6008

• UCREFRP Catalog Number: 6008
• Author: Archer, D. L., H. M. Tyus, L. R. Kaeding, C. W. McAda and B. D. Burdick.
• Title: Colorado River Fishes Monitoring Project
• USFW Year: 1984.
• USFW - Doc Type: Second Annual Project.
• Copyright Material: NO

INTRODUCTION
The fish community of the Colorado River was historically dominated by
endemic species -- species found nowhere else. Because of their adaptation
to the unique enviror~nent of the Colorado River system, survival of
these species is more tenuous than it is for less specialized species.
Alteration of the Colorado River has greatly reduced the populations of
some of these endemic species and continued alterations of the river
R could reduce many of these species to extinction.
The recent decline in abundance and range of three endemic fishes,
Colorado squawfish (Ptychocheilus Lucius), humpback chub (Gila cypha)
and bonytail chub (G elegans) has been significant enough to justify
classifying them as endangered by the United States Fish and Wildlife
Service.
Under the provisions of the Endangered Species Act of 1973, endangered
species designation dictates that Federal agencies involved in resource
development projects must not jeopardize the- continued existence of such
species. Proposed developments that would further reduce populations of
endangered species must be modified or canceled. Thus, the presence of
an endangered species can greatly influence the development of natural
resources. This has been a particularly controversial issue affecting
proposed Colorado River water projects.
Information on the distribution, abundance, and habitat associations of
endangered Colorado River fishes was required to determine the effects
that proposed water development projects might have on these fishes. In
1979 the Fish and Wildlife Service (FWS) and the Bureau of Reclamation
(BR) cooperated to develop the Colorado River Fishery Project (GRFP), a
research group whose pu rpose was to col lect and interpret information on
endangered Colorado River fishes. CRFP findings suggested that the
endangered Colorado squawfish and humpback chub may experience an
unusual.iy high rate of mortality during their first year of life (Miller
et al. 1983). If these causes of early mortality could be determined,
it might be possible to improve the survival of Colorado squawfish and
humpback chub.
The BR and FWS began the Colorado
(CRFMP) in 1982, to further expand
endangered Colorado River fishes.
of the present CRFMP study:
River Fishery Monitoring Program
on the information base for the
There are three specific objectives
1) To expand information on the distribution and movement of
r adult Colorado squawfish to and from spawning site locations
with the use of radio tagging. Area of study to include
the Yampa, Green, Gunnison, and Colorado rivers.
2) To verify flow requirements of adult Colorado squawfish in
relation to spawning success and survival of larval.
Colorado squawfish.