Ammonia

Ammonia comprises from 40 to 90% of the nitrogenous excretions in crustaceans and may be considered a toxic metabolite in culture systems. Shrimp would probably not be subjected to accumulations of ammonia above normal limits (0.7 mg NH4-N/1, 1.0 mg NO2-N/1, 0.75 mg NO3-N/1), but this can be a problem in systems where the seawater is recirculated. Nitrate/ammonia toxicity is exacerbated by pH increases, temperature increases, or salinity decreases (Delistraty et al., 1977).