7735

• UCREFRP Catalog Number: 7735
• Author: Bates, B., T. Chart and M. Moretti.
• Title: Colorado Squawfish Interagency Standardized Monitoring Program, Utah, 1986-90, Lower Green and Colorado Rivers.
• USFW Year: 1993.
• USFW - Doc Type: Publication Number 93-11,
• Copyright Material: NO

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COLORADO SgUAWFISH INTERAGENCY STANDARDIZED
MONITORING PROGRAM, UTAH, 1986-89

LOWER GREEN AND COLORADO RIVERS

INTRODUCTION

The Colorado squawfish (Ptvchocheilus 1ucius) is a large
minnow endemic to both the Green and Colorado Rivers. Once common
throughout the Colorado River basin, its population~ have
declined in the past 100 years. The squawfish was listed as
endangered on March 11, 1967 and has been given protective status
under the Endangered Species Act.

The Recovery Plan for the Colorado squawfish lists as one of
its objectives to monitor existing populations and detect
population flucuations exceeding 200%. To meet this objective the
Upper Colorado River Basin Coordination Committee has established
an Interagency Standardized Monitoring Program. The ISMP involves
the use of standardized data collection techniques to assess the
status and trends of the Colorado squawfish, as well as other
endangered fishes in the basin.

Responsibility for the development and implementation of the
monitoring program is shared by the Fish and wildlife Service,
and the states of Utah and Colorado. The Fish and wildlife
Service provides technical support for data analysis. The states
of Colorado and Utah have the responsibility to collect the data.

The Utah Division of Wildlife Resources has the
responsibility for data collection and computerization of data
collected in Utah segments of the Green and Colorado rivers.
These rivers have been further segmented by 2 administrative
regions, the Northeastern and Southeastern. This report
summarizes data collected on the lower Green and Colorado rivers
within Utah by personnel from the Southeastern Region from 1986
to 1990.

METHODS

Late Juvenile/Adult Monitorinq

Late juvenile/adult Colorado squawfish populations were
sampled on 2 selected reaches each on the Green and Colorado
rivers in April and May of each year from 1986 to 1990. The
reaches on the Green River were from river mile 115 near the town
of Green River to river mile 96 at Ruby Ranch, and from river
mile 56 to 40 at Mineral Bottom (Figure 1). On the Colorado River
the reaches were from river mile 99 to 86 near the Dolores River