Native Trout Are Returning to America's Rivers- page 2 | Science | Smithsonian

Native Trout Are Returning to America's Rivers

Native trout are returning to America's rivers and streams, thanks to new thinking by scientists and conservationists

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Does it matter?

"Well, it matters if you are concerned about biodiversity," says Robert J. Behnke, an emeritus professor of fisheries and conservation at Colorado State University and one of the country's leading trout biologists. "The first rule of intelligent tinkering is not to throw away a part because you do not understand where it goes or what it does," he adds, paraphrasing the conservationist Aldo Leopold. "You put brook trout in a stream and the cutthroats just disappear," he says. "They're so many brook trout in the West—that's why they're our leading candidate to poison."

Behnke, a blond, burly man who punctuates his conversation with puffs on an ever-present pipe, calmly watches a visitor squirm at the mention of poison. "Look, a lot of chemophobes don't like it, but these poisons have been declared perfectly safe by the Environmental Protection Agency. The federal courts have ruled that it's all right to use them."

Thus thousands of brookies have sacrificed their lives to make room for native fish in Western states. When fast-acting piscicides such as antimycin or rotenone have done their work and dissipated, natives are reintroduced to the stream.

Such poisoning and relocation programs have led, in part, to the recovery of many previously imperiled fish: the Gila trout, native to the mountains of New Mexico and southeast Arizona, recently had its status upgraded from endangered to threatened by the U.S. Fish & Wildlife Service. The once-endangered Paiute cutthroat of California, likewise now listed as threatened, has returned in decent numbers, as have the Lahontan cutthroat of Nevada and the Bonneville cutthroat of the Great Basin.

In the East, meanwhile, biologists at the Great Smoky Mountains National Park have begun poisoning some creeks to rid them of rainbow trout, imported from California in the 1930s and thriving in the Smokies ever since. By removing rainbows from about 40 miles of the park's 2,100-mile river system, the National Park Service hopes to make at least part of the Smokies a refuge for brookies again.

Perhaps the sweetest comeback belongs to the greenback cutthroat trout: declared extinct in 1937, the fish is swimming again in the Colorado Rockies, thanks to some scientific sleuthing by Behnke. "This botanist called and said there was a funny-looking trout in Como Creek, way up in the headwaters," Behnke recalls. "Nobody could figure out what it was." Behnke collected one of the funny-looking fish, combed through the early literature of exploration in the region and called for museum specimens collected by 19th-century expeditions. Comparing these with Como Creek's living fish in 1969, Behnke made a positive identification: the long-missing greenbacks, victims of overfishing and hybridization, were back. They had never really left, of course, just disappeared from view for a few decades. From the tiny group of fish Behnke discovered in Como Creek, some 60 new greenback populations have been transplanted throughout the Rocky Mountain National Park and surrounding national forests, ensuring a secure future for the trout that almost got away. The U.S. Fish & Wildlife Service has removed greenbacks from the endangered list; Colorado has honored them as its state fish; and anglers are even allowed to fish for them on a catch-and-release basis.

Behnke and I made a pilgrimage to the section of the Roosevelt National Forest where he rediscovered the greenbacks. We stood quietly among the aspens while peering into Como Creek, no more than three feet wide. One fish appeared as a shadow holding its place in the clear cold water, facing upstream. Bronze-sided and boldly spotted, it blended perfectly with the brown, pebbly creek bottom—proof that some environmental disaster stories have happy endings. We spotted more fish as we worked our way downstream, stopping where the tiny creek disappears under a roadway. Behnke strained for a last look, pausing before he spoke: "You'd never think there would be fish here."

After more than a century of piscatorial tinkering, nothing seems to be where it belongs—brookies to the west, rainbows to the east and browns all over. This happened for the best of motives: since the late 1800s, government agencies and private hatcheries have been raising fish and transporting them widely to provide food and sport for a growing nation. This long-accepted practice, thought to be modern, progressive and scientifically based, has only recently been questioned by biologists, conservation groups and game agencies concerned about the long-term health of trout populations.

"Nobody gave much thought to the ecological consequences," says Behnke. "A trout was a trout was a trout. It didn't matter what you put where—that was the old paradigm. But we're seeing more thought to managing for native and wild fish these days, and more reliance on habitat rather than hatcheries."

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