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Hatching Salmon Nature's Way
A report issued by the National Research Council last fall concluded that the widespread use of fish hatcheries has not only failed to slow the decline of anadromous fish runs, but actually contributed to this drop-off. Despite such criticisms, the four fall-run chinook salmon hatcheries in the Sacramento basin continue to produce millions of smolts every year. A proposed $30 million dollar hatchery on the Tuolumne River, however, hopes to show how improved hatchery production can help rather than hinder the beleaguered species.
The NRC's report argued that some hatcheries are producing fish in quantities that overwhelm wild salmon populations and, in turn, weaken the overall species. Hatchery-produced salmon - which tend to possess a relatively narrow range of genetic variation -may lack the ability to adapt to environmental stresses and changes. Once these less-adaptable, artificially-sustained populations dominate, disease or changing stream conditions can cause catastrophic loss and threaten to wipe out an entire run - or specific population - of salmon.
Cal Fish & Game's Bill Loudermilk, however, insists that fisheries cannot be restored to historic levels without hatcheries. Loudermilk wants to develop a new and different kind of hatchery on the Tuolumne which he calls a "supplementation" hatchery as opposed to the traditional large "production" hatchery. Whereas production hatcheries generally have large numeric goals to meet each year, a supplementation hatchery could vary and limit its production to dovetail with fluctuations in natural run numbers, says Loudermilk.
Other innovations focus on representing the full diversity of natural genes in the hatchery population. In the past, it was common to mix sperm from more than one male with each female's eggs to optimize fertilization rates. At Tuolumne, they hope to use only sperm from one male per female so that the genes from each parent have an equal opportunity of being expressed in the hatchery population (the previous system favored males with speedier sperm). Another technique along these lines would extend the egg fertilization process from a one shot deal to the entire spawning period of a particular run.
"New techniques can help fish managers avoid the problems of the past," says Loudermilk.
Peter Moyle, a fish specialist at UC Davis, is skeptical of the proposed Tuolumne hatchery. While he concedes that "they're thinking along the right lines," he is wary of constructing another hatchery. He explains that Loudermilk's innovative hatchery will be expensive and staff-intensive to operate. In his opinion, it will only work if there is secure funding down the road - otherwise, budget cuts will eliminate all the monitoring and staff time, leaving just the hatchery. "Once the hatchery is in place the temptation will be to use it as a production hatchery," says Moyle.
Moyle has written a letter to U.S. Fish & Wildlife expressing his opposition to the hatchery. He sees the Tuolumne river as an opportunity to implement and closely monitor natural restoration efforts. These efforts are being emphasized in such documents as U.S. Fish & Wildlife's draft restoration plan for anadromous fish - now being finalized - which was developed to meet the population doubling requirements of the 1992 Central Valley Project Improvement Act.
Moyle worries that Cal Fish & Game, which has already acquired the property for the hatchery, will go ahead with its plans without proper review. But he seems willing to be convinced that the new hatchery is a good idea. Without hatcheries, he concedes, salmon fisheries are unlikely to be maintained.
Contact: Bill Loudermilk (209)445-5415
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