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transported downstream. Drift net sampling was not included in the original scope of work but <br />was conducted because it is a useful technique to detect the presence of early life stages of <br />Colorado pikeminnow Ptychocheilus Lucius in other areas of the Green River system (Bestgen et <br />al. 1998). Sampling in 1993 was exploratory and limited in scope. In 1994, sampling was for a <br />full season, but in 1995 sampling was limited by high flows in the Yampa River which prevented <br />access to the sampling site until late summer. Samples were collected daily at mid-morning (ca. <br />0900 hr) with conical drift nets (0.15 mZ mouth diameter, 4 m long,~560 µm mesh) set near shore <br />in water 30-40 cm deep. Three nets were set on each sampling occasion for up to 2 hr, but <br />sampling ceased if debris load exceeded 3.8 L/sample. Water depth at which a white object <br />disappeared from sight was recorded as a measure of water turbidity. General Oceanics flow <br />meters (mode12030) suspended in each net mouth recorded water velocity during the net-set. <br />Samples were fixed immediately in 100 % ethanol and fish were removed from debris within 4 <br />hr and preserved in 100 % ethanol. Ethanol was used to ensure that fish otoliths were useful for <br />analysis if desired. <br />Collection oflarge-bodied fish.-Most collections oflarge-bodied fishes were by <br />electrofishing; angling and trammel nets were used on a limited basis. Two sampling trips in the <br />lowermost 8 km of Lodore Canyon were completed in autumn 1994 using angling as the sole <br />sampling technique. Raft-mounted electrofishers were used to sample the lower portion of <br />Browns Park and Lodore Canyon and employed either Coffelt VVP-15 or Smith-Root units. <br />Water conductivity was 300 to 700 microsiemens and electrofishing units usually produced 3-8 <br />amperes with about 350 volts. On the first two electrofishing efforts (12-15 July 1994, 12-14 <br />May 1995) a single raft (Coffelt VVP) was used; during the latter two electrofishing efforts (12- <br />14 September 1995, 29 April-1 May 1996) two electrofishing rafts (Coffelt and Smith Root <br />units) were used. Generally, 1.5-3 km reaches were electrofished before fish samples were <br />processed. Electrofishing effort was continuous throughout the reach and concentrated along the <br />bank, in deep pools, eddies, or near cover. We attempted to capture all fishes that were stunned <br />and efficiency was good because water was generally clear and fish were easily observed. Most <br />7 <br />