UW research finds that trout habitat improvements benefit native fish - Casper, WY Oil City News
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UW research finds that trout habitat improvements benefit native fish

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CASPER, Wyo. — Research out of the University of Wyoming has found that improvement to trout habitat can benefit native fish.

“Habitat improvements in the Laramie River intended to boost the brown trout fishery also have benefited native nongame fish,” UW said in an Oct. 25 release.

“That finding is good news for anglers, the introduced brown trout they pursue and native nongame species in Great Plains rivers, such as the Laramie River, say UW Department of Zoology and Physiology Professor Frank Rahel and his former graduate student, Jessica Dugan.”

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Dugan now works as a fisheries biologist with the Wyoming Game and Fish Department in Casper.

“’It is important to identify restoration actions that benefit native fishes even in the presence of nonnative fishes,’ the scientists wrote in a paper published in the North American Journal of Fisheries Management. ‘Our research shows it is possible for native small-bodied fishes to coexist with a large-bodied game species under the right conditions.’”

Trout did not come to the Laramie River or other Great Plains rivers until Europeans settled in the area in the 1800s.

“Brown trout, which are native to Europe, were introduced and are a popular game species for anglers,” UW says. “But the Laramie River also has nine species of native fish, including the creek chub, common shiner, longnose sucker and white sucker.”

“In some bodies of water, the introduction of brown trout, which prey on other fish, has harmed the populations of small, native fish species.”

Improvements to the trout habitat in the Laramie River included adding a series of five wood patches which was part of improvements to the Laramie Greenbelt, UW says.

“In the Laramie River, a number of habitat improvements have been undertaken to boost the brown trout fishery, including placement of trees and logs to create additional structure, and rock riprap to prevent channel meandering,” UW says. “At four locations in the river near Laramie — including the public Monolith Ranch and Laramie Greenbelt sites — Rahel and Dugan studied the impact of habitat improvements on both brown trout and the smaller native fish.”

Both brown trout and most of the native fish species are drawn to particularly the wood placed in the river, the research found.

“Both added wood and natural wood patches — exposed roots, submerged branches and log jams — provide spaces for the smaller fish to hide from the brown trout, which also favor the additional structure,” UW says.

The research could serve as a guide for future river habitat improvements. More complex wood structures are generally able to provide better habitate for small, native fish, the researchers found.

“’It is encouraging that small-bodied native fish will use added cover types intended to benefit brown trout,’ Rahel and Dugan say. ‘Providing a sport fishery while maintaining populations of native nongame fish is an ongoing challenge for fisheries managers.’”