Target strengths of Antarctic krill (Euphausia superba) at 38 and 120 kHz
Author Posting. © Acoustical Society of America, 1990. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 87 (1990): 16-24, doi:10.1121/1.399282. Enc...
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Language: | English |
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Online Access: | https://hdl.handle.net/1912/5649 |
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/5649 2023-05-15T13:53:14+02:00 Target strengths of Antarctic krill (Euphausia superba) at 38 and 120 kHz Foote, Kenneth G. Everson, Inigo Watkins, Jonathan L. Bone, Douglas G. 1990-01 application/pdf https://hdl.handle.net/1912/5649 en_US eng Acoustical Society of America https://doi.org/10.1121/1.399282 Journal of the Acoustical Society of America 87 (1990): 16-24 https://hdl.handle.net/1912/5649 doi:10.1121/1.399282 Journal of the Acoustical Society of America 87 (1990): 16-24 doi:10.1121/1.399282 Article 1990 ftwhoas https://doi.org/10.1121/1.399282 2022-05-28T22:58:45Z Author Posting. © Acoustical Society of America, 1990. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 87 (1990): 16-24, doi:10.1121/1.399282. Encaged aggregations of live krill in good to pristine condition have been ensonified at 38 and 120 kHz. Concurrent underwater television observations of behavior resemble those made by underwater divers in naturally occurring swarms, with comparably high densities of the order of 104 animals/m3 . Mean, single‐animal target strengths have been inferred from measurements of echo energy. For aggregations with mean lengths in the range [30,39] mm, the mean single‐krill target strengths are in the range [−88,−83] dB at 38 kHz and [−81,−74] dB at 120 kHz. Collateral measurements on some of the same encaged specimens determined a density contrast of 1.0357±0.0067 and sound‐speed contrast of 1.0279±0.0024, relative to seawater. These numbers have been used with the fluid‐sphere model as stated by Greenlaw [Limnol. Oceanogr. 24, 226–242 (1979)] . Computed backscattering cross sections have been averaged over the length distributions of each measured aggregation, resulting in target strength predictions in the range [−86,−80] dB at 38 kHz and [−79,−76] dB at 120 kHz. Article in Journal/Newspaper Antarc* Antarctic Antarctic Krill Euphausia superba Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Antarctic The Journal of the Acoustical Society of America 87 1 16 24 |
institution |
Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
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ftwhoas |
language |
English |
description |
Author Posting. © Acoustical Society of America, 1990. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 87 (1990): 16-24, doi:10.1121/1.399282. Encaged aggregations of live krill in good to pristine condition have been ensonified at 38 and 120 kHz. Concurrent underwater television observations of behavior resemble those made by underwater divers in naturally occurring swarms, with comparably high densities of the order of 104 animals/m3 . Mean, single‐animal target strengths have been inferred from measurements of echo energy. For aggregations with mean lengths in the range [30,39] mm, the mean single‐krill target strengths are in the range [−88,−83] dB at 38 kHz and [−81,−74] dB at 120 kHz. Collateral measurements on some of the same encaged specimens determined a density contrast of 1.0357±0.0067 and sound‐speed contrast of 1.0279±0.0024, relative to seawater. These numbers have been used with the fluid‐sphere model as stated by Greenlaw [Limnol. Oceanogr. 24, 226–242 (1979)] . Computed backscattering cross sections have been averaged over the length distributions of each measured aggregation, resulting in target strength predictions in the range [−86,−80] dB at 38 kHz and [−79,−76] dB at 120 kHz. |
format |
Article in Journal/Newspaper |
author |
Foote, Kenneth G. Everson, Inigo Watkins, Jonathan L. Bone, Douglas G. |
spellingShingle |
Foote, Kenneth G. Everson, Inigo Watkins, Jonathan L. Bone, Douglas G. Target strengths of Antarctic krill (Euphausia superba) at 38 and 120 kHz |
author_facet |
Foote, Kenneth G. Everson, Inigo Watkins, Jonathan L. Bone, Douglas G. |
author_sort |
Foote, Kenneth G. |
title |
Target strengths of Antarctic krill (Euphausia superba) at 38 and 120 kHz |
title_short |
Target strengths of Antarctic krill (Euphausia superba) at 38 and 120 kHz |
title_full |
Target strengths of Antarctic krill (Euphausia superba) at 38 and 120 kHz |
title_fullStr |
Target strengths of Antarctic krill (Euphausia superba) at 38 and 120 kHz |
title_full_unstemmed |
Target strengths of Antarctic krill (Euphausia superba) at 38 and 120 kHz |
title_sort |
target strengths of antarctic krill (euphausia superba) at 38 and 120 khz |
publisher |
Acoustical Society of America |
publishDate |
1990 |
url |
https://hdl.handle.net/1912/5649 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Antarctic Krill Euphausia superba |
genre_facet |
Antarc* Antarctic Antarctic Krill Euphausia superba |
op_source |
Journal of the Acoustical Society of America 87 (1990): 16-24 doi:10.1121/1.399282 |
op_relation |
https://doi.org/10.1121/1.399282 Journal of the Acoustical Society of America 87 (1990): 16-24 https://hdl.handle.net/1912/5649 doi:10.1121/1.399282 |
op_doi |
https://doi.org/10.1121/1.399282 |
container_title |
The Journal of the Acoustical Society of America |
container_volume |
87 |
container_issue |
1 |
container_start_page |
16 |
op_container_end_page |
24 |
_version_ |
1766258243703668736 |