Endangered
Humpback chub
Gila cypha
The humpback chub is a federally protected fish that lived originally in fast waters of the Colorado River system in the United States.
Appearance
The scales are embedded deeply across the surface of the fish, especially on hump. The fins are large and curved, and the origin of the dorsal are about equidistant between the snout and caudal fin base. The mouth is inferior, and overhung by the snout.
The caudal peduncle is thin and somewhat pencil-like but not greatly elongated, where the length of the caudle peduncle divided by length of head is less than 1.0.
Range and habitat
The humpback chub historically ranged from below present-day Hoover Dam in the Colorado River upstream into Colorado, and in the larger portions of Colorado River tributaries in Arizona, Utah, Colorado, and Wyoming. Presently, the species is restricted to six population centers in the Colorado and Little Colorado Rivers in Grand Canyon, Arizona, the Colorado River in Cataract Canyon, Utah, the Colorado River in Black Rocks, Colorado, and Westwater Canyon, Utah, the Green River in Desolation and Gray Canyons, Utah, the Green River in Dinosaur National Monument, Colorado and Utah, and the Yampa River in Dinosaur National Monument, Colorado. The humpback chub is found in Arizona at and around Coconino County, Colorado, and Little Colorado River in the Grand Canyon.
Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.
Breeding
The species spawns from April through June, at water temperatures of 19–21 °C (66–70 °F). The fish spawn in slower-moving backwaters, typically over a substrate of cobbles or boulders.
In crisis
The humpback chub's population in the Colorado River has been reduced dramatically, primarily due to habitat loss, such as the construction of Glen Canyon Dam. The fish's status as an endangered species has inspired a number of management measures, such as altering the operation of Glen Canyon Dam and removal of non-native predators. Populations were possible in and below the Flaming Gorge that were likely destroyed by the poisoning of the Green River associated with the construction of the Flaming Gorge Reservoir.
For 2008, the total population of the humpback chub in the Grand Canyon was estimated at 6,000 to 10,000. A combination of human causes and natural events seemingly has stabilized the population, particularly the experimental flooding of the canyon and the increase in water temperatures due to drought conditions over the 2000s decade.
Humpback chub is Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.
Sources
Written for this catalog from the English Wikipedia article on Humpback chub, Wikidata item Q139333. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.
