摘要：This paper summarises the results of a malacological survey of the Zrmanja River and its tributaries (Croatia). Although the Zrmanja River is one of the biggest rivers in Croatia belonging to the Adriatic Sea drainage area, its aquatic molluscs are poorly known. Altogether 29 species of aquatic non-marine molluscs (22 gastropods, 7 bivalves) were found in 14 sites in the Zrmanja River and 5 sites in its tributaries in 2009 and 2010. The freshwater part of the Zrmanja River upstream of the Jankovića buk (waterfall) represented by sites No. 4–9 is characterised by the highest diversity. In this part, two very rare and endangered species Dalmatinella fluviatilis and endemic Tanousia zrmanjae were found only as small populations. In the Krupa River the occurrence of an endemic gastropod Belgrandiella krupensis was confirmed.
