Size and Organ Specificity of Different Parasites in Wild Labeo

Studies were designed to explore the prevalence of various ecto and endoparasites on Labeo rohita an economical highly important fish. Parasites found in freshwater fishes are primarily protozoans, myxozoans, helminths (platyhelminths, nematodes and acanthocephalans) hirodineans and crustaceans. Although both ecto and endoparasites are common in fishes but internal parasites are more dangerous and cause extensive damage to their hosts. Skin and gills were scraped. Contents were placed on slide and observed under microscope. Then body of fish was exposed, gut and liver of each specimen were removed and processed for estimation of parasitic load. In general, there was a positive relationship between parasitism, age and size. Larger, older individuals seem more susceptible to parasitism than smaller ones which can not support parasitic burdon longer and succumb to death. Trematodes were quite abundant and were present on and in each organ studied during current endeavours. Protozoa, crustaceans and trematoda were dominant on skin while digenea and nematode were totally absent. Guts of all the samples were significantly highly loaded with parasites than livers. Qualitataively they did not vary but differences were quite significant (p<0.05) in quantitative estimation. This trend was uniformly observed in all the samples. No other parasite or its any development stage was visible in any sample irrespective of the site.