Abstract:  Under the conditions of water temperature (28±0.2)℃, salinity 29.8±0.2, pH  8.0±0.2 and dissolved oxygen 6.0mg/L, juvenile shrimp Marsupenaeus japonicus with body length of (49.28±4.79) mm was put in a 100 L white bucket with 20 L of water. NaNO2 (analytical pure) was dissolved in fresh seawater to prepare 2 000 mg/L mother liquor and make the concentration of nitrite (NO2--N) in the water of the test group 151.36, 239.88, 380.19, 602.56 and 954.99 mg/L. The acute toxicity of NO2--N to juvenile shrimp Marsupenaeus japonicus was studied by hydrostatic toxicity test. The results showed that the NO2--N toxicity was positively correlated with the concentration and stress period, the mortality rate of Marsupenaeus japonicus increased with the increase of NO2--N concentration at the same time, and the mortality rate of shrimp increased with time at the same concentration. The lethal concentration (LC50) of NO2--N to Marsupenaeus japonicus was 1806.100 mg/L in 24 h, 970.939 mg/L in 48 h, 780.050 mg/L in 72 h and 427.391 mg/L in 96 h, with safe concentration of 42.739 mg/L. The lethal time (LT50) was 120.008 h at concentration of 151.36, 111.954 h at 239.88, 94.207 h at 380.19, 78.810 h at 602.56, and 60.102 h at 954.99 mg/L. The test showed that the concentration of NO2--N should be controlled below 42.739mg/L in culture water of Marsupenaeus japonicus.

Key words:  Nitrite, juvenile shrimp Marsupenaeus japonicus, lethal concentration (LC50), lethal time (LT50)

摘要： 在水温（28±0.2）℃、盐度29.8±0.2、pH 8.0±0.2和溶氧6.0mg/L的条件下，将体长（49.28±4.79）mm日本囊对虾（Marsupenaeus japonicus）幼虾放在盛水20 L的100 L白桶中，用NaNO2（分析纯）溶于新鲜海水配制成2 000 mg/L的母液，使试验组水中亚硝酸盐氮（NO2--N）质量浓度为151.36、239.88、380.19、602.56、954.99 mg/L，采用静水毒性试验法研究了亚硝酸盐氮对日本囊对虾（Marsupenaeus japonicus）幼虾的急性毒性。结果表明，NO2--N毒性效应与质量浓度和胁迫时间呈正相关。在同一时间下日本囊对虾的死亡率随着NO2--N质量浓度的升高而增加；在同一质量浓度下对虾的死亡率随着时间的延长而升高。NO2--N对日本囊对虾24、48、72、96 h的半致死质量浓度（LC50）分别为1806.100、970.939、780.050、427.391 mg/L，安全质量浓度为42.739 mg/L。NO2--N质量浓度为151.36、239.88、380.19、602.56、954.99 mg/L的半致死时间（LT50）分别是120.008、111.954、94.207、78.810、60.102 h。试验表明，日本囊对虾养殖水体中NO2--N质量浓度应控制42.739mg/L以下。

关键词: 亚硝酸盐氮, 日本囊对虾幼虾, 半致死质量浓度, 半致死时间