集魚灯下の魚群の行動観察〔英文〕

概要

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Observations of the movements of japanese-mackerel and horse-mackerel attracted to lamps and their behaviour in relation to the purse-seine were conducted by utilization of two kinds of echo-sounders, while on board a light-boat of a roundhaul netter fleet. Moreover, horizontal movements of silvery anchovy and puffer drawn towards the surface by the lamps were (visually) observed.Except for the puffer, these fishes were very lively while under the lamps and the horizontal extent of movement of horse-mackerel and japanese-mackerel was estimated to range beyond 60 to 89 m at 27 to 40 m depth.A shoal of horse-mackerel or japanese-mackerel was seen to separate into upper and lower shoal delineated by the bottom margin of the purse-seine. The shoal remaining in bottom layer move away from the purse-seine but was attracted to the second lighting in the same position as before.These results are compared with those of other investigators in the discussion.
日本水産學會の論文