流速对红鳍银鲫幼鱼游泳状态的影响

在28℃水温下,采用特制的鱼类游泳行为测定装置,研究体重(125.94±13.87)g的红鳍银鲫(Barbodes schwanenfeldi)幼鱼在0.0m/s(对照组)和0.1m/s、0.3m/s、0.5m/s3种流速下的游泳行为。结果表明,从0.0～0.3m/s,红鳍银鲫幼鱼平均趋流率和摆尾频率均随着流速的增加而增大,而0.5m/s组在90min内随时间延长而下降。红鳍银鲫游泳状态明显受到所处流速的影响,在静水对照组以"逆流前进"和"顺流而下"为主,两者共占总观察时间的98%以上;各流速组均以逆流静止为主,且随着流速的增大,逆流静止所占时间比例从45.8%增加至81.3%,而逆流前进所占时间比例由24.1%减至5%以下;逆流后退所占时间比例以0.1m/s组最大,为16.4%;顺流而下的比例随着流速增大先减小后增大,3个流速组依次为13.7%、2.1%和10.9%。红鳍银鲫幼鱼的游泳速度(V)和摆尾频率(TBF)在逆流前进及逆流静止两种游泳状态下呈线性正相关,而在逆流后退和顺流而下两种状态下两者没有显著相关。

Effects of Water Velocities on Swimming Performances of Juvenile Tinfoil Barb Barbodes schwanenfeldi

Effects of water velocities (0, 0. 1, 0. 3 and 0. 5 m/s) on swimming performances of juvenile tinfoil barb Barbodes schwanenfeldi, weighing 125. 94 ± 13. 87 g, were investigated at the water temperature of 28℃. Swimming behaviors of the fish were monitored continuously for 90 min by a video tape recorder, and the video data were analyzed by computer packages. The results indicated that rheotaxis frequencies and tail beat frequencies of juvenile tinfoil barb increased with increasing water velocities from 0 to 0.3 m/s, but decreased at 0.5 m/s. The time of swimming performances varied obviously at different water velocities. At 0 m/s, the fish kept moving for more than 98% of the experimental time, and at other three water velocities, the fish were in fixed positions against the current (FP) mainly. When the water velocities rose from 0. 1 m/s to 0.5 m/s, the time of FP increased from 45. 8% to 81. 3% , but that of moving forward against the current ( MF) decreased from 24. 1% to 5% or less. The time of moving backward against the current (MB) reached the maximum at 0. 1 m/s, accounting for about 16.4% of the experimental time. The time of downstream (DS) accounted for 13.7% , 2. 1% , and 10. 9% of the experimental time at water velocities of 0. 1 m/s, 0. 3 m/s and 0. 5 m/s, respectively. Tail beat frequencies of the fish showed significantly positive relationship with swimming speeds in the MF and FP performances, but had no significant correlation with swimming speeds in DS and MB performances.