Fishes of the Drava river

Abstract

The chapter presents the fish fauna of the Croatian-Hungarian section of the river by overview the fish faunistic literature of studies conducted between 1992 and 2016, provides an example for littoral fish assemblages, and evaluates the ecological status of a river reach on this basis. It seems that 66 fishes, most of them belong to the family Cyprinidae and one cyclostomata species occur in the studied river section. However, the number of species regularly inhabiting the Croatian-Hungarian section could be about 51, because some species require different habitat type than the main channel of the studied section, or they are not able to reach the studied section due to migration barriers. There are also some taxa with unclear taxonomic status. Twenty-two species are listed in one of the annexes of the European Union Habitats Directive. The ratio of native to non-native species is 52:15. Monkey goby (Neogobius fluviatilis) and western tubenose goby (Proterorhinus semilunaris), two non-native Ponto-Caspian gobies, appear to be among the most abundant fishes in the littoral zone. Recently, other goby species (Ponticola kessleri, and N. melanostomus) formerly not known from the Drava have been found at the lower end of the studied river section and results anticipate their potential future spreading upstream. Fish assemblages tend to mirror an overall good ecological status and the rich fish fauna is of considerable nature conservation value due to the minimum alteration of habitats and the relative geographical proximity of the Danube. Therefore, for an effective conservation of the fish fauna the actual seminatural status of the Drava riverscape is to be maintained.