Parasites of non-native gobies in the Włocławek Reservoir on the lower Vistula River, first comprehensive study in Poland

Abstract

Key-words: alien species, goby fish, parasite community, Vistula River A parasitological study of Ponto-Caspian gobies, including the monkey goby Neogobius fluviatilis, racer goby Babka gymnotrachelus and tubenose goby Proterorhinus semilunaris, carried out over four years in the lower Vistula River is described. These fish species represent one of the most impressive invasions of European inland waters, connected with the spontaneous, east-to-west intracontinental movement observed in the last two decades. The parasite community consisted of 24 taxa. Typical for racer goby were: Trichodina domerguei, Diplostomum pseudospathaceum, Gyrodactylus proterorhini and glochidia of unionids. The list of parasites typical for monkey goby is supplemented with: Tylodelphys clavata (met.) and Eimeria sp., while the glochidia were rarely detected in this fish host. Holostephanus spp., Apatemon gracilis, Diplostomum gobiorum and glochidia predominated in parasite fauna of tubenose goby. Unlike the other species tested, P. semilunaris was poorly infected with T. domerguei and G. proterorhini. Parasites commonly distributed through native fishes in the observed area prevailed in gobies. Species rare in natives were also numerously represented. In this way, alien fish reinforce populations of those parasites in invaded waters. Parasites dragged to the colonized area (G. proterorhini, Holostephanus spp., A. gracilis and D. gobiorum) complement the community. Larval stages were typical for parasite fauna of all studied gobies.