9393

• UCREFRP Catalog Number: 9393
• Author: Crist, L. and R. Williams.
• Title: Five Year Flaming Gorge Research Program FY 1995.
• USFW Year: 1994.
• USFW - Doc Type: 32-41, Fg-I,
• Copyright Material: NO

influence of the high spring test flows and subsequent seasonal flows on the
formation and main#enance of Colorado squawfish nursery habitat and the
subsequent biological response by Colorado squawfish in the Green River.
The study depends on Study #1 for information on input of larval squawfish to
the nursery areas. This study in tum provides important information for
overwinter survival studies and links those studies with spring/summer/fall
flow studies.
Description of Work
An ongoing study by UDWR and USU that is under the lead of UDWR. The
study contains two major components. Utah Division of Wildlife Resources
and USU are categorizing Colorado squawfish nursery habitats based on
macro and meso habitat features related to the geomorpho{ogy of the system.
The biological value of the various types of habitats is being evaluated by
UDWR. Utah State University researchers will evaluate the geomorphic basis
of the nursery habitats and describe the influence of spring and summer flows
on the formation and maintenance of important habitats. Reclamation will
assist UDWR and USU by providing requested releases from FGD whenever
possible and providing necessary support and expertise for conducting
videoimagery research.
Study #34. Annual assessment of spawning success, larval distribution, and
habitat selection of mainstem razorback suckers.
Study Goals
This study will assess razorback sucker reproduction and larval abundance at
suspected spawning areas in the lower Yampa River Colorado, and the
Green River near Jensen, Utah.
Relationship to Research Program
Information on razorback sucker reproduction in the Green River is extremely
limited. Several suspected spawning locations are known in the Green River
above Jensen and in the lower Yampa River. However, it is not known if
razorback sucker successfully spawn at these locations. It is critical to know
if eggs and larvae are being produced so that flow requirements for spawning
can be identified and management for young fish attempted in downstream
nursery areas. {nformation from this study will be used to help refine spring
flow recommendations. This study ties directly with the Characteristics and
Use of Spring Habitats Study and Early Biology Study (completed). The
Analysis of Past Collections Study (completed) will also be used to support
this study.
Description of Work
This study is under the lead of the Service in cooperation with the LFL.
Additional funding and technical support has been provided by the NPS.
Light traps, drift nets, and seining are employed to determine if larvae are
being produced at suspected spawning bars. Preliminary information from
1993 and 1994 indicates that significant spawning of razorback sucker may
have occurred in the Green/Yampa system. However, fate of the larvae is
Flaming Gorge Research Program 24