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<br />170 <br /> <br />VALDEZ AND MUTH <br /> <br />and rest in pools, eddies, and deep runs (Beyers et <br />al. 2001). Larvae and juveniles use shallow, low-ve- <br />locity shorelines and backwaters (Haines and T yus <br />1990; Robinson et al. 1998). Adults prefer large <br />cool streams of20oC or less and occupy areas with <br />moderate to fast current and rocky substrates <br />(Banks 1964; Vanicek 1967; Holden and Stal- <br />naker 1975b; McAda et al. 1980; Tyus et al. 1982; <br />Sublette et al. 1990). Adults move little and tend <br />to remain in home ranges (Vanicek 1967; Holden <br />and Crist 1981; Cavalli 1999; Beyers et al. 2001). <br />Spawning in the upper basin occurs in spring and <br />early summer at water temperatures of 15.6- <br />24.60C (Holden 1973; Sigler and Sigler 1996). <br />Females broadcast adhesive eggs over mid-chan- <br />nel cobble/gravel bars that incubate 7-8 d at <br />15.6-17.70C, and emerging larvae 9-11 mm TL <br />are transported downstream by river currents <br />(Valdez et al. 1985). Fecundity is 5,000-20,000 <br />eggs per female (Smith 1966; McAda and Wydoski <br />1980). Larvae and young feed primarily on diptera <br />larvae, diatoms, and zooplankton (Maddux et al. <br />1987; Grabowski and Hiebert 1989; Muth and <br />Snyder 1995; Childs et al. 1998). Juveniles and <br />adults use the cartilagenous ridge inside each lip <br />to scrape algae, organic and inorganic debris, and <br />small aquatic insects from rocks and boulders <br />(Simon 1935; Banks 1964; Vanicek 1967; <br />Maddux and Kepner 1988; Muth and Snyder <br />1995). <br /> <br />Mountain Sucker <br /> <br />Mountain sucker reach a maximum size of305 mm <br />TL (Sigler and Sigler 1996). The body is elongate <br />with a moderately thickened caudal peduncle, and <br />the mouth is subterminal and sucker-like with dis- <br />tinct lateral notches. Like the bluehead sucker, it has <br />canilagenous scraping ridges inside each lip. Moun- <br />tain sucker is a species of special concern in Colo- <br />rado and has no direct federal protection. <br />Mountain sucker was once common in high <br />elevation streams of the Colorado River system. In <br />the upper basin, it is found in many tributaries at <br />elevations of 1,220-3,050 m (Tyus et al. 1982). Its <br />popularity as a forage and baitfish expanded its <br />range, and by 1940, mountain sucker was in many <br />reservoirs and tributaries (Sigler and Miller 1963). <br /> <br />During 1950-1970, mountain sucker expanded its <br />range ro drainages of the upper Green River <br />subbasin, including Ashley Creek, White River, and <br />Price River. Adults inhabit cool, clear tributaries <br />where they are tolerant to occasional turbidity and <br />are common over gravel, rubble, or boulder sub- <br />strates. Mountain sucker does not occur naturally <br />in lakes but survives in lakes if introduced. Adults in <br />winter and early spring are found adjacent to pools <br />in velocities of 0.5 m/s and depths of 1.5 m (Sigler <br />and Sigler 1987). Fecundity is 2,100-4,000 eggs <br />per female, and spawning is in late spring and early <br />summer when water temperatures are 17-190C <br />(Hauser 1969). Males mature at ages 2-4 and 127- <br />145 mm TL; and females mature at ages 3-5 and <br />122-130 mm TL. The diet of young and adults is <br />mostly algae and diatoms scraped from rock sur- <br />faces; and diptera, higher plants, animals, and de- <br />bris (Sigler and Sigler 1996). <br /> <br />Speckled Dace <br /> <br />Speckled dace is a small fish with an elongate body, <br />rounded fins, and a strong, thick caudal peduncle. <br />The mouth is subterminal, otten with a small bar- <br />bel at the end of each maxillary. Adults rarely ex- <br />ceed 75 mm TL. The species has no special state or <br />federal protection. Its status in the upper basin is <br />not well known, but genetic clades unique to spe- <br />cific drainages may be threatened by habitat alter- <br />ations, stream impoundment and dewatering, de- <br />graded water quality, and nonnative fishes (Oakey <br />et al. 2004). <br />Speckled dace is widespread in the upper ba- <br />sin, except where habitat has been eliminated or <br />degraded. The species has been extirpated locally <br />by predation and competition from nonnative spe- <br />cies, although its tolerance to low flows, high tem- <br />peratures, and low oxygen enables it to persist <br />where other species might perish. It is found in a <br />variety of habitats and tolerates a wide range of <br />water conditions, including cool mountain streams, <br />medium and large rivers, small impoundments, <br />small isolated desert springs, and intermittent <br />streams. <br />Speckled dace mature at 2 years of age, and <br />fecundity is 174-514 eggs per female (Sigler and <br />Sigler 1987). Spawning in the upper basin occurs <br />