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3 encompassed at least 25% of the backwater's surface area. The sampling crew would continue to travel downstream until a second suitable backwater was located within the 5-mile section. Defined as the secondary backwater, it would be sampled in the same manner. If no secondary backwater was found prior to the end of the 5-mi section, no additional sampling was done. This sampling procedure was repeated in each 5-mi reach. All Colorado squawfish large enough to reliably indentify in the field were measured for total length, counted, and released alive. In the primary backwater samples, all fish specimens were identified and counted. Fish too small to reliably identify in the field were preserved and subsequently identified in the laboratory. Samples from secondary backwaters were preserved after releasing all Colorado squawfish and other fish species that could be reliably identified. These samples were searched for small Colorado squawfish in the laboratory. The methodology, sample design, equipment specifications and data analyses required are fully described in the monitoring handbook. Results The data collected according to the above monitoring efforts are provided to the U. S._ Fish and Wildlife Service-Colorado River Fishes Project office in Grand Junction, where it is included in a centralized monitoring databank. Summaries of annual data collection throughout the Upper Colorado River Basin and calculated clf indices are provided to contributing agencies in an annual report (U.S. Fish and Wildlife Service 1987). Fall - Colorado squawfish YOY: Within Colorado, only 32 YOY Colorado squawfish were collected from 12 primary backwaters and 10 secondary backwaters in 1986 (Table 1). Mean clf indices for the two backwater types were 3.02 to 3.14 fish/100m2. Captured specimens averaged 24-26 mm total length, and ranged from 19-33 mm. Relative to results from the lower reach of the Colorado River in Utah, the abundance of YOY Colorado squawfish in the upper river reach within Colorado was quite low (68-84% lower than in Utah), but coefficients of variation of 118-212% for the clf indices indicated sampling variation was also considerable for all river reaches sampled. The mean length of Colorado squawfish YOY in the upper reach was slightly less than that observed in the lower reach, though the range of sizes collected for both reaches was similar. Eleven other species were collected in the seine hauls (Table 2). Most abundant in the upper reach of the Colorado River were fathead minnow (Pimephales promelas), bluehead sucker (Catostomus discobolus), and speckled dace (Rhinichthys osculus). Coefficients of variation for mean clf indices for all species ranged from 32-238% and averaged 134%, indicating seine sampling provided highly variable results. This tendency appeared characteristic of seine sample statistics for the lower Colorado-River reach and two reaches in the Green River (U.S. Fish and Wildlife Service 1987).