THE PREVALENCE OF LERNAEID ECTOPARASITES IN GRASS CARP (CTENOPHARYNGODON IDELLA)

The present study was conducted to investigate the prevalence of lernaeid ectoparasites in grass carp (Ctenopharyngodon idella). For this purpose, 597 fishes (Ctenopharyngodon idella) were examined for lernaeid ectoparasites at a private fish farm located in Multan, Pakistan. Four species of the genus Lernaea i.e. L. cyprinacea, L. polymorpha, L. oryzophila, and L. lophiara were recorded. It was observed that L. polymorpha had the highest (P<0.05) overall prevalence (7.54%), followed by L. cyprinacea (6.53%), Learnaea species which were not identified (2.18%), L. oryzophila and L. lophiara (0.67% each). The relationship between body weight and Lernaea infestation showed that the infection of Lernaea species was significantly (P<0.05) more prevalent in the weight group of 2501-4500g, while the parasites were not found in the weight groups of 4500-6500 and 6501-8500g. Relationship between body length and Lernaea species in fish was also calculated. According to these results, the Lernaea species had significantly (P<0.05) highest prevalence in length group of 9-14 cm and lowest in length groups of 15-20 and >20 cm.