Research begins to help four endangered fish species

Research studies have resumed in sections of the Duchesne, Green and Yampa rivers in Utah and Colorado to help recover four species of endangered fish — the humpback chub, bonytail, Colorado pikeminnow and razorback sucker.

Biologists with the Utah and Colorado divisions of wildlife and the federal government will conduct the work, which this year is focusing on the management of nonnative fish.

The work will happen from April through October on 482 miles of river in the Upper Colorado River Basin.

The northern pike and smallmouth bass have been identified as two of the non-native species that pose significant threats to the endangered species, because the non-natives are active predators that eat other fish and compete for food and space in the river.

Removal efforts of the northern pike have proven successful, with the abundance of the fish in the Green River, for example, decreasing by 90 percent since the program began there in 2001.

More problematic is the management of the smallmouth bass populations, which experienced a surge in 2006 and 2007 in sections of the Green and Yampa rivers.

Biologists are trying to recover the four species of endangered fish because they evolved 3 million to 5 million years ago and are only found in the Colorado River Basin. The biologists believe the fish are "indicator species" because they have been able to survive significant changes in the river system. The decline of these species may be a warning that other native species in the Colorado River system are at risk.

— Amy Joi O'Donoghue