Effect of Nitrite on Oxygen Consumption and Ammonia Excretion of the Fresh Water Crab Paratelphusa jacquemontii (Rathbun)

Abstract

In aquatic ecosystem, nitrite concentrations are elevated by pollution with nitrogenous wastes and imbalances in bacterial nitrification and denitrification processes. Nitrite is transformed by nitrification to nitrate under aerobic condition. The effects of nitrite on physiology were investigated in the fresh water crab, Paratelphusa jacquemontii (carapace length 4–5 cm and weight 50–70 g) for 96 h. The crabs were exposed to sublethal concentration (1/10th and 1/20th of 96 h LC₅₀) of nitrite for a period of 15 days. The treatments of these nitrites brought about significant decrease in oxygen consumption and ammonia excretion as compared to control. The significance of these studies as bioindicator for assessing the toxicity and economic importance of the crab are discussed.

Keywords: nitrite, oxygen consumption, ammonia excretion, paratelphusa jacquemontii