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EXECUTIVE SUMMARY The purpose of this study was to evaluate the survival and performance of pond-reared, radiotagged adult razorback sucker following stocking in the Upper Colorado and Gunnison rivers. Specific objectives were to determine movement, distribution, dispersal patterns, and habitat use of fish stocked in the river. Twenty radio-implanted razorback sucker were stocked in historical habitat in the Upper Colorado River between Debeque and Rifle, Colorado, and 21 were stocked in the Gunnison River near Delta, Colorado, in April 1994. An additional four adult radiotagged razorback sucker were stocked in the Gunnison River in September 1995. Stocked razorback sucker dispersed predominantly downstream following release in both rivers. In the Upper Colorado River the mean maximum displacement for the 20 fish was four times greater downstream than upstream (19.3 versus 4.8 miles). Ninety-six individual radio contacts were made periodically with 19 fish between 13 April 1994 and 11 August 1995. Radio contact ranged from 10 to 491 days. Five fish were contacted over a period of 400 days. Only nine radio contacts were made with three different fish during 1995. Eight fish exhibited both up- and downstream movement sometime during the contact period, only three fish exhibited greater upstream than downstream movement. Eleven fish exhibited only downstream movement. Three fish passed over the Government Hi ghl i ne Diversion and Price Stubb dams, and the Grand Valley Irrigation Diversion. One of these fish was later contacted in "Hotspot Pond" in the '15-Mile Reach'. At the end of the study, three fish moved back upstream near the point of release. Other than the three fish that moved back upstream near the point of release in the Upper Colorado River, movement patterns were similar for razorback sucker stocked in the Gunnison River. A total of 195 individual radio contacts was made periodically with 23 fish between 12 April 1994 and 1 November 1995. Radio contact ranged from 29 to 532 days. Eleven fish were monitored for 113 to 146 days; only one fish was contacted over 150 days. Of the thirteen radio contacts during 1995, eight were from two fish released 13 September 1995. The five other radio contacts were from one fish stocked in 1994. The mean maximum displacement for the 23 fish was nine times greater downstream than upstream (14.3 versus 1.6 miles). Six fish exhibited both up- and downstream movement sometime during the contact period; only one fish exhibited greater upstream than downstream movement (13.0 vs 7.9 miles). Fourteen fish moved entirely downstream. Post-stocking survival was less than anticipated in both river systems. At the termination of the study, in the Upper Colorado River, 3 fish were confirmed alive, 10 were missing, 2 were confirmed dead, and 5 were presumed dead. Confirmed mortality was 10%. Actual mortality was likely as high as 85% if missing and presumed dead fish were included. For fish stocked in the Gunni son Ri ver duri ng 1994 and 1995, 3 fi sh were confi rmed al i ve, 3 were mi ssi ng, 2 were confirmed dead, and 17 were presumed dead. Confirmed mortality was 8%; actual mortality might have been as high as 88% if missing and presumed dead fish were included. vii