7908

• UCREFRP Catalog Number: 7908
• Author: Valdez, R. A. and R. J. Ryel.
• Title: Life History and Ecology of the Humpback Chub ‎(
• USFW Year: 1995.
• Copyright Material: NO

xviii . Preface

non-native species. This multispecies approach,
balanced ~th the needs of other resources, will
provide a meaningful approach to managing the
Grand Canyon ecosystem.

While this report presents new and valuable
information on the humpback chub in Grand
Canyon, it is naive to assume that one study can
provide "all there is to know" about this population,
let alone give a full understanding of the aquatic
ecosystem in the canyon. While such complete
information would be valuable in fully assessing
effects of dam operations, a complete ecological
study would require time and thorough planning
(Marzolf 1991). Instead, the research process of
this study focused on specific aspects of life-history
and ecology which were deemed important for the
population and which may be affected by dam
operations. This study was constrained by available
research techniques (some of which were developed
during this project), modified dam operations,
concerns for personal safety, time, and money.
Despite these constraints, valuable information was
gathered and we feel that this report provides a
reasonable characterization of the species as we
know it today.

The study design, pwpose, and objectives of this
study were developed to integrate with other
investigations. Parallel and simultaneous studies of
the life-history and ecology of the species in the
Little Colorado River were conducted by other
researchers. The various research activities now
need to be integrated to produce a broad and more
comprehensive picture of humpback chub ecology in
the Grand Canyon, and to more fully assess the
effects of Glen Canyon Dam. Such integration must
extend to other disciplines, where they affect the
species, including geomorphology, climatology,
water quality, and other biological components of
the ecosystem. In addition, a more complete
understanding of humpback chub, both in terms of
ecology and population viability, will require
integrating information from populations throughout
the basin. This integration will provide a basis for
designing more broad-based ecological studies for
fishes within the entire Colorado River Basin.

Specific recommendations for management of Glen
Canyon Dam are not included in this report.
Instead, the effects of various operational
components on humpback chub were assessed in

Final Report

order to provide the information to Reclamation and
other cooperators of dam operations. We recognize
that recommendations for dam operations are
beyond the scope of this work, and perhaps
premature until the integration process is completed
Assessing economic effects of dam operations
designed to minimi7.e impacts to humpback chub is
also beyond the scope of this work, but we
recognize the importance of cost in evaluating any
"
management scheme. Researchers should strive to
develop a consolidated and integrated information
base by which managers and administrators can
make informed decisions on dam management.

This report is intended as a scientific document for
agency administrators and the scientific community.
We endeavored to present our findings in a manner
that is readable and understandable to a wide
audience. We did this to make the document
informative and Useful, and as a tribute to the
unique fishes that live in Grand Canyon. Consistent
with this effort, we have provided English and
metric units of measure, either jointly for ease of
conversion or individually in commonly used terms.
For example, river flow is presented as cubic feet
per second instead of cubic meters per second and
locations are referenced in river miles instead of
kilometers. Scientific and common names are
consistent with nomenclature of the American
Fisheries Society List of Common and Scientific
N ames of the United States and Canada. The
editorial style of the North American Journal of.
Fisheries Management was used except where
abbreviations and scientific notation were awkward
(e.g., cubic feet per second was abbreviated 'cfs'
instead of ft3/s). A glossary and list of
abbreviations are provided to facilitate
understanding of scientific terms used in the text of
this report.

This report is presented as ten chapters. Following
the Introduction (Chapter 1) and Study Design
(Chapter 2) are a characterization of Hydrology
(Chapter 3) and Water Quality (Chapter 4). The
next four chapters describe life history aspects of
humpback chub, including Distribution and
Abundance (Chapter 5), Demographics (Chapter 6),
Habitat (Chapter 7), Movement (Chapter 8), and
Food Habits (Chapter 9). The last chapter is an
Integration (Chapter 10) of information and a
discussion of effects of dam operations on the
humpback chub in Grand Canyon. An Executive