辽东湾多锚单片张网鱼虾分离网片的选择性研究

Theselectivity about separating mesh for fishes and shrimps of multi-anchored monolithic trap in Liaodong Bay

为掌握分离网片对多锚单片张网渔获分离效果的影响,解决鱼虾混获问题,采用主网衣网目尺寸为18 mm及加装35 mm网目尺寸的分离网片试验网,在辽东湾海域进行4网次有效生产试验研究。结果显示:网兜中的渔获种类以鱼类为主,约占网兜总渔获数量的85.0%,其中棘头梅童鱼(Collichthys lucidus)和斑尾刺虾虎鱼(Acanthogobiu sommaturus)的尾数分离率为79.76%、82.90%,优势体长组主要集中在91~110 mm和101~120 mm;网囊中的渔获种类以虾类为主,占网囊总渔获数量的80.0%以上,葛氏长臂虾(Palaemon gravieri)与中华安乐虾(Eualus sinensis)的尾数分离率为85.92%、85.47%,优势体长组主要集中在51~70 mm和31~50 mm。研究表明,加装分离网片后,试验网对渔获优势种分离效果明显,且能够为渔民带来较好的经济效益,本研究成果可为中国多锚单片张网的结构优化提供参考。

In order to grasp the effect of separating mesh on the catch separation effect of multi-anchor monolithic trap and to solve the problem of mixed catch of fish and shrimp,a test net with a mesh size of 18 mm for the main net jacket and a 35 mm mesh size separating mesh was used to conduct a four-network effective production test study in the sea area of Liaodong Bay.In this study,the main purpose of designing a multi-anchor monolithic trap device for separating fish and shrimp is to be used for separating different species of catches caught in the open-net operation.In this sea trial,due to the influence of various factors such as changes in offshore fishery resource stocks,operating seasons,operating locations,tides,and so on,the main dominant species caught were Collichthys lucidus,Acanthogobiu sommaturus,Palaemon gravieri and Eualus sinensis.The results showed that fish were the main species caught in the covered net,accounting for more than 85.0%of the total number of catches,the average separation rates of Collichthys lucidus and Acanthogobiu sommaturus were 79.76%and 82.90%,respectively;and the dominant length groups were concentrated in the range of 91-110 mm and 101-120 mm,respectively.Shrimp were the main species caught in the codend net,accounting for more than 80.0%of the total number of catches The average separation rates of Palaemon gravieri and Eualus sinensis were 85.92%and 85.47%,respectively;and the dominant length groups were mainly concentrated in 51-70 mm and 31-50 mm,respectively.The study shows that the test net has obvious effect on the separation of the dominant species after the installation of the separation net,and can bring better economic benefits to the fishermen,and the results of this study can provide a reference basis for the optimization of the structure of multi-anchor monolithic trap in China.