曳縄釣漁業の研究-1-潜航板の色の違いと漁獲との関係

概要

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In trolling, the effect of a plate depressor on fish catch may be very serious and it is said that the movement of the plate depressor is the most important. In the present paper the catching efficiency with plate depressors was studied from the point of view of their colors. The colors used were white, yellow, silver, pale-blue, red and black. The results obtained are as follows: In the twelve fishing experiments the pale-blue plate depressor which had the best catch was 3 times as high as the mean catching rate of yellow one which showed the poorest catch. The pale-blue, black and white plate depressors which showed better results in the above experiments were repainted yellow, and the red, yellow and silver ones which had not been effective in hooking repainted pale-blue, so that the good results obtained before might be achieved again, influenced by the favourable movements of the plate depressors. The fishing experiments conducted again showed that pale-blue plate depressors had 1.7 times as many catch as the yellow ones.