There is a growing concern that hatcheries could cause our Northwest fish to lose their wild streak -- and ability to survive. A laboratory in Idaho hopes to change that. Earthfix reporter Aaron Kunz explains.
In the southern Idaho desert, freshwater pours out of canyon walls from an underground aquifer and empties into the Snake River. The water is both fresh and a constant 60 degrees.
Narum: “We have all these natural springs where all we have to do it divert it from the rock wall using ditches or some kind of pipes to move it into the raceways where we’re rearing fish.”
The quality of water makes this the perfect place to raise and study fish. Shawn Narum is the lead scientist at the Hagerman Fish Culture Experiment Station. It’s operated by the University of Idaho, the U.S. Department of Agriculture, and the Portland-based Columbia River Inter-Tribal Fish Commission. Nerum works for the tribal commission.
Narum: “What they are trying to do is reform hatchery practices so they are having less genetic effects on these natural populations.”
Northwest waters are awash with controversy when it comes to wild salmon’s ability to survive with hatchery fish in their midst. Decades ago, hatcheries were the thought to be the perfect solution to sustaining the iconic runs of salmon and steelhead as river-blocking dams were constructed throughout the Northwest.
But by the 1990s, criticism of hatcheries was mounting: Bigger hatchery-reared fish gobble up juvenile wild fish and compete for prey. And fish raised in the crowded confines of hatcheries can carry disease into the wild.
To understand the biggest concern about hatchery fish, think back to what you learned in Biology 101 about ‘natural selection’ -- the notion that *only the fittest members of a species survive?
Salmon and steelhead don’t need to be among the fittest of their species to survive when they’re reared in captivity. They enjoy regular feedings and security from predators. Later in life, they can end up mating with wild fish, passing along inferior genetic traits.
Nick Gayeski is a staff scientist at the Wild Fish Conservancy in Washington state.
Gayeski: “The concern would be that after several generations of this there will be no more true wild fish. Because they will all be at some point have bred with progeny that have run through the hatchery for one or more generations. And if their fitness, reproductive fitness drops low enough, then you might have a population that truly can’t sustain itself.”
Sara Thompson is with the Columbia River Inter-Tribal Fish Commission. She thinks researchers will be able to prove critics like Gayeski wrong. The key is finding ways to produce more hatchery fish with the survival traits of wild fish.
Thompson: “and in order to do that we have to have the best available science to help inform those management decisions. This facility allows us to do that.”
Back in southern Idaho’s Hagerman lab, thousands of samples collected by biologists in Idaho, Oregon and Washington are fed into a machine that looks like a fish tank with robotic arms. Each one is holding syringes containing these bits from fish -- scales, fin clippings and stomach contents.
The sophisticated machine is a fast worker -- processing up to 1,000 samples at a time. by transferring them to vials for testing. From there, the machine determines the lineage of a single fish. It tells the scientists which fish were hatchery-raised. It can go back 10 generations to tell which of the fish’s ancestors came from hatcheries.
If researchers like Narum can pinpoint which hatchery fish are carrying the best genetic traits, they can help hatchery managers become more selective about which of these fish are used to repopulate hatcheries.
Narum: “We are able to use genetic techniques to evaluate where the most appropriate stocks - which ones are surviving and reproducing most effectively.”
Nick Gayeski, with the Wild Fish Conservancy, isn’t convinced that scientists can build a better hatchery fish. A federal scientific review panel spent nearly a decade researching 178 hatcheries in the Northwest. It made recommendations in 2009.
Gayeski: “There is always some more research that can be done but we need to put into practice the solid research-based recommendations.”
The panel’s recommendation that Gayeski would most like to see followed? Limits on the number of fish raised in hatcheries and released into the wild.
When it comes to the value of fish hatcheries, the tribes differ from non-tribal fish advocates in *this way: the return of robust salmon runs isn’t merely an ecological goal they can wait on for decades. Salmon and steelhead represent a sacred First Food. They are a primary source of nutrition -- as well as a treaty-guaranteed right.
Sara Thompson, with the Columbia River Inter-Tribal Fish Commission, says the tribes can’t simply sit by and wait for nature to run its course.
Thompson: “It’s not about preserving what salmon populations we have left. The tribes want to rebuild an abundant salmon population.”
Eventually, more hatchery fish that can pass on the genetic traits to evade predators and compete for food will lead to stronger runs of fish. That means less dependence on hatcheries.
And that’s something both hatchery critics and the tribes would like to see happen.
Copyright 2012 Northwest Public Radio