MICROHABITAT DISTRIBUTION OF METAZOAN PARASITES ON GILLS OF SILURUS ASOTUS IN JIANGKOU RESERVOIR, JIANGXI PROVINCE, CHINA

This paper deals with the proportional distribution, niche breadth and niche overlap of two metazoan parasites(copepods species, Ergasilus anchoratus Markewitsch, 1946 and Pseudergasilus parasiluri Yamaguti, 1936) and monogeneans (in the genus Silurodiscoides Gussev, 1976) found on gills of the fish, Silurus asotus L. from Jiangkou Reservoir in Jiangxi Province,China. E.anchoratus was the common and dominant metazoan parasite on gills of the fish in this locality as indicated by the higher infection levels, and distributed almost evenly on gill arches without any observed gill arch preference, as shown by the wide proportional distribution and broad niche breadth. P. parasiluri and monogeneans in Silurodiscoides were found also without any significant gill arch preference although they had a rather narrow niche breadth. The observed significant overlap between P. parasiluri and Silurodiscoides spp. may be simply due to the lower infection levels of the parasites. The observed pattern of unrestricted distributions of the parasitic copepods on gills of the fish may be accounted for, at least in part, by the moving ability of the copepods, and may also indicate that the parasite does not exhibit any feature of gill arch preference. However, further experimental research is needed to verify the microhabitat distribution of the parasites.