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Methods <br />Adult Sampling <br />Adult (> 200 mm TL) humpback chub were collected in the spring, summer, and <br />autumn of 2003 and 2004 (Table 1) on the descending limb of the hydrograph and during <br />base flows. Fish were sampled using raft-mounted pulsed DC Smith Root® <br />eectrofishing equipment throughout the study area and trammel nets (23m x 2m; 2.5 cm <br />mesh) in Split Mountain and Whirlpool canyons. Habitats sampled included small rapids, <br />pools, eddies and backwaters. <br />Electrofishing was accomplished with two boats each covering opposite banks of <br />the river throughout Yampa, Lodore, Whirlpool and Split Mountain Canyons. <br />Electrofishing was done entirely during daylight hours. Supplemental angling captures of <br />humpback chub were used from Recovery Program Project No. 110 (catfish removal, <br />volunteer angling). <br />Trammel nets were set approximately one hour before sunset and checked hourly <br />until two hours after sunset. Trammel nets were set in areas of Whirlpool Canyon <br />suspected to be occupied by humpback chub and in other deepwater areas in Whirlpool <br />and Split Mountain Canyons. <br />All humpback chub were measured for total length, weighed, scanned for the <br />presence of PIT tags, tagged (if necessary) with PIT tags and immediately released. <br />Locations of the captures were recorded. <br />4 <br />