7418

• UCREFRP Catalog Number: 7418
• Author: Tyus, H. M. and C. A. Karp.
• Title: Stream Flow Needs of Rare and Endangered Fishes, Yampa River, Colorado.
• USFW Year: 1988.
• USFW - Doc Type: Vernal, Utah.
• Copyright Material: NO

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sized non-native fishes in nursery habitats, particularly when increases or
decreases in river level reduces backwater availability.
Juveniles: Factors limiting distribution and abundance of juvenile Colorado
squawfish are difficult to assess because there is little available
information regarding their habitat requirements. Upstream movement of
juveniles is necessary to sustain viable populations, and thus, stream
blockage is viewed as a limiting factor.
Evidence of predation by non-native fishes in both artificial and.

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natural environments suggests that this factor limits growth and survival of
juvenile Colocado squawfish. Hendrickson and Brooks (1987) noted predation by
yellow bullhead anti largemouth bass on young Colorado squawfish stocked into
the Verde River, Arizona. Osmundson (1987) noted predation by largemouth
bass, green sunfish, black crappie, and black bullhead on young Colorado
squawfish in gravel pits near the Colorado River, Colorado, and indicated
predation by channel catfish may have occurred. In addition, Coon (1955)
reported channel catfish predation on Colocado squawfish in the Dolores River.
Flows aiding proliferation of these nun-native predators must be determined
and avoided, if possible.
Humpback chub
Distribution, abundance, and habitat requirements of humpback chub in the
Yampa River are not well known. Spring peak flows are critical because
spawning occurs during this period. rr^low reductions and decreased
temperatures have been implicated as factors curtailing spawning, and
increasing competition in the Colorado River (Kaeding and Zimmerman 1983).
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