The roundtail chub (''Gila robusta'') is a cyprinid fish in the genus '' Gila'', of southwestern

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. It is native to the Colorado River drainage basin, including the

Gila River The Gila River (; O'odham ima Keli Akimel or simply Akimel, Quechan: Haa Siʼil, Maricopa language: Xiil) is a tributary of the Colorado River flowing through New Mexico and Arizona in the United States. The river drains an arid watershed of n ...

and other tributaries, and in several other rivers. It is part of the “''robusta'' complex”, which includes the ''Gila robusta robusta'', ''G.r. grahami'', and ''G.r. seminuda.''

Description

The body of the roundtail chub is significantly larger forward of the dorsal fin, and posteriorly it is tapered towards the tail. The forehead area is concave. The mouth is largish, but does not reach as far as the pupil of the eye, and is overhung by the snout. The tail is deeply forked. Color is a grayish brown above, and a lighter shade below. Mature males sometimes acquire red-orange lower cheeks and paired fins during breeding season. Roundtail chub can reach almost , but usually only grow to about . Recently, it has been recorded at up to 43 cm in length.
Roundtail chub are also described to be “trout-like” because they possess a large mouth with the lower lip outlined in black. However, they lack the adipose fins found on trout species.

Range

Its range of is within the Colorado River drainage basin, found from the headwaters down to the mouth, in Utah, Colorado, Arizona, Nevada, and California, and northwest Mexico; as well as in other rivers of northwestern Mexico. This species is rather variable, and formerly accounted as several species, until intermediate forms were discovered. Recognized subspecies include: * ''Gila robusta grahami'' * ''Gila robusta jordani'' - small streams along the White River (Nevada) * ''Gila robusta robusta'' - small rivers * ''Gila robusta seminuda'' The roundtail chub has been extirpated from the Zuni and San Francisco Rivers of New Mexico. In Arizona, specifically in Gila, Mohave, and Yavapai Counties, the roundtail chub occupies several tributaries: Fossil Creek, Oak Creek, Burro Creek, Francis Creek, Big Sandy River, Santa Maria River, Boulder Creek, Trout Creek, Sycamore Creek, Beaverhead Springs, and throughout the Verde River. It is also found in the

and the

Rio Yaqui Rio or Río is the Portuguese, Spanish, Italian, and Maltese word for "river". When spoken on its own, the word often means Rio de Janeiro, a major city in Brazil. Rio or Río may also refer to: Geography Brazil * Rio de Janeiro * Rio do Sul, a ...

Biology

Roundtail chub is very prolific in nature.

Diet

Roundtail chub is a voracious predator, consuming large amounts of fish,

crayfish Crayfish are freshwater crustaceans belonging to the clade Astacidea, which also contains lobsters. In some locations, they are also known as crawfish, craydids, crawdaddies, crawdads, freshwater lobsters, mountain lobsters, rock lobsters, mu ...

, frogs, and insects. Roundtail chub adults primarily consume aquatic and terrestrial insects, other fishes, and sometimes algae. Roundtail chub juveniles eat smaller insects, crustaceans, and algae.

Conservation

The decreasing population of the roundtail chub is primarily the result of habitat loss as well as predation and competition by non-native fish. Although the populations in the Salt and Verde Rivers were stable ten years ago, they have been exponentially decreasing. Recent conservation efforts include more research to determine the mechanisms of their sudden disappearance, and population surveys conducted by the Arizona Game and Fish and US Forest Service (in progress). Arizona Game and Fish Department considers roundtail chub a sport fish. They put up a strong fight for anglers, and the meat is described as "firm, white and very mild tasting." Intermuscular bones or floating bones are present, which can be cut out prior to cooking. It is a candidate

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

of the United States Fish and Wildlife Service, under the

Endangered Species Act The Endangered Species Act of 1973 (ESA or "The Act"; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of ec ...

criteria.USFWS —Species Profile for Roundtail chub (Gila robusta)
. accessed 6.16.2013

References

Ira La Rivers Ira or IRA may refer to: *Ira (name), a Hebrew, Sanskrit, Russian or Finnish language personal name * Ira (surname), a rare Estonian and some other language family name *Iran, UNDP code IRA Law * Indian Reorganization Act of 1934, US, on status o ...

, ''Fishes and Fisheries of Nevada'' (University of Nevada Press, 1994), pp. 388–390 * {{Taxonbar, from=Q3764673 Chubs (fish) Gila (fish)

Chub Chub is a common fish name. It pertains to any one of a number of ray-finned fish in several families and genera. In the UK, the term ''chub'' usually refers to the species ''Squalius cephalus''. In addition, see sea chub. In family Cyprinidae ...

Fish described in 1853 Taxa named by Spencer Fullerton Baird Taxa named by Charles Frédéric Girard