5种鳗鲡幼鳗极限温度的耐受性初步研究

以日本鳗鲡（Anguilla japonica）、欧洲鳗鲡（A.anguilla）、美洲鳗鲡（A.rostrata）、印尼鳗鲡（A.bicolor pacifica）和菲律宾鳗鲡（A.mormorata）5种鳗鲡的幼鳗为试验对象,探讨其对极限高、低温的耐受性及种间差异。以自然水温为试验起始温度（日本鳗鲡、欧洲鳗鲡、印尼鳗鲡为27℃;美洲鳗鲡、菲律宾鳗鲡为24℃）,高温试验过程中每4h升1℃,低温试验每4h降1℃,直至全部受试个体死亡。试验结果表明,不同种的幼鳗对环境温度的耐受范围具有种间差异。日本鳗鲡、美洲鳗鲡、欧洲鳗鲡、印尼鳗鲡和菲律宾鳗鲡高温＂死亡高峰温度＂分别为39、38、37.5、39和38℃,日本鳗鲡对高温的耐受性最强,欧洲鳗鲡最弱,但种间差异不显著;日本鳗鲡、美洲鳗鲡对低温的耐受性最强,能在冰和水混合液中生存,欧洲鳗鲡、菲律宾鳗鲡和印尼鳗鲡对低温耐受性依次减弱,低温＂死亡高峰温度＂分别为2、5和10℃。

Preliminary study on tolerance of elver of 5 Anguilla species to ultimate water temperature

We studied the tolerance of elver of 5 Anguilla species（Anguilla japonica,A.anguilla,A.rostrata,A.bicolor pacifica and A.mormorata） to ultimate high and low water temperature as well as their difference.We used natural water temperature as initial temperature（27 ℃ for Anguilla japonica,A.anguilla and A.bicolor pacifica;24 ℃ for A.rostrata and A.mormorata）,and increased/decreased 1 ℃ every 4 h in high-temperature/low-temperature experiment respectively until all individuals died.The result indicates that the elvers of 5 Anguilla species show different tolerance to ultimate water temperature.The temperature for the highest mortality of A.japonica,A.rostrata,A.anguilla,A.bicolor pacifica and A.mormorata is 39,38,37.5,39 and 38 ℃,respectively.A.japonica tolerates high temperature best while A.anguilla worst,but the difference is insignificant.A.japonica and A.rostrata tolerate low temperature best and can survive in mixture of ice and water.As for the other 3 species,the temperature for the highest mortality of A.anguilla,A.mormorata and A.bicolor pacifica is 2,5 and 10 ℃,respectively.