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<br />The purpose of this study was to evaluate survival and growth of larval razorback suckers <br />following a "reset" of nonnative fish populations in floodplain habitat. However, because of the <br />draught a natural connection with the river did not occur. To overcome this problem water was <br />pumped into The Stirrup site and larval razorback suckers were stocking into two I;" acre <br />enclosures at different stocking densities. Each enclosure was stocked with densities of <br />nonnative fish similar to those observed during an initial connection period. Following stocking <br />zooplankton densities and water quality was monitored at the site through the study. Survival <br />estimates for razorback suckers were tabulated in late July at the conclusion of the study. <br /> <br />Survival of larval razorback suckers inside each enclosure was detected and progress is <br />on track given the flow conditions. Further progression regarding larval razorback sucker <br />survival in floodplain habitat will occur when larval fish are stocked into a floodplain site <br />without enclosures during a year flows are adequate for natural inundation. This will more <br />closely mimic a natural scenario than can be achieved with enclosures and artificial maintenance <br />of water in the site. If adequate flows occur next year this study could be completed at the end <br />of next summer. <br /> <br />IV. Study Schedule: 2002 - 2004 <br /> <br />V. Relationship to RIPRAP: <br />GREEN RIVER ACTION PLAN: MAIN STEM <br />II. Restore habitat <br />II.A.3. Implement levee removal strategy at high priority sites. <br />II.A.3.c Evaluation <br /> <br />VI. Accomplishment of FY 2002 Tasks and Deliverables, Discussion of Initial Findings and <br />Shortcomings: <br /> <br />Task I: Stock larval razorback suckers into two !I.-acre enclosures at The Stirrup. <br /> <br />Larval razorback suckers were stocked into each enclosure at the site. There were 60,373 <br />larval razorback suckers stocked into one enclosure and 457,193 stocked into the other. Each <br />enclosure was also stocked with about 75 fathead minnows, 42 red shiners, 16 black bullheads, <br />12 green sunfish and 4 carp. A 16' X 16' control pen received 1,000 larval razorback suckers <br />and no nonnative fish (Appendix Table I). <br /> <br />Task 2: Field data collection <br /> <br />Between initial stocking and termination of the study, zooplankton densities inside each <br />enclosure and outside in open water were sampled weekly to document food availability. <br />Temperature and dissolved oxygen were monitored through 24 periods on several occasions per <br />week. Efforts to visually observe fish were also made during this period. Dissolved oxygen <br />levels remained adequate for fish survival through the study. Zooplankton levels were in decline <br />a few weeks before the end of the study. <br /> <br />C-6 rz page 2 <br />