The paddlefish Polyodon spathula is a large pelagic species that is native to the Arkansas River, including Keystone Reservoir. During the past century, paddlefish stocks have declined significantly in the Mississippi, Ohio, and Red rivers. However, stocks have increased in the Tennessee, Cumberland, and Arkansas rivers. Our objectives are to: (1) determine the distribution and abundance of the paddlefish in the Arkansas River below Kaw Dam, the lower Cimarron River, and Keystone Reservoir and (2) identify the location and habitat characteristics of paddlefish spawning sites throughout the system. Paddlefish were capture in large mesh gill nets in winter at randomly selected sections of the reservoir. Fish were measured, weighed, and jaw tagged. A population estimate was computed for paddlefish in Keystone Reservoir in 1996 and will be computed in 1997 and 1998. Due to low water flow in the Arkansas and Cimarron rivers, no apparent spawning occurred in 1996. Ultrasonic telemetry will be used to monitor the spawning movements and identify spawning areas of the adult paddlefish in 1997. Preliminary results indicate a population estimate of 7,779 fish (95% CI of 5,734 - 26,044). Eighty-four percent of paddlefish collected was in the Cimarron Arm, 12% in the Arkansas Arm, and 4% in the main pool. Catch rates were higher in the Cimarron Arm than the Arkansas Arm and main pool, but the mean size of fish in the Cimarron Arm was smaller. There were no differences in mean size and catch rates of fish collected in 127 mm mesh and 203 mm mesh, although incidental catches (blue catfish, flathead catfish, and striped bass) was higher in 127 mm mesh.