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Annual flows varied greatly throughout this study. Daily flows in 1992 and 1994 were below average, 1993 and 1995 were above average and flows in 1996 were only slightly above average as determined by the USGS at the Near Cisco, Utah, gage (1914-present). Only three significant correlations were found between spawning success as measured by YOY captures and a variety of flow metrics. July YOY CPE both above and in Westwater Canyon were found to be positively correlated with the previous year's peak flow. This relationship held true for August catch rates in Westwater Canyon, but the relationship was not significant. In addition, August CPE above the canyon was negatively correlated with the amount the June monthly flow deviated from the historic June monthly flow (CISJUNDEV). August CPE in the canyon was also negatively correlated with CISJUNDEV, however, the relationship was not significant. In Figure 8, it appears that chub reproductive success was optimized when the Colorado River peaked near 30,000 cfs as it did in 1996. Flows much less than this and flows much greater were likely _ outside the optimum flow window indicating the relationship is not linear. More data points are needed to validate this relationship and better define the boundaries of this flow window. The above-canyon August relationships were the most varied because of the 1993 data point when high catch rates were recorded during high flows. From this single data point, we might postulate that the optimum flow window for roundtail chub (humpback chubs are scarce in this stretch of river) reproduction is broader or shifted toward higher flows. Another alternative may be that suitable spawning habitat is available at higher flows in the stretch of river upstream of the canyon. The link between July catch rates and the previous year's peak both above and within Westwater Canyon stems from the high July catch rates in 1994 (low water year) and 1996 (moderate water year). Both 1994 and 1996 followed high water years. Although production was down in 1995, it may have created an optimum spawning situation the following year, particularly in the Westwater Canyon sub- reach. This finding indicates the need for a variety of flows from year to year and the importance of flows in excess of 40,000 occasionally. Historically (period of record 1914 - 1962), a peak flow of 40,000 cfs as recorded at the Cisco, Utah, gage was exceeded 55% of the time. The results of this study suggest that a flow frequency of 40,000 cfs once in 3 years may be adequate to benefit native chubs. Fish community monitoring efforts in Desolation Canyon, 1992-1996, provided a measure of chub reproductive success, but were not designed to elucidate flow relationships (Chart and Lentsch 1998). YOY chub catch rates there were greatest in 1993, the second highest flow year of that study. Catch rates were down again in 1995, the highest flow year, as they were during the low flows of 1992 and 1994, which indicates a similar flow relationships as found in Westwater. Day and Crosby (1997) conducted a much more intensive examination of YOY chub (and pikeminnow) habitat use, reproductive success and flow relationships in Desolation, 1994-1996. Their catch rates were greatest in 1994 (low flow year), lowest in 1995, and moderate in 1996. They did not sample in 1993. Although the authors of that study were unable to develop conclusive flow relationships based on three years of study, it appears their findings do not fall in complete accordance with the findings of this study. The chub population and the fish community in general in Desolation is vastly different than that found in Westwater Canyon and any comparisons between the canyons are consequently complicated (Chart and Lentsch 1998). YOY Chub Habitat Above Canyon. Roundtail YOY in this reach of the river were found in all habitat types sampled. The overwhelming majority of available low velocity habitats were backwaters, but YOY chubs were found in the less frequently sampled habitats (shorelines, secondary channels, pools and isolated pools) as well. The densities of YOY chubs were greatest in the backwaters indicating some selection for that habitat type. Backwater habitats were readily available until Colorado River flows exceeded 9000 cfs, but total 22