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<br />1 <br /> <br /> <br /> <br /> <br />1 <br />1 <br /> <br />~~~ <br />The purse of this report is to summarize taxonomy, physical characteristics, and life <br />history information for roundtail chub Gila robusta, flannelmouth sucker Catostomus <br />latipinnis, and bluehead sucker Catostomus discobolus in the Colorado River Basin <br />(CRB), Southwest USA, and to document their historical and recent distribution and <br />abundance. We also discuss potential reasons for decline, describe current research and <br />management, and make recommendations that may enhance conservation status of the <br />three fish species. Information presented in the following document is intended to <br />support development of conservation plans for roundtail chub, flannelmouth sucker, and <br />bluehe-ad sucker by identifying research and management needs. <br />Gila robusta belongs to a complex of medium-sized chubs inhabiting large rivers and <br />streams in the CRB. Although lacking the extreme morphological adaptations of bonytail <br />Gila elegans or humpback chub G. cypher, roundtail chubs successfully inhabit Iarger <br />rivers, utilizing slow-moving, deep pools and riffles for cover and feeding. Unlike <br />bonytail and humpback chub, roundtail chubs also reside in smaller tributary streams. <br />Roundtail chubs feed opportunistically, consuming aquatic and terrestrial insects, fish, <br />~~ <br /> <br /> <br />f <br /> <br /> <br /> <br />-algae, and occasionally lizards. Like roundtail chubs, flannelmouth suckers use mainstem <br />and tributary streams and occupy pools, deep runs, and rifles. Flannelmouth suckers are <br />benthic omnivores, consuming algae, detritus, plant debris, and aquatic invertebrates. <br />Although bluehead suckers occupy both mainstem and tributary streams, they tend to <br />occur further upstream than either flannelmouth suckers or mundtail chubs. Bluehead <br />suckers prefer habitats with rocky substrates. Bluehead suckers are facultative <br />herbivores, consuming algae, detritus, plant debris, and occasionally aquatic <br />invertebrates. <br />Similar to the federally protected Colorado pikeminnow Ptychocheilus Lucius, razorback <br />sucker Xyrauchen texanus, bonytail, and humpback chub, the distribution and abundance <br />Final Report September 2t~12 <br />iii <br /> <br />