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近年来东海由于环境恶化和过度捕捞,小黄鱼资源量发生了严重的衰退。为更有效可持续利用小黄鱼资源,本试验就东海区底拖网菱形目50、55、60、65、70、75和80 mm网囊网目对小黄鱼进行选择性研究,采用套网法对不同尺寸的网目网囊的选择性进行了分析比较。结果表明:(1)当网囊为50和55 mm时产生较高逃逸率,但仍捕获大量当年生经济幼鱼;(2)随着网目由小变大,囊网捕获小黄鱼的平均体长、体重也逐渐变大;(3)拖网时间加长,由于网囊中渔获积累产生的堵塞效应,严重影响非目标鱼类的逃逸率;(4)根据小黄鱼的50%选择体长(L0.5)与不同网目尺寸拟合的直线:L0.5=2.625M-30.7(R2=0.915)。结合现行可捕标准以及渔业生产,建议拖网网目尺寸至少为60 mm。
In recent years, due to environmental deterioration and over-fishing in the East China Sea, a serious recession has occurred in the resources of small yellow croaker. In order to more effectively and sustainably use the resources of small yellow croaker, the test was conducted to study the selectivity of small yellow croaker on the 50, 55, 60, 65, 70, 75 and 80 mm meshes of the trawl rhizome in the East China Sea. The selectivity of the mesh network was analyzed and compared. The results showed as follows: (1) When the cysts were 50 and 55 mm, a higher escape rate was found, but a large number of annual economic juveniles were still caught. (2) Length and body weight gradually become larger; (3) the trawling time is prolonged, and the blockage effect caused by the accumulation of catches in the cysts severely affects the escape rate of non-target fish; (4) According to 50% of small yellow croaker body length (L0 .5) Lines fitted to different mesh sizes: L0.5 = 2.625M-30.7 (R2 = 0.915). In conjunction with current capture standards and fisheries production, trawl mesh sizes of at least 60 mm are recommended.