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each individual fish. <br />Substrate and Flow <br />In an attempt to discover how substrate and flow together affected bonytail spatial <br />selection, pumps were added to the substrate tanks. Thus flow and substrate <br />experiments were combined. Low, medium, and high velocity treatments were used. <br />As before, five bonytail chubs were added and allowed to acclimate for at least five <br />days. Their average weight and length were 8.5 grams and 95 mm respectively. During <br />the experiments, observations were done during 0700-0900 and 1500-1700. Each tank <br />was observed for 20 minutes in which vertical (depth) and horizontal positions of each <br />fish were noted every five minutes. Available vertical positions included low, mid-depth, <br />and surface (0-8 cm, 8.1-16 cm, and 16.1-24 cm from the bottom, respectively). <br />Observations lasted at least three days, which included three day and three night <br />observations. Velocities were mapped with a flow meter at deep, medium, and shallow <br />depths (3 cm, 10 cm, and 23 cm from the bottom respectively). Three velocity readings <br />were taken every 20 cm (horizontal distance). A transparency of the flow key was <br />made and overlapped onto the data sheets with the fish positions to determine nose <br />velocities of each individual fish. When fish were found inside the gravel substrate we <br />assumed velocities to be 0.0 m/s. <br />Red Shiner Interactions <br />Once the preferred habitat selection of bonytail was determined, the above experiments <br />were repeated with red shiners present to determine the effects of this nonnative fish on <br />bonytail habitat selection. The same substrate, flow and substrate, and flow <br />experiments were run with five bonytail chubs and five red shiners under the same <br />conditions described earlier. <br />13