Growth, mortality, fecundity, egg diameter, and age at maturity were determined from samples of 270 paddlefish Polyodon spathula collected from the Atchafalaya River basin and Lake Pontchartrain, Louisiana, during a commercial harvest moratorium from 1987 to 1989. Early growth of paddlefish determined from back-calculation of annular measurements on dentary cross sections was high relative to paddlefish populations in the upper Mississippi River drainage; lengths of age-1 fish ranged from 411 to 455 mm in eye-fork length. Natural mortality of Louisiana paddlefish was high (26-48%), and data suggested a reduction in age at maturity (100% females mature at age 10), lower fecundity (average fecundity, 9,500 eggs/kg body weight), and larger eggs (average diameter, 2.67 mm) relative to other paddlefish populations. Changes in reproductive life history characteristics may reflect rapid growth and high natural mortality rates. As the postmoratorium commercial fishery for Louisiana paddlefish develops, conservative harvest regulations should be promulgated until the effects of harvest on paddlefish stock dynamics can be determined.