9420

• UCREFRP Catalog Number: 9420
• Author: Maddux, H. R., J. A. Mizzi, S. J. Werdon and L. A. Fitzpatrick.
• Title: Overview of the Proposed Critical Habitat for the Endangered and Threatened fishes of the Virgin River Basin.
• USFW Year: 1995.
• USFW - Doc Type: Salt Lake City.
• Copyright Material: NO

PART III -BIOLOGICAL OVERVIEW
Background
These listed fishes are endemic to the Virgin River Basin. Historically, the Virgin River
flowed into the Colorado River in southeastern Nevada. Today, the Virgin River empties
into the Overton Arm of Lake Mead. The native f sh fauna of the Virgin River was
dominated by minnows (cyprinids) and suckers (catostomids). There are six fishes native to
the river: woundfin, Virgin River chub, Virgin spinedace, speckled dace (Rhinichthys
osculus), desert sucker (Catostomus clarlta~, and flannehnouth sucker (C. latipinnis). All of
the native fishes of the Virgin River are on the decline and most aze in danger of extinction
due to habitat loss, water diversions and dewatering, dam construction, nonnative species,
and to a lessor extent parasitism, and livestock and mining operations.
Habitats and Status of Listed Fishes
General--These listed fishes evolved in the Virgin River Basin and were adapted to the
natural environment that existed prior to the beginning of large-scale water development.
Thus, they were adapted to a system of fluctuating seasonal and annual flows influenced by
wet, average, and dry climatic periods. Recent population declines and extirpation of
endemic fish species within much of their former range have been associated with rather
rapid and widespread anthropogenic changes. These changes have altered physical and
biological chazacteristics within the Virgin River Basin and occurred so rapidly that the
native fishes have not had time to adapt to them.
Woundfin--The woundfm is considered to be the most highly specialized species in the
cyprinid tribe Plagopterini, subfamily Leuciscinae (Miller and Hubbs 1960). It is the sole
representative of the monotypic genus Plagopterus. The historical range of this species
included the mainstem Virgin River in Utah, Arizona, and Nevada; the Salt River, Arizona;
the Gila River, near Yuma, Arizona; the Colorado River neaz Yuma, Arizona; and the
Muddy River in Nevada. However, the current distribution of the species is now restricted
to the area between LaVerkin Springs on the mainstem of the Virgin River and the lower
portion of LaVerkin Creek in Utah, downstream to Lake Mead (Virgin River Fishes
Database).
The species has been transplanted by Arizona Game and Fish Department (AGFD) into four
localities in Arizona., the Hassayampa River, Salt River, Sycamore Creek, and Paria River
(AGFD, unpub. data). In the Hassayampa River, 500 fish were stocked in February of
1972. Reproduction occurred in the summer of 1972, but a flood in September 1972
destroyed the entire population (Hinckley, Arizona State University, pers. comm. 1977). In
March 1972, 350 woundfm were also stocked in the Salt River, Arizona, but none have been
taken there since. In Sycamore Creek (Agua Fria drainage) a few specimens stocked in
spring 1972 (AGFD, unpub. data) survived severe flooding in 1972-1973, and two
individuals collected in late August 1973 were gravid. However, none have been collected in
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