In November 1984, the First Marine Ranch using acoustic sound was set up at Saiki Bay. Subsequently, Motonoma and Hotojima Marine Ranches in May and in November 1987, respectively. Sea Bream fry, which had been trained by conditioned reflex of acoustic sound (300Hz, 50dB) with supply of food, were released at the Marine Ranches. Field surveys were conductted to examine the effectiveness of the acoustic sound in making fish shoal stay around the feeding buoy.
As a result, it was shown that fish shoal released in November stayed for a while at the area around the feedingbuoy.
It was also found that although, it moves to adjacent natural fish reefs to pass the winter when, water temperature falls to 15-16℃, it retums to the area of feeding buoy again when water temperature rises 18-19℃. The mean rate of recapture of stocking sea bream were 11.7 and 28.3% for 0+ and 1+ age groups, respectively. Although, the mean body length of the released sea bream was a little smaller than natural one, tOtalmortority coefficient was lower about 25% than natural one. As a whole, it was thus concluded that the Marine Ranches using the acoustic sound were successful in controlling fish shoal.