渔网渔法学-围网渔业技术1教学课件.ppt

2002-7-3 * 7、网头部分纲索 叉纲：位于网具两端网头上下边缘，主要承受外力和固定网头形状。装在网头上边缘的一根为上叉纲，下边缘一根为下叉纲，形状似“V”形，常用一根纲索对折，也有用二根纲索末端相接。 网头绳：结缚于网具前网头，连接于带网头船或舢板或浮筒上的带网纲索。主要作用是放网时拖带网头，常用乙纶绳或白棕绳。 包括叉纲、网头绳和跑纲 跑纲：结缚于网具后网头，由网船边围边松放的带网纲索。主要作用是作业时扩大包围圈，以协调操作，常用钢丝绳。 2002-7-3 * 二、无囊围网网图的识读 东黄海捕捞鲐鲹鱼的932.00m×283.20m单船无囊围网网衣展开图为例，说明图中各种符号、数字的意义。 2002-7-3 * Part1 purse seine boat with turntable and seine Part2 large purse seine type boat with turntable removed for ring net fishing Part3 small purse type boat with ring net Part4 small purse seine type boat with ring Part5 Cannery ring net boat(formerly lampara boat) Part6 ring net boat Part7 Heavily loaded ring net 2002-7-3 * Position of boats in hauling lampara,purse seine and ring net, (scale: lampara boat ,50 feet;other boats ,60 feet;all nets,200 fathoms.) 2002-7-3 * The ring net, or purse lampara, is a cross between the purse seine and the relatively light lampara. It first appeared at San Pedro, California, in 1918, Hauling a mackerel ring net. The purse ring can be seen bunched at the stern of the boat, July,1929. 2002-7-3 * 挪威 由于近海鲱鱼资源丰富，加上毛鳞鱼资源开发利用，因而围网渔业是挪威的主要渔业。20世纪60年代末，为加强开发毛鳞鱼资源，围网渔业得到了迅速发展。 20世纪70年代开始建造大船代替旧船和小船，船大且有加工设备，大部分渔船装有横向推进器。先进、安全、可靠的三滚筒式起网机；船上的渔用电子扫描声纳在世界上享有较高的声誉。 20世纪80年代挪威试验研究六角形网目围网，并获得成功，对提高下纲沉降速度，增加捕鱼深度和减小网圈变形等起到了明显的作用。 2002-7-3 * 世界各国围网作业 A group of fishermen using purse seine nets off Idinthakarai in Tirunelveli district. (Call to revoke ban on using purse seine nets ) 2002-7-3 * Wooden-hull Purse Seiner 2002-7-3 * Purse seine, Kodiak Island 2002-7-3 * Purse seine towing net in Colvos Passage. 2002-7-3 * 扬帆出海 荷兰 鲱鱼是生活在北太平洋或北大西洋的寒带至温带的回游鱼。 Pacific Herring 2002-7-3 * Herring Harvest: Purse Seining Purse Seining Photographs from the Gulf of Maine Fishery 2002-7-3 * workers are pumping the catch from a purse-seine net into a carrier vessel. Menhaden(大西洋油鲱) are processed into animal feeds and are also used in the pharmaceutical industry as a source of high-grade omega-3 oils.  A school of