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hypothesized that upstream movement of young adults is a response to resource gradients. More specifically, we hypothesized that upstream dispersal results from individuals seeking foraging areas more likely to meet the changing food requirements of a growing piscivore. Hence, we also investigated spatial variation in Colorado squawfish body condition and abundance of likely forage species. STUDY AREA Our study area included the entire portion of the upper Colorado River occupied by Colorado squawfish, from the downstream confluence with the Green River in Utah upstream to the Grand Valley Diversion Dam at Palisade, Colorado. It also included the lowermost 3.5 km of the Gunnison River, between Redlands Diversion Dam and the confluence with the Colorado River (Fig. 1). Colorado River locations described herein are in river kilometers (RK) from the Green River confluence (RK 0.0) and are conversions of river miles mapped by Belknap and Belknap (1974). Based on the distributional pattern of adults and juveniles, the study area (Fig. 1) was partitioned into a lower reach that extended from RK 0.0 upstream to the lower end of Westwater Canyon (RK 181.0), and an upper reach, from the upper end of Westwater Canyon (RK 200.0) to RK 298. 1, the upstream terminus of the study area. Westwater Canyon, a 19-km section dominated by large rapids and turbulent eddies, was excluded for logistical reasons and because past studies have indicated few Colorado squawfish are found there (McAda and Kaeding 1991). METHODS Distribution and movement To document distribution of Colorado squawfish, we systematically captured individuals from throughout the study area over a four-year period (1991-1994). The river was divided into seven strata based on major changes in average channel gradient (Fig. 1); our study area consisted of three strata upstream and three downstream of Westwater Canyon (Stratum 4). The distribution of various sizes of Colorado squawfish was examined by comparing mean lengths of captured fish among river strata using standard ANOVA and the Tukey-Kramer multiple-comparison test. We also used a T-test to make between-year comparisons of mean length within strata. To measure movements of Colorado squawfish, locations of first and subsequent captures of tagged fish were compared. Our primary capture method was to set trammel nets in backwaters, flooded ponds and flooded canyon mouths because these calm habitats were known to attract Colorado squawfish during the spring runoff period (Osmundson and Kaeding 1989). We began B-2