智利竹鱼拖网最适网囊网目尺寸探讨

Discussion about optimum mesh size of cod end for Chilean jack mackerel trawl

摘要:

根据拖网网囊网目尺寸与鱼体生物学存在关系 ,对智利竹鱼的优势叉长组成、形体特征、初次性腺成熟时的叉长等进行了分析。通过现场测试得出 2 0 0 0年智利竹鱼的优势叉长为 2 5 0～ 30 0mm ;体高、体宽和体周与叉长存在线性关系 ,分别为 2a =0 .185 8L - 3 .5 2 19,2b =0 .1339L - 4.2 99,c =0 .480 3L - 3 .4794。并对智利竹鱼拖网网囊网目尺寸进行了分析与计算 ,认为智利竹鱼拖网网囊的最适网目内径为 115～ 12 0mm。

Abstract:

This paper deals with the dominant fork length composition, shape characteristics and the fork length of Chilean jack mackerel (Trachurus murphyi) at the first sexual maturity, based on the relationship between the cod end mesh size and the biological characteristics of the fish body. The measurement results show that the dominant fork length of Chilean jack mackerel in 2000 is between 250-300mm. The linear relationships between the fork length(L) and the height(a), width(b) and girth(c) of fish bodies can be respectively described as 2a=0.1858L-3.5219, 2b=0.1339L-4.299 and c=0.4803L-3.4794. The optimum inner mesh size of the cod end for Chilean jack mackerel trawl is 115-120 mm.