7086

• UCREFRP Catalog Number: 7086
• Author: U.S. Fish and Wildlife Service.
• Title: Indexed, Annotated Bibliography of the Endangered and Threatened Fishes of the Upper Colorado River System.
• USFW Year: 1977.
• USFW - Doc Type: Denver, Co.
• Copyright Material: YES

171. Holden, P. B. In Press. Distribution and
abundance of the fishes of the Lower
Escalante River, Utah. Southwestern
Naturalist 10 pp. (Abstr.)
Fish sampling with seines in the lower 80 km of
the Escalante River, Utah, yielded four native
and six introduced species. Native species
dominated the upper portion of the study area,
and the introduced red shiner, Notropis lutrensis,
dominated the lower portion. The competitive
advantages between native species and the red
shiner appeared dependent on habitat diversity
with native species dominating in diverse
habitat.
172. Holden, P. B. 1968. Systematic studies of the
genus Gila (Cyprinidae) of the Colorado
River basin. M.S. thesis, Utah State
University, Logan. 74 pp. (Abstr.)
Three hundred and nine specimens of Gila from
the Colorado River basin were studied. A form
of numerical taxonomy, taximetrics, was used to
help classify the specimens. The data from
these fish indicate that many of the present
hypotheses concerning their taxonomy are not
valid. The concept of ecosubspecies or ecologi-
cal subspecies does not fit the Colorado basin
Gila. The roundtail and bonytail chubs, G.
robusta Baird and Girard and G. elegans Baird
and Girard, respectively, currently treated as
subspecies, are well separated morphologically
and therefore are better considered two valid
species. The relationship between G. cypha
Miller and G. elegans is clouded by the presence
of what appear to be integrade forms. Future
investigations are needed to piece together the
puzzle surrounding these two fish. The subspecies
name seminuda (Cope and Yarrow), presently
attributed to fish from throughout the Colorado
basin, more correctly is allied to the robusta.
of the Virgin River. Preliminary study indicated
this population may be sufficiently different
to warrant subspecies recognition. No specimens.
of G, robusta intermedia (Girard) were examined
but the literature suggests this form may also
be a valid species.
FISH
SURVEY
HABITAT
COMPETITION
ESCALANTE R.
39
ENDANG. FISH
TAXONOMY
DISTRIBUTION
DESCRIPTION
AGE AND GROWTH
SPAWNING
LIFE HISTORY
COLORADO R.
1, 2 , 22
73