9498

• UCREFRP Catalog Number: 9498
• Author: Nesler, T. P.
• Title: Stocking Plan for Endangered Coloraod River Fish Species.
• USFW Year: 2001.
• USFW - Doc Type: Denver.
• Copyright Material: NO

I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I

.

Introduction

This plan represents a revised and updated approach to the stocking needs for. Colorado
River endangered fishes presented in Nesler (1998). Since the completion of the previous plan,
considerable effort has been expended in detennining quantified recovery goals for each of the
four federally listed fish species (Nesler 2000, USFWS 2001a,b,c,d in draft). These goals inClude
criteria for minimum population abundance. At Biology Committee meetings for both the San
Juan River and Upper Colorado River Endangered Fish Recovery Programs, the direction was
agreed upon to revise stocking plans to be consistent with population abundance criteria developed
within the draft recovery plans for each fish species. This revised plan incorporates those criteria
as the target stocking objectives for each species' population.

The propagation and stocking of the Colorado River endangered fishes.is recognized as
one of five primary approaches to attaining the recovery goals for the four listed species-razorback
sucker, Colorado pikeminnow (fonnerly squawfish), bonytail, and humpback chub. The direction
to perfonn tasks related to propagation, augmentation, and restoration stocking are clearly
identified in the Recovery Implementation Program report (U.S. Fish and Wildlife SelVice 1987),
the recovery action plan (U.S. Fish and Wildlife SelVice 1998), and the annual propagation
operation plan (Czapla 1997). The annual propagation operation plan will need to be revised to
reflect the revised fish stocking needs described here.

Three razotback sucker stocks, three Colorado pikeminnow stocks, five humpback chub
stocks, and one bonytail stock have been identified (Wydoski 1995, Czapla 1999). Populations
of these species in Colorado rivers that contribute to, or are inCluded within the critical habitat
range of these presumptive stocks inClude razorback SlIcker and Colorado pikeminnow populations
in the Colorado River from Rifle downstream to the state line, and in the Gunnison River from
Delta downstream to its confluence as part of the Upper Colorado River stocks for both species.
Colorado pikeminnow populations in the Yampa and White rivers contribute to the Yampa and
Green River-Desolation/Gray Canyon stocks. Presumptive stocks of humpback chub in Colorado
include the populations in the Yampa River and Colorado River at Black Rocks Canyon. Bonytail
populations formerly occurred in Colorado, based on captures and identifications of this species
in the Yampa, Colorado, and Dolores rivers in historic and anecdotal accounts (Kaeding et al.
1986, Tyus and KalJ> 1989, Quartarone 1993), but are now extirpated. This species is now
represented by only one captive stock at Dexter National Fish Hatchery in New Mexico. Relict
wild stocks exist in Lake Havasu and Lake Mohave in the Lower Colorado River Basin, but are
comprised of very old, senescent adults (USFWS 1990a).

This stocking plan provides the rationale for conducting restoration stocking forthe four
endangered fish species in select rivers of western Colorado within the Upper Colorado River
Basin, and inCludes priorities among species and river reaches, genetics risk assessment, and
criteria for contribution to recovery success as well as expectations and limitations.

I