基于海上实测的秋刀鱼舷提网沉降和提升性能研究

Sinking and rising performance of saury stick-held based on field measurements

根据2015年7-10月和2016年6-10月蓬莱京鲁渔业有限公司"鲁蓬远渔019"在西北太平洋进行的海上秋刀鱼舷提网网具性能测试所获得的数据,采用线性回归方法,分析了舷提网在沉降和提升阶段,网衣的沉降深度和提升深度以及网具沉降速度和提升速度的变化状况。利用广义加性模型(GAM)探讨秋刀鱼舷提网沉降深度和提升速度各自有效的影响因子,且分析了这些影响因子与舷提网主要性能参数两者之间的关系。结果发现:(1)网衣沉降深度随时间连续增加;网具下纲和侧纲的沉降速度都是先逐渐增大,然后缓慢减小,直至沉降过程结束;网衣沉降速度波动剧烈,无规律性变化。(2)网具下纲、侧纲的提升速度均快速达到最大值然后随时间连续降低,下纲的最大提升速度大于侧纲,网衣提升速度无规律性变化,上下波动剧烈。(3)GAM模型结果显示,30 m水层流速、60 m水层流速、下纲纲索松放长度3个因子对网衣最大沉降深度有显著性影响(P<0.05),影响程度依次为30 m水层的流速>下纲纲索松放长度>60 m水层流速。30 m水层流速和绞网速度两个因子对平均提升速度有着显著性影响(P<0.05),其中,绞网速度影响最大。

Based on the data collected by saury stick-held operating in the Northwest Pacific from July to October in 2015 and from June to October in 2016,we analyzed the sinking depth and the rising depth of netting,sinking speed, rising speed of different parts of saury stick-held at various sinking and rising stages of the net. The present study analyzed the relationship between sinking depth（D） and other variables,including hauling velocity（V0）, length of leadline（L）, length of sideline（L1） and current speed（V10, V30 and V60） of 10 m, 30 m and 60 m layers, and the impact factors on rising speed（V） were also estimated using the generalized additive model（GAM）. Results show that：（1） the sinking depth of netting increases along with the time was in gradually increasing trend, and the sinking speed of leadline and sideline increased rapidly at first, then declined gradually along with the time, and the sinking speed of netting fluctuated considerably with no regular changes.（2）The rising speeds of leadline and sideline declined gradually with increasing time, and the highest rising speed of leadline was faster than the sideline, and the rising speed of netting fluctuated considerably.（3） the analysis of stepwise GAM shows that three factors have a significant impact on the sinking depth（P0.05） and the significance can be ordered by V30, L, and V60. The analysis of stepwise GAM shows that two factors have a significant impact on the rising speed（P 0.05） and the significance can be ordered by V0 and V30.