Skip to main content
U.S. flag

An official website of the United States government

An experiment to control nonnative fish in the Colorado River, Grand Canyon, Arizona

August 17, 2011

The humpback chub (Gila cypha) is an endangered native fish found only in the Colorado River Basin. In Grand Canyon, most humpback chub are found in the Little Colorado River and its confluence with the Colorado River. For decades, however, nonnative rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta), which prey on and compete with native fish, have dominated the Grand Canyon fish community. Between 2003 and 2006, scientists with the U.S. Geological Survey and Arizona Game and Fish Department experimentally removed 23,266 nonnative fish from a 9.4-mile-long reach of the Colorado River near where it joins the Little Colorado River. During the experiment, rainbow trout were reduced by as much as 90% and native fish abundance apparently increased in the reach. Concurrent environmental changes and a decrease in rainbow trout throughout the river make it difficult to determine if the apparent increase in native fish was the result of the experiment.

Citation Information

Publication Year 2011
Title An experiment to control nonnative fish in the Colorado River, Grand Canyon, Arizona
DOI 10.3133/fs20113093
Authors Lewis G. Coggins,, Michael D. Yard
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Fact Sheet
Series Number 2011-3093
Index ID fs20113093
Record Source USGS Publications Warehouse
USGS Organization Southwest Biological Science Center

Related Content