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on the depth of the water, as depths greater than 1.2 m could not be effectively seined. Depletion was ~ conducted with a series of seine hauls starting as close to the main-channel as possible and working towards the end. The length and width of the backwaters and the individual seine hauls were measured to calculate area seined and catch-per-unit-effort (CPE; #fish/m2). ~ The first seine haul in each backwater was visually scanned for native fish. If native fishes appeared to comprise > 50% of the contents, all fish were immediately returned alive and the crew proceeded to the next habitat. This was intended to minimize mortalities of native fish. If the initial haul ~ contained < 50% native fish, it and all other seine hauls were quickly examined for native fish which were identified by species, counted, measured, and returned to the habitat, or kept in buckets until the process was finished and then returned, while all nonnative fish were identified by species or classified as NNC, ~ and counted. If seine hauls produced relatively few nonnative fish, all fish were identified and counted in the field. If seine hauls produced too many fish to identify individually, fish were collectively classified as NNC or identified to other nonnative species and split into subadult/adult categories (less than or greater than 40 mm TL, respectively). Nonnative cyprinids were usually grouped into one category (NNC) for processing so individual percent compositions are unavailable for red shiner, sand shiner and fathead minnow. In some cases, entire samples or subsamples were preserved (after identified native fish were released alive) to be enumerated later. Samples from approximately eight habitats per trip were preserved. Nonnative fish not preserved were buried on site. Backwaters above and below the treatment reaches were sampled as controls. Control sites were sampled as described above except that all fish were returned alive to the backwater to compare CPE between treated and untreated areas. Only one seine pass was conducted. 2.2.1 Green River Methods Nonnative cyprinid removal efforts on the Green River were primarily intended to benefit ~ razorback sucker (Xyrauchen texanus) and Colorado pikeminnow (Prychocheilus lucius). From 1994- 1999, razorback sucker larvae were found in the lower Green River during spring high flows, in large flooded washes (Muth et al. 1998, Chart et al. 1999). Razorback sucker spawn on the ascending limb of ~ the hydrograph (Bestgen 1990; Muth 1995; Muth et al. 1998). Timing of depletion sampling on the Green -4-