Measurements of Sound Speed and Density Contrasts of the Moon Jellyfish (Aurelia aurita s.l.) for Hydroacoustic Model

Kang, Di; Lee, Chang-Won; Lee, Hyung-Been; Kim, Mi-Ra

doi:10.4217/opr.2012.34.1.085

Cited by 3 publications

(1 citation statement)

References 13 publications

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“…Preventing or mitigating such damage requires the acquisition of a wide range of information, including migration routes as well as physiological and ecological behaviors of jellyfish [5]. Methods of studying the distribution and migration routes of jellyfish include visual surveys, aerial surveys, and sample collection using sampling gears [6]. Such methods are useful to rapidly determine the level of occurrence but pose difficulties for analyzing the distribution by water column [7,8].…”

Section: Introductionmentioning

confidence: 99%

Comparison of Distribution and Density of Nemopilema nomurai by Water Columns Using Echo Counting and Echo Integration Methods

Kim

Lim

Chae³

et al. 2020

Sustainability

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In this study, the distribution of Nemopilema nomurai in the waters of Mijo-myeon, Namhae and Gijang-gun, Busan was analyzed; furthermore, echo counting and echo integration methods were used to compare the distribution density. The acoustic system used in the study was a split beam scientific echosounder operating at 38 and 120 kHz (EK-60, Simrad, Norway). Echo counting and echo integration methods were used to determine the density of N. nomurai distributed in the survey areas. The distribution of N. nomurai by water columns, estimated using an echo counting method, was concentrated at approximately 10 m deep in the waters of Mijo, Namhae and 10–50 m deep in the waters of Gijang, Busan; moreover, the distributed depth varied by the surveyed date and time. It was shown that analyzing the acoustic scattering strength of jellyfish obtained from the echo counting method would be more effective for distributional survey of N. nomurai with two frequency system.

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Section: Introductionmentioning

confidence: 99%

Comparison of Distribution and Density of Nemopilema nomurai by Water Columns Using Echo Counting and Echo Integration Methods

Kim

Lim

Chae³

et al. 2020

Sustainability

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Broadband backscattering from scyphozoan jellyfish

Kahn

Lavery

Govindarajan

2023

The Journal of the Acoustical Society of America

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As the ecological importance of gelatinous organisms becomes increasingly appreciated, so has the need for improved knowledge of their abundance and distribution. Acoustic backscattering measurements are routine for fisheries assessments but are not yet widely used to survey populations of gelatinous zooplankton. The use of acoustic backscattering techniques to understand the distribution and abundance of organisms requires an understanding of their target strength (TS). This study presents a framework for a sound scattering model for jellyfish based on the Distorted Wave Born Approximation that incorporates size, shape, and material properties of individual organisms. This model, with a full three-dimensional shape rendition, is applied to a common species of scyphomedusa (Chrysaora chesapeakei) and verified experimentally with broadband (52–90 and 93–161 kHz) laboratory TS measurements of live individuals. Cyclical changes in the organism's shape due to swimming kinematics were examined, as well as averages over swimming position and comparisons with scattering from simpler shapes. The model predicts overall backscattering levels and broad spectral behavior within <2 dB. Measured TS exhibits greater variability than is predicted by scaling the size of the organism in the scattering model, showing that density and sound speed vary among individuals.

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An estimation of the sound-speed and density of moon jellyfish (Aurelia aurita) in Korean waters

Yoon

Hwang²

2013

Journal of the Korean society of Fisheries Technology

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The sound-speed and density contrasts are important factors in estimating the target strength (TS) of moon jellyfish (Aurelia aurita). In this study, the sound-speed and density contrasts were measured using time-offlight and neutral buoyancy methods, respectively. The sound-speed contrast of A. aurita was from 0.9966 to 1.0031 (mean±SD, 0.9999±0.0017) and no distinct differences in temperature or pulsation activity and weak were found. The density contrast was from 0.9994 to 1.0004 (mean±SD, 1.0000±0.0002). The density of A. aurita was substantially different but the density contrast of A. aurita was shown to be similar to that in the sampling location. The results can be used to estimate of TS of A. aurita by acoustic model.

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Measurements of Sound Speed and Density Contrasts of the Moon Jellyfish (Aurelia aurita s.l.) for Hydroacoustic Model

Cited by 3 publications

References 13 publications

Comparison of Distribution and Density of Nemopilema nomurai by Water Columns Using Echo Counting and Echo Integration Methods

Comparison of Distribution and Density of Nemopilema nomurai by Water Columns Using Echo Counting and Echo Integration Methods

Broadband backscattering from scyphozoan jellyfish

An estimation of the sound-speed and density of moon jellyfish (Aurelia aurita) in Korean waters

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