Acute toxicity of nitrate on Penaeus monodon juveniles at different salinity levels

Penaeus monodon juveniles (total length 28.4 +/- 6.2 mm) were exposed to different concentrations of nitrate-N (nitrate as nitrogen) using the static renewal method at different salinity levels. The 48-, 72-, 96-h LC50s (median lethal concentrations) of nitrate-N for P. monodon juveniles were 2876,1723,1449 mg/l in seawater of 15 parts per thousand (g/kg); 3894,2506,1575 mg/l in 25 parts per thousand; 4970, 3525, 2316 mg/l in 35 parts per thousand, respectively. The "safe level" for rearing juvenile P monodon was estimated to be 145,158 and 232 mg/l nitrate-N in 15 parts per thousand, 25 parts per thousand and 35 parts per thousand, respectively. The relationship between LC50 of nitrate-N (mg/l), salinity (S), exposure time (t) and the interaction between salinity and exposure time (St) is as follows: LC50 = 3917.467 + 102.456S - 42.634t - 0.342St (R-2 = 0.775) (C) 2002 Elsevier Science B.V All rights reserved.