Author(s): A Gopalakrishnan
This article reports the changes in growth, production and histology of Penaeus monodon infested with loose shell syndrome in modified extensive grow-out ponds. The carapace of the affected shrimp is papery in nature and the gill is brown in colour. The gill filament shows fouling by protozoa and muddy particles. Hepatopancreas tissue reveals the absence of fat globules in its cells. Secondary infection of shrimp is caused by microbes and this fouling leads to the severity of the disease. In the loose shell-affected pond, the final average body weight of shrimps on 147 days of culture is 27.87 g, but in the case of the normal pond it is 31.29 g on the 140th day. The average daily growth rate of the loose shell-affected shrimp is 0.18 g and in the normal pond it is 0.22 g. The mean final survival rate of the loose shell-affected pond is 60.65% and in the normal pond it is 81.95%. The mean biomass production of the affected pond is 1058.97 kg/ha–1 . and in the normal pond it is 1915.21 kg ha–1 . The poor survival and biomass production in the loose shell-affected pond is due to cannibalistic behaviour of the shrimp during loose shell disease. There is also a derangement of parameters, especially salinity and temperature in the loose shell-affected pond.