Bopyrid isopods parasitizing on the cultured fresh water prawn,Macrobrachiummalcolmsoniiin South India

The bopyrid isopods are common in wildMacrobrachiumspp. but not common in aquaculture condition. This is the first study that reports the parasitizing of bopyrid isopods on the culturedM. malcolmsonii. Bopyrid isopod (Probopyrus buitendijki) was identified in the branchial cavities of the fresh water prawn,M. malcolmsoniifrom grow-out culture pond at Kuriyamangalam, India.Macrobrachium malcolmsoniiis a new host forP. buitendijki. A total of 1323M. malcolmsoniiwere checked for this study. The overall prevalence of the parasitic infestation was reached 46.2 %. The parasitic infection was higher in female (83 %) than in male (3.4 %). Highest prevalence of infestation was found in the median size group (7-8 cm) (58.7 %). Infected females were not berried unlike uninfected prawns. The parasites cause infertility and does not found any organ deformities due to the infestation. The parasite was inversely attached in the gill chamber with no lesion on the gill but the infected branchial chamber became bulged.