KEVIN J. FREY AND TOM J. TIMMONS, Hancock Biological Station, Murray State University, P.O. Box 9, Murray, Kentucky 42071-0009, USA

The distribution and food habits of larval gizzard shad Dorosoma cepedianum and threadfin shad D. petenense were examined in Ledbetter Embayment, Kentucky Lake during 1994. Two bow-mounted pushnets were used to sample shad at the surface and euphotic depth from May through early July. Distribution of both gizzard and threadfin shad was patchy during the day and night at both sampling depths. There was no indication of discrete movements of gizzard or threadfin shad within the embayment. Both species exhibited greater densities in the euphotic zone at night and at the surface during the day. Spatial overlap between gizzard and threadfin shad increased during the day and feeding overlap decreased during the night as the season progressed. Feeding selectivities of gizzard and threadfin shad were similar. Predation on zooplankton by both species of shad was partitioned by time (diel period) and by size of prey. Partitioning of prey was more pronounced during June when cladocerans received greater preference during the night and rotifers during the day by gizzard and threadfin shad. Additionally, prey was not selected by gizzard and threadfin shad in proportion to its abundance during May or June or by threadfin shad during July.