摘要
为评价东海近海桁拖网渔具对主要鱼类的尺寸选择性,使用对比作业法,在吕四渔场开展了4个航次的、不同网目结构网囊(菱形、方形及横向使用的菱形网目)的选择性试验。在选择性分析中,将几何相似原理运用于选择性曲线模型(Richards曲线),使用假设检验理论对选择性曲线模型进行简化。对不同主要鱼类渔获数据的拟合结果显示,模型具有良好的拟合性,但存在航次间差异;模型简化结果显示,选择性曲线可以简化为Logistic曲线。选择性分析结果显示,对于短吻舌鳎,横向使用的菱形网目网囊L50(50%选择体长)最大,而SR(选择范围)最小,菱形网目网囊L50最小,而SR最大;对于棘头梅童鱼和小黄鱼,菱形网目网囊的L50最小,SR最大,横向使用的菱形网目网囊L50最大,而方形网目网囊SR最小;除不同结构的网目扩张程度不同以外,鱼体体型结构的特殊性以及网囊结构也可能是导致选择性差异的主要原因。
In order to assess the size selectivity for fishes of beam trawl fishing in offshore of the East China Sea, experiments of codends with different mesh configuration, including diamond mesh, square mesh and turned through 90° diamond mesh （T90） in 4 sea trials have been carried out and catch data were collected by comparative fishing method. In analysis of size selection, the selectivity curves （ Richards curve, which could be simplified to Logistic curve by hypothesis test） were considered geometrically similar. The results of model fit and simplification demonstrated that selectivity models fit well to the pooled catch data of fishes but between-trials variation was found, and Richards selectivity curves of codends with different configuration could be simplified to Logistic curves. As for Cynoglossus abbreviatus, comparisons of selectivity parameters （L50s, 50% retention lengths and SRs, Selection Ranges） among codends with different mesh construction showed that L50 s and SRs of T90 codends were maximum and minimal respectively while those of diamond mesh codends were converse with T90 codends. As for Pseudosciaena polyactis and Collichthys lucida, L50 s and SRs of diamond mesh codends were in the same manner but the SRs of square mesh codends were minimal. Besides the mesh openness, the special construction of fish body and codends were considered as the possible reasons for the difference in size selectivity of codends with different mesh configuration.
出处
《上海水产大学学报》
CSCD
北大核心
2008年第4期457-463,共7页
Journal of Shanghai Fisheries University
基金
教育部高等学校博士学科点专项科研基金(20050264004)
国家科技支撑计划(2006BAD09A05)
上海市重点学科建设项目(T1101)
关键词
尺寸选择性
多囊桁拖网
方形网目
菱形网目
横向使用
鱼类
size selectivity
multi-codends beam trawl
square mesh
diamond mesh
turned through 90° mesh
fishes
