网囊周长对单桩张网渔具选择性的影响  

Effect of codend circumference on size selectivity of single-stake stownet

作　　者：张健[1] 石建高[2] 彭永章 陈小康[1] 

机构地区：[1]大洋渔业资源可持续开发省部共建教育部重点实验室,上海海洋大学,上海201306 [2]农业部海洋与河口渔业重点实验室,中国水产科学研究院东海水产研究所,上海200090 [3]江苏省启东市海洋与渔业局,江苏启东226200

出　　处：《大连海洋大学学报》2011年第6期532-538,共7页Journal of Dalian Ocean University

基　　金：国家自然科学基金资助项目(NSFC31001138);上海市教育委员会科研创新项目(11YZ156);上海市重点学科建设项目(S30702);国家科技支撑计划项目(2006BAD09A05)

摘　　要：改变网囊周长是改善过滤性渔具网囊选择性的主要技术措施之一。为了评价网囊周长对中国近海渔业使用的单桩张网网囊选择性的影响,使用套网试验法对不同网目尺寸(25 mm和35 mm)的传统网囊和减小30%周长的网囊进行选择性试验,并对黄鲫Setipinna taty和小黄鱼Pseudosciaena polyactis渔获体长数据的选择性进行了分析。结果显示:减小网囊周长可改善对渔获体长的选择性,即减小周长的网囊的50%选择体长(L50)较传统网囊大,而选择范围较小,对于较小的个体,选择性得到较为明显的改善;对比其它文献的研究结果,减小30%周长的网囊的L50要比相同网目尺寸的菱形和方形网目网囊大,但网囊周长对其尺寸选择性影响的具体规律有待于进一步研究。Reduction in circumference of codends has been proved one of the efficient technical methods for improvement of the size selectivity in filter fishing gear. The traditional codends and the codends with 30% circumference reduction with 25 and 35 mm mesh size were tested on a commercial stownet using the covered codend technique in order to assess the effect of codend circumference on size selectivity of Chinese offshore single-stake stownet. Selectivity analysis for hairfin anchovy Setipinna taty, small yellow croaker Pseudosciaena polyactis catch composition indicated that the codends with reduced circumference were more selective, i.e. with higher 50% retention length L50 and narrower selection range（SR） than the traditional codends with same mesh size, especially for small individuals. Compared with the size selectivity information from pervious literatures, L50 of the circumference 30% reduction codends were higher than those of diamond and square mesh codends. The mechanism for the effect of circumference on size selectivity is discussed, and further study is necessary to find out the trend of the effect.

关 键 词：单桩张网 尺寸选择性 网囊周长 黄鲫 小黄鱼 

分 类 号：S972[农业科学—捕捞与储运]