个体大小对草鱼耐高温能力及升温过程中群体行为的影响

为考察个体大小对升温过程中草鱼的耐高温能力和群体行为的影响, 研究以草鱼(Ctenopharyngodon idellus)幼鱼为实验对象, 结果显示: 大个体群体的个体游泳速度明显大于小个体群体(P=0.039), 个体间距离和最近邻距离显著高于小个体群体(P<0.001); 大个体鱼群的极性与小个体群体并无差异。虽然大个体群体的致死高温与小个体群体无差异, 但前者的临界高温显著大于小个体群体(P<0.001)。升温过程会使鱼群个体游泳速度变快, 个体间距离和最近邻距离也相应增加, 但游泳速度同步性和群体极性维持不变。研究表明: 个体大小的增加可增强草鱼幼鱼对环境水温的耐高温能力; 升温不会影响不同个体大小草鱼幼鱼群体的协调性, 但会降低草鱼幼鱼的群体凝聚力。

THERMAL TOLERANCES AND COLLECTIVE BEHAVIOR DURING WATER TEMPERATURE RISING IN JUVENILE GRASS CARP (CTENOPHARYNGODON IDELLUS)

Global warming affects the survival, reproduction, collective behavior, and population dynamics of the fish. To examine thermal tolerance and collective behavior during the heating in the Cyprinidae fish, our study selected the juvenile grass carp (Ctenopharyngodon idellus) as the experimental fish. The thermal tolerance, individual swimming speed, synchronization of speed, inter-individual distance, and other behavioral parameters were obtained in both the large and small body size juvenile grass carp groups. Compared with the small body size group, the large body size group has higher swimming speed (P=0.039), higher inter-individual distance (P<0.001), higher nearest neighbor distance (P<0.001), and higher critical thermal maximum (P<0.001). There is no difference in the group polarization and lethal thermal maximum between the two groups. During the process of water temperature rising, individual swimming speed of the juvenile grass carp increased profoundly, while the inter-individual distance and nearest neighbor distance are also increased, but the synchronization of speed and the group polarization remained unchanged. These results showed that increase of individual body size can enhance the thermal tolerance of the juvenile grass carp. Water temperature rising do not affect the coordination of the juvenile grass carp group, but reduce the cohesion of the juvenile grass carp group.