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The effects of Glen Canyon Dam operations on early life stages of rainbow trout in the Colorado River

Fact Sheet 2011-3002

Grand Canyon Monitoring and Research Center
By:
,

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Abstract

The Lees Ferry reach of the Colorado River-a 16-mile segment from Glen Canyon Dam to the confluence with the Paria River-supports an important recreational rainbow trout (Oncorhynchus mykiss) fishery. In Grand Canyon, nonnative rainbow trout prey on and compete for habitat and food with native fish, such as the endangered humpback chub (Gila cypha). Experimental flow fluctuations from the dam during winter and spring 2003-5 dewatered and killed a high proportion of rainbow trout eggs in gravel spawning bars, but this mortality had no measurable effect on the abundance of juvenile fish. Flow fluctuations during summer months reduced growth of juvenile trout relative to steadier flows. A high-flow experiment in March 2008 increased both trout survival rates for early life stages and fish abundance. These findings demonstrate that Glen Canyon Dam operations directly affect the trout population in the Lees Ferry reach and could be used to regulate nonnative fish abundance to limit potential negative effects of trout on native fish in Grand Canyon.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
The effects of Glen Canyon Dam operations on early life stages of rainbow trout in the Colorado River
Series title:
Fact Sheet
Series number:
2011-3002
Edition:
-
Year Published:
2011
Language:
ENGLISH
Publisher:
U.S. Geological Survey
Contributing office(s):
Southwest Biological Science Center
Description:
4 p.
Online Only (Y/N):
N
Additional Online Files(Y/N):
N