Management of non-native northern pike and smallmouth bass remains the focus of research conducted by Utah and Colorado biologists participating in the Upper Colorado River Endangered Fish Recovery Program.
This is the second year of experimental removal efforts to determine if the numbers of certain non-native fish species in rivers can be reduced to a level where they no longer threaten the survival of the endangered humpback chub, bonytail, Colorado pikeminnow and razorback sucker.
Scientific evidence demonstrates that these non-native fish species, as well as channel catfish, pose a significant threat to the survival of endangered fish because they prey upon them and compete for food and space.
"This research will help identify the level of management required to minimize the threat of non-native fishes to the endangered fishes to satisfy criteria for recovery of these species," said Robert Muth, director of the recovery program. "We will assess the data each year to determine future nonnative fish management actions."
Efforts will expand from last year to include additional river sections, work crews and removal trips. From April through October, biologists will work in 515 miles of the Colorado, Yampa, Green and Duschesne rivers.
In Utah, smallmouth bass and northern pike are the fish targeted for removal.
Although channel catfish were included in last year's research effort, capture methods proved inadequate for effective removal.
With the exception of Yampa Canyon, where effective removal has been demonstrated, channel catfish control has been discontinued.
If new technologies can be developed that are more effective at capturing catfish, the recovery program may implement catfish capture and removal in the future and evaluate the results.
Follow-up sampling from this year's northern pike and smallmouth bass efforts will determine if management efforts reduced the numbers of targeted non-native fishes in sections where they were removed.
Monitoring of endangered and other native fishes will determine if numbers of these species increase. This year's nonnative fish management effort is the largest known riverine project of its kind.
It is a collaborative effort among the Utah Division of Wildlife, the Colorado Division of Wildlife Resources, the U.S. Fish and Wildlife Service, the Recovery Program and biologists from Colorado State University.
"It's important for us to learn whether removing non-native fish is an effective way to increase the number of native fish in the river system," commented Kevin Conway, director of the Utah DRW. "This year's nonnative removal projects are part of that evaluation."
Earlier this year, recovery program partners, which include state and federal agencies, environmental groups and water and power user organizations in Utah, Colorado and Wyoming, adopted a policy that addresses the process of identifying and implementing non-native fish management actions needed to recover the endangered fish.
"This was a landmark event because it clearly demonstrates that these diverse organizations recognize that management of non-native fish is essential to achieve and maintain recovery of the endangered fishes," said Ralph Morgenweck of USFWS. "The policy also recognizes the dual responsibilities of state and federal fish and wildlife agencies to conserve listed and other native fish species while providing for recreational fishery opportunities."
The recovery program is implementing several other actions to recover endangered fishes in addition to non-native fish management. Efforts are ongoing to provide river flows, restore habitat, construct fish ladders and screens, produce and stock endangered fish and monitor results.
The recovery program was established in 1988 on a volunteer basis.
For more information, call the Salt Lake City DWR office at 801-538-4700.