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<br /> <br /> <br /> <br />L <br />L? <br /> <br />1 <br /> <br /> <br /> <br /> <br />1 <br /> <br />fl <br /> <br /> <br /> <br />length of channel catfish significantly (p < 0.05) decreased and fewer large channel <br />catfish were collected. Few changes in distribution, abundance, and size class of <br />common carp were observed. Additional removal efforts were concentrated on a discrete <br />eight mile reach of the San Juan River between two water diversion structures. These <br />intensified efforts have led to seasonal declines in both channel catfish and common carp <br />abundance and significant declines in mean size class of channel catfish. Significant <br />reductions in distribution and abundance of large bodied non-native fishes in the San <br />Juan River by mechanical removal may reduce negative interactions with native fishes <br />and assist in the recovery of both the Colorado pikeminnow and razorback sucker. <br />Research and Monitoring <br />Translocation of humpback chub (Gila cypha) above Chute Falls, Little Colorado <br />River <br />Sponholtz, Pamela J.1, Dennis M. Stone 1, and Kara Hilwig2 <br />'USFWS, AZFRO-Flagstaff; z Northern Arizona University. <br />In summer 2003, the Arizona Fishery Resources Office, along with personnel from the <br />Arizona Game and Fish Department, released 283 humpback chub (HBC) into the Little <br />Colorado River (LCR), above Chute Falls, near river kilometer 16.2. HBC were captured <br />via baited hoop nets and seining near the confluence of the Colorado River. All <br />translocated fish were implanted with a yellow elastomer tag near the dorsal fin insertion <br />on the left side to identify them from downstream populations. This action was part of <br />the December 6, 2002, Biological Opinion on the proposed experimental releases from <br />Glen Canyon Dam and removal of nonnative fish. As a conservation measure for this <br />project, the U.S. Bureau of Reclamation, Grand Canyon Monitoring and Research Center, <br />and the National Park Service agreed to relocate approximately 300, 50-100 mm HBC to <br />upstream areas of the LCR in an attempt to increase survivorship of HBC. It is hoped <br />that this translocation will increase HBC recruitment to adulthood by allowing them an <br />opportunity to exploit the abundant food resources, warmer water temperatures, and <br />reduced competition/predation by fewer large-bodied fishes associated with this area. <br />During post-translocation monitoring efforts in October 2003, we captured (42) HBC <br />during three days using baited hoopnets from river kilometer 14.5 to 16.8. Of the 42 <br />HBC captured, 9 individuals had no elastomer tag. However, significant fading of the <br />elastomer tag occurred in nearly all HBC captured that retained the tag. One of the <br />larger individuals (143mm) was found 0.5 km upstream of the release site and had no <br />visible tag. This suggests either upstream movement by HBC from below Chute Falls or <br />significant growth and subsequent loss of the elastomer tag. In addition, the largest <br />marked individual was 134mm, which indicates that this fish experienced at least 34mm <br />of growth between the release date, August 1, and the monitoring date of November 1 (92 <br />days). All HBC captured were implanted with a 134.2Khz PIT tag and released back into <br />13 <br />