Recruitment in a freshwater unionid (Mollusca : Bivalvia) community downstream of Cave Run Lake in the Licking River, Kentucky

Unionids, fish, and glochidia were collected to determine why recruitment h ad ceased or had been dramatically decreased in a speciose unionid communit y in the Licking River at Moores Ferry, Kentucky, 35.4 km downstream of Cav e Run Lake. Only six unionid glochidia were collected with drift nets, and only six fish collected had infestations of glochidia. A small percentage ( 10.1%) of the unionids observed had their gills modified as marsupia. An an alysis of water temperature and discharge indicated no significant differen ce in average monthly discharge (p > 0.05) and a significant decrease in te mperature (p < 0.05) between pre- and post-impoundment periods. Average mon thly discharge and temperature may not be as biologically important as the spikes of discharge and corresponding sudden decreases in temperature that are caused by releases of hypolimnionic water from the reservoir.