Abstract

Objective: To investigate the occurrence, seasonal prevalence and histopathological effect of the Philometra piscaria (P. piscaria) infestation in ovaries of orange-spotted grouper Epinephelus coioides (E. coioides) from the southeast coast of India. Methods: The normal and infected gonads of orange-spotted grouper were collected from Parangipettai and Pazhayar landing center. Prevalence, mean intensity of nematode infection and percentage of gonadal somatic index (%GSI) of normal and infected gonads was examined. The histopathological abnormalities of nematode infected gonads were studied. Results: In this study, among 452 fishes examined, 200 were infected with the nematode. The maximum prevalence (53% and 65%) of P. piscaria on E. coioides was observed in post-monsoon season 2015 from Parangipettai and Pazhayar landing center respectively. The mean intensity of nematode infection was found higher in post-monsoon season (4.62 ± 0.40) and average intensity of nematode infections was (2.42 ± 0.60). Values of %GSI showed increasing trend from April with a peak in June in both infected and uninfected fishes. The histopathological studies of infected fish gonads revealed tiny ovary wall with ruptured oocytes, necrosis of gonad cells and nuclei scattered in early and late yolk stage. Conclusions: The varying degrees of gonadal damage caused by P. piscaria reveal a severe threat to the reproductive success of E. coioides.

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