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ASCR > Inst. Vertebrate Biology > Dept. Fish Ecology > Markéta Ondračková – Research Interests |
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Parasite communities in fish hostMetazoan parasites of juvenile fishParasite infections of young-of-the-year (0+) juvenile fish are the best model for studies on the development of parasite communities on fish host, because they are free of parasites when entering the habitat. I investigated metazoan parasite fauna in four cyprinid species during the first seven months of their life. The results showed that 0+ juvenile fish were parasitized mainly by parasites with direct life cycle (Monogenea). Also, juvenile fish served as the important intermediate host for Digenea. Parasite communities of fish in fragmented habitats
Current studies on parasite diversity try to determine which factors, host or environmental, are the best determinants of parasite species richness. The main purpose of our project is to investigate spatio-temporal changes of both several isolated fish assemblages and fish parasite communities simultaneously, in relation to some abiotic and biotic environmental factors affecting both types of analysed biological systems under the conditions of fragmentated habitats. We investigated parasite fauna in fish from different types of water bodies. Our results showed that parasite fauna in fish from lentic and lotic water differed mainly in the number of parasites species, and that flooded borrow pits and backwaters represented the most preferable habitat for digenean parasites, contrary to rivers, where mostly monogenean and crustacen parasites occurred. Posthodiplostomum cuticola metacercariae in fish host
Posthodiplostomum cuticola (Digenea: Diplostomatidae) is a common parasite of freshwater fishes. In fish intermediate host, this parasite is known as the agent of the black-spot disease. The externally visible black-spot cysts located in the skin, fins and muscles are caused by melanin surrounded metacercariae. 
I investigated interactions between Posthodiplostomum cuticola metacercariae and fish intermediate hosts on the level of fish host individual, population and community. P. cuticola was found to parasitize only cyprinid fish with tendency to infect preferably fish of Leuciscinae. Pathological effect was found only in juvenile fishes. The infection of P. cuticola showed a seasonal pattern with maximum in October and no effect on overwinter survival was detected. Parasite-enhanced growth was documented for 0+ juvenile fish. Maximum enhanced growth of parasitized fish was found in months with low zooplankton densities. At low population densities of the 0+ fish, P. cuticola might affect a recruitment of juvenile fish indirectly by increased predation. Predator selectivity to the infected fish was documented experimentally.
Parasite infection of introduced species
The problem of the introduction of new species into the ecosystem usually creates general concern about its effects on the native biota. Parasite release has been suggested as important in allowing an introduced species to become invasive and also introduction of diseases may represent serious threats to the health and survival of susceptible native populations. We currently investigate parasite fauna of several fish species non-native in the waters of Slovak Danube River. Lepomis gibbosus has been introduced at the beginning of 20th century and we focused on monogenean parasites of this fish species. During last decade, Neogobius fluviatilis, N. kessleri, N. gymnotrachelus and N. melanostomus have been introduced into the Slovakian waters of the Danube River. We investigate metazoan parasites of Neogobius spp. in different types of habitat, focusing on the importance of food consumption, fish community and native parasite communities on the parasite fauna of introduced species.
Parasite fauna of Danio rerio in Bangladesh
The zebrafish (Danio rerio) is one of the most important model organisms in biology. Remarkably, almost nothing is known about its natural behaviour and ecology. Zebrafish is an abundant fish in the floodplain of the River Ganges; in Bangladesh, and West Bengal in India, inhabiting ditches and ponds. Recently, I became involved in a project on biology and ecology of zebrafish in Bangladesh. My interest in this project is aimed to understand the role of parasites in the behaviour and ecology of zebrafish.
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