7400

• UCREFRP Catalog Number: 7400
• Author: Valdez, R. A.
• Title: The Endangered Fish of Cataract Canyon
• USFW Year: 1990.
• USFW - Doc Type: Final Report.
• Copyright Material: NO

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This contracted st.udy was performed by BIO/WEST, Inc. for the Bureau of Reclamation (Reclamation).
lt was conducted as part of the responsibility of federal agencies, under the Endangered Species Act
of 1973, P.L93-205, to protect and, where possible, promote the recovery of endangered species.
Since inception of this legislation, Reclamation has been actively involved in collecting information on
the Colorado squawfish (Ptychochei/us lucius), humpback chub (Gila cypha), bonytail (Gila elegans), and
razorback sucker (Xyrauchen texanus), in cooperation with the U.S. Fish and Wildlife Service. In 1979,
these agencies formed the Colorado River Fisheries Project to investigate and monitor the life history
and biological requirements of the endangered fish in the Colorado River Syst.em.

In 1981, Reclamation initiated funding for the collection of biological data on the Colorado squawfish
in the Gypsum Canyon area of Lake Powell, following the discovery of a concentration of 45 adults in
that area in the spring of 1980. From 1982 through 1984, Reclamation monitored the movement of adult
Colorado squawfish in this region using radiotelemetry. Sample efforts associated with this study also
revealed small numbers of adults in the Imperial/Gypsum Canyon areas in July and August. as well as
larval Colorado squawfish, indicating that spawning was occurring in the area or immediately upst.ream
in Cataract Canyon. .

These initial investigations prompted further studies, and in 1985 Reclamation contracted Ecosyst.ems
Research Institute to conduct a 1-year pilot st.udy in Cataract Canyon. This led to a 3-year contract to
BIO/WEST, Inc. (1986-1988) and became known as the Cataract Canyon Studies.

This investigation was designed to answer three questions: (1) Where are the endangered fish
spawning in Cataract Canyon?, (2) Is there a population of humpback chub in Cataract Canyon?, and
(3) To what extent does the operation of Lake Powell influence nursery habitat of Colorado squawfish
in the Gypsum Canyon area? Answers to these questions will assist Reclamation to more effectively
operate Glen Canyon Dam and Reservoir along with other Reclamation facilities for the protection of the
endangered Colorado River fishes, as prescribed under the Endangered Species Act of 1973.

This report is accompanied by two supplements documenting different aspects of this investigation:
(1) The Cataract Canyon Database, which is a collection of six computer diskettes containing dBASE
111+ data files, and a printout of all the data collected, and (2) The Chub Biography, which is a collection
of photographs and detailed morphometric descriptions of all the Gila spp. collected. These
supplements were dist.ributed only to the Bureau of Reclamation, U.S. Fish and Wildlife Service, National
Park Service, and Utah Division of Wildlife Resources. Copies of these supplements are only available
at cost from BIO/WEST, Inc.

BIO/WEST, Inc. encourages interaction from readers of this document. Please sent comments to:

BIO/WEST, Inc.
1063 W. 1400 N.
Logan, Utah 84321

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