军曹鱼幼鱼盐度适应性研究

Study on adaptability of juvenile of Rachycentron canadum to salinity

目的:在室内控制条件下,研究不同海水盐度对全长为(13.70±0.91)cm,体质量为(9.74±0.85)g的军曹鱼幼鱼存活和生长的影响.方法:将30 d 70%存活率的盐度作为适宜存活临界盐度,将增长率为最佳增长率70%时所对应的盐度作为适宜生长临界盐度,最适存活盐度、最适生长盐度范围则为多重比较无统计学差异且存活率、日生长率最高的几个实验组所对应的盐度范围.结果:在水温为26.5~28℃,溶解氧大于6 mg/L的条件下,军曹鱼幼鱼的适宜存活盐度范围为3.68~37.43,最适存活盐度范围为10~34;适宜生长盐度范围为5.91~37.15,最适生长盐度范围为22~31.结论:军曹鱼作为广盐性鱼类,对盐度有较强的适应性,当盐度变化超出最适范围时,养殖军曹鱼幼鱼对高盐更为敏感.

Objective:Effects of various seawater salinities on the growth and survival of juvenile of Rachycentron canadum[total length was(13.70±0.91)cm,body weight was(9.74±0.85)g]by adopting indoor control measures were investigated.Methods:The salinity ensuring mortality of 70%for 30 d as a period of experiment was chosen as the survival critical salinity,while the salinity in the group with 70%as much as the highest growth rate was set to be the growth-suitable critical salinity.Based on these critical salinities,the optimum salinity suitable for the juvenile of Rachycentron canadum was studied.Salinities at which the highest survival or growth rates among groups were not significantly different by multiple comparison were set to be the optimal survival or growth salinities.Results:The results showed that under the condition of water temperature of 26.5-28℃and dissolved oxygen greater than 6 mg/L,the suitable survival salinity of juvenile of Rachycentron canadum was 3.68-37.43,and the optimal survival salinity ranged from 10 to 34.The suitable growth salinity is 5.91 to 37.15,and the optimum growth salinity is 22 to 31.Conclusion:As a euryhaline fish,Rachycentron canadum has strong adaptability to salinity.When the salinity changes beyond the optimal range,the juveniles were more sensitive to low salinity.