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Subadult Fish Passage at Tusher Wash Diversion Dam <br />Subadult Tagging <br />A 16-foot long rubber raft, rigged with electrofishing gear, was used to sample fish in the <br />Green River from Swasey's Rapid (river mile [rm] 132) to the Green River State Park boat ramp <br />(rm 120). Most of the effort was expended between rm 132 and rm 125. Electricity was <br />produced with agasoline-powered generator and output current was controlled with a Coffelt <br />VVP-15 electrofishing unit. Output voltage was kept near six amperes. One spherical cathode <br />was used with one anode consisting of cable droppers. One person rowed the raft and controlled <br />the electrofishing gear while one or two people netted fish. Nearly all of the sampling was <br />conducted along shorelines and in shallow areas near islands. All fish captured were kept in a <br />live well until they were measured to the nearest millimeter and weighed to the nearest gram, <br />unless large numbers of fish were captured. In this situation, all native fish and a representative <br />sample ofnon-native fish were weighed and measured. The remaining fish were only <br />enumerated. Thirty-one Colorado pikeminnow and five Gila spp. were tagged with a Passive <br />Integrated Transponder (PIT tag) injected into the body cavity. Two-hundred thirty-one <br />flannelmouth suckers (C. latipinnis) and 182 bluehead suckers (C. discobolus) were tagged <br />below the dorsal fin with individually numbered T-bar Anchor tags (FLOY TAG and <br />Manufacturing, Inc.). Three-hundred thirty-four channel catfish, 35 common carp (Cyprinus <br />carpio) and 1 black bullhead (Ameiurus melas) were tagged below the dorsal fin with T-bar <br />Anchor tags that were not individually numbered. All tagged fish were released downstream of <br />Tusher Wash Diversion Dam. <br />Subadult Telemetry <br />Radio transmitters were used to collect movement data on native fish. Transmitters <br />produced by Advanced Telemetry Systems were implanted in seven Subadult Colorado <br />pikeminnow, nine Subadult flannelmouth suckers, and five subadult bluehead suckers. <br />Transmitters ranged in weight from 2.04 g to 7.59 g (life expectancy from 30 to 85 days) and <br />were never implanted in a fish unless the weight of the transmitter was less than two percent of <br />the weight of the fish. This protocol was followed in an effort to minimize the loss of <br />transmitters (as recommended in Marty and Summerfelt (1986)) and behavioral changes. All <br />transmitters were equipped with an external antenna; however, the antenna was coiled and placed <br />within the body cavity on five of the Colorado pikeminnow, since this configuration has been <br />shown to work well in this species (Tim Modde, U.S. Fish and Wildlife Service, personal <br />communication). <br />Fish that were to be implanted with a radio transmitter were first anesthetized with <br />tricaine methane sulfonate (Finquel brand of MS-222). Transmitters implanted in Colorado <br />pikeminnow were inserted in an incision made along the side of the fish in a position that was <br />anterior to the left pelvic fin. This location was used so that the transmitter would not rest upon <br />the incision. Transmitters implanted in flannelmouth suckers and bluehead suckers were inserted <br />in an incision along the midline of the ventral portion of the body. This location was selected <br />because lateral incisions in suckers (especially in bluehead suckers) tend to bleed copiously <br />(personal observation). A curved needle was used to make a small hole behind the incision used <br />to implant the transmitter (except in the case of five Colorado pikeminnow, as described above). <br />The antenna exited the body cavity through this opening. Fresh water was administered to the <br />gills of the fish during the surgery. Alcohol was used as a disinfecting agent, and saline solution ~ <br />4 <br />