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. . Subsequent to the first radio contact, most fish remained in a relatively localized reach of river. Mean total movement or the average sum of the distance moved up and down the river during the study was 6.0 miles (0.4 to 22.8 miles) for squawfish and 2.4 miles (0 to 10.8 miles) for razorback sucker. Mean net movement or the resultant distance moved either up (+) or down (-) river was 5.5 miles (-0.1 to +22.8 miles) for squawfish and 2.2 miles, (-10.8 to +0.8 miles) for razorback sucker. The similarity between total and net movement suggests that, other than moving up or down the river, the fish moved relatively little during the winter months. . . Observations during 24-hour monitoring indicate that fluctuating water levels were responsible for much of the diel movement. Most maior npvement,s by both species of fish coincided with either nSlnq or taIling river Ipvpl 1:.. ~ Ri ver fluctuations were erratic and unpredictable due to variable discharges from Flaming Gorge Dam and the time lag associated with the changes in flow to reach any given location downstream. This confounds interpreting the influence of other physical factors that may be responsible for activity or movements by the fish, such as time of day. . General Habitat Use . Colorado Squawfish. During the course of this study, approximately 332 hours were spent observing the 10 radiotagged Colorado squawfish. During the sum of these observation periods, the fish occupied three basic habitat types, including runs, backwaters and edc:fIiS. Of the total observation time, - - squawfish were found in runs approximately ~ of the time, backwaters ID of the time, and eddies 4% of the time. -- . These numbers, although indicating a preference by squawfish for a run type habitat, are probably, in part, due to the relative availability of the di fferent habitat types. Colorado squawfish were found predominately !rL moderately shallow (0.5-1.5 m deep), sandy bottom, ~~. This may be a function of the high availability of this habitat type within the study area. Although much of this habitat appeared devoid of coveL it became apparent during the course of the study that the specific locations of the fish within these runs were consistently associated with certain natural features of the river channel. These features, which include submerged sand ridges, sand bars and islands, provided localized areas of slower current within or adjacent to relatively higher velocity flows. Submerged sand rid~es or depositional areas within runs are a common feature of the river channel throughout the study area. Troughs or deeper areas of the channel were generally located just downstream of these ridges. Water velocities in these troughs were generally slower, especially in the lower portions of the water column. Squawfish were commonly located in these gough~ and were often quite sedentary, which suggests that the fish may be utilizing the areas for resting cover. Emergent sand bars and islands within the channel also proviaed current breaks that were frequently~illzed by the fish. . . . 19 .