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I I I I I I I I I I I I I I I I I I I Over time, the distance fish traveled declined and some fish appeared to take up residency in the shallow coves that typically had abundant cover. In several cases we were unable to detect any movement and suspected some fish had lost their tags. Into the fourth week of the study, we attempted to disturb several fish to determine if they would actually move and some moved distances greater than 100 m, only to return to their original location. Possibly juveniles had found cavities or "preferred" niches. During this period, reservoir elevations rose 10m and it became increasingly difficult to detect fish movement. While it was quite possible that fish simply were not moving, we felt it equally likely that transmitters had been shed. For purposes of analysis, we only present location data that we are certain represents fish movement (Table 1). Several transmitters were not detected in the search area, which prompted us to expand the weekly search area further downstream. During the week of August 12, two boat crews searched the entire 106 km reach between the confluence of the San Juan and Colorado rivers (RK 0) to Slickrock Rapids (RK 106). The search was not expanded any further upstream due to safety and power craft restrictions. Although the search effort was extensive, no additional fish were found. Over time, the distance fish traveled declined and some fish appeared to take up residency in selected spots. These areas usually were at the back of coves or in areas that had abundant cover. In several cases we were unable to detect any movement and suspected some fish had lost their tags or had died. Into the fourth week of the study, we attempted to disturb and move several fish to determine their status. Some fish moved distances greater than 100 m, only to return to their original location. Possibly juveniles had found cavities or "preferred" niches. During this period, reservoir elevations rose 10m and it became increasingly difficult to detect fish movement. While it was quite possible that fish simply were not moving, we felt it equally likely that transmitters had been shed. For purposes of analysis, we only present location data that we are certain represents fish movement (Table I). Lake Mohave The entire length (106 km) of Lake Mohave was surveyed, which normally took 2 days. We detected 17 of the initial 27 fish released but remained in contact with only 7 after the second week of the study. Of the 17, we detected 2 moving uplake, the rest moved down reservoir (Table 2, Figure 3). Habitat Use Habitat use was strikingly similar for both reservoirs. Fish were typically found within 10m from 62% of the time in Lake Mohave compared to 65% in Lake Powell (Figure 4). Fish found at distances greater than 50 m from shore only represented 15 to 20% of the sightings. 7