Aquatic molluscs of the Mre？nica River

Sa？etak Results of a malacological survey of the Mre？nica River are presented. The molluscan assemblages of this river between the boundary of the Eugen Kvarternik military area and the inflow to the Korana River near Karlovac were studied from 2013 to 2018. Altogether 29 aquatic molluscs (19 gastropods, 10 bivalves) were found at 9 sites. Theodoxus danubialis, Esperiana esperi, Microcolpia daudebartii and Holandriana holandrii were dominant at most of the sites. The molluscan assemblages were very similar to assemblages documented during previous research into the Korana River. The populations of the endangered bivalves Unio crassus and Pseudanodonta complanata were recorded. An extensive population of another endangered gastropod Anisus vorticulus was found at one site. Physa acuta is the only non-native species confirmed in the Mre？nica River