9425

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

INTRODUCTION
' in 1946, noted ichthyologist Robert Rush Miller recognized the need to establish baseline
information concerning the Colorado River Basin (CRB) fish fauna before further
' impacts from human development occurred (Miller 1946). By the tune public support
and sufficient knowledge were aligned to initiate conservation efforts, several endemic
fishes had experienced drastic declines in abundance (Table 1; Miller 1961, Hinckley
and Deacon 1968, Miller 1972, Hinckley 1991, Rinne and Hinckley 1991).
Among native CRB fishes, three of the least studied are the bluehead sucker Catostomus
discobolus Cope, flannelmouth sucker Catostomus latipinnis Baird and Girard, and
' roundtail chub Gila robusta Baird and Girard. Existing literature suggests that these
three fishes were historically (pre-1960s) common to abundant in all or parts of the CRB
' (Sigler and Miller 1963, Jordan and Evermann 1969, Hinckley 1973). Life- history
characteristics and patterns of distribution and abundance of roundtail chub and
' flannelmauth sucker are documented in a few reach-scale studies (e.g., Chart 1987,
Bestgen and Propst 1989, Douglas and Marsh 1998}, but information specific to bluehead
sucker is largely absent (McAda 1977, Holden and Hinckley 1980, McAda and Wydoski
1983). Range-wide distribution and status assessments have not occurred for any of the
' study species.
' The purpose of this report is to si~mmari~e taxonomy, physical characteristics, and life-
history of the three species, and to document their historic and recent patterns of
distribution and abundance. We also discuss population dynamics, and describe current
research and management efforts. Finally, we make recommendations for research and
' management that may increase knowledge of each species and enhance their protection
and conservation.

Final Report September 2002
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