South Cross Creek Reservoir is a 192 hectare subimpoundment of the Cumberland River (Lake Barkley) within Cross Creeks National Wildlife Refuge, Tennessee. Between April 1989 and March 1991, 542 harvestable-sized (>75 cm) paddlefish,Polyodon spathula, were measured, tagged, and returned to the reservoir. Using the Fisher-Ford method, we estimated the population at 1,689 paddlefish with an annual survival rate of 91%. The reservoir contains a higher density of paddlefish, 8.8 per hectare, than Lake Barkley (Cumberland River). A low level of exchange occurs between paddlefish in South Cross Creek Reservoir and Lake Barkley, with immigration and emigration occuring during spring flooding when the Cumberland River overflows into the subimpoundment. Fish movement appears to be more dependent upon the water temperature at the time of flooding than the level of flooding. If the water temperature does not exceed 10°C, the paddlefish may not be stimulated to migrate to spawning areas outside of the subimpoundment.