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crease in young of two common native fishes, bluehead sucker (Catostomus discobolus) and speckled dace (Rhinichthys osculus), and a decrease in young Colorado squawfish. During 1989, another year of low flows in the Colorado River, abundance of the three common introduced minnows further increased (Fig. 2.) Valdez (1990) noted a similar relationship between flows and abundance of red shiners, fathead minnows and sand shiners in lower reaches of the upper Colorado River (Potash to lower Cataract Can- yon) during 1985-1988. McAda and Kaeding (1989) examined the relationship between peak flows and the relative abundance of post-larval fishes in the upper Colorado River (Green River confluence to Grand Junction). They regressed peak discharge against mean numbers of fish per area seined. Their results indicated differing responses to peak flow among species, and between upper and lower river reaches within species, The overall pattern, however, support- ed earlier observations that the more common non-native fish species were in greatest abundance in summers following low spring flows and were in lowest densities during periods following high spring flows. Unfortunate- ly, even following extremely high record flows, these non-natives were not eliminated. Nonetheless, the importance of high flows in reducing densi- ties of these species was demonstrated. For Colorado squawfish, however, the trend was reversed: abundance of young-of-the year (YOY) squawfish in the lower reach increased with increased peak flows, although it was reduced following record-high discharges (Fig. 3). When the two record high-flow years were excluded from the analysis, catch rates of YOY were highly correlated with peak flow (r = 0.98; P < .01). Years of highest squawfish YOY abundance were 1985 and 1986 when peak flows at the State line gage were 38,200 and 32,800 cfs, respectively. McAda and Kaeding, 13