盐度渐变和骤变对褐点石斑鱼存活和摄饵的影响

以人工育苗所得的褐点石斑鱼苗为材料,水温28～31.5℃下,盐度范围0～70以组间距5共设置15个梯度,分别进行盐度渐变和骤变对鱼苗存活和摄饵影响的研究。结果表明:渐变实验中,以5/d升高或者降低盐度时,盐度10～55之间,鱼苗存活率100%;而在盐度降低至5时,平均存活时间为15.16 h,24 h存活率19.1%;盐度降至0,平均存活时间7.92 h,24 h存活率为0,盐度0时其平均存活时间与盐度5时的平均存活时间有极显著差异(P<0.01);盐度60,鱼苗基本不摄食,24 h平均存活时间38.51h,24 h存活率为89.8%,24～48 h存活率为89.8%;盐度65,鱼苗不摄食,平均存活时间10.95 h,24 h存活率0%;盐度65平均存活时间与盐度60之间有极显著差异(P<0.01);鱼苗在盐度25～45间摄食活动活跃。骤变实验中,盐度5～50,鱼苗存活时间>48 h;盐度0,24 h存活率5%,48 h存活率为0;盐度55,24 h存活率100%,24～48 h间存活率83.3%;盐度60,24 h存活率44.1%,48 h存活率降至11.1%;鱼苗在盐度65、70中24 h存活率0%;盐度0、65、70的处理组48 h平均存活时间的显著短于其它各组,盐度0～5、55～70为褐点石斑鱼苗骤变的极限生存盐度。

Effect of Gradient and Acute Salinity Stress Experiment on Survivorship and Food Intake of Brown-marbled Grouper, Epinephelus fuscoguttatus

The effects of gradient and a cute salinity stress on performance were determined for artificial rearing of brown-marbled grouper larvae,Epinephelus fuscoguttatus feeding on artificial meal.In the first experiment,performance was assessed after transfer from 30 at fourteen salinity treatments(0,5,10,15,20,25 30,35,40,45,50,55,60,65) at water temperature of 28℃-31.5℃,with the salinity increasing or decreasing 5 per 24h,Survival of fish was best within the range of 10–55,the larvae surviving all the experiments,the feeding behavior of fishes were normal in treatments of 25、 30、35、40、45,while fewer feed were consumed in treatments of 5、55、60.The mean survival time of larvae in treatments of 5,0,60,65 decrease dramatically to 15.16 h,7.92 h,38.51h,10.95h with an survival rate of 19.1%,0%,89.8%,0% in 24 h,or survival rate of 19.1%,0%,89.8%,0% in 48 h,respectively,one-way ANOVA test show significant deferent between both survival rates in 24h and survival time in treatments of 5,0,60,65,p<0.01.LSD multiple comparisons show that survival time(ST) in treatments are Significant deferent ST0