The Virgin chub or the Virgin River chub (''Gila seminuda'') is a medium-sized, silvery minnow, generally less than 15 cm long and reaching lengths of 25 cm. The back, breast, and part of the belly are embedded with small scales, naked in some individuals. The length of the head divided by the depth of the caudal peduncle typically results in a ratio of 4.0 to 5.0 (rarely exceeding 5.0, which approximates ''G. elegans''). The scales are typically lacking basal radii or are with extremely faint lines.

Range

It is restricted to the

Virgin River The Virgin River is a tributary of the Colorado River in the U.S. states of Utah, Nevada, and Arizona. The river is about long.Calculated with Google Maps and Google Earth It was designated Utah's first wild and scenic river in 2009, during the ...

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

Nevada Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...

, and

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...

. Another sizable population is found in the upper and middle reaches of the Muddy River in Nevada. The Arizona range of the Virgin chub is restricted to the Virgin River within Mohave County.

Habitat

In its native habitat, it occurs only in the mainstream of the Virgin and Muddy Rivers (Water within these rivers are generally somewhat warm, turbid, and saline), and very rarely in the immediate mouths of its major tributaries. The Virgin chub is most common in deeper areas where waters are swift, but not turbulent, and most often is associated with boulders or other types of cover.

Population trends

The Virgin chub is continuing to decline. In 1988 an attempt to remove red shiners (which are a common competitor with the Virgin chub) from 35 km of habitat on the Virgin River, ended in failure as populations of Virgin chub continued to be decimated by other factors including habitat modifications.

Management factors

Activities that are known to be detrimental to Virgin chub populations are the de-watering of habitats through the re-routing of stream water, stream impoundment, channelization, domestic livestock grazing, timber harvesting, mining, road construction, polluting, and stocking non-natives. Threats: widespread modification and reduction of habitat; dewatering by agricultural diversion; increased temperature, salinity, and turbidity of the Virgin River; introduction of non-native fish and parasite species. Management needs: protect and enhance habitat, including water quantity and quality; ameliorate effects of nonnative fish species in chub waters; re-establish additional populations.

Hybrid origin

The Virgin chub likely evolved via introgressive hybridization between the

roundtail chub The roundtail chub (''Gila robusta'') is a cyprinid fish in the genus '' Gila'', of southwestern North America. It is native to the Colorado River drainage basin, including the Gila River and other tributaries, and in several other rivers. It i ...

, ''G. robusta'', and the

bonytail chub The bonytail chub or bonytail (''Gila elegans'') is a cyprinid freshwater fish native to the Colorado River basin of Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming in the southwestern United States; it has been extirpated fro ...

, ''G. elegans''. Evidence for a hybrid origin of the Virgin chub is based on

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

and

allozymes Alloenzymes (or also called allozymes) are variant forms of an enzyme which differ structurally but not functionally from other allozymes coded for by different alleles at the same locus. These are opposed to isozymes, which are enzymes that perfo ...

. The

mitochondrial DNA Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial D ...

of the Virgin chub is nearly identical to that of ''G. elegans''.DeMarais, B.D., T.E. Dowling, M.E. Douglas, W.L. Minckley, and P.C. Marsh. 1992. Origin of ''Gila seminuda'' (Teleosti: Cyprinidae) through introgressive hybridization: implications for evolution and conservation. Proc. Natl. Acad. Sci. 89:2747-2751.

References

External links

List of Arizona Native Fishes

Arizona Desert Museum {{Taxonbar, from=Q3764748 Endangered fauna of the United States Fish of the Western United States Chubs (fish) Gila (fish) Fish described in 1875 Taxa named by Edward Drinker Cope Taxa named by Henry Crécy Yarrow Species endangered by habitat loss