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<br />INTRODUCTION <br /> <br />A perceived decline in the Grand Canyon humpback chub population in 2002 raised concern over <br />genctic viability, and a possible need was identified to take the species into a refuge or captive <br />propagation program. There was also concern expressed regarding genetic ramifications when <br />creating small founder populations by translocations into tributaries to the Grand Canyon. In <br />response to concerns about the status of humpback chub, Glen Canyon Dam Adaptive <br />Management Work Group formed an Ad Hoc Committee to consider actions to implement a <br />comprehensive research and management program for the humpback chub. Although the <br />comprehensive plan is still in draft, it identifies a genetics management plan for humpback chub <br />to detennine genetic relationships within and among populations of the endangered Gila cypha <br />(humpback chub) in the Colorado River ecosystem <br />(http://13 7.77.133 .lIuc/envprog/amp/amwg/mtgs/040ct25/H BC _ Projects. pdt), further genetics <br />research on humpback chub gentics is being conductcd at Colorado State University and is due <br />out by the end of this year. The U.S. Fish and Wildlife Service was requested to develop a <br />genetics management plan for humpback chub in the Colorado River Basin in order to identify <br />and direct research and managemcnt actions needed to ensurc current genetic diversity and <br />viability of humpback chub are preserved as actions are taken to recover the species. <br /> <br />HUMPBACK CHUB SPECIES STATUS <br /> <br />Six extant populations of humpback chub exist (Yampa Canyon, Desolation/Gray canyons, Black <br />Rocks, Westwater Canyon, CatarJct Canyon, and Grand Canyon). Similar morphometric and <br />meristic characteristics among thc six populations of Gila cypha (Douglas et al. 1998, 200 I; <br />McElroy and Douglas 1995; McElroy et al. 1997) and lack of genetic dilTerentiation among the <br />six populations suggest panmixis and extensive introgression with sympatric Gila species <br />(Dowling and DeMaris 1993). <br /> <br />The most current estimates of the mean number of wild adult humpback chub (greater than 200 <br />mm total length) are provided below. Information on Upper Colorado River Basin populations <br />was gathered from presentations at the August 2004 population estimates workshop. Many of <br />thesc estimates are preliminary (analyses ongoing), and some are contained in draft reports <br />undergoing pecr and Biology Committee review. Thcse data indicate recent downward trends in <br />the abundance of humpback chub in Black Rocks, W cstwater Canyon, and Desolation/Gray <br />Canyons. Information on the Grand Canyon population in the Lower Colorado River Basin is <br />provided by Grand Canyon Research and Monitoring Center, through the use of an Age- <br />Structured Mark Recapture program. <br /> <br />DRAFT HBC Genetics Management Plan-l <br /> <br />l.v900 <br />