9588

• UCREFRP Catalog Number: 9588
• Author: Bestgen, K. R. and e. al.
• Title: Population Status of Colorado Pikeminnow in the Green River Basin, Utah and Colorado.
• USFW Year: 2005.
• USFW - Doc Type: Fort Collins, CO.
• Copyright Material: NO

relatively short reaches within the study area that received only cursory sampling in this study
historically held few Colorado pikeminnow (Holden and Stalnaker 1975). The middle Green
River reach was sampled by the Utah Division of Wildlife Resources, Vernal, Utah.
The White River study reach was 167.4-RK long and extended from just below Taylor
Draw Dam downstream to the confluence with the Green River. Although Colorado
pikeminnow historically occurred above Taylor Draw Dam, few or none are thought to occupy
that reach since the reservoir began filling in 1984 (Martinez 1986; Martinez et al. 1994). The
White River winds through alluvial valleys interspersed with short bluffs. The U. S. Fish and
Wildlife Service, Vernal, Utah, was responsible for sampling the White River and the
Desolation-Gray Canyon reach of the Green River (below).
The Desolation-Gray Canyon Green River reach was 189.8-RK long and extended from
the head of Desolation Canyon at RK 395.9 downstream to near the lower end of Gray Canyon at
RK 206.1. That reach was mostly canyon-bound and geomorphically constrained. The reach
between RK 206.1 (at Tusher Diversion) and 193.2 was usually not sampled because of logistical
constraints.
The lower Green River reach was 193.2-RK long and extended from near the town of
Green River downstream to the confluence with the Colorado River (RK 0), and passed through
the low-gradient Labyrinth and Stillwater canyons. The Utah Division of Wildlife Resources,
Moab, Utah, was responsible for sampling there.
During low flow periods in all reaches, low-velocity habitat was near shore, in small
eddies and pools, and behind or adjacent to mid-channel sand or gravel bars. When flows were
elevated by snow-melt runoff in spring, main channel velocities were swifter, and low-velocity
16
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
i