9463

• UCREFRP Catalog Number: 9463
• Author: Badame, P. V. and J. M. Hudson.
• Title: Reintroduction and Monitoring of Hatchery-reared Bonytail in the Colorado and Green Rivers; 1996-2001.
• USFW Year: 2001.
• USFW - Doc Type: 03-13,
• Copyright Material: NO

with bonytail in 1995 and 1997 (Lentsch et al. 1996; Crowl and Rivera 2000) which examined the
physiological responses to various flow training regimes. The results of theses experiments were
mixed and did not point strongly toward flow training as a method to improve survivability.

PURPOSE AND OBJECTIVES

The purpose of this study is to reestablish wild bonytail populations in the upper Colorado River
basin and fulfill a long-term goal of the Bonytail Chub Recovery Plan; "reintroduce hatchery-
reared bonytail chub into the wild" (USFWS 1990). This includes developing a propagation and
rearing plan that will maximize survival in the wild, maximize genetic diversity and promote good
post-stocking survival.

The specific objectives of this study:

1. Reintroduction ofbonytail into the Colorado River, in the Professor Valley and in the
Green River, near the town of Green River, Utah.

2. Determine the appropriate number and size of bonytail to stock to maximize survival.

3. Determine movement and the potential for habitat utilization overlap between
honytail and roundtail. Investigate whether Gila species utilize similar micro- and
meso-habitats.

4. Determine if flow training results in enhanced survivorship of different size classes of
bonytail. This objective was the responsibility of Utah State University and has not
been field tested as ofFY 2001.

STUDY AREA

Potential bonytail release sites were evaluated based on several factors: 1) habitat availability, 2)
hybridization potential, 3) historical occupation, 4) predation potential, 5) concurrent sampling,
and 6) location convenience and available expertise. Three sites were selected as most suitable
for reintroduction based on these factors. The sites were the Green River below Gray Canyon
(RM 120-132), the Colorado River's Professor Valley area below Westwater Canyon (RM
90-60), and the section of the Green River near Island Park (RM 340-317).

The initial stocking location selected for the Colorado River was RM 96.2 in a large backwater
just below the mouth of the Dolores River. In 1997, the stocking site was moved down stream to
Dewey Bridge (RM 94.3). This remained the release location for the Colorado River through
2001. Monitoring occurred from RM 100 down to RM 0 at the confluence with the Green River
(Figure 1).

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