Gila Chub
Encyclopedia
The Gila chub is a species of ray-finned fish in the Cyprinidae family.
It is found in Mexico
and the United States
. The Gila Chub is closely related to Gila robusta robusta and Gila robusta grahami (Roundtail Chub
species). This species is commonly found in association with the Gila Topminnow, the Desert and Sonora Sucker, and the Longfin and Speckled Dace.
The Gila Chub has a large, chunky body, with large, thick scales. The body is dark overall, and sometimes is lighter on the belly. In larger females, a soft, fat, and broad hump sometimes develops on the nape of the neck. Mature, breeding males have a red or orange color on the lower cheek, back parts of the lips, and on parts of the fin. This coloration can also be found on the male’s caudal peduncle (tail side). Males usually grow to be only about 15 cm (5.9 in), while females can reach to 25 cm (9.8 in)—a significant difference.
The Gila Chub has been found in streams of the Gila River
drainage in Arizona
, and in the Santa Cruz River system in Sonora, Mexico; however, recently, the Gila Chub species has not been documented in the San Pedro drainage in Sonora, Mexico.
The Gila Chub has also been recently discovered in these specific drainages in Arizona: Santa Cruz River, Middle Gila River, San Pedro River
, Agua Fria River, and the Verde River
. These fish have also been extirpated from the Monkey Spring of the Santa Cruz River, and Fish and Cave Creeks of the Salt River
.
Gila Chub of the Gila River Basin usually occupies the smaller headwater streams, springs or marshes. Their choice of diverse habitats varies, depending on the season or age of the fish. Juveniles are found in riffles (a patch of waves), pools, and banks. However, in larger streams, these fish are found in parts of heavy vegetation, for cover and foraging. Gila Chubs are also considered to be highly “secretive” when it comes to habitats; since fish of this species are constantly looking for deeper waters near cover and shade.
Gila Chubs are omnivores, and their diet mainly includes aquatic (and terrestrial) insects. These fish are also known to consume other fish at large sizes, which include eating Speckled Dace
(Rhinichthys osculus) and other small cyprinid fish. Juveniles feed throughout the day while the adults are out during the early morning and late night; juveniles usually consume insects and algae.
Gila Chubs have a unique breeding season, which occurs from late spring to summer (some populations can go as far as late winter if the water temperature stays constant). The breeding period is long because Gila Chub mature in their second or third year, and are more active at this age. Reproduction occurs in heavily vegetated areas. Actively breeding fish have distinct intense coloration—parts of the body become fire-red (ventro-lateral surfaces) and the eyes transform to a yellow-orange.
Little is known about the population of Gila Chub in Mexico, but the populations that reside in Arizona are expected to decrease because of these ongoing threats: aquifer pumping, stream diversion, habitat alterations by non-native crayfishes, and mainly, predation/competition with nonnative fishes. Currently, the Gila Chub are sharing the waters with green sunfish
(Lepomis cyanellus) in many areas; however, introducing any other kind of exotic fish to the Gila Chub must be managed and observed (it is crucial to their survival). In fact, the Gila Chub has been extirpated on many occasions because of exotic fish such as the largemouth bass
(Micropterus salmoides).
According to the Arizona Fish and Game Department, the Bureau of Land Management Phoenix District is proposing translocations of the Gila Chub from Silver Creek to an adjacent stream in the Agua Fria headwaters. Here, the Arizona Game and Fish Department can complete their status review of warranting the Gila Chub under the Endangered Species Act.
It is found in Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
and the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. The Gila Chub is closely related to Gila robusta robusta and Gila robusta grahami (Roundtail Chub
Roundtail chub
The roundtail chub is a cyprinid fish of the Colorado River drainage, including the Gila River and the Rio Yaqui in western North America, part of the “robusta complex”, which includes the Gila robusta robusta, G.r. grahami, and G.r...
species). This species is commonly found in association with the Gila Topminnow, the Desert and Sonora Sucker, and the Longfin and Speckled Dace.
Description
The Gila Chub has a large, chunky body, with large, thick scales. The body is dark overall, and sometimes is lighter on the belly. In larger females, a soft, fat, and broad hump sometimes develops on the nape of the neck. Mature, breeding males have a red or orange color on the lower cheek, back parts of the lips, and on parts of the fin. This coloration can also be found on the male’s caudal peduncle (tail side). Males usually grow to be only about 15 cm (5.9 in), while females can reach to 25 cm (9.8 in)—a significant difference.
Range
The Gila Chub has been found in streams of the Gila River
Gila River
The Gila River is a tributary of the Colorado River, 650 miles long, in the southwestern states of New Mexico and Arizona.-Description:...
drainage in Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
, and in the Santa Cruz River system in Sonora, Mexico; however, recently, the Gila Chub species has not been documented in the San Pedro drainage in Sonora, Mexico.
The Gila Chub has also been recently discovered in these specific drainages in Arizona: Santa Cruz River, Middle Gila River, San Pedro River
San Pedro River (Arizona)
San Pedro River is a northward-flowing stream originating about ten miles south of Sierra Vista, Arizona near Cananea, Sonora, Mexico. It is one of only two rivers which flow north from Mexico into the United States. The river flows north through Cochise County, Pima County, Graham County, and...
, Agua Fria River, and the Verde River
Verde River
The Verde River is the north and northwestern watershed of the Salt River–Verde River Watershed that co-join and enter the Gila River at Phoenix, Arizona, located in the U.S. state of Arizona...
. These fish have also been extirpated from the Monkey Spring of the Santa Cruz River, and Fish and Cave Creeks of the Salt River
Salt River (Arizona)
The Salt River is a stream in the U.S. state of Arizona. It is the largest tributary of the Gila River. The river is about long. Its drainage basin is about large. The longest of the Salt River's many tributaries is the Verde River...
.
Habitat
Gila Chub of the Gila River Basin usually occupies the smaller headwater streams, springs or marshes. Their choice of diverse habitats varies, depending on the season or age of the fish. Juveniles are found in riffles (a patch of waves), pools, and banks. However, in larger streams, these fish are found in parts of heavy vegetation, for cover and foraging. Gila Chubs are also considered to be highly “secretive” when it comes to habitats; since fish of this species are constantly looking for deeper waters near cover and shade.
Diet
Gila Chubs are omnivores, and their diet mainly includes aquatic (and terrestrial) insects. These fish are also known to consume other fish at large sizes, which include eating Speckled Dace
Speckled dace
The speckled dace , also known as the spotted dace and the carpita pinta, is a member of the carp family. It is found in temperate freshwater in North America, from Sonora to British Columbia....
(Rhinichthys osculus) and other small cyprinid fish. Juveniles feed throughout the day while the adults are out during the early morning and late night; juveniles usually consume insects and algae.
Reproduction
Gila Chubs have a unique breeding season, which occurs from late spring to summer (some populations can go as far as late winter if the water temperature stays constant). The breeding period is long because Gila Chub mature in their second or third year, and are more active at this age. Reproduction occurs in heavily vegetated areas. Actively breeding fish have distinct intense coloration—parts of the body become fire-red (ventro-lateral surfaces) and the eyes transform to a yellow-orange.
Conservation
Little is known about the population of Gila Chub in Mexico, but the populations that reside in Arizona are expected to decrease because of these ongoing threats: aquifer pumping, stream diversion, habitat alterations by non-native crayfishes, and mainly, predation/competition with nonnative fishes. Currently, the Gila Chub are sharing the waters with green sunfish
Green sunfish
The green sunfish is a species of freshwater fish in the sunfish family of order Perciformes. A panfish popular with anglers, the green sunfish is also kept as an aquarium fish by hobbyists. They are usually caught by accident, while fishing for other game fish...
(Lepomis cyanellus) in many areas; however, introducing any other kind of exotic fish to the Gila Chub must be managed and observed (it is crucial to their survival). In fact, the Gila Chub has been extirpated on many occasions because of exotic fish such as the largemouth bass
Largemouth bass
The largemouth bass is a species of black bass in the sunfish family native to North America . It is also known as widemouth bass, bigmouth, black bass, bucketmouth, Potter's fish, Florida bass, Florida largemouth, green bass, green trout, linesides, Oswego bass, southern largemouth...
(Micropterus salmoides).
According to the Arizona Fish and Game Department, the Bureau of Land Management Phoenix District is proposing translocations of the Gila Chub from Silver Creek to an adjacent stream in the Agua Fria headwaters. Here, the Arizona Game and Fish Department can complete their status review of warranting the Gila Chub under the Endangered Species Act.
Source
- Gimenez Dixon, M. 1996. Gila intermedia. 2006 IUCN Red List of Threatened Species. Downloaded on 19 July 2007.