Background. Fishes of the family Gobiidae may be definitive-, intermediate-, or paratenic hosts of parasites with mature stages infecting a variety of vertebrates, including humans. This group of fishes constitutes a convenient ecological model for studying the processes of colonisation by parasites. Learning these processes may contribute to a better, more complex, understanding of organismal interrelationships within respective habitats. The aim of this study was to compare the helminth infection levels of different gobiid species in the north-western Black Sea (NWBS). Materials and methods. The fishes were sampled within 1996–2003 at different seasons (excepting winter) in the NWBS. A total of 2102 specimens of 10 goby species—the black goby, Gobius niger, the knout (toad) goby, Mesogobius batrachocephalus, the mushroom goby, Neogobius eurycephalus, the monkey goby, N. fluviatilis, the round goby, N. melanostomus, the ratan goby, N. ratan, the syrman goby, N. syrman, the marbled goby, Pomatoschistus marmoratus, the tubenose goby, Proterorhinus marmoratus, the grass goby, Zosterisessor ophiocephalus—were examined for helminths. The Czekanowski–Sørensen index (Ics) was used for comparing the helminth faunas. The infection indices were compared using the discriminant analysis. Results. The fishes examined yielded a total of 24 helminth species. Four parasite species were common for all hosts surveyed: Cryptocotyle concavum MET, C.lingua MET, Dichelyne minutus, and Acanthocephaloides propinquus. Telosentis exiguus infected six host species, Eustrongylides excisus—five of them, while Pygidiopsis genata Streptocara crassicauda L3 were found in four gobiids. Five parasites species (Proteocephalus gobiorum, Asymphylodora pontica, Acanthostomum imbutiformis MET, Raphidascaris sp. L3, and Streptocara crassicauda) were common for three host fish species, while another four helminths (Bucephalus polymorphus MET, Nicolla skrjabini, Contracaecum rudolphii L3, and Acanthocephalus lucii) were found in two gobiids only. A total of ten parasite taxa were found to infect single hosts species (Bothriocephalus gregarius PL, Ligula pavlovskii PL, Proteocephalus gobiorum PL, P. subtilis, Proteocephalus sp. PL, Paratimonia gobii, Aphalloides coelomicola, Aphalloides coelomicola MET, Contracaecum microcephalum L3, and Anisakidae gen. sp. L3). The most stable indices of gobiid infection were determined for nematode D. minutus. Conclusion. The observed differences in the species composition of helminth faunas of different gobiids were related to the zoogeographical origin of a host species, the ecological specificity of their habitats (e.g. salinity), and the biology of individual parasites.

Black Sea, gobiids, fish parasites, helminth fauna, discriminant analysis