Cultivation network for Pisces and fish preserve null for Pisces cultivation

摘要

PROBLEM TO BE SOLVED: To provide a crawl capable of performing superior cultivation of fishes, making the most of the characteristics of a copper-base alloy, by using a net made of copper-base alloy. SOLUTION: A crawl 13 for cultivation of fishes is constituted by suspending a cultivation net 3 for fishes with plural floats 4 and attaching sacrificial anodes 5 composed of zinc plates to respective corner parts 3b of the cultivation net 3, respectively. The cultivation net 3 is constituted of a wire made of seawater corrosion resisting copper-base alloy having a composition consisting of, by weight, 62.0-69.0% copper, 0.2-1.0% tin, 0.02-0.15% antimony, one or two elements selected from 0.02-0.15% phosphorus, 0.1-1.0% nickel, and 0.05-0.8% iron, and the balance zinc with inevitable impurities. The mutual spacings S, S' between neighboring floats 4, 4' are regulated to =30cm, respectively, and the positions of respective sacrificial anodes 5 are located at a depth of 10-50cm from the surface of the sea, respectively.