Managing nonnative fish species

The Upper Colorado River Endangered Fish Recovery Program is working to recover endangered fish while also working to minimize the impact on non-native sport fishing. In general, stocking nonnative fish species in the upper Colorado River basin has been confined to areas where there is little potential conflict with endangered fish. But trout tend to live in different parts of the river, and are not considered competitors with endangered fish. Trout are cold-water fish that prefer temperatures 10 to 15 degrees cooler than those in downstream sections of the river where endangered fish are found.

• In fall 1996, federal and state wildlife agencies in Colorado, Utah and Wyoming finalized an agreement on stocking of nonnative sport fish. Nonnative fish stocking agreement details.
• The Utah Division of Wildlife Resources, Colorado Division of Wildlife, and the Service have removed more than 20,000 nonnative channel catfish, 10,000 nonnative sunfish and bass, and 200,000 nonnative minnows from rivers in the Upper Colorado River Basin.
• A project to remove and relocate nonnative adult northern pike from the Yampa River was initiated in 1999.
• Chemical reclamation of ponds adjacent to the Colorado and Gunnison rivers to reduce sources contributing nonnative fishes to riverine habitats started in 1998 and continued in 1999. To date, 104 ponds have been surveyed, and 19 have been chemically reclaimed. This project is ongoing.
• A fish barrier net was installed in 1999 in Highline Lake Reservoir near Grand Junction, Colorado, to reduce escapement of nonnative sport fishes from the reservoir and into reaches of critical habitat in the Colorado River.