A detailed microbiological and parasitological survey of salmonids and indigenous fish in the upper reaches of selected river systems in Natal was undertaken. Fish were collected from the rivers by electro-fishing, from dams by gill netting and from hatcheries along the rivers. A total of 678 fish from 26 different sites along 8 river systems were collected. No parasites could be detected on fi...

The combination of exceptionally high species diversity, high host specificity, and a complex reproduction system raises many questions about the underlying mechanisms triggering speciation in the flatworm genus Gyrodactylus. The coevolutionary history with their goby hosts was investigated using both topology- and distance-based approaches; phylogenies were constructed of the V4 region of the ...

Histopathological changes in gills of a native fish Capoeta aculeata, naturally-infected with parasites were studied. The specimens (15.5 to 22.8 cm) were collected from Choghakhor lagoon in West Iran. 35 (11%) of the total 318 studied fishes were infected with gill parasites. Overall, six protozoan and metazoan parasite species were collected from fishes including Ichthyophthirius multifiliis,...

In many species male sexual characteristics are known to be affected negatively by parasites, which render their hosts unattractive to females, but how parasites affect the mating decisions of their female hosts has received little attention. The monogenean parasite Gyrodactylus turnbulli reduces the sexual display and colour intensity of male guppies, Poecilia reticulata, which makes them less...

To test the hypothesis that host-switching can be an important step in the speciation of gyrodactylid monogenean flatworms, we inferred the phylogeny within a cluster of parasites morphologically close to Gyrodactylus salaris Malmberg 1957, collected from Atlantic, Baltic and White Sea salmon (Salmo salar), farmed rainbow trout (Oncorhynchus mykiss), and grayling (Thymallus thymallus) from Nort...

Biological indicators are species that can be employed to monitor environmental quality and ecosystem health. Different groups of organisms such as plants, animals, bacteria and parasites regularly produce certain molecular signal in response to changes in their environmental milieu. Parasites are important tools for providing wealth of information on physicochemical quality, environmental stre...