Research on the luring of fish schools by utilizing underwater acoustical equipment

The device for gathering fish schools by using underwater acoustical equipment was conceived on the idea that if fish schools could be lured to a location and driven into a fish net by emitting the effective sound, fishing efficiency could be increased. The underwater sound projector of a flat frequency response from 150Hz up to 4,500Hz was produced, corresponding to acoustic features of fish. Yellowtail responded to their swimming and bait eating sound of 5-17dB re 1 ubar. The catch of squid was definitely more for the periods of emitting effective sound than for the periods of not emitting sound. Mackerel and jack mackerel responded to its swimming and bait eating sound of higher than 22dB and ascended. In the stationary net fishing, fish was lured by sound into the net and the big catch never got before was obtained.