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<br />Seinin has been su ested as a removal techni ue for nonnative c rinids in backwaters <br />g gg q YP <br />(Lentsch et al. 1996). The rapid removal of the majority of fish in the first three or four passes <br />suggests a minimum of three seining passes should be made to ensure adequate removal offish <br />from a backwater. The three pass seining removal could also be used to generate population <br />estimates of young Colorado pikeminnow in backwaters. <br />CONCLUSIONS <br />1) Determine the relationship between availability, formation, and maintenance of Colorado <br />pikeminnow nursery habitat and test release flows from Flaming Gorge Dam. <br />- Establishing a single discharge that is intended to maximize habitat availability every <br />yeaz is inappropriate. Year to yeaz baz topography, and hence habitat availability <br />changes annually. The dischazge that maximizes habitat availability also changes each <br />year, and the habitat availability curve in any year has multiple modes. <br />- As measured at Oura at com ara s <br />y p ble base flows of 45 m /s (1590 cfs) m the summers of <br />1992, 1993 and 1994, total habitat area decreased in 1993 from 19921evels, although <br />azea of deep (quality) habitat increased. In 1994, total habitat area increased, but deep <br />(quality) habitat decreased substantially. <br />i - On the study bar at Ouray, the 1993 peak flow of 570 m3/s (20130 cfs) simplified bar <br />topography and raised bar elevations. Secondary (scour) channel habitat was available <br />at 50-136 m3/s (1765 cfs), and maximized between 100 and 136 m3/s (3530-4800 cfs). <br />The 1994 peak flow of 330 m3/s (11655 cfs) lowered bar elevations. Superimposed bars <br />added shoreline complexity. Several small habitats were available at flows of 50-90 <br />m'/s (1765-3180 cfs). Secondary (scour) channel habitat was available at flows from <br />100 to 136 m3/s 3530-4800 cfs). <br /> - Total and quality habitat availability iri the fall was negatively correlated with high <br /> spring flows at Ouray and Mineral Bottom. Number of backwaters was not correlated <br /> with flow. <br /> - <br />Habitat availability was also negatively associated with high flows at the time of <br /> sampling, although not significantly correlated. <br /> - Habitat availability in the summer and fall at Ouray and Mineral Bottom was minimized <br /> at sampling flows greater than 141 m3/s (5000 cfs), and maximized but variable at <br /> sampling flows from 56 to 113 m3/s (2000 to 4000 cfs) at Mineral Bottom. <br />2) Develop definitions for habitat types based on fluvial geomorphological processes. <br />- General habitat descriptions of large scale habitat features were developed, and used by <br />the biological sampling. More specific habitat types were defined for the study bar and <br />xiv <br />