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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Sciaenids Habitat Survey in Coast Water by Passive Acoustic Method

Tu, Chang 27 July 2004 (has links)
There are many Sciaenid species found in coastal water of Taiwan, and most of them can generate sound in the spawning season. However due to overfishing, the populations of these high economic value fishes have been greatly decreased. To study and protect Sciaenid, whose habitat should be identified to set up seasonal protection zones. In this study, easy and low cost measure by using passive sonar is proposed to map the habitat in the field. Measurement and analysis of Sciaenid¡¦s sound were performed to investigate its acoustic characteristic, and frequency range was found to be 350 to 1,500 Hz. The statistical distribution of sound levels can be built up by enough field measurement, therefore source levels can be defined in this method. In the addition, the transmission loss of in site shallow water was studied to compute the real decaying factor (TL=n*logR) of the survey site. By using 3 sonobuoys, with known source level distribution and transmission loss, the distance of possible habitat can then be inverted. Through enough measurements, the map of coastal habitat of Sciaenid can be generated with efficiency and accuracy.

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