Twenty-two larval fish taxa were collected from Wee Tee Lake, a backwater tributary of Santee River, South Carolina, and 2 adjacent main river sites during the spring of 1981 and 1982. Pomoxis spp., Alosa aestivalis, Dorosoma petenense, D. cepedianum, and Perca flavescens were the most abundant species collected in both Wee Tee Lake and Santee River during both years. These species were significantly (P < 0.05) more abundant in the lake than in the river, indicating a better spawning habitat in the lake. A. aestivalis and D. cepedianum appeared to spawn concurrently and exhibited similar patterns of diel periodicity. D. petenense spawned later and exhibited a different diel pattern. Flood control operations in the Santee River prior to the detection of larvae in 1982 appeared to alter time and duration of spawning and reduce species diversity and abundance of larval fish.