羅網魚から推測されるキスまき刺網における羅網過程

概要

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To determine the catching process in encircling gillnets, statistical analyses were made of catch and direction of enmeshing obtained from two comercially operated encircling gillnets (Izumi- and Eguchi-nets). Underwater observation of the behavior of the two nets was made by two divers during experimental operation. Izumi-net was of double wall nettings 100-120m long with a scare net and completely closed on hauling, and Eguchi-net was of a single wall netting 245m long and not closed on hauling. Japanese whiting, red seabream, crimson seabream, Richardson dragonets, and lizardfish were enmeshed before they were encircled by the nets. In the Eguchi-net, the fishes were enmeshed on both sides. Japanese whiting swimming behind the moving net were found to try to pass through the mesh to join the fish swimming in front of the net, and were enmeshed inwards. This schooling-related behavior probably partly caused the inward enmeshing in Eguchi-net. In the Izumi-net, fishes were driven well and all enmeshed outwards, probably due to the higher visibility of this net.
日本水産學會の論文