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4 The stream reach (river mile 50-60) in the Delta area on the Gunnison River may also be a candidate site for experimental stocking of razorback sucker. This reach appears to be the last location where large numbers of razorback sucker were known to occupy the Gunnison River (Wiltzius 1978). This reach also contains relatively abundant side channel and backwater habitats and native suckers and roundtail chub are numerous and non-native predaceous fishes are less abundant than in other reaches. Channel catfish are virtually nonexistent upstream of Redlands Diversion Dam (Valdez et al. 1982; unpublished USFWS data [one channel catfish, total length = 644 mm, weight = 3,250 g, was captured at river mile 17, July 1992]). Although this reach is impacted by water diversions and peak spring flows have been reduced by upstream dams of the Aspinall Unit, these dams may provide a mechanism to deliver flows downstream to manage the recovery of razorback sucker in the Gunnison River. To increase the likelihood that a sufficient number of stocked fish will survive to allow for an evaluation of stocking success, fish may have to be released at multiple sites within the river reach targeted for stocking. Rearing Sites Natural backwaters are important habitats for razorback sucker in the upper Colorado River (Valdez and Wick 1981). These fish use these quiet areas during various life stages. Habitat enhancement of natural riverine features may play an important role in an augmentation program and has been suggested as a means to assist the recovery of the razorback sucker (Valdez and Wick 1981). Existing side channels, tributaries, and old river oxbows could be utilized as either seasonal backwaters or managed as year-round rearing habitats. For example, side channels diked for flood control in the Yampa 24 4 4 4 4