A Study on the Noises of Fishes

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For the development of acoustic fishing method, the noises of fishes have been recorded and analy/'ed by many scientists. Some specimens of fishes were selected as such Cyprinus carpio, Ctenopharyngodon idellus Carassius carassius, and pagrosol1ms major in this experiment. The noises such as feeding noise, driving away noise, jumping noise and fi llip noise were recorded by the tape recorder, Sony Model 262, through the underwa te r microph I one, Oki ST 6582, and analyzed in frequencies bv octave band analyzer, Rion SA-55, and sound pressure level of source by sound level meter, Rion NA-opNN The supplied feed was placed within 5em apart from the hydrophone. The result of analyzed noises were as follow. Cyprinus carjJio; Feeding noise 250- 500 cps, 92- 99 dB Driving away noise 125-2, 000 eps, 101-112 dB Jumping noise 125-2, 000 eps, 99-116.5 dB Ctenopharyngodon idcllus; Driving away noise 125-1, 000 cps, 96-109 dB Carassius carassius; Feeding noise 250- 500 cps, 91. 5- 99.5 dB Driving away noise 125-1, 000 eps, 99-108 dB Carassius auratus Feeding noise 250 eps, 94-101 dB Driving away noise 125-1, 000 cps, 98-110 dB Pagrosomus major Feeding noise 230-500 cps, 90-101 dB Fillip noise 500 cps, 98-108 dB (1) Feeding noise was produced as like as snap noise of twig and gulping down saliva noise in human and dominant frequency range of the noise is 250-500 cps and noise level 90-101 dB. (2) It was found that feeding noise were not a monotonic but a complex tones though fish took the same food. (3) Driving away noise was produced not so keen and the wave form of the noise is rising very sharp and big amplitude in the oscillograph. Dominant frequency range of this noise was about 150-1, 000 cps and noise level 96-112 dB except thut of carp. (4) The frequency of snapper's fillip noise, when it produced by caudal fin in swimming at the surface of water, was 500 cps and noise level 93-108 dB snd that of jumping noise of carp about 150-2, 000 cps and noise level 99-116.5 dB.