白熱灯及び螢光水銀灯の集魚効果と水中照度
1959 年 25 巻 1 号 p. 17-21
詳細
1959 年 25 巻 1 号 p. 17-21
On the Tachibana Bay of Nagasaki Prefecture purse sein anchovy fisheries, using lights, is carried on (Fig. 1). The author investigated the fish gathering effects of lamps. One Incandescent lamp of 2 KW, (1 KW, 2 globes, D. C. 100-120 V) was generally used another Fluorescent mercury-vapour lamp of 2 KW, (1 KW, 2 globes 100 V, A. C. 60 cycles) was specially prepared for this experiment with a 6 KW A. C. dynamo on a boat (Plates). The author compared the submarine illumination under each lamp and also the fish gathering effects of each lamp.
The fish gathering effect of the mercury vapour lamp was better than the incandescent lamp. This was especially true during the early period after lighting, when fishes of comparatively medium length gathered (scomber and so on). In this case the fishery was mainly for anchovy. The fish school that gathered under the mercury-vapour lamp were swimming actively. However, during the later stages on the illumination of the mercury-vapour lamp it was found necessary either to weaken the illumination to change the lamp to the incandescent variety or find some means by which the illumination of the mercury-vapour lamp could be maintained.
The author supposes that the effective illumination for the gathering of anchovy is below 0.1 Lux. The illumination of the mercury lamp is about 30% more than that of the incandescent lamp and this is proportional to one dimension of length in water. (Figs. 2 & 3).
