8135

• UCREFRP Catalog Number: 8135
• Author: Valdez, R. A.
• Title: Occurrence of Threatened and Endangered Fishes of the Colorado River in the Vicinity of the Proposed Jacobson Hydro No. 1 Project.
• USFW Year: 1984.
• USFW - Doc Type: Logan, Utah.
• Copyright Material: NO

4-1

4.0 SPECIES DISCUSSIONS

4.1 Introduction

The species of concern in this project are the Colorado squawfish,
humpback chub, bony tail , and razorback sucker. The first three fishes are
listed as I endangered. by the U.S. Department of Interior and the Colorado
Wildlife Commission. The fourth fish is federally listed as a 'candidate.
species and listed by Colorado as 'threatened'. Also included in this
discussion are the sport fishes usually encountered in the project area.

Table 1 is presented to show the nearest location of the most recent
captures of the target fishes relative to the proposed JH-l site.

Table 1. Nearest location of most recent captures of threatened and
endangered fishes relative to the JH-l site (river miles 188.2)
in the Upper Colorado River.

SPECIES DISTANCE IN MILES FROM JH-l SITE
Upstream Downstream

a,b

Colorado squawfish

a

3.1
44.3
53.2
10.2

Humpback chub

a

Bony tail

Razorback sucker

17.3

a
No recent confirmed reports of the species upstream of the project site.
b
See discussion in subsection 4.2.

4.2 Colorado squawfish.
The Colorado squawfish is the largest minnow native to North America.
The maximum size of fish caught recently is about 3 feet in length and 12 to
15 pounds in weight. The species was once distributed throughout much of the
Colorado River System, but is now found only in the upper basin (Holden and
Wick 1982). The Colorado squawfish was first included in the original list