Estimation on Audibility of Large Cetaceans for Improvement of the Under Water Speaker

In order to avoid collisions between the hydrofoil (HF) and cetaceans, the Under Water Speaker (UWS) has been installed on the HF. Because of its potential in utility, the authors tried to improve the UWS to minimize the risk of the collisions. Under the project, they examined three subprojects; 1) Analyzing the characteristics of the HF underwater noise; 2) Assessing audibility of major large cetaceans by measuring their vocalizations and 3) An anatomical prediction of the audible range by examining the cochlear basal membrane. Through the analyses, it was identified that the noise produced by the HF was a broad-band noise with approximately 150dB re 1μPa-m. That noise level was lower than those of larger boats suggesting difficulties for cetaceans in sensing approach of the vessels. In addition, analysis of their vocalizations and anatomical observation indicated that dominant frequency of their audible range was lower than signals produced by the existing UWS.


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  • Accession Number: 01495473
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 26 2013 1:52PM