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<br />the left pelvic fin. <br /> <br />All native fish implanted with PIT tags exceeded 150 mm. All nonnative <br />fish captured that were tagged with Floy tags were at least 200 mm. All fish <br />that were fin clipped were at least 100 mm. Only fish captured downstream of the <br />GVIC Diversion were marked. No fish were marked after 28 August nor upstream of <br />the GVIC Diversion Dam during this study. <br /> <br />Centrarchids (largemouth bass and smallmouth bass) and ictalurids (channel <br />catfish) that were captured up- and downstream of the GVIC Diversion Dam as "by- <br />catch" were removed and disposed. Mountain whitefish were not marked or tagged <br />and were released alive. All other nonnative fishes (carp, white sucker, and <br />sucker hybrids) except salmonids collected upstream of the diversion dam were <br />removed. <br /> <br />Sampling upstream of the diversion dam with electrofishing attempting to <br />recapture marked fi sh that had moved from the downstream reach was conducted once <br />prior to spring runoff and 10 times during post-runoff river stage. Sampling <br />downstream of the diversion dam to mark and tag fish also resulted in recapturing <br />some of the fish previously marked and tagged. Prior to- and following runoff, <br />eight days were dedicated to each sampling effort downstream of the diversion <br />dam. <br /> <br />Sampling was conducted either from an outboard-powered, 16-foot, aluminum <br />jon boat or from a 14-foot, oar-powered rubber raft. The jon boat was equipped <br />with a 5-kilowatt Honda generator and a Coffelt@ VVP-15 voltage pulsator to <br />adjust the voltage and amperage transmitted to the water. The rubber raft was <br />used during low-flow conditions and was equipped with a 5-kilowatt Vanguard@ <br />generator and a Smith-Root@ 5.0 GPP voltage pulsator. Investigators used direct <br />current and tried not to exceed 300 volts or 12 amps to minimize injury to fish, <br />while maximizing electrofishing effectiveness. <br /> <br />The second method incorporated telemetry to follow movements of sub-adult <br />and adult Colorado pikeminnow captured in the 15-mile reach that had been <br />implanted with LOTEK@ coded transmitters (model no. MCFT-7A). The transmitter <br />weighed 29.0 g (air weight). was 83-mm long with a 16-mm circumference, and had <br />a theoretical life of about 360 days. It was surgically implanted <br />interperitoneally into adult Colorado pikeminnow using techniques outlined by <br />Hart and Summerfelt (1975) and Tyus (1984). The transmitter had an external <br />antennae, that consisted of a plastic-coated metal cable, that was approximately <br />16-inches long, and that extended outside the fish which required slight <br />modification in surgical technique (Ross 1982). <br /> <br />Lotek@ SRX 400 telemetry receivers were used to monitor movements of <br />transmitter-taggE!d fish. One land-based tracking station was deployed in mid- <br />April 1998 at the GVIC Diversion Dam. This station consisted of a data-logging <br />receiver and two, four-filament Vagi antennae arrays that constantly monitored <br />and recorded signals from tagged Colorado pi kemi nnow. One antennae array <br />constantly checked for fish immediately downstream of the diversion dam whereas <br />another antennae checked for fish passing through the newly-constructed notch. <br />Because the land-based. data-logging receiver was powered by a photovoltaic panel <br />equipped with a solar battery that stored electricity, the data logger was <br /> <br />6 <br />