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ROUNDTAIL CHUB <br />Historically, roundtail chub were known to commonly occur in most medium to large tributaries <br />of the Upper Colorado River Basin (Vanicek 1967, Holden and Stalnaker 1975, Joseph et al. <br />1977). Roundtail chub historically occurred in lower elevation (below 7,546 ft.) streams, <br />including the Colorado, Dolores, Duchesne, Escalante, Green, Gunnison, Price, San Juan, San <br />Rafael, White, and Yampa rivers (Bezzerides and Bestgen 2002). Roundtail chub are often <br />found in stream reaches that have a complexity of pool and riffle habitats (Bezzerides and <br />Bestgen 2002). Adults are found in eddies and pools adjacent to strong current and use instream <br />boulders as cover (Sigler and Sigler 1996, Brouder et al., 2000). Roundtail chub begin spawning <br />when water temperatures reach about 65 °F (Vanicek and Kramer 1969, Joseph et al. 1977). In <br />most Colorado River tributaries this increase in temperature coincides with a decrease in <br />discharge after peak runoff (Bezzerides and Bestgen 2002). <br />FLANNELMOUTH SUCKER <br />The flannelmouth sucker is a good indicator species for flow and habitat relationships (Stewart <br />and Anderson 2006 -CR1). The flannelmouth sucker is a large fish reaching up to almost 2 feet <br />in length. Historically, the flannelmouth sucker was commonly found in most, if not all, medium <br />to large, lower elevation rivers of the Upper Colorado River drainage (upstream of Glen Canyon <br />Dam). Within the State of Colorado, flannelmouth sucker are present in the Colorado River and <br />numerous tributaries including the Gunnison River up to the Aspinall Unit reservoirs (Bezzerides <br />and Bestgen 2002), the Uncompahgre River (Sigler and Miller 1963) and the Dolores River. <br />Flannelmouth suckers are typically found in slower, warmer rivers in plateau regions of the <br />Colorado River drainage (Deacon and Mize 1997). They usually inhabit the mainstem of <br />moderate to large rivers but are occasionally found in small streams. This species frequents <br />pools and deep runs but can also be found in the mouths of tributaries, riffles, and backwaters. <br />Flannelmouth sucker typically spawn in the Upper Colorado River basin between April and June <br />(McAda 1977, McAda and Wydoski 1980, Snyder and Muth 1990, Tyus and Karp 1990). <br />BLUEHEAD SUCKER <br />The bluehead sucker provides the most information for justifying instream flow needs to <br />maintain the native fish assemblage (Stewart and Anderson 2006 -CR1). The bluehead sucker is <br />a large fish reaching up to 17 inches in length. This species is found in a large variety of river <br />systems ranging from large rivers with discharges of several thousand cfs to small creeks with <br />less than a couple of cfs (Smith 1966). Adult bluehead suckers exhibit a strong preference for <br />specific habitat types (Holden and Stalnaker 1975). This species has been reported to typically <br />be found in runs or riffles with rock or gravel substrate (Vanicek 1967, Holden and Stalnaker <br />1975, Carlson et al. 1979, Sublette et al. 1990). The bluehead sucker is known to feed on <br />invertebrates, which have their highest densities in riffles. Although the species generally <br />inhabits streams with cool temperatures, bluehead suckers have been found inhabiting small <br />creeks with water temperatures as high as 82.4° F (Smith 1966). <br />Instream Flow Recommendation(s) <br />The CDOW & BLM are recommending 325 cfs, high flow period (spring /summer), and 115 cfs, <br />low flow period (fall /winter), based on their data collection efforts. These flow <br />recommendations are based on the physical and biological data collected to date and do not <br />incorporate any water availability constraints. <br />5 <br />