鲢幼鱼在不同水流速度下的暴发-滑行行为策略

在水温（18±1）℃的条件下，以全长（11.70±0.57）cm的鲢（Hypophthalmichthys molitrix）幼鱼为研究对象，测定其不同流速（16.5、22.0、27.5、33.0、38.5、44.0、49.5和55.0 cm/s）下的持续游泳时间、调头百分比和暴发-滑行运动数据。结果表明，鲢的平均持续游泳时间先随流速的增加而减小，后随流速的增加而增加。当流速33.0 cm/s时，平均持续时间最短为118.6min，其中各组试验鱼的最大可持续游泳时间均可达到200min。调头百分比随流速的增加迅速减小，当流速≥44.0 cm/s时，不再出现调头行为。暴发-滑行游泳的平均暴发时间随流速的增加呈上升趋势（y=0.03x+2.64，R2=0.92，P<0.05）。平均对地暴发距离均在30-45 cm，没有显著性差异（P>0.05），平均绝对暴发距离存在极显著性差异，且随流速的增加而增加（y=4.98x-5.63，R2=0.98，P<0.001）。平均对地暴发速度没有显著性差异（平均对地平均速度和最大速度分别在9-12 cm/s、12-16 cm/s，P>0.05）。平均绝对暴发速度与水流速度之间存在线性正相关关系（平均绝对平均暴发速度:y=0.98x+10.74，R2=1.00，P<0.001；平均绝对最大暴发速度:y=1.02x+13.75，R2=0.99，P<0.001）。研究表明鲢在不同的流速下采取的暴发-滑行行为策略不同。

STRATEGIES OF BURST-COAST SWIMMING BEHAVIOR OF JUVENILE SILVER CARP AT DIFFERENT FLOW VELOCITIES

At the water temperature of (18±1)°C, the current study investigated the strategies of burst-coast swimming behavior of juvenile Silver carpsHypophthalmichthys molitrix (at full length of 11.70±0.57 cm) such as swimming du-ration, percentage of turned-around, burst time, distance and speed in the burst-coast performance at different flow ve-locities (16.5, 22.0, 27.5, 33.0, 38.5, 44.0, 49.5 and 55.0 cm/s). Results showed that the average swimming duration of silver carps first decreased and then increased with the increasing flow velocity. The shortest duration time is 118.6min when fish swim at 33.0 cm/s. The maximum duration of swimming in each group was more than 200min. The percen-tage of turned-around quickly decreased with the increasing flow velocity, while no turned-around behavior occurred at the flow velocity≥44.0 cm/s. The average burst time of burst-coast swimming of silver carp were positively associa-ted with flow velocity (y=0.03x+2.64,R2=0.92,P<0.05). Average burst distances relative to the ground for each group were at the range of 30—45 cm without significant difference (P>0.05). However, the average absolute burst distances increased significantly with the increase of flow velocity (y=4.98x–5.63,R2=0.98,P<0.001). The average mean burst velocities relative to the ground and average maximum burst velocities relative to the ground had no significant diffe-rence (P>0.05), which were at the range of 9—12 cm/s and 12—16 cm/s, respectively. There was a positive linear rela-tionship between average absolute burst velocity and flow velocity (absolute average mean burst speed:y=0.98x+10.74, R2=1.00,P<0.001. The absolute average maximum burst speed formulated byy=1.02x+13.75,R2=0.99,P<0.001). These data proved that silver carp took different burst-coast behavior strategies at different flow velocities.