7012

• UCREFRP Catalog Number: 7012
• Author: Cross, J. N.
• Title: Ecological Distribution of the Fishes of the Virgin River ‎(Utah, Arizona, Nevada)‎.
• USFW Year: 1975.
• USFW - Doc Type: University of Nevada,
• Copyright Material: NO

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The disruption of the Colorado River system with the advent of
man has spelled disaster to many of the native fishes in the basin.
Dams have transformed the Colorado into a series of lakes containing
exotic species of game fish; water is diverted for agriculture (dry
farming is unusual in the basin) and urban utilization (often in
extrabasin areas); ranching and arroyo cutting have altered the
appearance of the desert.
The Virgin River is one of the few unrestricted streams remaining
in the arid 4lest. Its native ichthyofauna, outnumbered more than
two to one by exotic species, persists, though at least one species is
facing extinction.
The small amount of literature pertaining to the fish fauna of the
Virgin River deals mainly with taxonomy and records of occurence although
a few eco]ogic studies have been completed. Deacon and Bradley (ms)
collected rather extensively during the 1960's, but no comprehensive
survey. has been attempted.
The purpose of this study is threefold: (1) to determine the
distribution of the fishes, (2) to ascertain the status of the native
fish populations, and (3) to provide a basis of information to predict
the impact on the native species of proposed physical alterations to the
river system.