氨氮和亚硝酸盐对斜带石斑鱼苗的急性毒性效应

Acute toxic effects of ammonia and nitrite on Epinephelus coioides fry

研究了水温（25±0．5）℃，盐度30～31，pH值7．9～8．1，溶解氧4．5～5．5mg／L条件下氨氮和亚硝酸盐对不同规格斜带石斑鱼（Epinepheluscoioides）苗的急性毒性效应。试验结果表明，氨氮对平均全长4．4cm的斜带石斑鱼苗的24、48、72、96hLC50及安全质量浓度分别为5．62、3．50、2．93、2．68及0．27mg／L，对应的非离子氨及安全质量浓度分别为0．23、0．14、0．12、0．11及0．011mg／L；氨氮对平均全长10．5cm斜带石斑鱼苗的24、48、72、96hLC50及安全质量浓度分别为58．6、56．2、53．3、51．4及5．13mg／L，对应的非离子氨及安全质量浓度分别为2．41、2．32、2．20、2．12及0．21mg／L；亚硝酸盐对全长4．4cm的斜带石斑鱼苗的24、48、72、96hLC50及安全质量浓度分别为288．4、281．8、270．4、267.3及26．7mg／L；亚硝酸盐对全长10．5cm的斜带石斑鱼苗的24、48、72、96hLC50及安全质量浓度分别为354．8、346．7、280．5、208．4及20．8mg／L。

The acute toxic effects of ammonia and nitrite on different sized fries of Epinephelus coioides were studied. The temperature was set at （25±0.5）℃, salinity 30-31, pH 7.9-8.1, and dissolved oxygen 4.5-5.5 mg/L in the experiment. The results showed that the half lethal concentrations （LCs0） and the safe concentrations of ammo- nia on the fries of E. coioides with body length 4.4 cm at 24, 48, 72 and 96 h were 5.62, 3.50, 2.93, 2.68 and 0.27 mg/L, respectively, and their corresponding non-ionic ammonia concentrations were 0.23, 0.14, 0.12, 0.11 and 0.011 mg/L, respectively. The LCs0 and the safe concentrations of ammonia on the fries with length 10.5cm at 24h, 48h, 72 and 96 h were 58.6, 56.2, 53.3, 51.4 and 5.13 rag/L, respectively, and their corresponding non-ionic ammonia concentrations were 2.41, 2.32, 2.20, 2.12 and 0.21 mg/L, respectively. The LC50 and the safe concentrations of nitrite on the fries orE. coioides with length 4.4 cm at 24, 48, 72 and 96 h were 288.4, 281.8, 270.4, 267.3 and 26.7 mg/L, respectively; The LC50 and the safe concentrations of nitrite on the fries with length 10.5 cm at 24, 48, 72 and 96 h were 354.8, 346.7, 280.5,208.4 and 20.8 mg/L, respectively.