9712

• UCREFRP Catalog Number: 9712
• Author: U.S. Fish and Wildlife Service.
• Title: Genetic characterization of Virgin River chub.
• USFW Year: 2008.
• USFW - Doc Type: Dexter National Fish Hatchery and Technology Center
• Copyright Material: NO

Genetic variation as measured by heterozygosity for all populations surveyed was
higher than the mean estimate for freshwater fish in general; and. mean allelic richness
over all loci for all chub populations fell within one standard deviation of the mean for
freshwater species. The Moapa River population had the lowest values of mean allelic
richness (A = 5.34), expected heterozygosity (HE = 0.56) and numbers of unique alleles.
The Dexter populations had similar levels of genetic variation (A ranged from 6.11 to
6.28; HE = 0.67) in comparison to the Virgin River populations (A ranged from 6.15 to
6.22; HE ranged from 0.67 to 0.68).
Introduction:
The Virgin River chub (Gila seminuda) is a member of the minnow family
(Cyprinidae) that averages 20 cm (8 inches) in total length (USFWS 1994).
Although originally treated as a subspecies of G. robusta, Virgin River chub was later
determined to be a full species of hybrid origin (DeMarais et al. 1992). Historically,
Virgin River chub was found in the Moapa River, NV, and in the mainstem Virgin River
from Pah Tempe Springs, Utah downstream to the confluence with the Colorado River in
Nevada (Cope and Yarrow 1875, Cross 1975, as cited by USFWS 1994). At
present, Virgin River chub still occur in these waters, however, the species distribution in
the Virgin River has diminished notably. Virgin River chub occurs only from Pah Tempe
Springs, Utah to the Mesquite Diversion near the border of Arizona and Nevada. The two
core areas thought to contain the largest existing populations include: the 7.5 mile reach
of the mainstem from the State Route 9 bridge near LaVerkin to just below Gould's
Wash in Utah, and the 5.5 mile reach from the lower mouth of the Virgin River Gorge to