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为检测方目网囊对蓝圆鱼参和多齿蛇鲻的选择作用 ,2 0 0 0年 1 1～ 1 2月在南海北部海域试验了 4种目大的方目网囊。结果表明 ,方形网目网囊有利于释放纺缍形 (如蓝圆 鱼参)、圆形或近圆形 (如多齿蛇鲻 )两种形体鱼类的小、幼鱼 ,且对后者的释放效果更好。当网囊目大分别为 45、5 0mm时 ,蓝圆鱼参的5 0 %选择体长 (L0 .5)分别为 1 2 1 2 2、1 2 8 77mm ;当网囊目大分别为 40、45、5 0mm时 ,多齿蛇鲻的L0 5分别为 1 2 4 1 2、1 2 6 75、1 3 9 3 2mm。通过不同目大网囊对蓝圆鱼参、多齿蛇鲻选择性比较分析 ,发现 5 0mm目大方目网囊的选择效果好于 40、45mm目大的网囊 ,因此 ,在南海区拖网渔业中采用 5 0mm目大的方目网囊是必要的 ,同时建议将 1 5 0mm作为蓝圆鱼参、多齿蛇鲻的最小可捕叉长标准。
In order to test the function of Mesophytome on the selection of bluefin fish and polyp snakehead, four large mesophytes were tested in the northern South China Sea from January to February in 2001. The results showed that the square mesophyll cyst is good for the release of small and juvenile fish of both spiny (such as blue-bellied fish), round or nearly circular (eg, serpent), and the latter Release better. When the size of the cysts were 45 and 50 mm respectively, the 50% body length (L0.5) of the cyprinids were 1 2 1 2 2 and 1 2 8 77mm, respectively. When cysts were 40 , 45,5 0mm, L0 5 of the snakeheads were respectively 1 2 4 1 2,1 2 6 75,1 3 9 3 2mm. Through the comparative analysis of blue-eye fish and blue-tooth snakehead fish, the results showed that the selection effect of the 50-mm eyes was better than that of the 40,45-mm eyes. Therefore, in the South China Sea trawl fishery In the use of 50mm mesh mesh mesh stenosis is necessary, at the same time it is recommended to be 150mm bluefin ginseng, the smallest snake Crocodile can be caught the long standard.