Ecological plasticity of tubenose goby, a small invader in South Moravian waters

Abstract

The western tubenose goby Proterorhinus semilunaris, an invasive Ponto-Caspian fish species, has established populations in a wide range of habitat types in the Dyje/Morava river basin (Danube basin; Czech Republic). In this study, we assessed tubenose goby tolerance to environmental variables potentially contributing to its spread and performance in new habitats. Of the seven aquatic habitats examined (lowland rivers, brooks, backwaters, oxbow lakes, borrow pits, reservoirs and carp aquaculture ponds), all except small brooks proved suitable for survival and reproduction, with habitat size the only limiting factor. Diet analysis indicated chironomid larvae as preferred prey, though tubenose gobies were able to switch to other food items under specific conditions (e.g. high macrozoobenthos density), suggesting feeding plasticity. Fish condition was positively correlated with individual diet range, but not with parasite burden. Eighteen metazoan parasite taxa were identified, greatly exceeding the known parasite fauna from the species’ native range. Parasite species richness decreased significantly with fish host dominance. Foraging plasticity, the ability to occupy different habitats and cope with parasitism observed in this study all may have important implications for tubenose goby dispersal success and invasiveness.