8290

• UCREFRP Catalog Number: 8290
• Author: Day, K. S. and C. Crosby.
• Title: An Assessment of Young-of-the-Year Colorado Squawfish ‎(Ptychocheilus lucius)‎ Use of Backwater Habitats in the Green River, Utah.
• USFW Year: 1997.
• USFW - Doc Type: FG-33,
• Copyright Material: NO

INTRODUCTION
Populations of endemic fish species in the upper Colorado River Basin ha
some drastically, over the past several decades. Four species; Colorado squaw
(Ptychocheilus Lucius), razorback sucker (Xyrauchen texanus), humpback chub (G
bonyt.ail chub (G. elegans); have been listed under the Endangered Species Act.
causes of species declines are construction of mainstem and off-channel dams
alter natural flow patterns and introduction and proliferation of non-native s
have severely impacted the upper Colorado River and its tributaries. The Gree
however, has not been as dramatically impacted and provides the primary remain
at least two of these species. This is likely related to the abundance of qua
(Archer et al. 1986). Since construction of Flaming Gorge Dam, however, the G
channel has narrowed and become less complex (J. Schmidt, unpubl. report). Fo
maintenance of habitats is less certain than in the past. In addition, many o
are now overrun with non-native species. Non-native fishes may compete for li
and/or prey directly on native species. These factors are thought to impact r
native fish into adult populations.
The acknowledged importance of nursery habitat to endangered fishes, and
their maintenance led to the study of relationships to nursery habitat availab
characteristics and young-of-the-year (YOY) Colorado squawfish use described h
goals of this study were: 1) describe the relationship between available and s
habitats, 2) determine the relationship between quantity of nursery habitats a
summer period to the number of YOY Colorado squawfish present in nursery habit