Ectoparasitic community ecology of freshwater fishes of River Penna, YSR Kadapa District, Andhra Pradesh, India

A total of 18 freshwater fish species (n= 859) belonging to 10 families from River Penna, Andhra Pradesh were examined for metazoan ectoparasites from July 2017 to June 2019, of which only 12 fish species were infected with at least one parasitic species. The mean prevalence of infection was 63.9%, the average abundance was 13.9 parasites per fish due to very heavy infestation of some parasites. Prevalence of infection in these 12 infected fishes ranged from 98.9% (Wallago attu) to 30% (Salmostoma bacaila) and mean intensity from 44.3 (Oreochromis niloticus) to 1.0 (Glossogobius giurus). The infra and component communities of parasites were fairly peculiar. The dominance pattern of the major taxa was in the order Monogenea > Copepoda > Isopod. Siluridae (W. attu) showed the richest parasite fauna (n=5) followed by Bagridae (M. vittatus, n= 3) and Cichlidae (O. niloticus, n= 3) whereas 09 infected fish species showed very poor fauna. The parasite fauna of W. attu was the most heterogeneous while the remaining fish species were the most homogenous. The results specify that the freshwater fishes of River Penna harbour a poor and less diverse species. The results also put forward the fact that the lesser scales on the body of carnivorous fishes enable the ectoparasites to penetrate the skin and gills more easily.