8214

• UCREFRP Catalog Number: 8214
• Author: Modde, T., D. Irving and R. Anderson.
• Title: Habitat Availability and Habitat Use of Endangered Fishes in the Yampa River during Baseflow Periods.
• USFW Year: 1997.
• USFW - Doc Type: Vernal, Utah and Grand Junction, Colorado.
• Copyright Material: NO

sites would not be used to estimate habitat availability, but would provide insight into developing
criteria as to what riffle depth adult Colorado squawfish can pass. If this occurs, we will be able to
adjust the 1.0 maximum depth criterion either up or down. A slight adjustment in the maximum
depth value could result in a significant change in suitable discharge.

Based on the data from 1996, it appears that some, though isolated, adult Colorado squawfish
habitat is maintained in most clusters at flows as low as 1 cfs. At flow between 80 and 100 cfs, it
appears that adult squawfish habitat is maintained at about 70% of the median base flow. In regard
to the fish passage question, it appears that flow of 160 to 185 cfs would allow fish movement over
70% of the riffles measured. Thus, it appears that site isolation may occur prior to the reduction in
habitat availability. Flows that may restrict fish movement between pools at sites sampled in 1996
appear before substantial declines in habitat availability. Nontheless, any interpretation made in
this report are based soley data collected in 1996 and is subject to change or modification based on
the collection of a data in 1997.

LITERATURE CITED

Bovee, K.D., and R. Milhous. 1978. Hydraulic simulation in instream flow studies: theory and
techniques. Instream flow paper No.5. U.S. Fish and Wildlife Service, FWS/OBS-78/33. Fort
Collins, CO.

Gordon, N.D., T.A. McMahon, and B.L. Finlayson. 1992. Steam hydrology: an introduction for
ecologists. Wiley and Sons.

Hydrosphere Resource Consultants. 1995. Yampa River basin recommended alternative detailed
feasibility study. Final Report. Submitted to Colorado River Conservation District. Glenwood
Springs, CO.

Miller, W.H., D.L. Archer, H.M. Tyus and R.M. McNatt. 1982. Yampa River fishes study. Final Report
for Memorandum of Understanding 14-16-0006-81-931(IA), U.S. National Park Service. U.S.
Fish and Wildlife Service, Salt Lake City, UT.

Miller, W.J., and D.E. Rees. 1997. Colorado squawfish habitat use and movement during summer low
flow in the Yampa River upstream of Cross Mountain Canyon. Annual Report submitted to
Colorado River Water Conservation District. Glenwood Springs, CO.

Modde, T., and G. Smith. 1995. Flow recommendations for endangered fishes in the Yampa River. Final
Report submitted to the Recovery Implementation Program for the Recovery of Endangered
Fishes in the Upper Colorado River Basin. U.S. Fish and Wildlife Service, Denver, CO.

Nesler, Thomas P. 1995. Interactions between endangered fishes and introduced gamefishes in the
Yampa River, Colorado, 1987-1991. Colorado Division of Wildlife, Aquatic Research Section, Ft.

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