7167

• UCREFRP Catalog Number: 7167
• Author: Miller, W. H., R. A. Valdez and P. G. Mangan.
• Title: Fisheries Investigations of the Upper Colorado River, Rifle to Debeque, Colorado.
• USFW Year: 1981.
• USFW - Doc Type: Salt Lake City, Utah.
• Copyright Material: YES

INTRODUCTION
Personnel of the U.S. Fish and Wildlife Service's Colorado River
Fishery Project are conducting research on the distribution, movement,
habits, and spawning requirements of endangered fishes in the Colorado
River. This work is being conducted, in part, under a Memorandum of
Understanding with the Bureau of Land Management (BLM) in Colorado
(MOU No. CO-910-MU9-933). The following information report describes a
field investigation made July 14-16 between Rifle and DeBeque, Colorado,
and is intended to provide information to the Glenwood Springs Resource
Office of BLM.
STUDY AREA ' Y.
The study area for this report was the 31-mile section of the
Colorado River between Rifle and DeBeque, Colorado. This river section
is characterized by a low gradient, braided channel with cobble bottom.
The riparian zone has experienced some alterations from riprap, diversion
structures and a gravel removal operation.
SAMPLING METHODOLOGY
The sampling equipment used included two 16-foot ion boats equipped
for electrofishing, two 1-10 inch trammel nets, and two seines (1/2 inch
and 1/4 inch mesh).
Both shorelines and main channel were electrofished from 20-30
minutes every hour between 1000 and 1900 hours, as both boats motored
downstream from Rifle. Seines were hauled through backwaters between
electrofishing periods. Seining was restricted to backwaters due to the
difficulty and inefficiency of seining through the cobble bottom of the
main channel. An additional 30 minutes of electrofishing was done by
one boat at dawn. Trammel nets were set at 2000 hour and recovered the
next morning between 700 and 900 hours.
DATA COLLECTED
Fifteen species and four hybrids were collected between Rifle and
DeBeque (Table 1). Approximately 1,000 fish were recorded during the
survey. Flannelmouth suckers were the most abundant species captured
followed by roundtail chubs and bluehead suckers (Table 2). The composition
of the catch was consistent throughout the section though catch per unit
effort was lower below Battlement Creek. Flannelmouth and bluehead
suckers were caught in shallow (0.5-2.5 feet deep) riffles and runs over
cobble bottom. White suckers were caught in lower velocities than the
other suckers, frequenting pools, eddies, and the mouth of backwaters.
Roundtail chubs were found in deep (up to 24 feet deep) pools and eddies.