海州湾秋季坛子网网目选择性研究

Selectivity of Codend Mesh of Stow Nets with Double Pile Vertical Hole in Haizhou Bay in Autumn

2018年秋季,利用囊网内径网目为25、35、45、55 mm的坛子网在黄海海州湾渔场N 35°02.335′,E 119°24.842′附近海域进行了11网次试验。从Logistic选择性模型、坛子网不同网目对主要渔获物小黄鱼的选择性曲线、渔获物组成、幼鱼比例及选择性分析等方面,研究坛子网网囊的选择性。试验结果显示,坛子网九月主要渔获物为小黄鱼、带鱼和三疣梭子蟹;随网囊网目尺寸的增加,渔获物质量逃逸率及尾数逃逸率均迅速增加,网目尺寸为55 mm时其值均超过80%,且质量逃逸率及尾数逃逸率的值比较接近;渔获物组成中,小黄鱼、银鲳和三疣梭子蟹幼体比例非常高,基本全为幼体,带鱼幼鱼比例也超过70%;根据小黄鱼的可捕体长,获得坛子网针对小黄鱼的最适网囊网目尺寸,为(40.59±3.19)mm。研究结果可为我国海州湾渔具管理以及渔业资源的可持续发展与管理提供科技支撑。

A stow net with codend mesh of 25,35,45 and 55 mm was operated 11 times in the sea area near Haizhou Bay fishing ground N 35°02.335′,E 119°24.842′in the Yellow Sea in autumn of 2018 to probe into the selectivity of stow nets through Logistic selectivity model,selectivity curve of different meshes to small yellow croaker Pseudosciaena polyactis,composition of catches,proportion of juveniles and selectivity analysis.Results showed that the dominant species caught by the stow net were small yellow croaker,silver hairtail Trichiurus lepturus and swimming crab Portunus trituberculatus in September.Escape percentage of catch weight and number was rapidly increased with the increase in the mesh size,even over 80%at mesh size of 55 mm.There were high percentages of juvenile small yellow croaker,butterfish Pampus argenteus and swimming crab,almost all juvenile fish,over 70%in silver hairtail in the catches.Based on the minimum catch length of small yellow croaker,it was concluded that the optimum mesh size of the stow net was(40.59±3.19)mm.The findings provided a scientific basis for the sustainable development of fishery resources and fishery management in Haizhou Bay.