Acoustic scattering of broadband echolocation signals from prey of Blainville's beaked whales : modeling and analysis
Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2006 Blainville's beaked whales (Mesoplodon densirostris) use broadband, ultrasonic echolocation signals (...
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/1283 2023-05-15T18:33:33+02:00 Acoustic scattering of broadband echolocation signals from prey of Blainville's beaked whales : modeling and analysis Jones, Benjamin A. Canary Islands 2006-09 938802 bytes application/pdf https://hdl.handle.net/1912/1283 en_US eng Massachusetts Institute of Technology and Woods Hole Oceanographic Institution WHOI Theses https://hdl.handle.net/1912/1283 doi:10.1575/1912/1283 doi:10.1575/1912/1283 Beaked whales Acoustic models Thesis 2006 ftwhoas https://doi.org/10.1575/1912/1283 2022-05-28T22:57:10Z Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2006 Blainville's beaked whales (Mesoplodon densirostris) use broadband, ultrasonic echolocation signals (27 to 57 kHz) to search for, localize, and approach prey that generally consist of mid-water and deep-water fishes and squid. Although it is well known that the spectral characteristics of broadband echoes from marine organisms are a strong function of size, shape, orientation and anatomical group, little is known as to whether or not these or other toothed whales use spectral cues in discriminating between prey and non-prey. In order to study the prey-classification process, a stereo acoustic tag was mounted on a Blainville's beaked whale so that emitted clicks and corresponding echoes from prey could be recorded. A comparison of echoes from prey selected by the whale and those from randomly chosen scatterers suggests that the whale may have, indeed, discriminated between echoes using spectral features and target strengths. Specifically, the whale appears to have favored prey with one or more deep nulls in the echo spectra as well as ones with higher target strength. A three-dimensional, acoustic scattering model is also developed to simulate broadband scattering from squid, a likely prey of the beaked whale. This model applies the distorted wave Born approximation (DWBA) to a weakly-scattering, inhomogeneous body using a combined ray trace and volume integration approach. Scatterer features are represented with volume elements that are small (less than 1/12th of the wavelength) for the frequency range of interest (0 to 120 kHz). Ranges of validity with respect to material properties and numerical considerations are explored using benchmark computations with simpler geometries such as fluid-filled spherical and cylindrical fluid shells. Modeling predictions are compared with published data from live, freely swimming ... Thesis toothed whales Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Woods Hole, MA |
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Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
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English |
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Beaked whales Acoustic models |
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Beaked whales Acoustic models Jones, Benjamin A. Acoustic scattering of broadband echolocation signals from prey of Blainville's beaked whales : modeling and analysis |
topic_facet |
Beaked whales Acoustic models |
description |
Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2006 Blainville's beaked whales (Mesoplodon densirostris) use broadband, ultrasonic echolocation signals (27 to 57 kHz) to search for, localize, and approach prey that generally consist of mid-water and deep-water fishes and squid. Although it is well known that the spectral characteristics of broadband echoes from marine organisms are a strong function of size, shape, orientation and anatomical group, little is known as to whether or not these or other toothed whales use spectral cues in discriminating between prey and non-prey. In order to study the prey-classification process, a stereo acoustic tag was mounted on a Blainville's beaked whale so that emitted clicks and corresponding echoes from prey could be recorded. A comparison of echoes from prey selected by the whale and those from randomly chosen scatterers suggests that the whale may have, indeed, discriminated between echoes using spectral features and target strengths. Specifically, the whale appears to have favored prey with one or more deep nulls in the echo spectra as well as ones with higher target strength. A three-dimensional, acoustic scattering model is also developed to simulate broadband scattering from squid, a likely prey of the beaked whale. This model applies the distorted wave Born approximation (DWBA) to a weakly-scattering, inhomogeneous body using a combined ray trace and volume integration approach. Scatterer features are represented with volume elements that are small (less than 1/12th of the wavelength) for the frequency range of interest (0 to 120 kHz). Ranges of validity with respect to material properties and numerical considerations are explored using benchmark computations with simpler geometries such as fluid-filled spherical and cylindrical fluid shells. Modeling predictions are compared with published data from live, freely swimming ... |
format |
Thesis |
author |
Jones, Benjamin A. |
author_facet |
Jones, Benjamin A. |
author_sort |
Jones, Benjamin A. |
title |
Acoustic scattering of broadband echolocation signals from prey of Blainville's beaked whales : modeling and analysis |
title_short |
Acoustic scattering of broadband echolocation signals from prey of Blainville's beaked whales : modeling and analysis |
title_full |
Acoustic scattering of broadband echolocation signals from prey of Blainville's beaked whales : modeling and analysis |
title_fullStr |
Acoustic scattering of broadband echolocation signals from prey of Blainville's beaked whales : modeling and analysis |
title_full_unstemmed |
Acoustic scattering of broadband echolocation signals from prey of Blainville's beaked whales : modeling and analysis |
title_sort |
acoustic scattering of broadband echolocation signals from prey of blainville's beaked whales : modeling and analysis |
publisher |
Massachusetts Institute of Technology and Woods Hole Oceanographic Institution |
publishDate |
2006 |
url |
https://hdl.handle.net/1912/1283 |
op_coverage |
Canary Islands |
genre |
toothed whales |
genre_facet |
toothed whales |
op_source |
doi:10.1575/1912/1283 |
op_relation |
WHOI Theses https://hdl.handle.net/1912/1283 doi:10.1575/1912/1283 |
op_doi |
https://doi.org/10.1575/1912/1283 |
op_publisher_place |
Woods Hole, MA |
_version_ |
1766218180289626112 |