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3 <br />video. Individual habitats were mapped onto aerial videographs and overlays to determine seasonal <br />overlap, and to determine their persistence through time. Habitat persistence was evaluated beginning <br />with post-flood habitats and ending in spring prior to the flood. <br />Habitats were classified by relating types of habitats back to the hydrological process which <br />formed them (John Schmidt USU) (Table Al). The development of each habitat is also related to <br />fluctuating flow levels and was divided into three stages: 1) low velocity flow (side channels and <br />shoreline areas), 2) backwaters (areas with no flowing water and one end open to main channel), and <br />3) isolated pools (areas with no access to the main channel). <br />We collected fish from each habitat using a 1.2m by 4m seine, with 1.6mm mesh size. The <br />number of seine hauls varied from one to three with the size of the habitat. In general, habitats wider <br />than 4m but less than 25 meters long were seined once, those between 25 and SOm seined twice, and <br />those > SOm seined three times. In large habitats, the seine hauls were usually made at the transects. <br />Habitats less than 4m wide and 25m long were completely seined in one pass. <br />Native fish were identified, measured and released in the field. Colorado squawfish mortalities <br />were preserved in ethanol during the first two years of the study, and were transferred to the Larval <br />Fish Laboratory at Colorado State University (CSU) for future analysis of scales and otoliths. Non- <br />native fishes were identified and separated into adult/subadult categories in the field, or were <br />preserved in fornialin for later identification and enumeration. Mean catch-per-effort (CPE) in area <br />(#fish/100m2~ and volume (#fish/100m3~ was calculated per trip from all fish collected, divided by the <br />area and volume sampled in all seine hauls. <br />