A low-frequency acoustic scattering model for small schools of fish

Feuillade, C.; Nero, Redwood W.; Love, Richard H.

doi:10.1121/1.414503

Cited by 48 publications

(48 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When fish school, as is common in shallow water, the scattering picture is more complicated. The Naval Research Laboratory (NRL) has developed a scattering model for small-sized fish schools that includes all orders of multiple scattering interactions between the fish (with the aggregate scattering field calculated by coherent summation) [4]. Another set of complications arises when fish are in the presence of reflecting boundaries [5].…”

Section: Introductionmentioning

confidence: 99%

Broadband Models for Predicting Bistatic Bottom, Surface, and Volume Scattering Strengths

Gauss¹,

Gragg²,

Wurmser³

et al. 2002

View full text Add to dashboard Cite

Standard Form 298 (Rev. 8-98)Prescribed by ANSI Std. Z39.18Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Approved for public release; distribution is unlimited. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) SPONSOR / MONITOR'S ACRONYM(S) 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) SPONSOR / MONITOR'S REPORT NUMBER(S)Multistatic active system performance can be driven by reverberation from the ocean boundaries and biologics. Providing accurate sonar performance predictions of reverberation, in turn, relies on providing accurate estimates of bistatic scattering strengths. This report presents new three-dimensional models that provide physics-based estimates of the dependence of scattering strength on the incident and scattered grazing angles, the bistatic angle, the acoustic frequency (10 to 10000 Hz), and physical descriptors of the environment (such as bottom properties for the bottom model, wind speed for the surface model, and fish properties for the volume model). The bottom model describes scattering from rough, elastic interfaces, while the surface model describes scattering from both the rough air-sea interface and subsurface bubbles. The volume models describe scattering from dispersed bladdered fish, including boundary-interference effects. For all, parameter studies along with data-model comparisons demonstrate the importance of using physics-based scattering models to describe the complex acoustic interaction processes at the ocean boundaries. These broadband models can enhance sonar performance prediction capabilities through their inclusion as submodels in both active performance/reverberation models

show abstract

Section: Introductionmentioning

confidence: 99%

Broadband Models for Predicting Bistatic Bottom, Surface, and Volume Scattering Strengths

Gauss¹,

Gragg²,

Wurmser³

et al. 2002

View full text Add to dashboard Cite

show abstract

“…Also, as in Nero et al (2004), only first-order scattering is assumed with no extinction, the resonance properties of the individual fish are assumed to not be affected by the presence of neighboring fish, and a simple incoherent summation of the backscattering cross-sections of the individual fish was made. The first two assumptions are valid because of the relatively low densities of fish observed in this study (fish separations of the order 5-25 body lengths), and the third is from the fact that the distributions of the fish are random and do not resemble a crystalline lattice (Feuillade et al 1996;Nero et al 2007;Hahn 2007). There is a typographical error in Nero et al (2004) in the factor, z, that corrects the resonance frequency for the nonspherical shape of the swimbladder.…”

Section: Data Processing and Modelingmentioning

confidence: 99%

Resonance classification of mixed assemblages of fish with swimbladders using a modified commercial broadband acoustic echosounder at 1–6 kHz

Stanton

Sellers

Jech

2012

Can. J. Fish. Aquat. Sci.

View full text Add to dashboard Cite

Recently developed broadband acoustic methods were used to study mixed assemblages of fish spanning a wide range of lengths and species. Through a combination of resonance classification and pulse-compression signal processing, which provides for high-range resolution, a modified commercial broadband echosounder was demonstrated to provide quantitative information on the spatial distribution of the individual size classes within an assemblage. In essence, this system spectrally resolves the different size classes of fish that are otherwise not resolved spatially. This method reveals new insights into biological processes, such as predator-prey interactions, that are not obtainable through the use of a conventional narrowband high-frequency echosounder or previous broadband systems. A recent study at sea with this system revealed aggregations containing bladdered fish 15-30 cm in length (Atlantic herring (Clupea harengus) and silver hake (Merluccius bilinearis)) and a variety of species of smaller fish 2-5 cm in length. These observations infer that the smaller 2-5 cm fish can be colocated in the same aggregations as their predator, the larger silver hake, as well as pre-spawning herring. While this technological advancement provides more information, there remain challenges in interpreting the echo spectra in terms of meaningful biological quantities such as size distribution and species composition.Résumé : Des méthodes acoustiques à large bande récemment mises au point nous servent à étudier des peuplements mixtes de poissons couvrant un large éventail de longueurs et d'espèces. Par une combinaison de classification des résonances et de traitement des signaux de compression des impulsions qui fournit un haut degré de résolution, un échosondeur commercial modifié à large bande s'avère capable de fournir des données quantitatives sur la répartition spatiale des classes d'âge individuelles au sein d'un peuplement. Spécifiquement, le système permet une résolution spectrale des différentes classes de taille des poissons qui autrement ne peuvent être distinguées dans l'espace. La méthode ouvre de nouvelles perspectives sur les processus biologiques, tels que les interactions prédateurs-proies, qu'on ne peut obtenir par l'emploi d'un échosondeur ordinaire de haute fréquence à bande étroite, ni par les systèmes à large bande plus anciens. Une étude récente en mer avec ce système montre des rassemblements de poissons à vessie natatoire de longueurs de 15 à 30 cm (harengs atlantiques (Clupea harengus) et merlus argentés (Merluccius bilinearis)), ainsi qu'une variété d'espèces de poissons plus petits de longueurs de 2-5 cm. Ces observations laissent croire que les poissons plus petits de 2-5 cm peuvent être localisés ensemble dans les mêmes rassemblements que leurs prédateurs, les merlus de plus grande taille et les harengs avant la fraie. Bien que cette avancée technologique fournisse plus d'information, il reste des défis pour interpréter les spectres des rétrodiffusions en regard de quantités biologiques sig...

show abstract

“…Fig. 3a shows a representative 2D FC with a unit cell ( Here the dimensions of the unit cell are 1 2 40 cm a a = = and R = 2 cm which represent a single air filled fish swimbladder [3]. In a two dimensional periodic lattice the pressure ( )…”

Section: Work Completedmentioning

confidence: 99%

Spatio-Temporal Characterization of Bio-acoustic Scatterers in Complex Media

Sabra¹

2013

View full text Add to dashboard Cite

Award number: N000141110259 LONG TERM GOALSTo develop a numerically efficient methodology for modeling the acoustic response of large aggregate of biological scatterers to parameterize acoustic models for long-range SONAR measurements OBJECTIVECharacterization of biologically-induced ocean reverberation features is key to effectively parameterize acoustic models and thus ultimately improve the detection performance of long-range SONAR systems. In particular, scattering from fish schools can significantly contribute to volume reverberation in the open ocean measured by mid-frequencies tactical SONAR (1kHz-10kHz), especially if the resonance frequencies of the fish' air-filled swim bladder is excited. Furthermore, multiple scattering effects from the incident acoustic wave and the collective arrangement of fish lead to complicated frequency response functions. The bio-acoustics properties of the fish body and geometry can also contribute to the scattering response and can be incorporated into an accurate scattering model. The objective of this research is to characterize the relevant spatial and temporal scales of bio-acoustic scatterers generating ocean reverberation to effectively parameterize acoustic models and improve the detection performance of long-range SONAR systems. To do so, we developed an efficient modeling technique to predict the scattered fields from large fish schools (which can cause especially high falsealarm rate for mid-frequency SONAR systems.), which readily account for the fish acoustic properties, school's spatial configuration and multiple scattering effects.

show abstract

A low-frequency acoustic scattering model for small schools of fish

Cited by 48 publications

References 0 publications

Broadband Models for Predicting Bistatic Bottom, Surface, and Volume Scattering Strengths

Broadband Models for Predicting Bistatic Bottom, Surface, and Volume Scattering Strengths

Resonance classification of mixed assemblages of fish with swimbladders using a modified commercial broadband acoustic echosounder at 1–6 kHz

Spatio-Temporal Characterization of Bio-acoustic Scatterers in Complex Media

Contact Info

Product

Resources

About