温度和流速对细鳞鲑(Brachymystax lenok)幼鱼游泳能力的影响及其与呼吸代谢的关系

EFFECTS OF TEMPERATURE AND FLOW VELOCITY ON SWIMMING OF JUVENILE MANCHURIAN TROUT BRACHYMYSTAX LENOK(PALLAS) AND THE RELATIONSHIP TO RESPIRATORY METABOLISM

通过鱼类游泳代谢测定装置,研究了5个温度(4、8、12、16和20°C)水平下细鳞鲑(Brachymystax lenok)幼鱼的爆发游泳速度(BS)、临界游泳速度(UCrit)及其测定过程中的呼吸代谢率和不同恒定流速临条件下的最大续航游泳时间,并分析比较了幼鱼摄食与空腹状态下相关测试指标的差异,探讨了温度和流速对细鳞鲑幼鱼游泳能力的影响。结果表明,5个温度水平下摄食组和空腹组细鳞鲑幼鱼的BS不存在显著差异(P>0.05),且各实验组的BS对温度均无依赖关系,其摄食组和空腹组的线性拟合方程分别为Y摄食=–0.0336x2+0.2424x+0.27(R2=0.929)和Y空腹=–0.045x2+0.317x+0.192(R2=0.9158);5个温度水平下,摄食组和空腹组细鳞鲑幼鱼的UCrit分别为:(0.42±0.0038)和(0.43±0.001)、(0.42±0.0038)和(0.46±0.0099)、(0.46±0.0025)和(0.47±0.0076)、(0.43±0.0081)和(0.43±0.0010)、0.47±0.0014和(0.48±0.0012)m/s,且随着温度升高和流速增大,摄食组较空腹组的呼吸耗氧率分别增加了17.80%(4°C)、32.24%(8°C)、19.39%(12°C)、39.39%(16°C)和19.48%(20°C);在最适温度条件下(16°C),不同测试流速对摄食组和空腹组细鳞鲑幼鱼的最大续航游泳时间存在显著性差异(P<0.05),采用非线性拟合得到了8个测试流速与最大续航游泳关系的幂函数模型,由幂函数方程可知,最大续航游泳时间与测试流速呈负相关性,摄食组与空腹组存在显著性差异(P<0.05),且随着流速增大,其最大续航游泳时间缩减剧烈。本研究认为,在设计大坝鱼道过程中应充分考虑不同温度条件和摄食条件下鱼类的爆发游泳速度和临界游泳速度参数,且如果考虑春秋季节细鳞鲑幼鱼上溯的有效通过率,那么鱼道的入口流速应小于0.65m/s,鱼孔处流速小于0.42 m/s。

We determined the burst swimming speed（BSS）, the critical swimming speed（CSS） and the respiratory metabolism of at five different temperatures（4, 8, 12, 16 and 20°C）, and the maximum sustained swimming（MSS） time of juvenile Manchurian trout Brachymystax lenok（Pallas） by a fish swimming-MO2 determining device. Differences between feeding and fasting groups were compared. The effects of temperature and flow velocity on the swimming ability were evaluated. The results show there was no significant difference（P〉0.05） in BS between the feeding and fasting groups at five temperatures. Values of CSS of the two groups at the five temperatures were, respectively,（0.42±0.0038） and（0.43±0.001）,（0.42±0.0038） and（0.46±0.0099）,（0.46±0.0025） and（0.47±0.0076）,（0.43±0.0081） and（0.43±0.0010）, and（0.47±0.0014） and（0.48±0.0012） m/s. Furthermore, comparing to the fasting group, oxygen consumption rate of the feeding group increased by 7.80%（4°C）, 32.24%（8°C）, 19.39%（12°C）, 39.39%（16°C）, and 19.48%（20°C） with the increases in temperature and flow velocity. The MSS times were significantly different in flow velocity in all groups. In addition, we constructed power exponential equations of the MSS time vs flow velocity, indicating a negative correlation between them. The MSS time decreased significantly with the increase in flow velocity. Therefore, the BSS and CSS at different conditions of temperature and feeding should be carefully considered in the design of fishway at a dam. Particularly, when considering the upstream migration in spring and autumn, flow velocity at the entrance of fishway should be〈 0.65m/s, and 〈0.42 m/s at the hole of fishway.