Status of freshwater fish in Croatian Adriatic river systems Original Research Article

Approximately 64 species of freshwater fish occur in Croatian Adriatic river systems. Fifty of these are native, the remainder being introduced or translocated. Of the 40 species endemic to the Mediterranean area 11 occur only in Croatia. Others are distributed mostly in the karstic area of Bosnia and Hercegovina, some in Montenegro, Macedonia, Slovenia and Italy, while a few are distributed throughout the whole northern Mediterranean. River regulation, hydroelectricity generation and industrial pollution, plus very restricted distributions, are the main causes for endemic fish being endangered. The most important Croatian endemic fish are the six species of the genus Paraphoxinus and Leuciscus ukliva, Leuciscus polylepis, Leuciscus svallize, Aulopyge hugeli, Salmothymus obtusirostris, Knipowitschia mrakovcici, and the endemic subspecies of Salmo trutta.