3100

• UCREFRP Catalog Number: 3100
• Author: Valdez, R. A.
• Title: Cataract Canyon Fish Study ‎(Fisheries Biology and Rafting)‎
• USFW Year: 1985.
• USFW - Doc Type: Final Report.
• Copyright Material: NO

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1.0 INTRODUCTION

This document is the final report submitted to the U. S. Bureau of
Reclamation (USBR) for Contract No. 5-CS-40-02820, entitled Fisheries
Biology and Rafting. Six progress reports were submitted during the
investigation, one for each of six sample trips; ERI (C046-0l to C046-06).

1.1 Objectives

The objectives of this investigation were to:

1. assess the summertime importance of the Upper Colorado River in
Cataract Canyon to the endangered Colorado squawfish,

2. locate and describe Colorado squawfish spawning areas in Catar'act
Canyon by rel ocati ng rad iotagged adul ts captured and rel eased earl ier
in the year in Upper Lake Powell,

3. identi fy nursery areas used by young Colorado squawfi sh in Cataract
Canyon,

4. determine the occurrence of young Colorado squawfish in Upper lake
Powell and assess the possible influence of fluctuating lake levels on
their habitat and well-being, and

5. identi fy the importance of the Colorado River in Cataract Canyon and
Upper Lake Powell to the endangered humpback chub, bonyta il, and the
candidate razorback sucker.

l.2 Background

This investigation was conducted as part of USBR's ongoing program on
endangered fishes in the Upper Colorado River Basin. That program has
included the Colorado River Fishery Project (CRFP), a major effort conducted
from 1978 to 1981 with the U.S. Fish and Wildlife Service (USFWS) to
investigate and monitor the life history and biological requirements of the
endangered fi shes.

During CRFP, 45 large adult Colorado squawfish were captured in upper
Lake Powell, near Gypsum Canyon (Figure 1) in April 1980 (Persons et al.
1982; Valdez et ale 1982). This large concentration of squawfish brought
attention to the waters of upper Lake Powell and to their possible
importance to the endangered fishes. In 1981, USBR began collecting
biological data on the Colorado squawfish with an intensive gill netting
program in the vicinity of Gypsum - Canyon. Since then, gill netting has
extended downstream to the Dirty Devil River near Hite Marina. Efforts have
also expanded to radiotelemetry for monitoring movement, as well as seining
for young fishes.

Although larval Colorado squawfish have been collected in the vicinity
of Gypsum Canyon, their origin is unknown. Not enough is known of the
behavior or drift rates and distances of larval squawfish to determine if
these fish drifted from known or suspected spawning areas in the Green,
Yampa, or Colorado Rivers or if the fish were spawned in Cataract Canyon,
illlJ\ediately upstream of Gypsum Canyon and Lake Powell. Since spawning