Hang Yang, Jing Cheng, Taolin Tang, Jun Chen, Guodong Li
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In an anechoic tank, we used wide-band echosounder and 70 kHz, 120 kHz, and 200 kHz split-beam transducers to measure the TS of jellyfish swimming omnidirectionally. The results show a difference of approximately 4 dB in the jellyfish’s normalized TS at 70 kHz (frequency range: 45 kHz to 95 kHz) and 200 kHz (frequency range: 160 kHz to 260 kHz) center frequency. The normalized TS of jellyfish varies by around 8 dB between horizontal and vertical swimming orientations. For jellyfish swimming horizontally, the TS and bell diameter have the following least squares fits: <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M1\"> <mi>T</mi> <msub> <mrow> <mi>S</mi> </mrow> <mrow> <mi>D</mi> <mn>70</mn> <mi>k</mi> <mi>H</mi> <mi>z</mi> </mrow> </msub> <mo>=</mo> <mn>20</mn> <mtext> </mtext> <mi mathvariant=\"normal\">log</mi> <mtext> </mtext> <mi>D</mi> <mo>−</mo> <mn>89.36</mn> <mfenced open=\"(\" close=\")\" separators=\"|\"> <mrow> <msup> <mrow> <mi>r</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msup> <mo>=</mo> <mn>0.83</mn> </mrow> </mfenced> </math> ; <math xmlns=\"http://www.w3.org/1998/Math/MathML\" id=\"M2\"> <mi>T</mi> <msub> <mrow> <mi>S</mi> </mrow> <mrow> <mi>D</mi> <mn>200</mn> <mi>k</mi> <mi>H</mi> <mi>z</mi> </mrow> </msub> <mo>=</mo> <mn>20</mn> <mtext> </mtext> <mi mathvariant=\"normal\">log</mi> <mtext> </mtext> <mi>D</mi> <mo>−</mo> <mn>93.85</mn> <mfenced open=\"(\" close=\")\" separators=\"|\"> <mrow> <msup> <mrow> <mi>r</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msup> <mo>=</mo> <mn>0.83</mn> </mrow> </mfenced> </math> . The swimming orientation has significant effects on TS estimation and model construction.","PeriodicalId":14894,"journal":{"name":"Journal of Applied Ichthyology","volume":"58 1","pages":"0"},"PeriodicalIF":0.7000,"publicationDate":"2023-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Acoustic Target Strength of Jellyfish, Nemopilema nomurai, Measured at Multi-Frequency and Multi-Orientation\",\"authors\":\"Hang Yang, Jing Cheng, Taolin Tang, Jun Chen, Guodong Li\",\"doi\":\"10.1155/2023/6650863\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The jellyfish Nemopilema nomurai occupies an important position in the Northwest Pacific ecosystem, and monitoring its biomass is necessary to ensure the protection of fishery resources and the safety of offshore industrial production. The acoustic method has been proposed for jellyfish flux estimation and bloom warning, in which the target strength (TS) of the jellyfish is a crucial parameter. However, varied swimming orientations of jellyfish aggregation result in different backscatter strengths. The acoustic echo characteristics in horizontal swimming orientations and multi-frequency broadband signals are yet to be revealed. This study aims to obtain the TS of jellyfish in various orientations and to comprehensively investigate the jellyfish acoustic echo features at various frequency broadband sounds. In an anechoic tank, we used wide-band echosounder and 70 kHz, 120 kHz, and 200 kHz split-beam transducers to measure the TS of jellyfish swimming omnidirectionally. The results show a difference of approximately 4 dB in the jellyfish’s normalized TS at 70 kHz (frequency range: 45 kHz to 95 kHz) and 200 kHz (frequency range: 160 kHz to 260 kHz) center frequency. The normalized TS of jellyfish varies by around 8 dB between horizontal and vertical swimming orientations. For jellyfish swimming horizontally, the TS and bell diameter have the following least squares fits: <math xmlns=\\\"http://www.w3.org/1998/Math/MathML\\\" id=\\\"M1\\\"> <mi>T</mi> <msub> <mrow> <mi>S</mi> </mrow> <mrow> <mi>D</mi> <mn>70</mn> <mi>k</mi> <mi>H</mi> <mi>z</mi> </mrow> </msub> <mo>=</mo> <mn>20</mn> <mtext> </mtext> <mi mathvariant=\\\"normal\\\">log</mi> <mtext> </mtext> <mi>D</mi> <mo>−</mo> <mn>89.36</mn> <mfenced open=\\\"(\\\" close=\\\")\\\" separators=\\\"|\\\"> <mrow> <msup> <mrow> <mi>r</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msup> <mo>=</mo> <mn>0.83</mn> </mrow> </mfenced> </math> ; <math xmlns=\\\"http://www.w3.org/1998/Math/MathML\\\" id=\\\"M2\\\"> <mi>T</mi> <msub> <mrow> <mi>S</mi> </mrow> <mrow> <mi>D</mi> <mn>200</mn> <mi>k</mi> <mi>H</mi> <mi>z</mi> </mrow> </msub> <mo>=</mo> <mn>20</mn> <mtext> </mtext> <mi mathvariant=\\\"normal\\\">log</mi> <mtext> </mtext> <mi>D</mi> <mo>−</mo> <mn>93.85</mn> <mfenced open=\\\"(\\\" close=\\\")\\\" separators=\\\"|\\\"> <mrow> <msup> <mrow> <mi>r</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msup> <mo>=</mo> <mn>0.83</mn> </mrow> </mfenced> </math> . The swimming orientation has significant effects on TS estimation and model construction.\",\"PeriodicalId\":14894,\"journal\":{\"name\":\"Journal of Applied Ichthyology\",\"volume\":\"58 1\",\"pages\":\"0\"},\"PeriodicalIF\":0.7000,\"publicationDate\":\"2023-10-23\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Applied Ichthyology\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1155/2023/6650863\",\"RegionNum\":4,\"RegionCategory\":\"农林科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"FISHERIES\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Applied Ichthyology","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1155/2023/6650863","RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"FISHERIES","Score":null,"Total":0}
引用次数: 0
摘要
野水母(Nemopilema nomurai)在西北太平洋生态系统中占有重要地位,监测其生物量是保障渔业资源保护和海上工业生产安全的必要条件。提出了一种用于水母通量估计和水华预警的声学方法,其中水母的目标强度(TS)是一个重要参数。然而,水母聚集的游动方向不同,导致背散射强度不同。水平游动方向和多频宽带信号的声回波特性尚未揭示。本研究旨在获得水母在不同方位的TS,全面研究水母在不同频率宽带声下的声回波特征。在消声池中,我们使用宽频带回声测深仪和70 kHz、120 kHz和200 kHz分束换能器测量水母全方位游动时的TS。结果表明,水母在70 kHz(频率范围:45 kHz至95 kHz)和200 kHz(频率范围:160 kHz至260 kHz)中心频率下的归一化TS差异约为4 dB。水母的标准化TS在水平和垂直游泳方向上的变化约为8 dB。对于水平游动的水母,其TS与钟形直径的最小二乘拟合为:TS ds 70 k H z = 20 log D−89.36 r 2 = 0.83;T S D 200k H z = 20 log D−93.85 r 2 = 0.83。游动方向对TS估计和模型构建有显著影响。
Acoustic Target Strength of Jellyfish, Nemopilema nomurai, Measured at Multi-Frequency and Multi-Orientation
The jellyfish Nemopilema nomurai occupies an important position in the Northwest Pacific ecosystem, and monitoring its biomass is necessary to ensure the protection of fishery resources and the safety of offshore industrial production. The acoustic method has been proposed for jellyfish flux estimation and bloom warning, in which the target strength (TS) of the jellyfish is a crucial parameter. However, varied swimming orientations of jellyfish aggregation result in different backscatter strengths. The acoustic echo characteristics in horizontal swimming orientations and multi-frequency broadband signals are yet to be revealed. This study aims to obtain the TS of jellyfish in various orientations and to comprehensively investigate the jellyfish acoustic echo features at various frequency broadband sounds. In an anechoic tank, we used wide-band echosounder and 70 kHz, 120 kHz, and 200 kHz split-beam transducers to measure the TS of jellyfish swimming omnidirectionally. The results show a difference of approximately 4 dB in the jellyfish’s normalized TS at 70 kHz (frequency range: 45 kHz to 95 kHz) and 200 kHz (frequency range: 160 kHz to 260 kHz) center frequency. The normalized TS of jellyfish varies by around 8 dB between horizontal and vertical swimming orientations. For jellyfish swimming horizontally, the TS and bell diameter have the following least squares fits: ; . The swimming orientation has significant effects on TS estimation and model construction.
期刊介绍:
The Journal of Applied Ichthyology publishes articles of international repute on ichthyology, aquaculture, and marine fisheries; ichthyopathology and ichthyoimmunology; environmental toxicology using fishes as test organisms; basic research on fishery management; and aspects of integrated coastal zone management in relation to fisheries and aquaculture. Emphasis is placed on the application of scientific research findings, while special consideration is given to ichthyological problems occurring in developing countries. Article formats include original articles, review articles, short communications and technical reports.