Copepod parasite Lepeophtheirus kabatai (Ho & Dojiri, 1977) infestation in orange spotted grouper, Epinephelus coioides (Hamilton, 1822) and its control in captivity

Abstract

Parasitic infection in the orange spotted grouper Epinephelus coioides (Hamilton, 1822) and its control measures in captive conditions were studied. Wild collected groupers after 8 weeks of rearing in captivity showed lethargy and sluggishness. The caligid parasite, Lepeophtheirus kabatai (Ho & Dojiri, 1977) was identified from the affected fishes. This parasite was also prevalent in wild fish, however at lower prevalence (11%). The mean intensity of L. kabatai in fishes reared in captivity was 92.85±10.71, whereas in wild fish it was 3.54±1.61. Infected cultured fish were randomly assigned to one of five treatment groups (Group A, B, C, D and E). Group A fishes were given dip treatment in freshwater for 5 min, whereas groups B, C, D and E were given bath treatment in formalin @ 50, 100, 150 and 200 mg l-1 respectively for 30 min, followed by 5 min dip in freshwater. Group E fish were fully free of the infestation and no re-infestation was seen in them even after two months. This is the first study to confirm L. kabatai infestation in orange spotted grouper in both wild and cultured fish; and formalin treatment @ 200 mg l-1 was found effective control the infestation in captivity.