Pathogenology Of Monogeneans Of Marine-Fish In Taiwan Strait

Species composition of marine-fish monogeneans in Taiwan Strait were investigated during 1998 to 2001. Study on the population dynamics of two species of Dactylogyrus and the infective status of the marine-fish monogeneans of Taiwan Strait were conducted.13 species of marine-fish parasitic monogeneans were collected and described, which belong to 12 genus, 7 families. Among of which, 2 are new species and 5 genus are new records in China. In total, 65 species offish were sampled, of which 18.5% were infected with monogeneans.The investigations show that the seasonal fluctuation of infective rates of the two Dactylogyrus are similar, but there is difference on their intensity.The life history of Neobenedenia melleni was observed in laboratory. The morphological feature of the egg, oncomiracidium and larvae were described. The results indicate that it took 16 days or so from oncomiracidium to adult.The microhabitats of D. inversus and D. gotoi, pathology and histochemistry response of perch were investigated by serial sectioning the gills of naturaly infected fishes. The results show that D. inversus attaches to the primary filament of gill while D. goto; attaches to the secondary filament. Infection by these parasites causes breakdown of organic integrity, hyperplasia, swelling and fusion of the respiratory epithelium, leucocyte infiltration, fibrosis and necrosis. Histochemical responses indicate that infection by these parasite causes variation of protein and carbohydrate in the gills. Furthermore, variation of the quanlity and the contents of mucous cell induces by the infection of Dactylogyrus.Additionally, scanning electron microscopy of Neobenedenia melleni were observed.