深水围网沉降性能的测试及渔法研究

本文根据近几年来在较深水域的渔场探捕实践和我国机轮围网现有设备条件，设计了深水围网网具，在较深水域的渔场进行了探捕作业。在不同流速、括纲长度和绞收速度等情况下，对网具沉降速度和深度分别作了测试和分析，从而得出了上述变量与网具沉降性能的关系。结果如下：(1)围网网具各部位的自然沉降速度是不同的，取鱼部最慢，网翼中部次之，后网翼最快。在放网过程中，网具各部位都按慢——快——慢的不规则速度自然沉降的。(2)在围网作业过程中，流速愈大，愈不利于网具沉降；括纲愈长，愈有利于网具沉降；括纲绞速愈快，网具沉降深度的损失愈大，在一定流速范围内，括纲绞速对网具的沉降起主要作用。

AN EXPERIMENTAL RESEARCH ON SINKING PERFORMANCE OF PURSE SEINE IN DEEPER WATERS OF THE EAST CHINA SEA

According to the trial fishing practice in the deeper waters of the EastChina Sea and depending upon the installation conditions of our available purse seiners.a type of purse seine for operating in deepers waters was designed in recent years. Thenet sinking speed and net sunk depth of the purse seining method were tested andanalyzed in the cases of various current speed, unequal length and different haulingspeed of pursing cable, so that the relationship of these three varibles to net perfor-mance was obtained. The results are summerized as follows: 1) It is different to measure the natural sinking speed of the three parts of netbody. As for the comparison of their speed, the hauling end of net is at the first, themid-part of net is the second, and the bunt is the third. The natural sink of all partsof the net body appears as fast-slow-fast irregularity. 2) During the full period of operation, the fast current speed and the quickhauling of pursing cable are more disadvantageous for net sinking, while the longerpursing cable is more advantageous for the same one. In certain speed range, thehauling speed of pursing cable plays a main role in the sinking performance of the net.