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pooled samples (p<0.025). Migrating sand wave backwaters were also used more than expected d constricted reach eddies slightly less than expected for pooled samples. The pooled F distribution of backwater habitat classes between Colorado squawfish use habitats and unused r habitats was not different 0.187 even thou si (p= ) gh gnificant differences existed in some months (Table 7). Jn July, scour backwaters were under represented in Colorado squawfish use distributions and shoreline eddies more than observed in the distribution of unused habitats (p=0.50). In August samples, there was also a significant difference in distribution (p~0.05), but this was driven by greater use of migrating sand waves and lower use of shoreline eddies. Finally, in September Colorado squawfish backwater type distribution, scour habitats were again more prevalent and shoreline eddies less prevalent than in the distribution for unused backwaters. Significant differences were identified for 10 backwater variables when samples were pooled across sampling periods. Wilcoxon signed-rank analyses showed that backwaters used by s~Ph~ Colorado squawfish had larger surface area, shallower mouth, less cover, greater volume and greater difference ff t~em~erature from the main channel (Table 8). Here again, significance varied with month of sampling effort. In the single June sample, only area and length were greater in used backwaters at the 95% level. Volume was significantly less (p=0.054). In July, cover was Iess, main channel temperature more and depth of substrate more at sites used by Colorado squawfish. August results were similar to the pooled results except, mean backwater temperature and mean width were greater for backwaters used by Colorado squawfish. September also had some similarities to pooled results. However, in September samples, Colorado squawfish used backwaters with lower mean temperature and which were shallower than unused backwaters. In April, all area and volume related measures were greater, as was mean substrate depth. Mean temperature and temperature difference were greater for used 20