Humpback chub

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Humpback chub
Humpback chub - upper Colorado River cropped.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Cypriniformes
Family: Cyprinidae
Genus: Gila
Species:
G. cypha
Binomial name
Gila cypha

The humpback chub (Gila cypha) is a federally protected fish that lived originally in fast waters of the Colorado River system in the United States. This species takes its name from the prominent hump between the head and dorsal fin, which is thought to direct the flow of water over the body and help maintain body position in the swift currents of the Colorado river. The body is almost entirely scaleless, retaining only about 80 mid-lateral scales along the lateral line. The fish is very streamlined, with a thin caudal peduncle and a deeply forked tail. The back is a light olive gray, the sides silver, and the belly white. The dorsal fin usually has nine rays, and the anal fin 10 or more. Maximum recorded length is 38 cm. [2]

Contents

The humpback chub mostly consumes invertebrates and, to a lesser extent, other fish. They feed at all levels from the bottom to the surface. The species spawns from April through June, at water temperatures of 19–21 °C (66–70 °F). The males develop nuptial tubercles on the head and paired fins. The fish spawn in slower-moving backwaters, typically over a substrate of cobbles or boulders. Young fish stay near shore and in quiet areas, preferring slightly more turbid water. [3]

The humpback chub's population in the Colorado 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 costly and controversial management measures, such as altering the operation of Glen Canyon Dam and removal of non-native predators. [4]

Description

The humpback chub has a streamlined body, with a concave skull on its dorsum. 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. The head length divided by the caudal peduncle is less than 5.0. 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 pharyngeal arch is small, with a short lower ramus. [3]

Range

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 [when? as of 2023?] the species is restricted to six population centers in: 1) the Colorado and Little Colorado rivers in Grand Canyon, Arizona; 2) the Colorado River in Cataract Canyon, Utah; 3) the Colorado River in Black Rocks, Colorado, and Westwater Canyon, Utah; 4) the Green River in Desolation and Gray canyons, Utah; 5) the Green River in Dinosaur National Monument, Colorado and Utah; 6) and the Yampa River in Dinosaur National Monument, Colorado. [5] The Humpback Chub is found in Arizona at and around Coconino County, Colorado and Little Colorado rivers in the Grand Canyon. [6]

Habitat

In general, species persists only in turbulent, high gradient, canyon-bound reaches of large rivers in the Colorado River Basin. The young prefer shallow, low-velocity nearshore pools in the Little Colorado River, and progressively move to deeper, faster areas with increasing size and age. [7] In the Colorado River in Grand Canyon, young-of-year are found in backwater and other near-shore, slow-velocity sites, [8] with similar ontogenetic tendencies. Adults in the Colorado River in Grand Canyon and in the Upper Basin are associated with large eddy complexes. [9] Humpback chub appear to be more active at night. [10]

Parasites and diseases

The population in the Grand Canyon has been previously infested with the parasitic copepod Lernaea cyprinacea, [11] and Asian tapeworm, Bothriocephalus acheilognathi . [12] Kaeding and Zimmermann also reported 13 species of bacteria, six protozoans, and the fungus Saprolegnia to infect humpback chub. [10]

The historic range of the humpback chub is uncertain, but the distribution was presumably more contiguous than in the present. There were possible populations 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. [13] The fish's distribution within the Grand Canyon has contracted since the construction of Glen Canyon Dam. [12]

For 2008, the total population of the humpback chub in the Grand Canyon was estimated at 6,000 to 10,000. [14] This is a 50-percent increase over the estimation of 2001 and a reversal of the declining trend between 1989 and 2001. It seems that a combination of human causes and natural events stabilized the population, particularly the experimental flooding of the canyon and the increase in water temperatures due to drought conditions over the last decade [which decade?]. [14]

Management and conservation

Threats: altered hydrology and cold tailwater releases from reservoirs; Predation by and competition with nonnative fishes; and, parasitism.

Management needs: ameliorate effects of reservoirs; ameliorate effects of nonnative fish and parasite sources in chub waters; monitor status of all populations. Also need to be concerned about genetic isolation of populations by dams.

The humpback chub's status as an endangered species has prompted elaborate and expensive programs to restore its numbers, largely by modifying the releases from Glen Canyon Dam, creating artificial floods to replicate historic conditions in the Colorado, and removal of non-native predators, such as rainbow trout. [4]

Effective April 20, 1994, seven reaches of the Colorado River System (totaling 379 miles) were designated as Critical Habitat for Gila cypha. The Grand Canyon Protection Act of 1992 reduced stage fluctuation of water releases from Glen Canyon Dam. Glen Canyon Environmental Studies Phase I (1984–1987) and Phase II (1990–1995) research data used in development of Glen Canyon Dam Environmental Impact Statement and Biological Opinion. Upper Colorado River Basin Recovery and Implementation Plan guides recovery efforts for the species in the Upper Basin. [5]

Young Humpback chubs after release in Shinumo Creek Gila cypha IMGP1312.jpg
Young Humpback chubs after release in Shinumo Creek

After the Colorado had been extensively modified by dams, the Little Colorado River became the fish's stronghold in the Grand Canyon region. A second population is currently [when?] established in Shinumo Creek, another tributary to the Colorado River inside Grand Canyon National Park. The first 300 fish were released in Shinumo Creek in June 2009. Over the following two years additional young chubs were expected to be released there.

Federal officials have tried a number of experimental releases from Glen Canyon Dam in an attempt to replicate historic conditions and restore sandbars, beaches, and backwaters downstream. The first flood began on March 26, 1996, when Interior Secretary Bruce Babbitt stood before a large gathering of media and opened the first of four outlet tubes to begin the imitation inundation. The 1996 flood released nearly 337,000 US gallons (1,280,000 L) per second, enough to fill the Empire State Building or Sears Tower in 20 minutes, drained 117 billion US gallons (440,000,000 m3) from Lake Powell, and dropped the reservoir level by more than three feet. Initially, it appeared that the flood was a success, with sandbars and backwaters created downstream, but as the dam's operations returned to normal, the Colorado ate away at the new habitat and reversed the gains. Several other fake floods have been tried since 1996, with the releases now timed to coincide with an input of sediment from tributaries, but the results have been disappointing.

In recent years [when?], the number of humpback chub in the Grand Canyon region has increased significantly, but the reasons are unclear. Removal of non-native fish near the confluence of the Little Colorado River and Colorado River may have helped the species, but at the same time, drought was lowering the level of Lake Powell and causing water released from Glen Canyon Dam to be much warmer than normal. Typically, water released from the dam is too cold for chub to reproduce. [4]

Introduced smallmouth bass have been a predatory threat to humpback chub above the Glen Canyon Dam, but had not been able to get beyond Lake Powell. But as of 2022, smallmouth bass have been found below Glen Canyon Dam, possibly as a result of the low water level at Colorado River and Lake Powell. [15]

Related Research Articles

<span class="mw-page-title-main">Colorado River</span> Major river in the western United States and Mexico

The Colorado River is one of the principal rivers in the Southwestern United States and in northern Mexico. The 1,450-mile-long (2,330 km) river, the 5th longest in the United States, drains an expansive, arid watershed that encompasses parts of seven U.S. states and two Mexican states. The name Colorado derives from the Spanish language for "colored reddish" due to its heavy silt load. Starting in the central Rocky Mountains of Colorado, it flows generally southwest across the Colorado Plateau and through the Grand Canyon before reaching Lake Mead on the Arizona–Nevada border, where it turns south toward the international border. After entering Mexico, the Colorado approaches the mostly dry Colorado River Delta at the tip of the Gulf of California between Baja California and Sonora.

<span class="mw-page-title-main">Glen Canyon Dam</span> Dam in Arizona, USA

Glen Canyon Dam is a concrete arch-gravity dam in the southwestern United States, located on the Colorado River in northern Arizona, near the city of Page. The 710-foot-high (220 m) dam was built by the Bureau of Reclamation (USBR) from 1956 to 1966 and forms Lake Powell, one of the largest man-made reservoirs in the U.S. with a capacity of more than 25 million acre-feet (31 km3). The dam is named for Glen Canyon, a series of deep sandstone gorges now flooded by the reservoir; Lake Powell is named for John Wesley Powell, who in 1869 led the first expedition to traverse the Colorado River's Grand Canyon by boat.

<span class="mw-page-title-main">Lake Powell</span> Reservoir in Utah and Arizona, United States

Lake Powell is a reservoir on the Colorado River in Utah and Arizona, United States. It is a major vacation destination visited by approximately two million people every year. It holds 24,322,000 acre-feet (3.0001×1010 m3) of water when full, second in the United States to only Lake Mead - though Lake Mead has fallen below Lake Powell in size several times during the 21st century in terms of volume of water, depth and surface area.

<span class="mw-page-title-main">Gunnison River</span> Tributary of the Colorado River in Colorado, United States

The Gunnison River is located in western Colorado, United States and is one of the largest tributaries of the Colorado River.

<span class="mw-page-title-main">Virgin River</span> Tributary of the Colorado River in the southwestern United States

The Virgin River is a tributary of the Colorado River in the U.S. states of Utah, Nevada, and Arizona. The river is about 162 miles (261 km) long. It was designated Utah's first wild and scenic river in 2009, during the centennial celebration of Zion National Park.

<span class="mw-page-title-main">Flaming Gorge Dam</span> Dam on the Green River in Utah, United States

Flaming Gorge Dam is a concrete thin-arch dam on the Green River, a major tributary of the Colorado River, in northern Utah in the United States. Flaming Gorge Dam forms the Flaming Gorge Reservoir, which extends 91 miles (146 km) into southern Wyoming, submerging four distinct gorges of the Green River. The dam is a major component of the Colorado River Storage Project, which stores and distributes upper Colorado River Basin water.

<i>Gila</i> (fish) Genus of fishes

Gila is a genus of fish belonging to the family Cyprinidae, native to the United States and Mexico. Species of Gila are collectively referred to as western chubs. The chiselmouth is a close relative, as are members of the genus Siphateles. Several members of the genus are endangered or extinct due to loss of habitat caused by diversion or overuse of water resources, particularly in the western United States.

<span class="mw-page-title-main">Roundtail chub</span> Species of fish

The roundtail chub 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 is part of the "robusta complex", which includes the Gila robusta robusta, G.r. grahami, and G.r. seminuda.

<span class="mw-page-title-main">Razorback sucker</span> Species of fish

The razorback sucker is a suckerfish found in rivers and lakes in the southwestern United States and formerly northwestern Mexico. It can grow to 91 cm (3 ft) in length and is recognisable by the keel between its head and dorsal fin. It used to inhabit much of the Colorado River Basin but commercial fishing, river damming, and habitat loss have caused great declines in populations. It is now restricted to the Colorado River upstream of the Grand Canyon and to four reservoirs, Lake Mead, Lake Mohave, Lake Havasu, and Lake Powell.

<span class="mw-page-title-main">Kanab ambersnail</span> Subspecies of gastropod

The Kanab ambersnail, formerly classified as Oxyloma haydeni kanabense or Oxyloma kanabense, is a small, air-breathing land snail belonging to the family Succineidae, the ambersnails. This terrestrial pulmonate gastropod mollusc was previously considered a critically endangered subspecies or species. In 2013, a scientific investigations report by the United States Geological Survey concluded that the Kanab ambersnail is not a genetically distinct species. In June 2021, the Fish and Wildlife Service removed the Kanab ambersnail from the United States Fish and Wildlife Service list of endangered mammals and birds and classified it with other common ambersnails within the same taxa, officially negating its status as a distinct subspecies.

The Colorado pikeminnow is the largest cyprinid fish of North America and one of the largest in the world, with reports of individuals up to 6 ft (1.8 m) long and weighing over 100 pounds (45 kg). Native to the Colorado River Basin of the southwestern United States and adjacent Mexico, it was formerly an important food fish for both Native Americans and European settlers. Once abundant and widespread in the basin, its numbers have declined to the point where it has been extirpated from the Mexican part of its range and was listed as endangered in the US part in 1967, a fate shared by the three other large Colorado Basin endemic fish species: bonytail chub, humpback chub, and razorback sucker. The Colorado pikeminnow is currently listed as vulnerable by the IUCN, while its NatureServe conservation status is "critically imperiled".

<span class="mw-page-title-main">Bonytail chub</span> Species of fish

The bonytail chub or bonytail 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 from the part of the basin in Mexico. It was once abundant and widespread in the basin, its numbers and range have declined to the point where it has been listed as endangered since 1980 (ESA) and 1986 (IUCN), a fate shared by the other large Colorado basin endemic fish species like the Colorado pikeminnow, humpback chub, and razorback sucker. It is now the rarest of the endemic big-river fishes of the Colorado River. There are 20 species in the genus Gila, seven of which are found in Arizona.

<span class="mw-page-title-main">Sonora chub</span> Species of fish

The Sonora chub is a species of ray-finned fish in the family Cyprinidae. It is found in Mexico and the United States.

<span class="mw-page-title-main">Gila chub</span> Species of fish

The Gila chub is a species of ray-finned fish in the family Cyprinidae. It is found in Mexico and the United States. The Gila chub is closely related to the roundtail chub. This species is commonly found in association with the Gila topminnow, the desert and Sonora sucker, and the longfin and speckled dace.

<span class="mw-page-title-main">Yaqui chub</span> Species of fish

The Yaqui chub is a species of freshwater fish in the family Cyprinidae. It is found in northern Mexico and the United States. The Yaqui chub is a medium-sized minnow fish that historically occurred in streams of Rios Matape, Sonora, and the Yaqui systems of Sonora, Mexico. It is one of the five species of the genus Gila in Arizona. The Yaqui chub is closely related to G. ditaenia, and G. orcutti ; and shares several physical characteristics with the G. orcutti, but proves different by having a black wedge near the base of the caudal fin.

<span class="mw-page-title-main">Spikedace</span> Species of fish

The spikedace is an endangered species of ray-finned fish in the family Cyprinidae. It is found in Arizona and New Mexico in the United States. It lives in fast-moving streams.

<span class="mw-page-title-main">Colorado River Storage Project</span> US Bureau of Reclamation project

The Colorado River Storage Project is a United States Bureau of Reclamation project designed to oversee the development of the upper basin of the Colorado River. The project provides hydroelectric power, flood control and water storage for participating states along the upper portion of the Colorado River and its major tributaries.

<span class="mw-page-title-main">Headwater chub</span> Species of fish

The headwater chub is a species of fish in the family Cyprinidae. It is found in Arizona and New Mexico.

The Virgin chub or the Virgin River chub is a medium-sized, silvery minnow, generally less than 15 cm (5.9 in) long and reaching lengths of 25 cm (9.8 in). 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. The scales are typically lacking basal radii or are with extremely faint lines.

<i>Catostomus latipinnis</i> Species of fish

Catostomus latipinnis is a North American fish identified by its enlarged lower lips. It belongs to the genus Catostomus, commonly known as suckers. Historically, the flannelmouth sucker ranged in the Colorado River Basin, including parts of Wyoming, Utah, Colorado, New Mexico, Nevada, California, and Arizona; however, this species has been entirely extirpated from the Gila River Basin in Arizona.

References

  1. ↑ NatureServe (2020) [errata version of 2014 assessment]. "Gila cypha". IUCN Red List of Threatened Species . 2014: e.T9184A174778456. doi: 10.2305/IUCN.UK.2014-1.RLTS.T9184A174778456.en . Retrieved 13 November 2021.
  2. ↑ William F. Sigler and John W. Sigler, Fishes of Utah (University of Utah Press, 1996), pp. 79-83
  3. 1 2 Minckley, W.L. 1973. Fishes of Arizona. Arizona Game and Fish Department, Phoenix. pp. 98-99.
  4. 1 2 3 Tobin, Mitch. Endangered: Biodiversity on the Brink. Golden, CO: Fulcrum, 2010.
  5. 1 2 Arizona Game and Fish Department. 1988. Threatened Native Wildlife in Arizona. Arizona Game and Fish Department Publication. Phoenix, Arizona. p. 4.
  6. ↑ "Archived copy" (PDF). Archived from the original (PDF) on 2010-05-28. Retrieved 2009-11-04.{{cite web}}: CS1 maint: archived copy as title (link)
  7. ↑ Gorman, O.T. 1994. Habitat use by humpback chub, Gila cypha, in the Little Colorado River and other tributaries of the Colorado River. Prepared for U.S. Bureau of Reclamation, Glen Canyon Environmental Studies, Flagstaff, Arizona. U.S. Fish and Wildlife Service, Arizona Fishery Resources Office, Flagstaff, Arizona. pp. 129.
  8. ↑ Maddux, H.R., D.M. Kubly, J.C. deVos, Jr., W.R. Persons, R. Staedicke, and R.L. Wright. 1977. Effects of varied flow regimes on aquatic resources of Glen and Grand canyons. Prepared for the Bureau of Reclamation, Contract No. 4-AG-40-01810. Arizona Game and Fish Department, Phoenix. pp. 291.
  9. ↑ Valdez, R.A., P.G. Mangan, R.P. Smith, and B. Nilson. 1982. Upper Colorado River fisheries investigations (Rifle, Colorado to Lake Powell, Utah). Pages 101-279 in W.H. Miller, J.J. Valentine, D.L. Archer, H.M. Tyus, R.A. Valdez, and L. Kaeding, editors. Part 2--Field Investigations. Colorado River Fishery Project. Bureau of Reclamation, Salt Lake City, Utah.
  10. 1 2 Kaeding, L.R., and M.A. Zimmermann. 1983. Life history and ecology of the humpback chub in the Little Colorado and Colorado rivers of the Grand Canyon. Transactions of the American Fisheries Society 112:577-594.
  11. ↑ Carothers, S.W., and C.O. Minckley. 1981. A survey of the fishes, aquatic invertebrates and aquatic plants of the Colorado River and selected tributaries from Lee's Ferry to Separation Rapids. Final Report, U.S. Bureau of Reclamation Contract 7-07-30-X0026, Lower Colorado Region, Boulder City, Nevada. Museum of Northern Arizona, Flagstaff, Arizona. pp. 401.
  12. 1 2 Angradi, T.R., R.W. Clarkson, D.A. Kinsolving, D.M. Kubly, S.A. Morgensen. 1992. Glen Canyon Dam and the Colorado River: responses of the aquatic biota to dam operations. Prepared for the Bureau of Reclamation, Upper Colorado Region, Glen Canyon Environmental Studies, Flagstaff, Arizona. Cooperative Agreement No. 9-FC-40-07940. Arizona Game and Fish Department, Phoenix. pp. 155.
  13. ↑ Holden, P.B. 1991. Ghosts of the Green River: impacts of Green River poisoning on management of native fishes. Pages 43-54 in W.L. Minckley and J.E. Deacon, editors. Battle Against Extinction: Native Fish Management in the American West. University of Arizona Press, Tucson. pp. 517.
  14. 1 2 USGS Grand Canyon Monitoring and Research Center: Humpback Chub, November 2011
  15. ↑ Peterson, Brittany (July 6, 2022). "Biologists' fears confirmed on the lower Colorado River". Yahoo!. Retrieved 2022-07-07.
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