Trophic niche overlap between non-indigenous round goby, <i>Neogobius melanostomus</i>, and native fishes in tributaries of the lower Danube River (Bulgaria)

Abstract The recent expansion of the round goby ( Neogobius melanostomus ) in tributaries lower Danube (Bulgaria) prompted assessing potential negative effects on local fish fauna such as competition for food resources. Diet overlap between and native fishes was analyzed using samples macroinvertebrates collected monthly a one-year period. Significant dietary N. Barbus petenyi , Perca fluviatilis Gobio gobio Vimba vimba observed. Dietary Iskar River found to be considerable mainly spring months. Conversely, Vit observed during summer late fall. main reason noted preference Chironomidae Hydropsychidae larvae Gammaridae. results suggest that there is species inhabiting Danube. Potentially harmful rare, protected area are discussed.