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<br />ECOLOGY AND CONSERVATION OF N ATNE FISHES IN THE UPPER COLORADO RIvER BASIN <br /> <br />171 <br /> <br />in summer with peak activity in June and July at <br />18.30e, It often spawns in sequence with two dis- <br />tinct high water events, spring runoff and late sum- <br />mer rain spates. Fertilized eggs are deposited over a <br />large spawning bed and hatch in 6 d at 11-190e, <br />Larvae remain in the gravel an additional 7-8 d <br />before emerging to congregate in warm shallows. <br />Young fish feed on midwater zooplankton and al- <br />gae, whereas juveniles and adults are bottom dwell- <br />ers and feed on benthic insects or plant material <br />(Sigler and Sigler 1996). <br /> <br />Kendall Warm Springs Dace <br /> <br />Kendall Warm Springs dace has a similar shape, <br />size, and appearance to speckled dace (Baxter and <br />Simon 1970; U.S. Fish and Wildlife Service 1982b). <br />Kendall Warm Springs dace was listed as federally <br />endangered in 1970 (35 FR 16047-16048) and <br />received protection under the ESA in 1973. Criti- <br />cal habitat was designated in 1975 (40 FR21499), <br />and a recovery plan was approved in 1982 (U.S. <br />Fish and Wildlife Service 1982b). <br />The species is endemic to one small stream, <br />Kendall Warm Springs Creek, Wyoming, which <br />flows into the Green River near Pinedale, Wyo- <br />ming (U.S. Fish and Wildlife Service 1982b). The <br />stream flows about 300 m before dropping over a <br />travertine embankment into the Green River that <br />naturally provides isolation and protection from <br />predator invasion. The species is associated with <br />numerous seeps and springs and the outflow stream <br />along the north face of a small limestone ridge. Little <br />information is available on the species' life history, <br />and the population is believed to be stable with <br />several thousand individuals. Kendall Warm <br />Springs dace occur in pools and eddies (Binns <br />1978). Instream plants provide important escape <br />cover, protection from the main current, and nurs- <br />ery areas for larvae (Gryska et al. 1998). Average <br />stream width is 1.8 m, depth is less than 0.31 m, <br />gradient is about 4%, and average streamflow is <br />about 0.2 m3/s. Kendall Warm Springs dace are <br />absent at the spring source and increase in num- <br />bers downstream with increased dissolved oxygen <br />(DO) and decreased carbon dioxide. Kendall <br />Warm Springs dace are nonmigratory and remain <br />within the 300-m length of stream, although indi- <br /> <br />viduals usually form small schools that may reflect <br />behavior or space limitations (U.S. Fish and Wild- <br />life Service 1982b). The temperature of the springs <br />is a constant 29.5 oc, and spawning may occur year <br />around. Individuals raised in a laboratory matured <br />at 2 years of age, and the number of eggs was gen- <br />erally several hundred per female (Baxter and <br />Simon 1970). Kendall Warm Springs dace are om- <br />nivorous but prefer vegetable matter and insects <br />(U.S. Fish and Wildlife Service 1982b). <br /> <br />Mottled Sculpin and Paiute Sculpin <br /> <br />Mottled sculpin and Paiute sculpin are small, stout <br />fish with a large dorso-ventrally compressed head <br />and slender tapering body (Sigler and Sigler 1996). <br />They are usually 100-150 mm TL, their heads are <br />large and proportionate to their bodies, and they <br />have large mouths and eyes. Mottled sculpin lack <br />scales and have small prickles that give the body a <br />rough texture, whereas Paiute sculpin have a smooth <br />body free of prickles. Paiute sculpin have a single, <br />large preopercular spine that is upturned, flattened, <br />and sharp, instead of the two short blunt preoper- <br />cular spines of mottled sculpin. These species have <br />no special state or federal protection and do not ap- <br />pear to be in decline in the upper basin, alrhough <br />their status is generally unknown. <br />Mottled sculpin inhabit cool tributaries of the <br />upper basin at elevations of 1 ,500-3,000 m (Tyus <br />et al. 1982). The species is rare in warm reaches <br />but increasingly abundant in higher elevation <br />streams with rocky substrates. Paiute sculpin in- <br />habit cool streams and deep cold lakes. The spe- <br />cies prefers moderate stream gradients, and is not <br />found in headwaters with extreme gradient or in <br />warm areas with low gradient. Males and females <br />of both species mature at 2 years of age. Both spe- <br />cies spawn at about l20C in May and June (Ebert <br />and Summerfelt 1969) in specific habitat along <br />rocky lakeshores and on stream riffles composed <br />of gravel and cobble 20-30 cm diameter. Females <br />typically attach clusters of 100-200 eggs to the <br />underside of stones where they are kept clean and <br />aerated by the male who generally remains until <br />the fry disperse. Eggs incubate 3-4 weeks, and lar- <br />vae 10 mm TL remain in gravel interstices for about <br />2 weeks until the yolk sac is absorbed. Nocturnal <br />