金枪鱼围网下纲提升特性的研究

Measurement and analysis of rising characteristics of tuna purse seine leadline

根据2014年2月~5月金枪鱼围网渔船＂金汇7号＂在中西太平洋作业时沿围网下纲缚扎的5只温度深度计（TDR-2050型）自动记录的30网次有效数据,对中西太平洋大型金枪鱼围网下纲取鱼部、中部及后网头部分的提升深度、提升速度与提升时间的关系进行了分析。结果表明：1）网具下纲各个部位提升速度各不相同,其中网具中部提升速度最快,其次为后网头、取鱼部;2）网具下纲各个部位提升深度都随提升时间增加而稳步提升,且都呈现出先稳定后波动的变化趋势,其中取鱼部与后网头的提升过程较为类似;3）在网具下纲提升速度方面,提升速度均随着提升时间的增加而逐渐加快,波动较为严重;4）水深70 m和120 m水层的流速对网具下纲提升性能影响显著（P〈0.01）。

According to the data collected from five micro-temperature and depth recorders （TDR-2050） attached along seine leadline of the tuna purse seiner named ＂JINHUI 7＂ operating in the Western and Central Pacific Ocean from February to May, 2014, we ana- lyzed the relationship among rising depth, rising speed and rising time of different parts of tuna purse seine leadline. The results show that ： 1 ） Rising speeds of different parts of leadline were different ： the fastest rising speed was the middle part, followed by the back wing end and the bunt. 2） With increasing time, the rising depths of different parts of leadline increased steadily, and the tendency was firstly stable, then fluctuate considerably; the rising process of the bunt was similar with that of the back wing end. 3 ） The rising speeds of different parts of leadline increased gradually with increasing time, and the rising speeds fluctuated considerably. 4 ） The current speeds at the 70-m and 120-m layers had very significant impact on the rising speed （P 〈0.01 ）.