Abstract: At water temperature（25.0±0.5）℃, the movement trajectories of the center of mass (CM) of electricity-stimulated juvenile Spinibarhus sinensis(body length（6.9±0.1）cm, n=23) during its fast-start escape response were recorded by using high-speed cinematography, and the kinematics at three stages of the fast-start performance was analyzed. The results showed that all the escape responses observed were of C-type fast-start with either a right or a left turning direction, and there were no significant differences in the kinematics of fast-start performance with different directions (P>0.05). The distance (d) of the CM during the whole escape response process increased significantly (P<0.05), while the linear velocity (V) increased significantly (P<0.05) at the beginning and reached its maximum (36 ms) by the end of stage 2. The linear acceleration (a) presented the highest value by the end of stage 2 (P<0.05) and the lowest value at stage 3. The angular velocity (ω) presented the highest value at the beginning of fast-start response, decreased significantly (P<0.05) at the first and second stages, and remained unchanged at a lower level at stage 3. There was no significant relationship between V and relative turning radius (RT_r) at stage 1. The results indicated that juvenile S. sinensis favored higher velocity escape strategy in fast-start process, possibly due to its streamline shape and rapid water habitat.

Key words: Wheat evolution materials, Water use efficiency, Nitrogen use efficiency