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Results of our analysis indicated that the river consisted of approximate- <br />ly equal proportions of complex and simple channel segments, though during <br />spring there was a slightly higher proportion (53.9%) of complex channel <br />segments and,during summer and winter there was a slightly higher propor- <br />tion (55.1%) of simple channel segments (Table 1). Using a binomial chi- <br />square test (Huntsberger et al. 1975), we found that adult Colorado squaw- <br />fish were located in the complex channel areas significantly (P < .001) <br />more often than would be predicted from the relative availability of those <br />habitats. Of 174 fish locations (21 different squawfish) during the spring <br />period, 84.5% were in complex-channel segments; of 169 summer locations <br />(17 squawfish), 71.0% were in complex segments; of 85 winter locations <br />(eight squawfish), 62.4% were in complex areas (Figure 1). We presume that <br />selection for such sites during spring was due to the use of warmer, <br />sheltered environments (backwaters, flooded gravel pits and side channels) <br />that serve as refuge from the high-velocity flows of the main channel. <br />During summer, braided areas provide a greater diversity of habitats for <br />squawfish to exploit; the downstream end of islands provide slack water <br />areas for resting while allowing close proximity to swifter areas for <br />foraging. This may also be important in winter, though possibly less so <br />due to the fishes lower activity level at the lower temperatures. <br />A reduction of peak flow allows vegetation to establish itself on areas <br />previously inundated by floods. This vegetation can stabilize the banks <br />and bars, thereby cutting off much of the course sediment which feeds <br />growth of bars and islands. Stabilized islands can become attached to the <br />floodplain resulting in reduction of braiding and simplification of the <br />channel (Schumm and Meyer 1979). <br />7