Effect of different salinity in ablated Indian white shrimp Fenneropenaeus indicus (H. Milne Edwards) in relation to ammonia and nitrite excretion

Abstract

The Indian white shrimp Fenneropenaeus indicus is widely distributed in the Indo-Pacific waters and it supports an active seasonal fishery along the south east coast of Tamilnadu. The effects of salinity on ammonia and nitrite excretion were investigated on the different stages of Fenneropenaeus indicus (H.Milne Edwards) at salinities of 20, 25 and 30 ppt Ammonia and nitrite excretion rates were inversely related with salinity and therefore were minimal at 30 ppt The results of this study suggest that the optimum salinity for adult Fenneropenaeus indicus is 30 ppt and that even minor (e.g., 5 ppt) deviation from this optimum causes significant physiological changes. Further the observed increases in ammonia and nitrite excretion during exposure to low salinities, which indicate higher energy expenditure and amino acid catabolism respectively, suggesting that the reproductive efficiency of Fenneropenaeus indicus adults might have been affected because of osmotic imbalance due to low salinity.