南海灯光罩网沉降性能研究

A study of sinking characteristics of light falling-net fishing in the South China Sea

根据2013年3月至4月南海灯光罩网渔船测定的沉降深度数据及搜集的渔船操作数据和海洋环境数据,对南海灯光罩网沉降深度和沉降速度与时间的关系进行了研究,并构建多元线性回归模型分析了灯光罩网最大沉降深度与放网时间、海流速度等因子的影响关系。结果显示:(1)网口纲一边沉降过程中沉降深度呈现两端深中间浅的趋势,网口纲两端最大沉降深度基本一致;(2)网口纲一边沉降速度呈现两端快中间慢的趋势,网口纲两端沉降速度都在10 m水深达到最大,而网口纲中部在5 m水深达到最大;(3)网具沉降深度与时间的关系式为H=-0.0008t2+0.4766t+1.2063(R2=0.9985),网具沉降速度与时间的关系式为:V=-1E-07t2-0.0018t+0.5269(R2=0.8813);(4)多元线性回归分析显示放网时间、风流向夹角、绞纲时间对网具最大沉降深度影响极为显著(P<0.001),而海流速度、风力对网具最大沉降深度影响不太显著(P<0.1);且各影响因子之间不存在多重共线性(κ=2.396<100)。可为改善南海灯光罩网沉降性能提供参考,并为海上生产提供指导。

Based on the data of the sinking depth, gear operating and the ocean environmental data collected on light falling-net fishing in the South China Sea during March to April 2013, the relationship between sinking depth（sinking speed） and time was studied, and the relationship between the maximum sinking depth and the relating was analyzed using multiple regression statistics. The results showed that the maximum sinking depths of the both ends of the lead line were deeper than that in the middle; the maximum sinking depths of the both ends of the lead line were consistent; the sinking speed of the both ends of the lead line was faster than the middle; the sinking speed of the both ends of the lead line achieved the maximum at depth of 10 m, and the middle achieved the maximum at 5 m; the relationship between the sinking depth and time could be described using the formula： H=-0.0008t2＋0.4766t＋1.2063（R2=0.9985）; and the relationship between the sinking speed and time could be described using the formula： V=-1E-07t2-0.0018t＋0.5269（R2=0.8813）;the results of the multiple regression statistics showed that the shooting duration, the direction angle between current and the wind, pursing time had a significant effect on sinking depth（P〈0.001）, and the current speed and wind speed had no significant effect on the sinking depth（P〈0.1）; there was no multicollinearity existed among the relating factors（κ=2.396〈100）. Our observations provide reference for ways to improve sinking characteristics in light falling-net fishing and a guide for fishing operations.