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Acoustic predation in a sailfish-flying fish cloak

When a sailfish circles to corral a school of flying fish in a vortex near the ocean surface, a tiny patch of arced surface waves confined to oppositely placed 70° sectors appears dispersing coherently, but why? It is modeled that, when the fish motions stop suddenly, the corralled school compacts,...

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Autor principal: Bandyopadhyay, Promode R.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10449807/
https://www.ncbi.nlm.nih.gov/pubmed/37620523
http://dx.doi.org/10.1038/s41598-023-40986-w
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author Bandyopadhyay, Promode R.
author_facet Bandyopadhyay, Promode R.
author_sort Bandyopadhyay, Promode R.
collection PubMed
description When a sailfish circles to corral a school of flying fish in a vortex near the ocean surface, a tiny patch of arced surface waves confined to oppositely placed 70° sectors appears dispersing coherently, but why? It is modeled that, when the fish motions stop suddenly, the corralled school compacts, the tail shed propulsion vortices touch, break and radiate the pressure released from the centrifugal vortex rotation creating an acoustic monopole. The surface-wave patch is a section of the sphere of radiation. The oppositely placed curved bodies of the sailfish and the flying fish act as concave acoustic mirrors about the monopole creating a reverberating bell-shaped cloak in between which vibrates the ear bones and bladders of the flying fish disorienting them. A cup of water firmly struck on a table induces a similar vibration of a purely radial mode. The sailfish circles around the school at a depth where the wind induced underwater toroidal motion in the vertical plane becomes negligible such that the flying fish is unable to sense the tailwind direction above, limiting the ability to swim up and emerge in the right direction to glide. Experiments confirm that the flying fish tail rigidity is too low for a quick ballistic exit, which is not called for either.
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spelling pubmed-104498072023-08-26 Acoustic predation in a sailfish-flying fish cloak Bandyopadhyay, Promode R. Sci Rep Article When a sailfish circles to corral a school of flying fish in a vortex near the ocean surface, a tiny patch of arced surface waves confined to oppositely placed 70° sectors appears dispersing coherently, but why? It is modeled that, when the fish motions stop suddenly, the corralled school compacts, the tail shed propulsion vortices touch, break and radiate the pressure released from the centrifugal vortex rotation creating an acoustic monopole. The surface-wave patch is a section of the sphere of radiation. The oppositely placed curved bodies of the sailfish and the flying fish act as concave acoustic mirrors about the monopole creating a reverberating bell-shaped cloak in between which vibrates the ear bones and bladders of the flying fish disorienting them. A cup of water firmly struck on a table induces a similar vibration of a purely radial mode. The sailfish circles around the school at a depth where the wind induced underwater toroidal motion in the vertical plane becomes negligible such that the flying fish is unable to sense the tailwind direction above, limiting the ability to swim up and emerge in the right direction to glide. Experiments confirm that the flying fish tail rigidity is too low for a quick ballistic exit, which is not called for either. Nature Publishing Group UK 2023-08-24 /pmc/articles/PMC10449807/ /pubmed/37620523 http://dx.doi.org/10.1038/s41598-023-40986-w Text en © This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply 2023 https://creativecommons.org/licenses/by/4.0/Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Article
Bandyopadhyay, Promode R.
Acoustic predation in a sailfish-flying fish cloak
title Acoustic predation in a sailfish-flying fish cloak
title_full Acoustic predation in a sailfish-flying fish cloak
title_fullStr Acoustic predation in a sailfish-flying fish cloak
title_full_unstemmed Acoustic predation in a sailfish-flying fish cloak
title_short Acoustic predation in a sailfish-flying fish cloak
title_sort acoustic predation in a sailfish-flying fish cloak
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10449807/
https://www.ncbi.nlm.nih.gov/pubmed/37620523
http://dx.doi.org/10.1038/s41598-023-40986-w
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