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^ Achi-square analysis of presence /absence YOY chub in Westwater Canyon by habitat depth indicated no selection -supporting the finding of opportunistic habitat use described above. Habitat depth was positively correlated with peak flows and more strongly correlated with flows at the time of sampling (See Table 11; pg 17). Shallow habitats were defined as those having a maximum depth < 0.7m. ^ Chub nursery areas in Westwater Canyon were not created by the transport and deposition of fine sediments. Habitats were relatively ephemeral, appeared in the same places from year to year, and were created as a function of river stage and resultant inundation of shoreline features, i.e. not a function of the high spring flows. Amount of embayment habitats was positively correlated with summer sampled flow. Throughout the study, summer flows were high during years of high spring peaks. We do not suggest creating higher flows during otherwise low flow _ summer conditions - i.e., if given the choice, manage for growth of YOY chubs (see below) as opposed to YOY chub habitat. However, summer flows near 6000 cfs, which increase the amount of embayment habitat relative to backwaters, may benefit humpback chub by controlling nonnatives. The same summer flow scenario may benefit humpback chub over roundtail chub if the Recovery Program ever decides to manage for one native species over another. ^ YOY Colorado pikeminnow were scarce in the study reach despite the presence of backwater habitats immediately upstream of Westwater Canyon. The nursery habitats were likely too close to spawning areas for drifting larvae to utilize them. ^ YOY densities of speckled dace and bluehead sucker CPE were positively correlated with Stateline peak flow (See Table 14; pg 19). ^ YOY densities sand shiner, fathead minnow, and red shiner CPEs were negatively correlated with Stateline peak flow (See Table 14; pg 19). ^ Densities of fathead minnow and red shiners were low in Westwater Canyon due to lack of preferred habitat. The benefits of spring flows in excess of 30,000 and 40,000 cfs identified earlier would negatively impact nonnative cyprinids. Recruitment ^ Recruitment through the third growing season was evaluated for three cohorts by comparing densities of YOY (fish / mZ) and subsequent densities of Age 1+ and 2+ chubs (fish / electrofishing hr). The 1994 cohort recruited best to the Age 1 year class, while the 1993 cohort did the worst. A suite of environmental variables were considered to better understand this observation. Although the 1994 Age 0 cohort was not particularly abundant they had grown better than the other cohorts. August 1994 flows averaged 2742 cfs and main channel temperature averaged 25.9°C. Steady flows of 3000 cfs as soon as possible after the spring peak, maintained through the winter would likely benefit Age 0 overwinter survival. Relationships between flow metrics and recruitment from Age 1+ to Age 2+ were less conclusive. The results of this analysis suggest that survival was high (undetermined) for juvenile chubs larger than 100 mm TL. ^ Electrofishing CPE decreased little throughout the summer once chubs reached 100mm TL suggesting high survival rates of juvenile chubs. 29