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9 <br />Canyon. Contact with fish numbers 3, 11, and 12 was lost between June <br />11 and July 7 (Fig. 4), after some migratory tendencies had been noted. <br />Radiotagged fish number 7 was presumed dead after several weeks of <br />sedentary behavior. After water levels receded, this fish was located <br />by triangulation and was apparently buried in a sand bar. Recovery <br />attempts were unsuccessful. <br />General Habitat Use <br />Changes in habitat use throughout the year are illustrated in <br />Fig. S. [This figure was prepared from monthly summaries of our <br />observations of habitat use (Appendix B).] In April, as water levels <br />were beginning to rise, main channel run habitat was most frequently <br />used, followed by tributary stream backwaters and eddies. Four of the <br />twelve fish radiotagged were originally captured in the flooded mouth of <br />Morgan Gulch, a tributary stream at river km 166.5 (mile 103.4). As <br />runoff flows increased in early May through mid-June backwater and eddy <br />habitats were frequently used. In May, backwater habitat use was evenly <br />divided between backed-up tributary streams (natural) and flooded, <br />dike-off side channels (man-made), identified in this report as main <br />channel backwaters. In June, fish were observed predominantly in the <br />tributary stream backwaters and main channel eddies. In July, as water <br />levels dropped, fish moved into main channel habitats. Run habitat was <br />used most frequently. In August, secondary side and chute channels were <br />used more extensively. Shoreline, run, and riffle habitats were equally <br />used in August, when much attention was given to the spawning area below <br /> <br />river km 32 (mile 20). During October and November, pool habitat was <br />utilized most extensively, followed by run, eddy and shoreline habitat.