Multiple sound scattering by densely packed shoals of marine animals

Andreeva, I. B.; Belousov, A. V.

doi:10.1006/jmsc.1996.0043

Cited by 8 publications

(10 citation statements)

References 4 publications

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“…Assuming that fish comprising the daytime sub-surface and near-surface pelagic fish aggregations were respectively about 60 and 30 cm FL, our estimates of mean packing densities for these aggregations would be in reasonable agreement with the values given by Andreeva and Belousov (1996). Moreover, the packing density of the sub-surface pelagic fish aggregation is quite similar to the mean fish density estimated by in the same area around moored FADs in French Polynesia.…”

Section: Comparison Of Results With the Literaturesupporting

confidence: 76%

“…References to packing densities of shoals of fish larger than small pelagic species are scarce in the literature (Pitcher and Partridge, 1979;Andreeva and Belousov, 1996). Assuming that fish comprising the daytime sub-surface and near-surface pelagic fish aggregations were respectively about 60 and 30 cm FL, our estimates of mean packing densities for these aggregations would be in reasonable agreement with the values given by Andreeva and Belousov (1996).…”

Section: Comparison Of Results With the Literaturesupporting

confidence: 60%

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Acoustic characterisation of pelagic fish aggregations around moored fish aggregating devices in Martinique (Lesser Antilles)

Doray¹,

Josse²,

Gervain³

et al. 2006

Fisheries Research

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International audienceSea cruises were conducted for 57 days over 16 months to characterise pelagic fish aggregations around two moored fish aggregating devices (FADs) in Martinique (Lesser Antilles). Echosounder surveys run in a star pattern were used in conjunction with obliquely beamed sonar observations. An echo-integration-by-shoal algorithm was implemented to isolate pelagic fish shoals from sound scattering layers and to compute mean morphometric, positional and density parameters. Tree regressions were used to select and classify pelagic fish target strengths (TS), with reference to their spatial and temporal characteristics. The main type of pelagic fish aggregation was a large sub-surface aggregation. It was observed during all daytime periods within a radius of 400 m. of the FAD. A smaller type of aggregation was observed closer to the surface and to the FAD in 65% of daytime periods. Large scattered fish were observed in 16% of daytime periods. At night, a medium-sized aggregation was detected in the sub-surface in 75% of night-time periods. The sizes of the fish inside the aggregations (determined from TS values) were lower in the small near-surface aggregation than in the large sub-surface aggregation. Mean packing densities of sub-surface medium fish and near-surface small fish aggregations (determined from TS and shoal acoustic density) were respectively 0.2 and 1.3 fish per m(3). The acoustic methodology and results are discussed with reference to the characteristics and performance of the echosounder and to the spatial structure of pelagic fish aggregations around moored FADs in Martinique

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Section: Comparison Of Results With the Literaturesupporting

confidence: 76%

Section: Comparison Of Results With the Literaturesupporting

confidence: 60%

Acoustic characterisation of pelagic fish aggregations around moored fish aggregating devices in Martinique (Lesser Antilles)

Doray¹,

Josse²,

Gervain³

et al. 2006

Fisheries Research

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show abstract

“…47 This effect is apparent in the EK60 echograms as smearing of the real school toward the seabed [ Fig. 2(b)].…”

Section: A Ek60 Simulationmentioning

confidence: 99%

Simulations of multi-beam sonar echos from schooling individual fish in a quiet environment

Holmin

Handegard

Korneliussen

et al. 2012

The Journal of the Acoustical Society of America

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A model is developed and demonstrated for simulating echosounder and sonar observations of fish schools with specified shapes and composed of individuals having specified target strengths and behaviors. The model emulates the performances of actual multi-frequency echosounders and multi-beam echosounders and sonars and generates synthetic echograms of fish schools that can be compared with real echograms. The model enables acoustic observations of large in situ fish schools to be evaluated in terms of individual and aggregated fish behaviors. It also facilitates analyses of the sensitivity of fish biomass estimates to different target strength models and their parameterizations. To demonstrate how this tool may facilitate objective interpretations of acoustically estimated fish biomass and behavior, simulated echograms of fish with different spatial and orientation distributions are compared with real echograms of herring collected with a multibeam sonar aboard the research vessel "G.O. Sars." Results highlight the important effects of fish-backscatter directivity, particularly when sensing with small acoustic wavelengths relative to the fish length. Results also show that directivity is both a potential obstacle to estimating fish biomass accurately and a potential source of information about fish behavior.

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“…Акустическое зондирование на основе обратного рассеяния звука позволяет изучать мелкомасштабную структуру морской среды и ее изменчивость, связанную с турбулентными образованиями, проявлением внутренних волн, наличием пузырьков, твердых взвесей, а также планктона и других биологических объектов. Наиболее изменчивым слоем водной толщи океана является верхний слой, и для этого слоя характерно сосредоточение биоресурсов и наличие интенсивных динамических процессов, существенно влияющих на распределение практически всех биологических объектов [1][2][3][4]. Данные о рассеянии звука имеются для сравнительно низких и средних частот звука, которые в основном использовались в рыбопоисковой технологии [1,2].…”

Section: Introductionunclassified

“…Наиболее изменчивым слоем водной толщи океана является верхний слой, и для этого слоя характерно сосредоточение биоресурсов и наличие интенсивных динамических процессов, существенно влияющих на распределение практически всех биологических объектов [1][2][3][4]. Данные о рассеянии звука имеются для сравнительно низких и средних частот звука, которые в основном использовались в рыбопоисковой технологии [1,2]. Информация о величине и природе высокочастотного рассеяния более скудна [3,4].…”

Section: Introductionunclassified

Исследования Акустических характеристик Верхнего Слоя Моря методом Многочастотного акустического Зондирования

Bulanov¹,

Korskov²,

Storozhenko³

et al. 2020

Podvodnye Issledovaniia I Robototehnika

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Описано применение акустического зондирования для исследования акустических характеристик верхнего слоя моря с использованием широкополосных остронаправленных инвертированных излучателей,устанавливаемых на дно. В основу метода положен принцип регистрации обратного рассеяния и отраженияот поверхности моря акустических импульсов с различной частотой, позволяющий одновременно измерятьрассеяние и поглощение звука и нелинейный акустический параметр морской воды. Многочастотное зондирование позволяет реализовать акустическую спектроскопию пузырьков в приповерхностных слоях моря,проводить оценку газосодержания и получать данные о спектре поверхностного волнения при различных состояниях моря вплоть до штормовых. Применение остронаправленных высокочастотных пучков ультразвукапозволяет разделить информацию о планктоне и пузырьках и определить с высоким пространственным разрешением структуру пузырьковых облаков, образующихся при обрушении ветровых волн, и структуру планктонных сообществ. Участие планктона в волновом движении в толще морской воды позволяет определитьпараметры внутренних волн спектр и распределение по амплитудам в различное время.This paper represents the application of acoustic probingfor the investigation of acoustical properties of the upperlayer of the sea using broadband narrow-beam invertedtransducers that are mounted on the sea bottom. Thismethod is based on the principle of the recording of thebackscattering and reflections of acoustic pulses of differentfrequencies from the sea surface. That simultaneouslyallows measuring scattering and absorption of the soundand non-linear acoustic parameter of seawater. Multifrequencyprobing allows performing acoustic spectroscopy ofbubbles in the near-surface layer of the sea, estimating gascontent, and obtaining data on the spectrum of the surfacewaves in various states of the sea up to a storm. Utilizationof the high-frequency narrow ultrasound beams allows us toseparate the information about plankton and bubbles and todetermine the structure of bubble clouds, created during thebreaking of wind waves, along with the structure of planktoncommunities with high spatial resolution. The participationof plankton in the wave motion in the seawater columnallows determining parameters of internal waves, such asspectrum and distribution of amplitudes at different times.

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Multiple sound scattering by densely packed shoals of marine animals

Cited by 8 publications

References 4 publications

Acoustic characterisation of pelagic fish aggregations around moored fish aggregating devices in Martinique (Lesser Antilles)

Acoustic characterisation of pelagic fish aggregations around moored fish aggregating devices in Martinique (Lesser Antilles)

Simulations of multi-beam sonar echos from schooling individual fish in a quiet environment

Исследования Акустических характеристик Верхнего Слоя Моря методом Многочастотного акустического Зондирования

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