6012

• UCREFRP Catalog Number: 6012
• Author: Miller, W. H., D. L. Archer, H. M. Tyus and K. C. Harper.
• Title: Colorado River Fishery Project
• USFW Year: 1982.
• USFW - Doc Type: Final Report.
• Copyright Material: NO

T
~ i S
INTRODUCTION
The activities described in this report were undertaken in June of
1979 in accordance with Memorandum of Understanding (MOU) No. 9-06-40-L-
IOI6 between the U.S. Fish ~ Wildlife Service (FWS) and the Bureau of
Reclamation (BR). Subject MOU prescribed a comprehensive investigation
of all facets of the life histories of the Colorado squawfish Ptyctiocheilus
lucius, humpback chub Gila cypha and the bonytail chub Gila elegans;
species listed as endangered under the National Endangered Species Act,
and the razorback sucker Xyrauchen texanus, recognized as rare by most
investigators acquainted with the Colorado River's aquatic fauna. The
technical reports describing the research conducted under this program
are appended under appropriate titles.
Scope of Study
The Memorandum of Understanding between FWS and BR presented a
table of biological needs for the four target species along with a PERT
chart (Appendix ). Broad areas of investigation included spawning
requirements; young and adult habitat requirements; migratory behavior;
interspecific competition; temperature, salinity, and chemical effects;
cultural technologies; disease and parasite diagnostics; and taxonomic
classification.
In 1980, BR's responsibility under the MOU to provide the hydraulic
and physico-chemical modeling for the Upper Basin was transferred to FWS
by amendment. This work was then delegated to the FWS Western Energy
and Land Use Team`s (WELUT) Instream Flow Group (IFG). A second amendment
to the MOU provided for investigation of the humpback chub in the vicinity
of the Little Colorado River in the Lower Colorado River Basin. Those
studies were to be concluded, in March 19$2. A third amendment expanded
field investigations to the Dolores and Gunnison Rivers during 1981. A
final report for those studies will be completed in February 1982 although
much of the information is presented in this report(A~2(~`"'`LYL)• L
Additional funds were provided by the Bureau of Land Management
(BLM) during 1980 and 1981 to address special concerns peculiar to their
Land management responsibilities. This report is also intended to
partially fulfill specifications of MOU No. CO-910-MU9-933 under which
those funds were committed.
Fisheries investigations in the Upper Basin were further expanded
during 1981 through agreements with the National Park Service and special
appropriations directly from Congress. This expansion extended invest-
gations further up the Green River and extensive distances up the Yampa
and White Rivers.
Field investigations under the MOU with BR included the Upper
Colorado River from Lake Powell to Debeque, Colorado and the Green from
its confluence with the Colorado River upstream to Split Mountain Gorge
(Figure 1), a total of 575 river miles (RM). A major objective was to
determine relative abundance and distribution of the target species and
to describe the habitats that they exhibited preferences for or were