Diet and feeding niche of five invasive species in the Bodrog River watershed.
Spreading of invasive fish species in Europe still continues. Studies of their feeding behavior and diet habits have shown that these species could negatively affect native ichthyofauna by competition and predation; they could also cause changes in feeding behaviour and feeding niche of Central European native species. The aim of this study is to refer similarities and differences in feeding behavior / feeding niche of altogether 83 specimens of five different species, namely Ameiurus melas, Lepomis gibbosus, Neogobius fluviatilis, Perccottus glenii and Proterorhinus semilunaris from the Bodrog River. Non-metric (NMDS and Bray-Curtis index) and non-parametric (PERMANOVA and ANOSIM) tests were used for determination of differences in food. Piankas and Levins statistical models were used for feeding niche overlap and niche width. Statistically significant differences were found in the diet composition of analysed species by ANOSIM. Chironomidae larvae (Diptera), class Ostracoda (Crustacea), family Baetidae (Ephemeroptera) larvae, Corophiidae and Copepoda explained about 60% of the dissimilarity in the diet composition by SIMPER test. At the site Borša, large feeding niche overlap was found between N. fluviatilis and P. semilunaris and intermediate between P. glenii and P. semilunaris. Broad niche width was observed in P. glenii and P. semilunaris differently of N. fluviatilis at this site. N. fluviatilis and P. semilunaris occurred at the site Ladmovce. Diet of these species was very similar in this biotope and we did not confirm significant difference in the food composition. Our findings suggest that in this case, the food offer in specific site was the most important factor in dietary habits and behavior of invasive fishes.