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The Mountain-Prairie Region


U.S. Fish and Wildlife Service
134 Union Boulevard
Lakewood, Colorado 80228

 April 24, 2006

Debbie Felker, Recovery Program, 303-969-7322, ext. 227
Mark Hadley, UT Division of Wildlife Resources



LAKEWOOD, Colo. – The Upper Colorado River Endangered Fish Recovery Program (Recovery Program) is continuing concerted efforts to manage northern pike and smallmouth bass in certain river reaches where scientific evidence shows that these nonnative fish species are impeding the recovery of the endangered humpback chub, bonytail, Colorado pikeminnow and razorback sucker.  

The experimental nonnative fish management research studies are designed to determine if management efforts are effective in reducing the numbers of targeted nonnative fishes in sections where they were removed; if endangered and other native fishes will increase in response to nonnative fish reductions; and where and how nonnative fishes are getting into the critical habitat sections of the Upper Colorado River Basin.   

Efforts will expand from last year to include additional river sections, work crews and removal trips.  From mid-March through September, biologists will work in 740 miles of the Green, Duschesne, Colorado, White and Yampa rivers in the states of Utah and Colorado. Depending on the river reach, they will target smallmouth bass and/or northern pike for removal. 

“These two nonnative species are active predators and are known to eat other fishes,” said Recovery Program Nonnative Fish Coordinator Pat Nelson.  “Removing them from areas inhabited by the endangered fishes will reduce negative interactions and give the endangered, and other native fishes, a chance to reproduce and survive.” 

Nonnative fish removed from the river will not be relocated to other waters because Utah adheres to fish disease control rules and policies that prohibit fish transfers between water bodies without prior health certification.  Certifying fish populations in large rivers as disease free would be nearly impossible. 

A third nonnative fish species -- channel catfish -- also poses a serious threat to the endangered Colorado River fishes and has been the subject of past research.  In 2003, capture methods proved inadequate for effective removal in most areas and expanding smallmouth bass populations were considered a greater threat.  As a result, channel catfish research will occur only in Yampa Canyon where effective removal has been demonstrated, and in the Duchesne River in Utah in cooperation with the Ute Indian Tribe. 

Three of the Recovery Program’s partners – the states of Colorado and Utah and the U.S. Fish and Wildlife Service – will conduct this year’s work.  Biologists from Colorado State University will also participate.   

“The Recovery Program has made progress toward recovering the endangered fishes on all fronts including providing adequate river flows, restoring habitat and reintroducing hatchery-raised fish through stocking,” said Recovery Program Director Bob Muth.  “Although some progress has been made in the area of nonnative fish management, this issue remains a challenge.  The Recovery Program appreciates the efforts being made by the states of Colorado and Utah and the U.S. Fish and Wildlife Service to find a feasible way to reduce negative interactions between predatory nonnative fishes and the endangered fishes.” 

Other management actions being taken to reduce the threat of nonnative fishes to the endangered fishes include screening reservoir outlets and berming ponds to prevent the escape of nonnative fishes into rivers.  The states’ nonnative fish stocking procedures prohibit introduction of certain nonnative fish species into river reaches occupied by the endangered fishes. 

Established in 1988, the Upper Colorado River Endangered Fish Recovery Program is a voluntary, cooperative program whose purpose is to recover the endangered fishes while water development proceeds in accordance with federal and state laws and interstate compacts.  For more information, call 303-969-7322, ext. 227 or visit the Recovery Program’s website:                  



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