencies.
The hatchery fish, the letter said, “could increase the extinction risk of the nearby wild and endangered coho salmon and threatened steelhead,” potentially bringing disease, diluting the genetics of wild fish stocks or out-competing natural fish for food and habitat in both ocean and freshwater areas.
“It’s not that we think the net pen project is necessarily a bad project,” the committee’s past chairman, Gordon Bennett, and president of Save Our Seashore, said, but the potential risks and mitigations need to be evaluated.
In addition, the committee wondered that since initial environmental reviews were done in recent years prior to releases of hatchery fish off Santa Cruz and Pillar Point in San Mateo County, why not in this case, too.
The Bodega Bay fish were to have come from a state-run hatchery that each year produces 2 to 4 million fries for release into the San Joaquin-Sacramento River system under a fishery enhancement program designed to boost fishing stocks.
In recent years, some of the Central Valley hatchery fish also have been trucked directly to coastal areas off Santa Cruz and Pillar Point, where they have been put into submerged net pens for acclimation to salt water before release to the open ocean.
Direct ocean release spared them the perils of high temperatures and restricted flows during the drought, along with possible death in the Sacramento River Delta’s huge, unscreened water diversion pumps.
In those cases, as well as in Bodega Bay, the expectation and hope was that surviving, spawning-age hatchery fish would return upstream through San Francisco Bay to the central valley system.
The plan for Bodega Bay was to hold the fish for a short time in the net pen to lessen the likelihood they’d imprint on the bay’s water and would return, instead, to the Mokelumne River.
The Bodega Bay pilot project also would involve releases well north of San Francisco Bay, raising additional concerns of a higher stray rate that could mean more of them seeking spawning grounds through Tomales Bay and perhaps Lagunitas Creek or even the Russian River, interfering with coho and also coastal Chinook.