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WARM WATER FISH LITERATURE REVIEW, by Rick Anderson (March <br />4, 2005) <br />The upper Colorado River basin, which is composed of the Colorado River and its tributaries <br />upstream of Lake Powell, is home to 14 native fish species, four of which are now endangered. <br />These four fish the Colorado pikemim7ow (Ptychoclreilzrs~ Iucius), razorback sucker (Xyra7rcl2en <br />taxar~~rs), bonytail (Gila elegans) and humpback chub (Gila cy~ha evolved in the Colorado River <br />basin and exist nowhere else on earth (www.r6.fws.Qov/coloradoriver). The Dolores River is a <br />significant tributary to the Colorado River and thus the status if its native fish community is of <br />keen interest to state and federal agencies that manage native fish. <br />The Colorado River Recovery Program commissioned a fish survey of the Dolores River <br />downstream of McPhee Reservoir in 1990 and 1991 to determine this rivers' suitability for <br />endangered Colorado River fishes (Valdez et al 1992). Prior to this investigation, little was <br />lc~7own about historical or present use of the Dolores River by Colorado pikeminnow. Valdez et <br />al. (1992) provided a review of earlier surveys: <br />`The Dolores River once supported unlalown numbers of Colorado pikenunnow <br />(Ptychocheilus lucius) and perhaps functioned as a spawning tributary for this species in <br />the upper Colorado River. Seethaler (1978) reported that T.M. Lynch seined small <br />pikeminnow from Paradox Valley in 1962. Several other collections of Colorado <br />pikeminnow were reported during the 1950's and 1960's by Lemons (1955), Nolting <br />(1956) and Coon (1965). The most recent collection of Colorado pikeminnow in the <br />drainage was an unconfirmed report by Horpestad (1973), who captured seven <br />individuals in the San Miguel River, approximately 6 miles above it's confluence with <br />the Dolores River. No Colorado pikeminnow were captured during a fishery survey of <br />the Dolores River by Holden and Stalnaker (1975) in 19721. More recent surveys by the <br />U.S. Fish and Wildlife Service (Service) in the early 1980 are also failed to located <br />Colorado pikenunnow in the Dolores River (Valdez et al 1982).' <br />Fish collections by Holden and Stalnaker (1975) included 11 species of which only four were <br />native (flannelmouth sucker, bluehead sucker, roundtail chub and speclded dace). Valdez et al. <br />(1982) collected a total of 16 species and also the same four native species. A total of 19 <br />species, including six native and thirteen non-native fish were captured in the 1990 and 1991 by <br />Valdez et al. (1992). The additional native fish collected in the 1991 survey were mottled <br />sculpin and Colorado pikeminnow. Mottled sculpin were only found in Reach 6, a reach not <br />sampled in prior surveys. Only four Colorado squawfish were collected in 1991 and all were <br />located within 2 lan of the confluence with the Colorado River. No other endangered species <br />including bonytail, humpback chub or razorback sucker were captured by Valdez et al. (1992). <br />Valdez et al. (1992) employed a variety of sampling gear that included seines, gill nets, trammel <br />nets and boat electrofishing. For all gear types combined the most common species captured <br />were red shiner (33.4%), sand shiner (23.1%) and fathead minnow (18.4%), all non-native <br />cyprinids. Combined the native species totaled 19% of the total catch with flannelmouth sucker <br />13 <br />