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success with other gears (i.e. hoop nets) for capturing humpback chub in the Yampa <br />population (T. Modde, pers. comm.). <br />Humpback chub were captured within their recent distribution ranges within <br />Dinosaur National Monument. Early records, greater than 50 years old, indicate a more <br />widespread distribution and higher abundance (Tyus 1998). Historical records indicate <br />the presence of humpback chub in Lodore Canyon, and upstream areas such as Red <br />Canyon and Flaming Gorge (Dotson 1959). <br />Our objective was to describe the distribution of the humpback chub population <br />within the boundaries of Dinosaur National Monument; however, other nearby areas may <br />contain humpback chub. Two humpback chub radio-tagged in the Little Snake River, a <br />tributary of the Yampa upstream of Yampa Canyon, moved and were relocated in Yampa <br />Canyon, (Hawkins et al. 2001). Habitats that may contain humpback chub also exist in <br />Cross Mountain Canyon, a high gradient, difficult to sample stretch of the Yampa River <br />upstream of the Little Snake River confluence. No sampling to establish their presence in <br />Cross Mountain Canyon or the Little Snake River was done in this study. <br />Proliferation of non native fishes and altered hydrologic and thermal regimes has <br />been implicated in the decline of native fishes in the Green River upstream of the Yampa <br />River confluence (Bestgen and Crist 2000) and in Yampa Canyon (Miller et al. 1982). <br />Direct predation on humpback chub by non native fishes has been documented in the <br />Little Colorado River (Marsh and Douglas 1997) and is suspected in Dinosaur National <br />Monument. Smallmouth bass have become abundant in the rivers of Dinosaur National <br />Monument since previous data on humpback chub were systematically collected. <br />Smallmouth bass were rare in Yampa Canyon in 1997 and have increased to 18.4% of the <br />10 <br />