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< 300 mm TL would be vulnerable to predation by many adult Colorado pikeminnow. In calculating catch rates, we pooled numbers of all species, native and nonnative, excepting spined fish (channel catfish and black bullhead) which we assumed to be largely invulnerable to predation. Comparisons of catch rates among strata, among sampling periods, and between habitat types were made using ANOVA on log-transformed (In) data and the Tukey-Kramer multiple comparison test. All strata within the Gunnison River were not sampled as part of this study, primarily because this area had recently (1992-1994) been sampled (e.g. Burdick 1995) and data were therefore already available. Stratification of the Gunnison River by Burdick was similar to that done for this study. Also, electrofishing equipment used in the two studies were the same. However, the years of study were different (one overlapping year), the sampling seasons were somewhat different between studies, and the length and number of study reaches within strata were different (Burdick had only one reach 9 km long). My goal was to link the earlier sampling results to this study while accommodating the differences in technique between the two studies. To do this, the techniques used for the Colorado River strata in this study were used on one Gunnison River stratum to allow a direct comparison with the Colorado River strata results. Burdick's 1992-1994 data for four Gunnison River strata (between Redlands and Hartland diversion dams) were then partitioned in the manner used in this study and his results for this one stratum (sampled in both studies) were then compared with the other three Gunnison River strata sampled only during his study. Stratum 12 of this study corresponds to Stratum 4 (Bridgeport to Escalante) in the Burdick study. Body Condition Comparisons of fish relative body condition (Kn) among strata and among seasons were also used as a means to assess food availability. My analysis focused on the three common soft- rayed, fusiform, native species that likely serve as forage for large adult Colorado pikeminnow (> 550 mm TL): bluehead sucker Catostomus discobolus, flannelmouth sucker C. latipinnis, and roundtail chub Gila robusta. As noted by Hawkins (1992), relative condition (Kn) is a better statistic than is the more widely used Fulton's condition factor (K) because relative condition is comparable between fish of different lengths; Fulton's condition factor does not account for allometric growth and therefore varies by fish length making comparisons among sizes inappropriate (see Le Cren 1951). Relative condition is the observed mass (K) of a given fish divided by the expected mass (Me) for a fish of its length: Kn = M * 100 A The expected mass (Me) is calculated using constants derived from length-weight regressions: Log,Af., _ ((Log,o length) slope) + y-intercept 6