7153

• UCREFRP Catalog Number: 7153
• Author: Holden, P. B.
• Title: Study of the Habitat Use and Movement of the Rare Fishes in the Green River, Utah.
• USFW Year: 1978.
• USFW - Doc Type: Logan, Utah.
• Copyright Material: NO

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Perhaps the most noteworthy specimens found during the present
study were the young-of-the-year razorback suckers. These repre-

sent, to our knowledge, the first young razorbacks reported from
the upper Colorado Basin. A more detailed taxonomic analysis of

these specimens, including comparison with known razorbacks frr-m

Willow Beach National Fish Hatchery, will be carried out in le

near future to verify the preliminary identification.

Preferred Habitat of Rare Fishes

The data from this study show that young-of-the-yea?' and

juvenile squawfish prefer backwaters where there is little or no

current and a silt bottom. Juveniles prefer deeper areas than
young-of-the-year. Vanicek (1967) indicated that YO'Jng squawfish
(age groups O-II) were found in areas where IIcurrer,t was slight
or lacking." Holden and Stalnaker (1975) found yaung-of-the-year
in shallow backwaters and juveniles in backwater~ and eddies 2 to

3 feet in depth.
The data indicate that subadult squawfish prefer runs and
eddies as opposed to backwaters. Vanicek (1967) found a similar
pattern. Holden and Stalnaker (1975) indicated that slow water

was preferred to runs and fast eddies, and b.;ckwaters were used

.during high water. A collecting trip in May of 1976, conducted
by the Colorado River Fishes Recovery Team from Jensen to Ouray,
produced approximately 30 subadult and adult squawfish. All of
these fish were taken in backwaters. These data suggest that

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