南海北部张网主要技术参数的变化分析

根据2000～2005年和1983～1985年渔具渔法调查资料，对南海北部张网主要技术参数进行了比较分析。结果表明，与1983～1985年相比，现阶段张网网口纲长、网口网目尺寸和网身末段网目尺寸等稍有增大，网衣拉直长、网囊长和网囊网目尺寸等略有减小，网身长与网囊长之比、网身大头宽与小头宽之比等明显增大，其平均值分别由原来的5．8：1、19．8：1增至现在的13．8：1和26．2：1。张网主要技术参数的变化反映了张网渔具结构已经随着渔业资源的衰退发生了变化，但这种变化并不是积极的、革命性的改革。为合理利用渔业资源和促进张网渔业可持续发展，应根据南海北部渔业资源的特点研究相适应的选择性张网捕捞技术或装置，减少对幼鱼、幼虾资源的损害。

Changes of the major technical parameters of stow nets in the coast of northern South China Sea

In this paper,the main technical parameters of stow nets were analyzed based on the investigation of fishing gears and methods along the coast of the northern South China Sea during 2000~2005 and 1983~1985,respectively.Comparing with the data of stow nets investigated during 1983~1985,the mouth line length(C),mouth mesh size and mesh size of extension piece of the nets during 2000~2005 increased slightly,but stretched netting length(L),cod-end length(Lc) and cod-end mesh size decreased slightly.The Lb/Lc(Lb:body length) and the Wb/Ws(Wb:mouth width,Ws:extension piece width) increased averagely from 5.8:1 to 13.8:1 and from 19.8:1 to 26.2:1,respectively.With exhaustion of fishery resources in the coast of northern South China Sea,the main technical parameters of stow nets have changed for the net configuration,but the changes is not positive and revolutionary.To exploit rationally the coast fishery resources and to promote sustainable fishery development,based on behaviors and characteristics of fishery resources in the coast of northern South China Sea,the more advanced selective fishing techniques or devices for stow nets should be developed to reduce the damages to fries and young fishes and shrimps.