Nitrite is an intermediate product either in the bacterial nitrification of ammonia,or in the bacterial denitrification of nitrate.The concentration of nitrite may reach 50 mg L-1 in intensive aquacultural systems due to an imbalance in biofilter resulting from overcrowding effect and poor water recirculation.High levels of nitrite in water were potential factors triggering stress on aquatic organisms.The sensitive indicators of stress evaluation for the Chinese mitten-hand crab Eriocheir sinensis were sele...