流速对黑鲷幼鱼游泳行为及运动生理的影响

FLOW VELOCITY EFFECTS ON SWIMMING BEHAVIOR AND EXERCISE PHYSIOLOGY OF JUVENILE ACANTHOPAGRUS SCHLEGELII

  • 摘要: 研究黑鲷(Acanthopagrus schlegelii)游泳行为和运动生理, 为其近海网箱养殖和增殖放流野外驯化提供技术支持。研究采用泳道呼吸仪测定19℃、不同流速下黑鲷幼鱼体长(12.38±0.69) cm, 体重(45.99±9.05) g的游泳行为、呼吸代谢和生理生化指标。结果表明: 黑鲷幼鱼的相对感应流速约为1.42 BL/s(体长/s), 临界游泳速度Ucrit约为76 cm/s, 暴发游泳速度约为114 cm/s; 摆尾频率与流速呈显著的线性正相关关系; 静止耗氧率约为332.25 mg/(kg·h), 运动耗氧率与流速呈二次多项式关系, 最低耗氧率出现在3.6 BL/s流速下, 约为185.65 mg/(kg·h); 单位距离耗能与流速呈幂函数关系, 在4 BL/s流速即约66%Ucrit流速处单位距离耗能最小且随流速增加基本保持不变。静水时黑鲷幼鱼的中位生存时间最短, 约3h, 低(1 BL/s)、中(3 BL/s)流速下中位生存时间最长, 在10h以上; 静水时窒息点约为0.34 mg/L, 低、中流速下约为1.70 mg/L, 高流速时约为3.18 mg/L。低、中流速下(20%Ucrit和50%Ucrit)肌糖原、肝糖原和磷酸肌酸的含量均较高, 而静水和高流速下血乳酸含量较高, 与耗氧率、窒息点的变化趋势一致。综上, 推荐黑鲷网箱养殖的流速不宜超过0.8 m/s, 放流鱼苗的适宜训练流速为1.5—3.5 BL/s, 驯化时间在2周以上为宜。

     

    Abstract: Acanthopagrus schlegelii is an important fish species for enhancement and release in Chinese coastal waters. To study its swimming behavior and exercise physiology can provide technical support for the offshore cage culture and the feralization train of the enhancement and release. In this study, the swimming behavior (induced velocity, critical swimming speed, burst swimming speed and tail beat frequency), respiratory metabolism (oxygen consumption rate (Mo2), cost of transport (COT), median survival time and suffocation point), physiology and biochemistry (lactate, glycogen, glucose, phosphocreatine and hydrocortisone) of juvenile Acanthopagrus schlegelii body length of (12.38±0.69) cm, weight of (45.99±9.05) g at 19℃ and different flow velocities were measured in a loop test flume produced by Loligo Systems in Denmark. The results showed that the relative induced velocity of juvenile Acanthopagrus schlegelii was about 1.42 BL/s (body length/s), the critical swimming speed was about 76 cm/s, and the burst swimming speed was about 114 cm/s. The tail beat frequency had a significant linear positive correlation with the flow velocity. The standard metabolic rate was about 332.25 mg/(kg·h), and the activity metabolic rate had a quadratic polynomial relationship with the flow rate. The lowest oxygen consumption rate appeared at the flow rate of 3.6 BL/s, which was about 185.65 mg/(kg·h). The cost of transport had a power function relationship with the flow rate, and the minimum cost of transport appeared at a flow rate of 4 BL/s, which was about 66% Ucrit flow rate. The shortest median survival time of juvenile Acanthopagrus schlegelii was in the still water with about 3hours, and the longest median survival time was under the low (1 BL/s) and medium (3 BL/s) flow rates with more than 10h. Suffocation point was about 0.34 mg/L in the still water, 1.70 mg/L at the low and medium flow rates, and about 3.18 mg/L at high flow rate. The contents of glycogen and phosphocreatine in white muscle and liver were higher at the low and medium flow rates (20% Ucrit, 50% Ucrit). The level of blood lactate was higher in the still water and at high flow rate, which correlated with oxygen consumption rate, suffocation point change trend was consistent. In conclusion, it is recommended that the flow rate for cage culture of juvenile Acanthopagrus schlegelii should not exceed 0.8 m/s, the appropriate training flow rate should be within the range of 1.5—3.5 BL/s, and the acclimation time should be more than 2 weeks.

     

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