不同盐、碱度下3品系尼罗罗非鱼幼鱼网箱养殖的生长比较

Growth comparison among three strains of Oreochromis niloticus juvenile in net cage under different salinity-alkalinity waters

以慢性驯化后的上海、山东、河北品系尼罗罗非鱼(Oreochromis niloticus)幼鱼为试验材料,比较它们在盐度组(0、15和20)、碳酸氢钠(NaHCO3)碱度组(1 g.L-1、2 g.L-1和3 g.L-1)以及盐碱混合组(15,1 g.L-1;15,2 g.L-1;15,3 g.L-1;20,1 g.L-1;20,2 g.L-1和20,3 g.L-1)条件下网箱养殖成活率和日均增重率差异。62d试验结果表明,上海、山东、河北品系尼罗罗非鱼幼鱼在不同盐度、碱度、盐碱混合处理组中的成活率差异不显著(P>0.05),而日均增重率的差异显著(P<0.05)。随着盐度、碱度增加,尼罗罗非鱼生长速度大体呈下降趋势;盐碱混合组生长速度较单盐、单碱组减慢。还发现不同品系尼罗罗非鱼在不同盐碱梯度下表现出不同的相对生长优势。研究结果为尼罗罗非鱼适宜养殖的盐碱范围确定、品系筛选提供了重要的基础资料。

We chose Nile tilapia Oreochromis niloticus juvenile from Shanghai, Shandong and Hebei strains, which were chronically acclimated, as experimental groups, and studied their survival rate and average growth rate in net cage under different salinity waters （0, 15, 20）, NaHCO3 alkalinity waters （1 g·L^-1, 2 g.L-1, 3 g·L^-1）, and salinity-alkalinity waters （15, 1 g·L^-1; 15, 2 g·L^-1 ; 15, 3 g·L^-1 ; 20, 1 g·L^-1 ; 20, 2 g·L^-1 ; 20, 3 g·L^-1）. The 62 days experiments show that there is no significant difference in the survival rate among three strains under different salinities, alkalinities and salinity-alkalinity waters （ P 〉 0. 05 ） , while there is significant difference in average growth rate （ P 〈 0.05 ）. The average growth rate of three strains roughly tend to decline with increasing salinity and alkalinity, while the growth rate of salinity-alkalinity group increases slower than those of treated with salinity and alkalinity. Besides, Shanghai, Shandong and Hebei strains show some relative growth advantages in different salinity and alkalinity gradients, respectively. The study provides some basic data for determination of optimum growth salinity-alkalinity and for selection of Nile tilapia strain.