Humpback Chub Page

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Description The humpback chub (Gila cypha) is an endangered, native fish of the Colorado River that evolved around 3-5 million years ago. The pronounced hump behind its head gives this fish a striking, unusual appearance. It has an olive-colored back, silver sides, a white belly, small eyes and a long snout that overhangs its jaw. Like the Colorado pikeminnow and bonytail, the humpback chub is a member of the minnow family. The humpback chub is a relatively small fish by most standards – its maximum size is about 20 inches and 2.5 pounds. By minnow standards it is a big fish, though not like the giant of all minnows – the Colorado pikeminnow. Humpback chub can survive more than 30 years in the wild. It can spawn as young as 2 to 3 years of age during its March through July spawning season. Although the humpback chub does not have the swimming speed or strength of the Colorado pikeminnow, its body is uniquely formed to help it survive in its whitewater habitat. The hump that gives this fish its name acts as a stabilizer and a hydrodynamic foil that helps it maintain position. The humpback chub uses its large fins to “glide” through slow-moving areas, feeding on insects that become trapped in water pockets. Status and distribution The humpback chub was listed as endangered by U.S. Fish and Wildlife Service in 1967 and given full protection under the Endangered Species Act of 1973. Historically, humpback chub inhabited the swift and turbulent waters in canyons of the Colorado River and three of its tributaries: the Green and Yampa rivers in Colorado and Utah, and the Little Colorado River in Arizona. The species was first discovered in 1946. Before that time, few people ventured into these treacherous regions – including fishery biologists. Today, five self-sustaining populations of humpback chub occur in the Upper Colorado River Basin. Two to three thousand adults can occur in the Black Rocks and Westwater Canyon core population in the Colorado River near the Colorado/Utah border. Several hundred to more than 1,000 adults may occur in the Desolation/Gray Canyon core population in the Green River. Populations in Yampa and Cataract canyons are small, each consisting of up to a few hundred adults. The largest known population of humpback chub is in the Lower Colorado River (LCR) Basin in the Grand Canyon -- primarily in the LCR and its confluence with the main stem of the Little Colorado River. In 2009, the U.S. Geological Survey announced that this population increased by about 50 percent from 2001 to 2008. The agency estimates that the number of adults is between 6,000 and 10,000, with the most likely number being 7,650 individuals.

---	Fish Species of the Colorado River in Lower Glen Canyon and Grand Canyon	---

Updates Indication of skip-spawning in the 2015 LCR monitoring. Is this related to food limitation and the decline of the trout population? Body condition of humpback chub has been declining with the decline in macroinvertebrates in the drift. Note that most of the drift occurs in the summer when macroinvertebrate production is high. This decline in macroinvertebrate production coincides with the population expansion and subsequent decline in the rainbow trout population indicating a competition issue between rainbow trout and humpback chub. Humpback chub numbers in Grand Canyon have been increasing since the early 2000s LCR remote PIT tag arrays RValdez_Talus shoreline habitat used by HBC

INFORMATION "NNFC will occur if necessary because it is a conservation measure required under the ESA to ensure protection of the HBC." Mitigation for the impact of implementing NNFC on resources of tribal concern is addressed under the NHPA OA for NNFC. The (HBC) juvenile abundance estimate for the mainstem at the LCR is over 2,500 fish, and is above the conservation measure trigger for nonnative fish control in the FWS biological opinion of 900.130220 AMWG Minutes Presentations and Papers 2016 Mark-Recapture and Fish Monitoring Activities in the Little Colorado River in Grand Canyon Colorado River in Grand Canyon from 2000 to 2015 Effects of Turbidity on Predation Vulnerability of Juvenile Humpback Chub to Rainbow and Brown Trout Recovery Plan update for Humpback Chub Humpback chub in the Little Colorado River, Monitoring of Juveniles, Sub-Adults, and Adults and Translocations Humpback Chub Translocations to Havasu and Shinumo Creeks, Grand Canyon National Park Humpback chub (Gila cypha) that Spawn in the Little Colorado River: Status and Potential Drivers Factors that Influence Juvenile Humpback Chub Survival Use of Ultrasonic Imaging to Evaluate Egg Maturation of Humpback Chub (Gila cypha) in Grand Canyon Monitoring Humpback Chub Aggregations in the Mainstem, 1991-2015 2015 Havasu Creek Translocation Update Native-nonnative Interactions; Factors Influencing Predation and Competition Chute Falls Translocation Update Humpback Chub Translocations to Shinumo and Havasu Creeks, Grand Canyon National Park Humpback Chub in the Colorado river: Status and Trends of Aggregations, Changes in Range Early Life History of Humpback Chub: Patterns and Potential Drivers Biological Opinion Trigger Update: January 2015 2014 HBC Downlisting and Kanab Ambersnail Delisting 2014 Shinumo Creek Flood Modeling Long Term Effects of HFEs on Trout and HBC Colorado River fish monitoring in Grand Canyon, Arizona: 1990-2013 humpback chub, Gila cypha, aggregations Results from Colorado River Site and ongoing population modeling 2011 GCMRC Update - Chub, Temperature, and Sediment Other Stuff POTENTIAL THREATS: 141029 USFWS HBC Down listing -Topic Smallmouth Bass -- In early 2000, smallmouth bass increased dramatically in abundance in the Yampa River and Upper Colorado River. Just over a decade later, the species cannot be brought under control. "Prior to Glen Canyon Dam, the Colorado River was dominated by highly predacious non-native channel catfish. Catfish are warm water fish...Regular flooding of the LCR may be keeping catfish out of the LCR and cold water in the Colrado River does not provide habitat for catfish or other warm water fish. Without Glen Canyon Dam chubs may have been extirpated from Grand Canyon, catfish would still be the dominant fish in the Colorado River and the LCR." (090711_Minority Report to TWG_FFF_Mark Steffen) Should a disaster such as a landslide cut off the Little Colorado chub from the mainstem, the species could quickly become extinct -Article LINK