Hatcheries are frequently used to bolster wild salmon populations. But over time, hatchery fish can become closely related to one another, and can contribute to declines in unique wild populations. Eventually, hatchery-dominated areas can resemble one giant population. Just as intensive monoculture practices make food crops more vulnerable to disease or bad weather, a dependence on hatcheries can leave a fishery open to huge swings in fortune.
"The first lesson [of this paper] is that a wild multi-stock fishery can function very well on its own better than we've ever done with any kind of hatcheries," says Jack Stanford, an ecosystem scientist at the University of Montana who was not involved with the research. "Hatcheries are counterproductive if the goal is to sustain very healthy wild fisheries, especially in light of climate change."
Beyond hatcheries, the study results hold other important implications for wildlife management strategies in the US and beyond. In terms of habitat protection, for example, California is currently working on lessening the blow to Chinook salmon, delta smelt, Central Valley steelhead, and green sturgeon in the Sacramento and San Joaquin delta. A March 2010 report by the National Research Council supported recommendations by the Fish and Wildlife Service and the National Marine Fisheries Service to reduce the number of engineered diversions, such as dams and water diversion channels, in these river systems, on the grounds that they have negative consequences for these endangered species.
"In the Sacramento River, we have a history of exploitation and degradation going back to the gold rush," says Steve Lindley, a research ecologist with the National Marine Fisheries Service in Santa Cruz, CA, who was not involved with the research. "It's radically simplified the habitats that salmon depend on in the valley. In Cal
|Contact: Liz Neeley|
Communication Partnership for Science and the Sea