General Description

The humpback chub, Gila cypha,is a member of the minnow family which can grow quite large reaching lengths up to 480 mm, or (about 19 inches long) and is endemic to the Colorado River Basin.  The body is laterally compressed and tapering abruptly to a narrow caudal peduncle with a deeply forked tail fin and large fan-like falcate fins.  The head is narrow and flattened and may be dorsally concave, with small eyes and a protruding fleshy snout and inferior, subterminal mouth.  A fleshy dorsal hump develops behind the head as the fish matures.  Subadults have an olivaceous back and silvery sides fading to a creamy white belly; adults are light olivaceous and slate-gray dorsally and laterally, with a white belly tinged with light orange and yellow.

The humpback is a river obligate species spending most of its life in deep canyon bound sections of river, utilizing both the mainstem and tributaries.  Spawning congregations of adults are found in the spring near gravelly cobble deposits.  Following the spawn many individuals return to mainstem habitats.  Young of year humpback are initially found in shoreline eddy/backwater habitats and move towards deeper flowing water as they get older.

Legal Status

The humpback chub was listed as endangered species by the U.S. Fish and Wildlife Service on March 11, 1967.

Humpback chub were listed as endangered in Arizona in 1969.  Humpback chub is currently classified as a “wildlife species of concern” in Arizona.

Humpback chub does not does not currently carry a special state designation in California.

Humpback chub does not does not currently carry a special state designation in Nevada.

Diet

Humpback chub are typically omnivores with a diet consisting of insects, crustaceans, plants, seeds, and occasionally small fish and reptiles. They appear to be opportunistic feeders, capable of switching diet according to available food sources, and ingesting food items from the water’s surface, mid-water, and river bottom. Diets of humpback chub from the LCR and mainstem differ markedly, reflecting available food sources.

More Information

Technical Reports on this species are found here.

U.S. Fish and Wildlife Service. 2008. Humpback Chub (Gila cypha) Recovery Goals: amendment and supplement to the Humpback Chub Recovery Plan. U.S. Fish and Wildlife Service, Mountain-Prairie Region (6), Denver, Colorado, located at this link (PDF).

Updated October 16, 2012

Historic abundance of the humpback chub is unknown, and historic distribution is surmised from various reports and collections that indicate the species presently occupies about 68% of its historic habitat in about 756 km of river.

Earliest collections of humpback chub are anecdotal and relate to early explorations of the Colorado River Basin that pre-date the species description in 1946.  The most common occurrences were found in the vicinity of the Grand Canyon.  Humpback chub have consistently been reported in the LCR and Colorado River in the Grand Canyon since 1967.  Numerous observations and captures have been made in the Upper Colorado River Basin since 1940; particularly in the Green River, Yampa River, White River, possibly the Little Snake River, and Lake Powell following completion of Glen Canyon Dam.

Six humpback chub populations are currently identified: (1) Black Rocks, Colorado; (2) Westwater Canyon, Utah; (3) LCR and Colorado rivers in Grand Canyon, Arizona; (4) Yampa Canyon, Colorado; (5) Desolation/Gray Canyons, Utah; and (6) Cataract Canyon, Utah.  Each population consists of a discrete group of fish, geographically separated from the other populations, but with some exchange of individuals. River length occupied by each population varies from 3.7 km in Black Rocks to 73.6 km in Yampa Canyon.

Click on the map below to see the distribution of the Humpback Chub using the interactive GIS map.

The humpback chub evolved in seasonally warm and turbid water and is highly adapted to the unpredictable hydrologic conditions that occurred in the pristine Colorado River system. They live and complete their entire life cycle in canyon-bound reaches of the Colorado River and larger tributaries; these habitats are characterized by swift deep water with rocky substrates. Researchers have found that dominant substrates were silt and sand for Young-of-year, and boulders, sand, and bedrock for juveniles and adults.

The Habitat Conservation Plan provides conservation measures specific to each species. Listed below are the species specific conservation measures for the humpback chub. Click on the arrows to expand the table.

This gallery includes photos of this species. If you require larger photos, please contact our webmaster Michelle Reilly at mreilly@usbr.gov.