Because the three parts trawl board, trawl and trawler are an integrity in trawlfishing, it is necessary to work out a mechanical calculation of the match.
由于在生产作业中网板、拖网和拖网船是一个整体，进行三者配合的力学计算是十分必要的。
2
In trawl fishery, there are many factors affecting the fishing effort of which, the vessel size, actual catching time and the improvement of trawl net are the main factors.
在底拖网渔业中有很多影响渔捞努力量的因素，其中船型大小、实际捕捞时间的长短以及网具改进是主要因素。
3
In the previous study of trawl fishery resources of East China sea and Huanghai sea, the number of hauls is usually taken as the unit of fishing effort.