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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Habitat alteration may also promote hybridization with other species (Valdez
and Clemmer 1982).
Competition between humpback chub and channel catfish was indicated by
capture of both species with baits in eddy habitats in Yampa River (Tyus and
Minckley 1988). Channel catfish comprised about 10% of the catch in the
previous study when temperatures were below 20C, but almost 50% when
temperatures exceeded 20C, in habitats from which humpback chub were
collected (1987). This dramatic increase in numbers of channel catfish at a
time of year when river level is dropping, eddy habitat availability is
declining, and water temperature is increasing, suggests that this species may
have some competitive advantage when resources become limiting. Channel
catfish may also prey directly on humpback chub, as speculated by Kaedi.ng and
Zimmerman (1983), who attributed bite marks on the latter to channel catfish.
Bonytail chub
The drastic decline of this species in Echo Park (D~i) may be a response
to flow and temperature changes resulting from closure of Flaming Gorge Dam.
Ongoing negotiations between FWS and BR regarding management of Flaming Gorge
for the indigenous rare and endangered fishes may improve the future of
bonytail chub in the Green River system.
Razorback sucker
Loss of spring peak flows is an important consideration because spawning
occurs on the ascending limb of the runoff period. The absence of young fish
throughout the Colorado River basin has been attributed to habitat alteration
(e. g., lower water temperatures (Marsh 1985)) and predation by non-native
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