定置网是沿岸及内陆水域的重要渔具之一,在世界渔业中占有一定的比重。由于定置网是一种被动性的渔具,因此定置网的渔获,大都取决于渔场里洄游鱼群的行动与数量,特别是鱼群的洄游量。实验证明,只有当渔场里的鱼群洄游量超过一定数量时,定置网才开始有渔获。因此,在鱼群洄游量少的水域,是无望得到渔获的。由此表明鱼群洄游量少的水域,不能形成定置网渔场。根据日本在相模湾道合定置网渔场和三陆沿岸大建定置网渔场实验的结果。为了分析用声纳探测的洄游鱼群数与定置网渔获量的关系,把被道合定置网渔获的狭头鲐和被大建定置网渔获的鲑鱼的各 Settlement network is one of the important fishing gear along the coast and inland waters, occupying a certain proportion in the world’s fisheries. Since the set net is a passive fishing gear, the catch of the set net depends largely on the movement and number of migratory fish stocks in the fishing grounds, particularly on the migratory stocks. Experiments show that only when the fish farms in the migration of more than a certain amount of time, the fixed network began to catch. As a result, there is no hope of gaining catch in waters with small fish stocks. This shows that fish stocks less water, can not form a fixed net fishing grounds. According to the results of Japan’s experiments on the fixed net fisheries at Sagami Bay Road junction fishing net and the Sanriku Coast. In order to analyze the relationship between the number of migratory fish detected by sonar and the catch of the catchment, the catch of the catch and the catch of the salmon by the anchorage