During 1994, 129 specimens of chub (Leuciscus cephalus L.) from two localities, polluted--Bolelouc, 80th river kilometer, near the city of Olomouc, and unpolluted--Brodské, 225th river kilometer, near the Lanzhot on the Morava river, were examined for metazoan parasites. Altogether 38 metazoan parasite species including helminths, leeches and glochidia belonging to 14 genera were found, 34 in the case of unpolluted locality (Brodské) and 28 in the polluted one (Bolelouc). In both localities, 24 parasite species (Dactylogyrus folkmanovae, D. naviculoides, D. prostae, D. vistulae, D. vranoviensis, Gyrodactylus carassii, G. gasterostei, G. gracilihamatus, G. scardiniensis, G. vimbi, Gyrodactylus sp., Paradiplozoon ergensi, P. homoion, P. megan, Paradiplozoon sp., Caryophyllaeus brachycollis, Diplostomum spathaceum--larval stage, Philometra abdominalis, Acanthocephalus anguillae, Pomphorhynchus laevis and Glochidium sp.) were found, 10 (D. crucifer, D. nanoides, G. hemibarbi, G. lamberti, G. leucisci, G. lomi, P. rutili, C. fennica, A. imitans, S. bramae) were identified solely in the unpolluted locality Brodské and 4 (D. fallax, G. laevis, P. ovata, G. kearni) parasite species were found only in the polluted locality Bolelouc. Differences in parasite species richness, the level of dominance, the structure of core and in satellite species were observed. Current methods of statistical evaluation were used.

Department of Zoology and Ecology Faculty of Science Masaryk University Brno Czech Republic

Metazoan parasite communities: support for the biological invasion of Barbus barbus and its hybridization with the endemic Barbus meridionalis

Paradiplozoon homoion Bychowsky & Nagibina, 1959 versus P. gracile Reichenbach-Klinke, 1961 (Monogenea): two species or phenotypic plasticity?