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<br />Methods <br /> <br />Study Area <br /> <br />The study area included the lower Yampa River in northwestern Colorado between river <br /> <br />kilometer (rk) 72.9 and 16.2 (Figure 1). This portion of river flows through Yampa Canyon which <br /> <br /> <br />is characterized by steep canyon walls, gravel to boulder substrate, high gradient and meandering <br /> <br />channel. The channel is fairly narrow with very little braiding. The canyon walls consist of red <br /> <br />talus boulder fields and shear Weber sandstone walls. Flows in the lower Yampa River are highly <br /> <br />variable, seasonally and annually (Modde and Smith 1995) with a 50% exceedence peak flows of <br /> <br />approximately 370 m3s (13,000 cfs) in May and average base flow of approximately 8.5 m3s (300 <br /> <br />cfs) in September. The entire study area, from Deerlodge Park to Echo Park, is located within <br /> <br />Dinosaur National Park Monument. <br /> <br />Approach <br /> <br />The testable hypthosis of this study is that channel catfish in the lower Yampa River <br /> <br />(within Dinosaur National Monument) cannot be significantly reduced in numbers using a variety <br /> <br />of gear types. To test this hypothesis we stratified the study area longitudinally to separate <br /> <br />differences due to landscape, and then designated treatment and control reaches within each <br /> <br />stratum. Removal of channel catfish occurred in treatment reaches during each pass, and removal <br /> <br />from control reaches occurred only during the last pass of the field season. Catch rates of the last <br /> <br />pass of the field season from treatment and control reaches were compared to determine if they <br /> <br />differed significantly. In addition, catch rates within treatment reaches were regressed with <br /> <br />cumulative catch to determine if a significant decline (i.e., slope) occurred within reaches. <br /> <br />3 <br />