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2 <br />ADULTS: Arizona State University (ASU) coordinated the collection of ripe <br />adult razorback suckers for release into Yuma Cove. Members of the NFWG <br />collected the fish with trammel nets in late January. Fish were inspected, PIT <br />tagged and released into Yuma Cove to spawn. Spawning was observed from <br />mid-February through April. Of the original 88 fish used as brood stock, 82 <br />were recaptured during the year and released back into the reservoir. Five <br />fish were found dead during the year, and one fish was not accounted for. <br />PIT tag retention was good for the 82 live recaptures, with only two fish <br />having to be retagged. <br />LARVAE/JUVENILES: Yuma Cove was monitored weekly following stocking <br />of adults. The first razorback sucker larvae appeared in Yuma Cove in late <br />February. Larvae growth was also monitored in the lake during this period. <br />Larval growth in Yuma Cove backwater was substantially greater than growth <br />in the lake (See Appendix B, Monitoring of larval razorback sucker growth <br />in L.Mohave - Spring 1992 by Mike Horn). <br />Overall, the growth of the young razorback suckers was phenomenal. Table <br />1 displays the mean size of juvenile suckers reared at Yuma Cove during 1992. <br />The larvae were first observed in late February at 11 millimeters length. They <br />doubled their size by late April (26 mm) and doubled again by early June (100 <br />mm). The fish reached 200 mm in late July and by October the average <br />juvenile razorback sucker captured in Yuma Cove was over the target release <br />length of 300 mm. <br />LIGHT TRAPS: In an effort to standardize and quantify larval fish <br />collections, razorback sucker larvae were monitored using light traps. <br />Different lighting techniques were developed and tested in Yuma Cove and <br />Arizona Bay. Traps using white light powered with gel-cell batteries proved <br />to be very effective in attracting sucker larvae. Trapping indicated spawning <br />in Yuma Cove peaked in March while reservoir larval densities continued to <br />increase until mid-April. A special report on the light trapping effort is <br />provided as Appendix C. <br />C <br /> <br />