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<br />additional parameters are identified that will improve our current index of relative abundance <br />(mean CPE). If parameters are identified that would add precision to this analysis, the 1989 <br />through 1991 video could be reinterpreted as well. <br />The Nursery Habitat study will also provide additional information on the reliability of <br />the current monitoring program as an index of relative abundance. Because the habitat study <br />samples a 10-mile subreach much more intensively than ISMP samples the same subreach, it <br />can serve as a check on the abundance index generated by the monitoring program. It will <br />determine if mean CPE from samples in two backwaters within a 5-mile subreach is <br />representative of CPE in the subreach as a whole. Another study that could evaluate ISMP <br />is being conducted by the Service in the Green River. Small Colorado squawfish are <br />collected using techniques similar to ISMP, marked with dye to identify their original <br />collection site, and released back into the river. Investigators then resample the same reach <br />looking for marked Colorado squawfish. The population estimate generated from this study <br />can be compared with mean CPE generated from ISMP for the same reach. Collection of <br />these two variables over several years will allow comparison of change in CPE with change <br />in estimated population size. <br />Aerial video is probably most useful as a tool for monitoring channel change in the <br />major rivers of the upper basin. Information about the distribution and abundance of <br />backwaters, channel width, and number and location of side channels at different flows falls <br />in that category. However, it is unlikely that relationships such as these will be valid for <br />long periods. Large runoff events or extended periods of reduced runoff could substantially <br />change the stream channel and thus the distribution and number of these physical parameters. <br />Channel changes could be monitored with aerial video flown at standard times of the year (or <br />at specific flow levels) and at regular intervals--every three to five years should be adequate. <br />Unfortunately, video only provides information about the shoreline and water surface. <br />Information about fish habitat, water depth, water velocity, channel profile, and other three- <br />dimensional parameters must be collected by field crews. <br />SUMMARY <br />The Interagency Standardized Monitoring Program estimates the relative abundance of <br />post-larval Colorado squawfish in important river reaches every fall. These data are used to <br />monitor trends in abundance among reaches and rivers, and to evaluate the effect of various <br />biological and physical parameters on reproductive success, growth, and survival of YOY <br />Colorado squawfish. As the program progressed, participants became concerned that mean <br />20 <br /> <br />1 <br /> <br /> <br />1 <br />I? <br /> <br /> <br />1 <br /> <br />1 <br /> <br /> <br /> <br /> <br /> <br /> <br />11