7362

• UCREFRP Catalog Number: 7362
• Author: Karp, C. A. and H. M. Tyus.
• Title: Habitat Use, Spawning, and Species Associations of Humpback Chub,
• USFW Year: 1989.
• Copyright Material: NO

The humpback chub persists in isolated locations, with largest
numbers reported from the lower 13 km of the Little Colorado River and
nearby mainstream Colorado River (Kaeding and Zimmerman 1983; C.O.
Minckley, in press), and in Black Rocks area of Ruby Canyon and Westwater
Canyon of the upper Colorado River (Valdez and Clemmer 1982; Kaeding et
al., in press). Smaller numbers are known to occur in the Green and Yampa
rivers (Holden and Stalnaker 1975a, 1975b; Valdez and Clemmer 1982; Tyus
et al. 1982). Cataract Canyon of the Colorado River may also support
humpback chub (Valdez and Williams, in press), but the genetic purity of
that population is uncertain because about 7,300 juvenile hatchery-
reared humpback chubs (derived from upper Colorado River Black Rocks
adults) were introduced there in 1981 (J. Valentine, Utah Division of
Wildlife Resources, written communication).
The distribution and status of humpback chub in the upper Green and
lower Yampa rivers (i.e., Dinosaur National Monument, DNM) are not well
documented, partly because some early workers collectively referred to
Colorado River chubs as "bonytails" or Gila species (e.g., Bosley 1960),
and some reported the presence of morphologically intermediate forms
(e.g., Holden and Stalnaker 1970). Chub remains in Indian sites dating
more than 1000 years old (Leach 1970) indicate that these fish were
present at that time, and may have been eaten by native Americans.
Earliest documentation of suspected humpback chubs in DNM may be
traced to isolated captures in survey studies associated with closure of
Flaming Gorge Dam in 1963 (Bosley 1960; see Vanicek et al. 1970 for review
of unpublished data). More recent studies also noted the rare presence of
the species in DNM, most captures occurring in the confluence area of the
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