PROTECTION STATUS: Not listed; candidate species (headwater chub only)
YEAR PLACED ON LIST: Candidate 2006
RANGE: Restricted to the Colorado River basin and possibly parts of northwestern Mexico
THREATS: Competition from nonnative species and habitat loss and degradation due to livestock grazing, water withdrawal, dams, roads, and urban and agricultural development
POPULATION TREND: The fish have been extirpated across much of their range, and many remaining populations are severely threatened and likely declining.