The Distribution Pattern of Freshwater Crayfish in Croatia

In order to improve our general knowledge on the distribution of the various species of freshwater crayfish of the family Astacidae in Croatia, we gathered all the available unpublished data, as well as data from the literature and those of our own investigations. Our research confirmed the presence of three crayfish species in Croatia: Astacus astacus (Linnaeus, 1758), Austropotamobius torrentium (Schrank, 1803), and Austropotamobius pallipes (Lereboullet, 1858), and we officially recorded the presence of Astacus leptodactylus Eschscholtz, 1823 and Orconectes limosus (Rafinesque, 1817). Biogeographical data suggest the following distribution pattern: A. astacus is distributed in the continental part of Croatia, forming both river and lake populations. A. pallipes is distributed in south and southwest Croatia (Lika, Istria, Dalmatia, and on some islands in the Adriatic Sea). A. torrentium can be found in streams at higher altitudes in the continental part of Croatia. Finally, A. leptodactylus is found in the rivers of eastern and central Croatia (Slavonia and Posavina), while O. limosus was discovered recently in marshes of the Nature Park Kopački rit (Slavonia). Some mixed populations of A. astacus and A. torrentium were detected. Some specimens of A. pallipes and A. torrentium were found in underground habitats. Research on the distribution of freshwater crayfish should be more intensive, and will be continued in the future.