Benedenia epinepheli (Yamaguti 1937), A Monogenean Parasite in Captive Broodstock of Grouper, Epinephelus tauvina (Forskal)

摘要

Grouper (Epinephelus spp.) is one of the most economically important cultured marine fish in Asia, particularly in Thailand, Malaysia, Philippines, Singapore, Indonesia and Taiwan. Over 10 species of grouper fish have been cultured in the region. In India, greasy grouper fish, Epinephelus tauvina is gaining importance as a candidate species for marine and coastal aquacul-ture. A study conducted on wild and captive broodstock of grouper (size range, 15-40 cm; body weight 0.2 - 4 Kg) collected from seanear Chennai revealed infection with monogenean parasites in a large number of fishes (27%). The present communication is the summary of the prevalence, taxonomy and pathology of these infection encountered in E. tauvina and the containment strategies.Acute infection of ectoparasitic monogeneans, Benedenia sp. was observed in 19 wild grouper (E. tauvina) fish and 12 of the broodstock fish maintained in captivity. The parasite measured 2.05 - 3.29 x 0.66 - 1.33 mm and was found to infest the gills, fins and skin of the fish. Fishes with advanced infestation were characterized by erratic swimming behaviour and restlessness. The fish with severe infections had small focal haemorrhages on the body, which often resulted in secondary bacterial infection leading to the sloughing of the skin and excessive mucus secretion. A description of the parasite and its pathobiology is discussed. Successful treatment of monogenean infection was carried out by short bath treatment with 100 ppm formalin. Freshwater bath was found effective in dislodging the parasite from the fish. Hydrogen peroxide (150 ppm) bath was found to be effective but revival of parasite was observed after short bath.