南极磷虾桁杆拖网网型结构与作业性能之间的关系

桁杆拖网是南极磷虾连续泵吸桁杆拖网捕捞系统重要组成部分之一，为深入了解该系统中桁杆拖网的作业性能特征，促进网具作业性能优化，本研究通过模型试验开展了网型结构和沉子重量对网具作业性能影响的探索，网型结构包括6种(3种腹网宽度，每种宽度采用2种缝合方式)，分别以A、B、C、AA、BB和CC表示，沉子重量3种。综合比较表明，不同试验网型作业性能优劣排序为BB>CC>C>A>B>AA，但差异不显著。缩小腹网宽度和斜目缝合均能有效提高网口垂直扩张、降低能耗系数，提高网具作业性能，尤其适用于较高拖速的作业场景。沉子重量与网具阻力、网口垂直扩张均呈显著正相关，但与能耗系数相关性不明显；为促进网口垂直扩张，合适的沉子重量配备随拖速增加而递增，拖速1.5 m/s的条件下，各试验网型其沉子配重应不低于3.05 t。试验条件下，各网型的网具阻力、能耗系数变化趋势较平稳，递变斜率变化较小，网具阻力与拖速呈幂函数关系，指数介于1.49～1.64。以上结论可为南极磷虾桁杆拖网属具配备以及优化设计提供参考。

Effect analysis of gear structure and sinker on the performance of Antarctic krill beam trawl

In order to improve the operating performance of Antarctic krill (Euphausia superba) continuous pumping truss trawl gear, this paper studied the performance of the fishing gear by changing the structure of the truss trawl net. In this experiment, the model net was converted according to the field criterion. The two scale ratios of the model net were 20 and 10 respectively. According to the size of the converted model net, the length of the lower mesh was adjusted to be 1.00m, 0.91M and 0.88M respectively. Two kinds of nets with or without cutting were made for each specification. The model test was carried out in the movable flume Laboratory of Shanghai Ocean University The performance of fishing gear with different structure parameters was analyzed and compared. The results showed that: (1) With the same length of the lower part, the resistance of the net that had been cut was less than that of the net that had not been cut. The resistance of different nets was that A-NET is less than C-NET and and C-NET was less than B-net. (2) With the same length of the lower part, the height of the net mouth of the trimmed net was lower than that of the uncut net. The height of the net mouth of the different nets was that the B-net was higher than the A-NET, and the A-NET was higher than the C-NET. (3) In the case of the same length, for A-NET, the energy consumption coefficient after cutting was higher than that without cutting, while for B-net and C-NET, the energy consumption coefficient was lower than that without cutting. For different nets, the energy consumption coefficient of B-net was less than that of C-NET, and that of C-NET was less than that of A-NET. In summary, the performance of nets B was better than that of nets A and C. The configuration of buoyancy power should ensure the vertical expansion of the net while using a smaller buoyancy configuration to reduce the angle of attack and resistance of the net.