Abstract
Seasonal changes in occurrence, infracommunity composition and microhabitat distribution of the monogenean parasites of gudgeon Gobio gobio (L.) were studied during two years in the River Haná (Czech Republic). Altogether 212 specimens of gudgeon were examined and a total of 6456 specimens of eight monogenean species were recorded: Dactylogyrus cryptomeres, Gyrodactylus gobiensis, Gyrodactylus gobii, Gyrodactylus gasterostei, Gyrodactylus vimbi, Gyrodactylus markakulensis, Gyrodactylus sedelnikowi and Paradiplozoon homoion. The occurrence of monogeneans correlated with seasonal changes of water temperature. In 2001, gyrodactylids peaked in March and D. cryptomeres in May, whereas in 2002, gyrodactylids peaked in May and D. cryptomeres in July. The majority of specimens of all Gyrodactylus species were found on the fins; the remaining specimens of Gyrodactylus were located on the body surface and gills, and all Dactylogyrus and Paradiplozoon specimens were located on the gills. The microhabitat distribution of the monogeneans changed in relation to changing water temperature and intensity of infection.