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(spawning and non-spawning individuals). Whether razorback <br />suckers exhibit non-annual spawning is unknown. <br />Ripe razorback suckers in the Green River were captured when <br />water temperatures were 14 to 16 C (range 9-20 C) and springtime <br />flows were increasing toward their peak (Tyus 1987, Tyus and Karp <br />1989, Tyus and Karp in press). When springtime flows were high <br />enough, many ripe razorback suckers moved from the cooler (15-16.5 <br />C) main channel of the Green River, into wanaer (17-21 C), flooded <br />lowlands (Tyus and Karp in press). <br />Razorback suckers typically move from deeper habitats to <br />shallower, swifter riffles and runs over gravel and cobble <br />substrate during the spawning season. McAda and Wydoski (1980) <br />radiotracked one adult that twice moved from quiet water into <br />shallow, swift water adjacent to a gravel bar in May 1975. Water <br />depth at the presumed spawning area ranged from 0.3 to 1.0 m, <br />water velocity from 0.4 to 1.0 m/sec, and substrate was 20-50 mm <br />in diameter. Osmundson and Kaeding (1989a) found an increased use <br />of shallower, faster run habitat, and flooded backwaters and <br />gravel-pits, by two razorback suckers in May. Tyus and Karp <br />(1989, in press) captured ripe razorback sucker adults in runs <br />over cobble, gravel, and sand substrate, mean water depth was 0.63 <br />m, and mean water velocity was 0.74 m/sec. Most ripe fish (91$, <br />n=177) were captured near Jensen, while 14 fish (7$) were captured <br />near the mouth of the Yampa River; specific riffles where spawning <br />presumably occurred were identified (Tyus and Karp in press). <br />Ripe flannelmouth and bluehead suckers were captured in large <br />38 <br />