Optimization of purse seines by large meshed sections and low lead weight. Theoretical considerations, sinking speed measurements and fishing trials.

Abstract

Theoretical considerations on material requirements and sinking speed by use of different mesh size and lead weight in purse seines are outlined. Measurements confirmed that the sinking speed varied with mesh size and lead weight according to hydrodynamic theory. The sinking speed was slightly influenced by mesh geometry. In fishing trials with white large meshed net in the last part of a purse seine it was never observed that herring or mackerel escaped through the large meshes neither in day nor at night. The results indicates that the construction of herring and mackerel purse seines may be improved with an economic benefit both with regard to building costs and catch success.