Wideband sounder for fish species identification at sea

Zakharia, Manell E.

doi:10.1006/jmsc.1996.0023

“…Studies of broadband acoustic scattering from individual zooplankton ͑e.g., Stanton et al, 1998͒ andfish ͑e.g., Reeder et al, 2004͒ have shown that structure in the spectra of high frequency, acoustic backscattering is, indeed, due to anatomical features and is highly affected by orientation. In addition, active broadband acoustic systems have been used in efforts to achieve reliable species recognition based on the spectral signature of backscatter from both individual fish ͑Au and Benoit-Bird, 2003͒ and aggregations of fish ͑Simmonds et al, 1996;Zakharia et al, 1996͒. These findings, combined with the evidence for spectral selection in captive dolphins, suggests that it is possible that free-ranging toothed whales use spectral features of broadband, acoustic backscattering to aid in the classification of prey. A few studies have shown prey selection by toothed whales in the wild ͑MacLeod et al., 2006;Whitehead et al, 2003͒, but the basis for such selection is not known.…”

Section: Introductionmentioning

confidence: 99%

Classification of broadband echoes from prey of a foraging Blainville’s beaked whale

Jones

¹

,

Stanton

²

,

Lavery

³

et al. 2008

The Journal of the Acoustical Society of America

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Blainville's beaked whales ͑Mesoplodon densirostris͒ use broadband, ultrasonic echolocation signals with a −10 dB bandwidth from 26 to 51 kHz to search for, localize, and approach prey that generally consist of mid-water and deep-water fishes and squid. Although it is well known that the spectral characteristics of broadband echoes from marine organisms vary as a function of size, shape, orientation, and anatomical group, there is little evidence as to whether or not free-ranging toothed whales use spectral cues in discriminating between prey and nonprey. In order to study the prey-classification process, a stereo acoustic tag was deployed on a Blainville's beaked whale so that emitted clicks and the corresponding echoes from targets in the water could be recorded. A comparison of echoes from targets apparently selected by the whale and those from a sample of scatterers that were not selected suggests that spectral features of the echoes, target strengths, or both may have been used by the whale to discriminate between echoes. Specifically, the whale appears to favor targets with one or more nulls in the echo spectra and to seek prey with higher target strengths at deeper depths.

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“…In contrast, lower-frequency broadband scattering measurements (< 120 kHz) to remotely characterize fish have been performed more prevalently (e.g. Zakharia et al, 1996;, including measurements involving explosives (e.g. Holliday, 1972;Thompson and Love, 1996;Nero et al, 1998;Love et al, 2004).…”

Section: Approachmentioning

confidence: 99%

Continued Analysis of High-Frequency Broadband Acoustic Scattering from Non-Linear Internal Waves during SW06

Lavery¹

2010

0

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LONG-TERM GOALSTo understand high-frequency broadband acoustic backscattering from small-scale physical processes, such as internal waves, turbulence, and microstructure, in shallow, stratified waters. OBJECTIVESThe primary objective of the overall research program was to measure high-frequency broadband acoustic backscattering in highly stratified, energetic environments and to determine the contribution to scattering from temperature and salinity microstructure. Testing the validity of existing scattering models and the initial development of new, and/or extensions of existing, simple physics-based scattering models was a secondary objective of this work.To accomplish the stated objectives, high-frequency broadband (150-600 kHz) acoustic backscattering measurements were performed during the generation, propagation, and dissipation of non-linear internal waves in August 2006 as a part of the SW06/NLIWI experiment. Almost coincident microstructure measurements were collected by Jim Moum with a profiling microstructure instrument, Chameleon. The contribution to scattering from biological organisms was quantified using netsamples, from which the zooplankton taxa, size, and depth (in coarse vertical bins) can be determined.Analysis of these data to date has focused on (1) determining the dominant scattering mechanisms giving rise to enhanced backscattering often associated with the passage of non-linear internal waves, with particular attention given to elevated scattering associated to Kelvin-Helmholtz instabilities, and (2) inverting the broadband scattering data for meaningful biological and physical parameters and comparing the acoustically-inferred to directly measured parameters, thereby allowing the validity of the scattering models to be tested.The primary objectives of the effort described here are: 1) to understanding and quantifying the contribution to acoustic backscattering from the seasonal pycnocline, 2) to investigate the statistics

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“…In contrast, lower-frequency broadband acoustic scattering measurements (< ~120 kHz) to remotely characterize fish have been performed more prevalently (e.g. Zakharia et al, 1996;Stanton et al accepted), including measurements involving explosives (e.g. Holliday, 1972;Thompson and Love, 1996;Nero et al, 1998;Love et al, 2004).…”

Section: Report Documentation Pagementioning

confidence: 99%

Analysis of High-Frequency Broadband Acoustic Scattering from Non-Linear Internal Waves During SW06

Lavery

¹

2009

0

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LONG-TERM GOALSTo understand high-frequency broadband acoustic backscattering from small-scale physical processes, such as internal waves, turbulence, and microstructure, in shallow, stratified coastal waters. OBJECTIVESThe primary objective of the proposed research was to measure high-frequency broadband acoustic backscattering in highly stratified, energetic environments and to determine the contribution to scattering from temperature and salinity microstructure. Testing the validity of existing scattering models and the initial development of new, and/or extension of existing, simple physics-based scattering models was a secondary objective of this work.To accomplish the stated objectives, high-frequency broadband (150-600 kHz) acoustic backscattering measurements were performed during the generation, propagation, and dissipation of non-linear internal waves in August 2006 as a part of the SW06/NLIWI experiment. Almost coincident microstructure measurements were collected by Jim Moum with a profiling microstructure instrument, Chameleon. The contribution to scattering from biological organisms was quantified using a multiple-opening and closing net and environmental sensing system (MOCNESS), from which the zooplankton taxa, size, and depth (in coarse vertical bins) can be determined. The particular effort described here focuses on the analysis on these data.

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Wideband sounder for fish species identification at sea

Cited by 62 publications

References 3 publications

Classification of broadband echoes from prey of a foraging Blainville’s beaked whale

Classification of broadband echoes from prey of a foraging Blainville’s beaked whale

Continued Analysis of High-Frequency Broadband Acoustic Scattering from Non-Linear Internal Waves during SW06

Analysis of High-Frequency Broadband Acoustic Scattering from Non-Linear Internal Waves During SW06

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