中西太平洋金枪鱼围网自由鱼群捕获率与渔场温跃层特性的关系

温跃层特性与金枪鱼表层渔业的捕捞成功率有关，但温跃层特性随海域与季节的不同而变化，因此对于捕捞成功率的影响也不同。分析了中西太平洋我国金枪鱼围网船队作业渔场的温跃层特性，并结合海上实测的围网沉降性能与对应的生产资料，探讨了金枪鱼围网捕获成功率与温跃层特性的关系，结果表明：（1）调查期间91.2%的网次所对应的温跃层顶界深度超过100 m，温跃层顶界深度较深是该海域渔场温跃层的重要特征；（2）围网最大沉降深度的95%置信区间为［185.0, 197.8］ m，渔场温跃层顶界深度的95%置信区间为［146.0, 158.3］ m，网具穿越温跃层顶界后继续沉降的深度的95%置信区间为［34.3, 44.0］ m；（3）相关分析表明，本研究中金枪鱼围网的捕获成功率与温跃层特性并不存在显著的相关性（P>0.05），这可能是由于当地渔场较深的温跃层顶界深度使得目标鱼种在网具到达温跃层之前拥有充分的逃逸时间和空间，从而导致温跃层内急剧变化的温度梯度失去了阻碍作用。

The relationship between the thermocline features and the rate of fishing success for free school caught by the tuna purse seiner in the Western and Central Pacific Ocean

The thermocline featuress are related to fishing success of surface tuna fishery, however, the thermocline is varied with the change of areas and seasons, so the impact of thermocline on the fishing operations is also different. The present study analyzed the thermocline features in the fishing ground of Chinese tuna purse seiner fleet operating in the Western and Central Pacific Ocean and explored the relationship between local thermocline feature and rate of fishing success for tuna purse seiners with combining to sinking depth of purse seine measured at the sea and the correpondent fishing information. The results showed that (1) the upper depths of thermocline for 91.2 percent settings were over 100 m in the survey, so the deeper upper depth of thermocline were the important features of thermocline in the fishing ground. (2) the 95% confidence intervals for maximum sinking depth of gear, the upper depth of thermocline, and sinking depth of purse seine within the thermocline ranged from 185.0 to 197.8 m, from 146.0 to 158.3 m and from 34.3 m to 44.0 m, respectively. (3) Correlation analysis showed that there is no significant correlation between rate of fishing success and thermocline (P>0.05), and the possible reason was that the deeper upper depth of thermocline in the local fishing ground allow targeted fish to escape in the larger space before they come close to the thermocline, so what in the sharp temperature gradient of thermocline lost the effect to obstruct the fish.