7125 ‎(2)‎

• UCREFRP Catalog Number: 7125
• Author: McAda, C. W.
• Title: Aspects of the Life History of Three Catostomids Native to the Upper Colorado River Basin.
• USFW Year: 1977.
• USFW - Doc Type: Utah State University,
• Copyright Material: YES

INTRODUCTION
The Colorado River system in the western United States has been
greatly modified during the past century, primarily by the construction
of dams for hydroelectric power generation and irrigation. The dams
have resulted in major hydrological and ecological changes in the large
rivers of the basin [Dolan, Hauard and Gallenson, 19741. The river
environment below the dams has been altered in three major aspects:
1) seasonal fluctuations in streamflow have been reduced and daily
fluctuations have been increased, 2) summer water temperatures are
lower and winter water temperatures are higher, and 3) turbidity is
reduced. Modifications of such proportions usually result in large
variations in the aquatic fauna found downstream [Pearson, Kramer,
and Franklin, 1968; Vanicek, Framer, and Franklin, 1970; Geen, 19741.
The dams and their alteration of the river environment are
believed to be major factors in the decline of four endemic Colorado
River fishes; the Colorado squawfish (PtychocheiZus Zucius), the
humpback chub (Gila eypha), the bonytail chub (GiZa elegans) and the
razorback suckers (%yrauehen texanus)[Vanicek, Kramer, and Franklin,
1970; AlinckZey, 1973; Holden and StaZnaker, 1975b]. The first two
fish have been officially designated "endangered" by the U. s.
Department of the Interior [1973], and the latter two were proposed
s Biologists who are presently working with this species prefer the
common name of "razorback" sucker rather than "humpback" sucker as
used by Bailey [1970]. Razorback is a literal translation of
xyrauchen and its use avoids possible confusion of the razorback
(humpback) sucker with the humpback chub.