9425

• UCREFRP Catalog Number: 9425
• Author: Bezzerides, N. and K. Bestgen.
• Title: Status Review of Roundtail Chub
• USFW Year: 2002.
• Copyright Material: NO

1

0
1

t
~~

ii

SPECIES DESCRIPTIONS
In this section taxonomy, physical descriptions, life-history characteristics, distribution
patterns, and population trends and status considerations are presented for roundtail chub,
flannelmouth sucker, and bluehead sucker. Appendix C lists streams of historical and
recent species occurrence, summarized by state.
Roundtail Chub
Gila robusta belongs to a complex of medium-sized chubs inhabiting lazge rivers and
streams in the CRB (Holden and Stalnaker 1970, Rinse 1976). Common names
including squawfish (Simon 1935), bonytail (Ellis 1914, Koster 1957, Banks 1964), Gila
trout (Ellis 1914), Verde trout (Miller and Lowe 1964), and Colorado chub (Vanicek and
Kramer 1969) have been used to describe roundtail chubs (Robins et al. 1991).
Roundtail chubs
are
morphologically
non-descript
when compared
to other members
of the Gila
complex (Figure
3). However,
-

. _ - ---
~.~~.
~ ~ ~'" ! ~~,wrii

_ ~
W~~~~
~~ 4. k111
-
. J ° .
~. f
~~ r~
~~~ ~ ~~ i+

Figure 3. Roundtail chub Gila robusta.
because differentiation from other sympatric Gila species can be difficult due to
morphologic intergradation between species, roundtail chubs have garnered significant
attention from scientists working to understand and preserve this group of cyprinid fishes
(e.g., Holden and Stahiaker 1970, Rinse 1976, Kaeding et al. 1990, Dowling and
DeMazais 1993, McEkoy and Douglas 1995, Douglas et al. 1998). For simplicity's sake,
only the large-river form that was historically referred to as G. robusta robusta will be
emphasized in this report. However, life-history information from studies in the upper
Gila River Basin (lazgely involving very similar G. nigra and/or G. intermedia) is
Final. Report September 2002
is
1