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the water has stratified. In shallow areas-with structure are slightly warmer than the Fnnd Hahitc the spring and fall, they can be found in (e.g., submerged trees) where water temperatures open reservoir. -`- Crappie fry feed mostly on zooplankton. They switch to larger prey (e.g., insects) quickly as they grow. Crappies become piscivorous early in life and the food of adult crappie is primarily fish if fish are available- as-forage (Carlander 1977). On the other hand, stunting often occurs in crappies if forage fish are not available. Discussion Related to Potential Competition/Predation It is not known how crappies and the Colorado squawfish might interact since crappies would occupy primarily reservoirs where knowledge of squawfish habitat, movements, and behavior are lacking. However, the piscivorous food habits of the crappie indicates that a potential for both competition with or predation upon the Colorado squawfish exists. DISCUSSION/SUMMARY The habitat used by centrarchids (e.g., largemouth bass, bluegill, and crappies) and channel catfish as well as their food habits and temperature preferences indicates that the potential exists for competion/predation with Colorado squawfish. In the 125-kilometer reach of the White River between Rio Blanco Reservoir and the Colorado-Utah state line (River Kilometers 71.8 to 243.0), native fishes comprised 74% of the total number sampled during 1983-1985 (Martinez 1986a). A single black crappie was collected below Rangely in 1984 during the sampling and a single northern pike (Esox Lucius) was caught by a rancher about 12 miles downstream from Rio Blanco Reservoir in 1983 (Martinez 1986a). No largemouth bass or bluegills were found in the White.River during the 1983- 1985 studies although it is possible that these species may become established in suitable habitat of Kenney Reservoir from Rio Blanco stocks. Optimum growth of the Colorado squawfish occurs at 25 C (Black and Bulkley 1985) and this species showed a preference for this temperature. At temperatures above or below the optimum (i.e., 2U and 30 C), squawfish growth was about 50% of the optimum. Waters in the Upper Colorado River Basin reach the 25 C optimum temperature for a short time during July and August (Appendix B in Archer et al. 1985). Backwaters and eddies along the mainstem rivers become even warmer and will attract warmwater predatory sport fish. Such fish have changed the community structure and availability of forage organisms through predation (Bremer 1964; Brown 1965; Curtis 1942; Lemly 1985; Meffe 1984; Minckley 1982; Moyle and Nikols 1973; Moyle, Li, and Barton 1986; Rivero 1936). The percentage of predatory sport fish has been low in most reaches of the Upper Colorado River Basin (Table 1). However, small numbers of predators may add significantly to morta-lity of larval and juvenile fishes in certain habitats where they are confined. Probably a more important consideration is the introduction of nonnative forage species that may compete with the early 9