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<br />Fish Community <br /> <br />Native Fishes <br /> <br />Upstream of the Redlands Diversion Dam (river mile 3), native fishes comprised <br />approximately 79% of all fishes collected with electro fishing during a recent riverwide inventory <br />(Burdick 1995). The predominant native fishes include bluehead sucker (Catostomus discobolus), <br />flannelmouth sucker (~. latioinnis), and roundtail chub Gila robusta (Burdick 1995). The <br />Gunnison River upstream of the Redlands Diversion Dam is currently occupied by a small <br />enclave population of Colorado squawfish and is historical habitat for the razorback sucker and <br />bonytail (G. elegans). Five adult Colorado squawfish were captured upstream of Redlands <br />Diversion Dam in the Gunnison River during fishery surveys conducted in ]993. In the swnmer <br />of 1993, one radio-tagged Colorado squawfish was located about 0.2 mile downstream of <br />Hartland Diversion Dam. <br /> <br />No razorback sucker were captured during this two-year survey. The last documented <br />capture of an adult razorback sucker from the Gunnison River was 1981 near river mile 53 <br />(Johnson Boy's Slough area) (Holden et al. 1982). Hartland Diversion Danl presently bisects a <br />] 7-mile long floodplain of the Gunnison River between Roubideau Creek (river mile 50) and <br />Austin (river mile 67). Although razorback sucker appear to be extirpated from the Gunnison <br />River, this 17-mile reach is considered a priority razorback sucker restoration site because it is <br />the only flooded bottomland habitat that exists in warm water reaches of the Gunnison River. <br /> <br />Historically, the upstream range and distribution of the razorback sucker in the warmwater <br />reaches of the Gunnison River are unknown. However, historical accounts indicate razorback <br />sucker were found both up- and downstream of Hartland Diversion Dam (Quartarone 1993; <br />Personal communications, Kenneth Jolmson, Wendell Johnson). How the razorback sucker <br />actually utilized the reach upstream of Hartland Diversion Dam is uncertain, but based on <br />floodplain habitat availability, it may have been used for spawning. Today the transition from <br />cold-water species (e.g., salmonids) to warmwater species (e.g., flarmelmouth and bluehead sucker <br />and carp Cvorinus~) is considered between the confluence with the North Fork (river mile <br />75) and Austin. Conceivably, the upstream range of the razorback sucker could be the confluence <br />with the North Fork because both the native llannelmouth sucker and bluehead sucker are <br />abundant upstream to this point. <br /> <br />Nonnative Fishes <br /> <br />Three nonnative small-bodied species, fathead minnow Pimeohales oromelas, sand shiner <br />Notroois stramineus, and red shiner Cvorinella lutrensis, are prevalent in the Gunnison River <br />upstream of Redlands Diversion Dam. During seining surveys conducted during 1992 and 1993, <br />these three species accounted for approximately 60% of all fish collected (Burdick 1995). In the <br />reach immediately downstream from Hartland Diversion Dam, fathead minnow and sand shiner <br />are abundant whereas red shiner and plains killifish Fundulus zebrinus are common and rare, <br />respectively. A very positive factor for razorback sucker reestablishment in the GUIUlison River <br />is the absence of charmel catfish lctalurus punctatus. Other piscivorous fishes that are rare to <br /> <br />3 <br />