Paddlefish Management, Propagation, and Conservation in the 21st Century

<em>Abstract</em>.—We evaluated the influence of prey composition and abundance on survival and growth of age-0 paddlefish <em>Polyodon spathula </em>in 0.5-ha rearing ponds. Cladoceran abundance was measured in the spring of 1999 (<em>n </em>= four ponds), 2000 (<em>n </em>= six ponds) and 2005 (<em>n </em>= five ponds) at Gavin’s Point National Fish Hatchery, South Dakota. Using an information theoretic approach, we found that density of small cladocerans (e.g., <em>Bosmina</em>) at the time of larval stocking was the best supported model in explaining paddlefish survival. In contrast, estimates of <em>Daphnia </em>abundance (initial, mean, and maximum density) were poor predictors of paddlefish survival. Neither the magnitude of <em>Daphnia </em>abundance nor whether abundance was increasing or decreasing in the ponds after stocking appeared to influence paddlefish survival. Paddlefish growth, however, was positively related to mean <em>Daphnia </em>abundance in ponds. These patterns highlight the need to better understand larval feeding ecology of paddlefish and the role of electrosensory detection as it relates to prey composition and abundance.