斑石鲷(Oplegnathus punctatus)游泳性能研究

流速作为深远海养殖海区选址的重要依据,也是影响鱼类游泳能力的重要因素之一,为评价深远海养殖良种斑石鲷(Oplegnathus punctatus)的游泳能力,明确最适放养规格,分别以体重50、150、250、350g的斑石鲷为研究对象,利用鱼类游泳能力及运动消耗检测装置,在24℃条件下,解析了不同规格的斑石鲷在四种流速下的续航时间、暴发游泳速度(U_burst)、临界游泳速度(U_crit)和运动耗氧率(MO₂),并计算出其单位位移耗能(COT)和最适游泳速度(U_opt)。结果表明,鱼体规格和流速均会对实验鱼续航时间产生影响显著(P<0.001,F=25.401,df=1),50g斑石鲷在60cm/s流速下续航时间显著小于其他三种规格(P<0.05),在大于60cm/s流速下,四种规格斑石鲷续航时间均小于30min;250g和350g斑石鲷暴发游泳速度显著高于50g与150g(P<0.05);斑石鲷临界游泳速度与体重成正相关(R=0.96),不同规格下临界游泳速度存在显著差异(P<0.05);各规格实验鱼间最适游泳速度无显著差别(P>0.05)。以上结果表明,不同规格斑石鲷游泳能力存在显著差异,其中250g和350g斑石鲷耐流能力显著优于50g和150g。综上所述,斑石鲷在深远海海域进行陆海接力养殖时,建议放养250g以上规格,且养殖海域流速不超过60cm/s。

Study on swimming ability of spotted knifejaw (Oplegnathus punctatus)

To examine the swimming ability of spotted knifejaw (Oplegnathus punctatus) and obtain optimal specification to resist current, four different body weights (50, 150, 250, and 350 g) were chosen to determine the endurance swimming time, burst swimming speed, critical swimming speed, and sports oxygen consumption rate (MO₂) with sports consumption measuring device. The energy consumption per unit displacement (COT) and the optimum swimming speed were calculated using corresponding equations. Results show that both body weight and flow velocity affected obviously the swimming times (P<0.001, F=25.401, df=1). The swimming time of the 50g group was significantly less than those of the other three groups at flow velocity of 60 cm/s (P<0.05). Meanwhile, the swimming time of all groups was less than 30 min in flow velocity above 60 cm/s. The swimming speed of the 250g and 350g groups was significantly higher than those of the 50g and 150g groups (P<0.05). In addition, the critical swimming speed showed significant differences in different groups (P<0.05). However, the trend of exercise oxygen consumption rate was opposite to the unit displacement energy consumption curve. There was no significant difference in the optimal swimming speed among different groups (P>0.05). Correlation analysis showed that the critical swimming speed and burst swimming speed were significantly and positively correlated with the optimal swimming speed (R=0.781, P<0.05). Therefore, the weight of 250 g, 350 g, and above could resist sea current of below 60 cm/s in flow rate. These findings could help adjust the aquaculture conditions in RAS and offshore fish farming.