All this week, the people at Coleman National Fish Hatchery, in the northern reaches of the Sacramento Valley, are working 16 hours a day or more on a massive salmon lift. Starting Monday and continuing through Friday, they're trucking about 400,000 or 500,000 juvenile fall-run chinook each day — more than 2 million this week if everything goes right. And that's just the beginning of an operation that will eventually end up moving all 12 million of the fall-run fish the hatchery has been raising since last year.
These young fish — they've been raised to "60 to a pound" size, are about 4 or 5 inches long and are physically ready to begin the transition from fresh- to saltwater — normally ride surges of spring runoff down the Sacramento River something like 350 miles to the Golden Gate. But not this year. The severity of this year's drought has reduced river flows to the point where wildlife officials say they believe 100 percent of the fish produced at Coleman would die before they reach the Golden Gate. The causes: fish getting lost and trapped in the Delta because of the way water is being managed there this year, predators and high water temperatures.
So, the U.S. Fish and Wildlife Service is working the California Department of Fish and Game to truck all 12 million of the juvenile Sacramento River fall-run from Coleman. The state, which normally trucks most of the young fall-run chinook it raises in four state hatcheries, will truck all 18 million or so fish it's raising now. By the beginning of summer, 30 million baby salmon will have gotten a ride past hostile river channels to the Delta and Bay. That's more than 240 truck loads, at an additional cost of nearly $1 million.
The potential downside to trucking all these fish: It could further undermine the complicated effort to establish salmon populations that are healthy and sustainable over the long term. That's because the trucked fish don't have the opportunity to imprint on their natal streams; when they return as adult fish in the next two to four years, they will be far more likely to stray to other rivers, mix with other populations of chinook, including the tenuous populations of fall-run fish that reproduce outside the hatcheries. Research suggests that hatchery fish are less hardy and adaptable than wild fish; their dominance in the Central Valley thus may pose a danger of weakening the salmon population.