Artisanal fishing net float loss and a proposal for a float design solution

Abstract Plastic floats from fishing nets are commonly found washed up on beaches in southern Brazil. They are usually broken and show signs of having been repaired. Characteristics of floats and interviews with fishermen suggest two main causes of float loss. First, collisions between active gear, bottom trawl nets for shrimp, and passive gear, drift nets for fish, destroy nets and release fragments of them, including floats. Second, the difficulty with which floats are inserted on the float rope of the nets when they are used near the surface. Floats are inserted to replace damaged or lost floats, or they may be removed if it is desired that the nets be used in deeper waters. Floats may thus be poorly fixed to the cables and lost. Here a new float design that offers greater safety in use and for the replacement of floats is described and tested.

摘要：巴西南部海滩常可见到渔网塑料浮子被冲上岸。此类浮子多已破损，且带有修复痕迹。通过对浮子特征的分析以及对渔民的访谈，可归纳出浮子丢失的两大主要原因：其一，虾用底拖网这类主动作业渔具与鱼用流刺网这类被动渔具发生碰撞时，会损毁网具并释放包括浮子在内的网具碎片；其二，当网具在近海面作业时，浮子难以安装至网具的浮子绳上。渔民安装浮子用于替换破损或丢失的浮子，若需将网具用于更深水域，则需移除浮子，此过程可能导致浮子与绳索固定不牢，进而发生丢失。本文介绍并测试了一款新型浮子设计，该设计可提升使用及更换浮子时的安全性。