桁拖网渔具分隔网片对虾类的分隔效率  

Separating efficiency of separator panels rigged in beam trawls for shrimps

作　　者：张健[1] 孙满昌[1] 彭永章 叶旭昌[1] 钱卫国[1] 

机构地区：[1]上海市高校大洋生物资源开发和利用重点实验室,上海海洋大学海洋科学学院,上海200090 [2]江苏省启东市海洋与渔业局,江苏启东226200

出　　处：《中国水产科学》2008年第5期845-852,共8页Journal of Fishery Sciences of China

基　　金：国家科技支撑计划项目(2006BAD09A05);教育部高等学校博士学科点专项科研基金项目(20050264004);上海市重点学科建设项目(T1101).

摘　　要：利用分隔网片将桁拖网渔具网囊分为上下2层(虾囊和鱼囊)以实现虾类和鱼类渔获分离,对于改善桁拖网渔具作业性能、提高目标种类渔获质量以及实现选择性捕捞具有重要的意义。为分析不同网目尺寸(60mm、75mm和90mm)分隔网片对主要渔获种类的分隔效率,在吕泗渔场开展了2个航次的海上生产实验。利用分隔装置性能分析模型,对哈氏仿对虾(Parapenaeopsis hardwickii)和葛氏长臂虾(Palaemon gravier)的渔获数据进行拟合。结果表明,不同虾类接触分隔网片的概率没有显著性差异;虾类个体50%接触概率体长约为40mm,表明大多数进入网具的虾类都能接触分隔网片。随着分隔网片网目尺寸增大,50%选择体长也逐渐增大。因此,分隔网片的分隔效率随之提高。鱼囊和虾囊的网目尺寸相同,但结构有所差异。比较在不同网囊尺寸选择性假设条件下渔获数据的拟合结果后发现,鱼囊和虾囊具有相同选择性的假设更为合理;通过比较发现,分隔网片对虾类的尺寸选择性与相同网目尺寸的网囊选择性具有较大的差异。本研究还对产生这一差异的原因进行了探讨。Research on development of separating beam trawl is important not only to improving the fishing efficiency and quality of catch, but also to achieving the idea of species-selective fishing. The codend of beam trawl could be divided into two levels （the upper for shrimp catch and lower for fish catch） by inserting a separator panel into the codend and extension. In order to analyze separating efficiency of the separator panels with different mesh sizes （60mm, 75mm and 90mm）, experiments in 2 sea trials were carried out in the Lvsi Fishing Ground. A model for separating efficiency assessment was fitted to the size frequency of spear littoral shrmip （Parapenaeopsis hardwickii） and Chinese ditch prawn （Palaemon gravieri） catch. The results demonstrate that the contact probability parameters are not significantly different between the two shrimp species and the 50% contact probability length is approximatey 40 mm, which indicates majority of shrimp individuals contact the panels. With the increase of mesh size of separator panels, 50% retention lengths increase and the size selectivity and separating efficiency for shrimps of the panels will be improved correspondingly. The hypothesis that the size selectivities of different codends （codends for shrimps and fishes） for shrimps were identical and can be verified according to model fitness in different hypothesises, though the constructions of different level codends are identifiably different. The significant difference between size selectivity of codend and separator panels is found and the reasons for the difference are discussed.

关 键 词：桁拖网 分隔网片 分隔效率 哈氏仿对虾 葛氏长臂虾 

分 类 号：S972.13[农业科学—捕捞与储运]