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stocked in the Upper Colorado River at the Rulison Bridge (RM 229.9) on 23 May 2001 (unpublished FWS data). Between 1999 and 2001, 31,531 domestic-reared juvenile (mean TL=172 mm; range TL=lOfr310 mm) razorback sucker were stocked in the Upper Colorado River near Parachute, Colorado (RM 226.5 and 229.9) (Burdick 2003). Both dams at Price-Stubb (RM 188.3) and Government Highline restrict movement offish further upstream in the Upper Colorado River. The most upstream point that fish can now move in the Upper Colorado River is Price-Stubb Dam. One radio-tagged adult Colorado pikeminnow was detected twice at the base of Price-Stubb Dam in two successive years, frommid-July through late-September of both 1986 and 1987 (Osmundson and Kaeding 1989). Ten sub-adult and adult Colorado pikeminnow were captured between Price-Stubb and the Grand Valley Irrigation Company (GVIC; [RM 185.3]) dams between mid-August and late-September during 1998 within 1.4 miles of each other (Burdick 1999). Fish passage is being pursued by the Recovery Program at both Government Highline Diversion and Price-Stubb dams. Completion of the pre-construction phase for fish passage at Government Highline is scheduled for FY2003; completion of the project is now scheduled for late-summer of 2004. At Price-Stubb Dam, a downstream rock-pass channel is the preferred alternative. The most recent preferred passageway alternative for Government Highline is a switchback design constructed primarily of concrete, similar to the passageway at the Redlands Diversion Dam on the Gunnison River (personal communication, Terry Stroh, Bureau of Reclamation, Grand Junction). Construction of a fish passage facility at Price-Stubb Dam is now tentatively scheduled to start in late-2004 and be completed in early-2005. Since fish passage at Government Highline Diversion Dam was not established during this study, preliminary information on the use of this fish passageway by Colorado pikeminnow radio tagged during this study was not obtained. It is uncertain if Colorado pikeminnow, whether those that are translocated and stocked upstream of Government Highline Diversion Dam or those that might move upstream from downstream reaches through the fish passageway at this diversion dam, will remain and spawn upstream in the reach between Rifle and the diversion dam. Or, will translocated Colorado pdceminnow move downstream prior to spawning, spawn somewhere downstream, and then return upstream using the fish passageway provided them at the various diversion dams? The reach upstream from Palisade is on the fringe of the species range. And, although Anderson (1997) recommended that there was appropriate habitat and available native forage for reintroduction of Colorado pdceminnow, it is unknown whether warm enough water temperatures exist upstream of Government Highline Diversion Dam for Colorado pikeminnow to remain or to spawn. And if so, will this limit Colorado pikeminnow spawning or their upstream distribution? 3