Skip Links

USGS - science for a changing world

U.S. Geological Survey Fact Sheet 2011–3093

An Experiment to Control Nonnative Fish in the Colorado River, Grand Canyon, Arizona

By Lewis G. Coggins, Jr., and Michael D. Yard

Thumbnail of and link to report PDF (1.3 MB)Summary

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.

  • This report is also available in print from:

    USGS Information Services, Box 25286,
    Federal Center, Denver, CO 80225
    telephone: 888 ASK-USGS; e-mail: infoservices@usgs.gov

For additional information contact:
SBSC Staff, Southwest Biological Science Center
U.S. Geological Survey
2255 N. Gemini Drive
Flagstaff, AZ 86001
http://sbsc.wr.usgs.gov/

This report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.


Suggested citation:

Coggins, L.G., Jr., and Yard, M.D., 2011, An experiment to control nonnative fish in the Colorado River, Grand Canyon, Arizona: U.S. Geological Survey Fact Sheet 2011-3093, 2 p.




Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://pubsdata.usgs.gov/pubs/fs/2011/3093/index.html
Page Contact Information: GS Pubs Web Contact
Page Last Modified: Tuesday, 29-Nov-2016 17:45:58 EST