A study on the spatial distribution of two congeneric monogenean species Pseudodactylogyrus anguillae Yin et Sproston, 1948 and P. bini Kikuchi, 1929 on the gills of large size European eel Anguilla anguilla (L.) were conducted. Results were analysed with regard to: single-species infection, mixed infection and general occurrence of the parasites in the eel population. Statistical analysis reve...