桁拖网作业中鱼虾分隔的初步试验研究

1996年末,我们在浙江渔场进行了桁拖网作业的鱼虾分隔试验,如同我们过去对这类渔具所作的放大网目以释放鱼、虾幼体;伸长吊纲,提高网口以增加对三疣梭子蟹的捕捞产量(季星辉等,1984)一样,本次试验也是这类网具选择性研究的内容之一,目标是改善桁拖网的选择性。在提高这种作业经济效益的同时,充分兼顾保护渔业资源和海洋生态环境的社会效益。 试验工作是在现有多囊捕虾桁拖网上,选择其中一个囊网,用一片目大为100mm的网片进行分隔,使鱼进入原囊网下方增设的盛鱼囊袋,而虾因其遇惊会弹跳的习性,穿过分隔网片进入原囊网。实践证明,分隔的效果是明显的,虾的分隔率达到55～68％,鱼的分隔率达到95％。现有的试验是初步的,我们将创造条件继续下去。

Preliminary Experimental Studies on the Separation of Shrimp from Fish in Beam trawling

The experiment of separating shrimp from fish with beam trawl was conducted on Shengshan fishing ground of Zhejiang province at the end of 19%. The purpose of the experiment was to improve the selective performance of beam trawl and to raise the economic efficiency of productive fishing activity, and to give consideration to the conservation of marine fishery resources and ecological environment as well. The scope of this experiment, just as we made before, related to the selectivity of fishing gear, including to enlarge the mesh size for releasing the juvenile from the net and to increase the length of beam trawl hanging line and to raise the height of net mouth. The experiment work was carried out using the multi - bag beam trawl by choosing one bag optionally in which a separating net of 100mm mesh size was inserted to lead the fish getting into the lower bag temporarily attached to the original bag, while the shrimp would jump up, pass through the mesh and then fall into the upper original bag. It showed that the separation result was satisfactory and the separation rate reached about 55-68% for shrimp and 95 % for fish.