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floodplain wetland (Christopherson et al. 2004), evaluated growth and survival of larval <br />razorback sucker following "reset" (i.e. elimination) of the fish population due to an <br />extended drought and subsequent drying of the floodplain depression. Two enclosures <br />were used to control the experiment. Nonnative fish species obtained from the river and <br />a nearby floodplain were introduced at densities present during the natural connection of <br />the river with the floodplain wetland (Birchell et. al. 2002). Larval razorback sucker and <br />bonytail were then stocked into the enclosures at very high densities. These razorback <br />sucker and bonytail larvae along with introduced nonnative species were maintained in <br />the enclosures for approximately three months. During this time, nonnative species <br />reproduced and dramatically increased in numbers. Subsequent sampling to evaluate <br />growth and survival revealed that several thousand larval razorback sucker and bonytail <br />survived in the presence of abundant nonnative fishes. <br />This study evaluates survival of larval razorback sucker and bonytail at much <br />lower densities following reset of the floodplain fish population than those described in <br />Christopherson et. al. 2004. It provides the Recovery Program with an estimate of the <br />density of larval razorback sucker and bonytail necessary for measurable survival in the <br />presence of expected predator densities in a reset floodplain wetland. <br />Specific objectives were to: <br />1. Evaluate survival and growth of larval razorback sucker in the presence of <br />nonnative predators by introducing larvae into experimental enclosures over a <br />range of densities. <br />2 <br />