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ecology of the endangered fishes (see Table 1.1, McAda 2001). The end product of these investigations will be to produce biologically- based, seasonal flow recommendations for the Gunnison River and Colorado River downstream of the confluence that will benefit endangered and native fishes. Results of these studies will be used by FWS's Division of Ecological Services to write a biological opinion for operation of the Aspinall Unit, and to identify recovery actions appropriate for the Gunnison River. Besides fish passage being restored at Redlands and an interim flow of 300 cfs being recommended for the reach between Redlands Dam and the confluence with the Colorado River, other restoration efforts for endangered fish have begun in the Gunnison River. From 1995 through July 2001, about 14,473 juvenile, sub- adult, and adult domestically-reared razorback sucker have been stocked in the Gunnison River near Delta. The reintroduction program is scheduled to continue at least through 2001 (Burdick et al. 1995). The short-term goal of this stocking program is to repatriate razorback sucker to the Gunnison River so that a population can be established. The long-range goal is to establish self- sustaining populations of at least 10 adult razorback sucker per river mile in the Gunnison River between Hartland and Redlands Diversion dams (Burdick et al. 1995). Fish Community The FWS conducted an intensive ichthyofaunal investigation in 75 miles of the Gunnison River in 1992 and 1993. Twenty-one fish species (7 native and 14 nonnative) and three catostomid hybrids were collected (Burdick 1995). This indicated that the Gunnison River, although regulated by upstream reservoirs and dams for over 30 years, still harbors a healthy population of native fishes. Native fishes comprised 79% of all the large-bodied fishes collected with electrofishing in the warmwater reaches of the Gunnison River in 1992 and 1993. B1 uehead- sucker and flannel mouth sucker were two of the most common native fishes in the Gunnison River. Bluehead sucker comprised 36%.of the catch in 1992 and 1993 together whereas flannel mouth sucker comprised 29% of the catch in those two years. Roundtail chub was the third most common native fish (14%). Common carp, fathead minnow, red shiner, and sand shiner are the most abundant of the nonnative fishes in the Gunnison River. White sucker are very abundant in the Gunnison River near Delta and appear to be expanding downstream (Burdick 1995). During the same investigation, three small-bodied nonnative cyprinids (fathead minnow, sand shiner, and red shiner) were extremely abundant and comprised the majority of all fishes collected in backwaters and low-velocity habitats with both hand nets (83%-1992; 47%-1993) and seines (46%-1992; 23%- 10