Effect of isopod parasite, Cymothoa indica on gobiid fish, Oxyurichthys microlepis from Parangipettai coastal waters (South-east coast of India).

The present study reported for the first time on the effect of isopod parasite, Cymothoa indica infestation on Oxyurichthys microlepis an ecologically important gobiid fish from Parangipettai coastal environment (South-east coast of India). The loss of weight in host fishes (male 20.47 and female 32.84%) were observed due to parasitism. The weight of uninfested female fish was found to be higher than that of infested one. The calus like thickening developed on the gill arch and gill filaments of host fish due to the persistent irritation caused by the appendages of the parasite. The reduction of gill surface area was observed due to the attachment of the parasites. The maximum reduction noticed in the first gill arch is mainly due to the heavy pressure exerted by the parasite. Details of gross lesions observed in the branchial chamber, buccal cavity and body surface was enumerated. Heavy infestations of parasitic juveniles have the potential to kill small fingerlings. The swimming capacity of the fish was also found to be affected.