Journal of the Korean Society of Fisheries and Ocean Technology (수산해양기술연구)
- Volume 16 Issue 1
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- Pages.1-15
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- 1980
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- 2671-9940(pISSN)
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- 2671-9924(eISSN)
The Underwater Noise of Fishing Gears in Operation
망어구의 수중소음에 관한 연구
Abstract
An underwater recording system was designed to measure the sound spectra of the underwater noises produced by fishing gears in operation. Recorded were noi~es from three types of fishing gears: an anchovy set net, three anchovy boat seine net and a stern trawlnet. Acoustic analysis were made using a heterodyne analyzer, a digital frequency analyzer and a level recorder. The no;'e produced by the anchovy set net was found in the high frequency region of the onset of ambient noise spectrum with a slope of - 6 dB/octave. Here the ambient noise spectrum is higher, though similar in shape, than Knudsen spectrum, and is attributed to the breaking action of the coastal wave. Measured noise spectra during the fishing operations of the anchovy boat seine nets are attributed to the background noise of the sea in the presence of the fishing vessels. The frequency distribution of the noise was 20~5, 000 Hz in the case of two steel anchovy boat seiners, and 20-3,000 Hz in the case of the wooden anchovy boat seiner. The predominant frequency range was 250~350 Hz and maximum sound pressure level was 122 dB (re
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