Reclamation Releases Environmental Assessment for Control of Non-Native Fish in the Colorado River to the Public for Review and Comment

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Date: January 31, 2011
Contact: Lisa Iams - BOR, 801-524-3673
Contact: Beverley Heffernan - BOR, 801-524-3712


The Bureau of Reclamation has released a Draft Environmental Assessment for the control of non-native fish in the Colorado River downstream from Glen Canyon Dam to the public for a 30-day review and comment period.

The EA analyzes the environmental consequences of a range of specific actions designed to control non-native fish, particularly rainbow and brown trout, known to prey on, and compete with, the endangered humpback chub in Grand Canyon. Some means of control are necessary to satisfy conservation measures contained in the 2008 Biological Opinion issued by the U.S. Fish and Wildlife Service for the Operation of Glen Canyon Dam, and the terms and conditions of a subsequent 2010 biological opinion.

"Protecting endangered native species is a key component of Reclamation's efforts to balance the complex and competing interests in the Colorado River downstream of Glen Canyon Dam," said Assistant Secretary for Water and Science Anne Castle. "The science we are bringing together through this study will help us wisely manage Colorado River flows and meet our water delivery and environmental responsibilities, while protecting the cultural values of native American communities."

Continued mechanical removal through the Glen Canyon Dam Adaptive Management Program was the primary method anticipated in the conservation measure, particularly at the confluence of the Colorado River mainstem and the Little Colorado River. However, several tribes represented on the Adaptive Management Work Group, particularly the Pueblo of Zuni, expressed concerns over the taking of life in a culturally sacred area and the adverse effect that this action has on the values of the Zuni people. To address these concerns, other potential methods of control are evaluated in the EA.

Reclamation worked with the U.S. Geological Survey Patuxent Wildlife Research Center to conduct a Structured Decision Making project to enlist cooperating agencies and AMP tribes in the development and analysis of potential alternatives to control non-native fish for evaluation in the EA. Government-to-government tribal consultation meetings are on-going and will be concluded prior to completion of a final decision on the proposed action.

Non-native fish control efforts identified in the EA would be focused within Glen Canyon National Recreation Area and Grand Canyon National Park. The proposed action is intended to reduce competition and predation on the humpback chub which threaten the potential recovery of the species, while attempting to address tribal concerns and avoid or minimize effects to other resources. The EA describes the current environmental conditions in Glen, Marble, and Grand canyons downstream from Glen Canyon Dam and discloses the direct, indirect, and cumulative environmental impacts that could result from the proposed action and alternatives.

The draft EA was prepared in accordance with the National Environmental Policy Act and is available at under the "Environmental Documents" link. A printed copy of the report is available at the Bureau of Reclamation Upper Colorado Regional Office, 125 South State Street, room 7218, Salt Lake City, Utah 84138.

Written comments may be provided to Reclamation through February 28, 2011 to the address above or via e-mail at e-mail us . For more information, or to request a printed or CD-ROM copy of the EA, please contact Glen Knowles at (801) 524-3781.


Last updated: February 24, 2015

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