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High resolution three-dimensional beam radiation pattern of harbour porpoise clicks with implications for passive acoustic monitoring

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High resolution three-dimensional beam radiation pattern of harbour porpoise clicks with implications for passive acoustic monitoring. / Macaulay, Jamie D.J.; Malinka, Chloe E.; Gillespie, Douglas; Madsen, Peter T.

I: The Journal of the Acoustical Society of America, Bind 147, Nr. 6, 06.2020.

Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avisTidsskriftartikelForskningpeer review

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@article{6f653ca4f22a4220baf429b6279ba34f,
title = "High resolution three-dimensional beam radiation pattern of harbour porpoise clicks with implications for passive acoustic monitoring",
abstract = "The source properties and radiation patterns of animal vocalisations define, along with propagation and noise conditions, the active space in which these vocalisations can be detected by conspecifics, predators, prey, and by passive acoustic monitoring (PAM). This study reports the 4π (360° horizontal and vertical) beam profile of a free-swimming, trained harbour porpoise measured using a 27-element hydrophone array. The forward echolocation beam is highly directional, as predicted by a piston model, and is consistent with previous measurements. However, at off-axis angles greater than ±30°, the beam attenuates more rapidly than the piston model and no side lobes are present. A diffuse back beam is also present with levels about -30 dB relative to the source level. In PAM, up to 50% of detections can be from portions of the beam profile with distorted click spectra, although this drops substantially for higher detection thresholds. Simulations of the probability of acoustically detecting a harbour porpoise show that a traditional piston model can underestimate the probability of detection compared to the actual three-dimensional radiation pattern documented here. This highlights the importance of empirical 4π measurements of beam profiles of toothed whales, both to improve understanding of toothed whale biology and to inform PAM.",
author = "Macaulay, {Jamie D.J.} and Malinka, {Chloe E.} and Douglas Gillespie and Madsen, {Peter T.}",
year = "2020",
month = jun,
doi = "10.1121/10.0001376",
language = "English",
volume = "147",
journal = "Acoustical Society of America. Journal",
issn = "0001-4966",
publisher = "A I P Publishing LLC",
number = "6",

}

RIS

TY - JOUR

T1 - High resolution three-dimensional beam radiation pattern of harbour porpoise clicks with implications for passive acoustic monitoring

AU - Macaulay, Jamie D.J.

AU - Malinka, Chloe E.

AU - Gillespie, Douglas

AU - Madsen, Peter T.

PY - 2020/6

Y1 - 2020/6

N2 - The source properties and radiation patterns of animal vocalisations define, along with propagation and noise conditions, the active space in which these vocalisations can be detected by conspecifics, predators, prey, and by passive acoustic monitoring (PAM). This study reports the 4π (360° horizontal and vertical) beam profile of a free-swimming, trained harbour porpoise measured using a 27-element hydrophone array. The forward echolocation beam is highly directional, as predicted by a piston model, and is consistent with previous measurements. However, at off-axis angles greater than ±30°, the beam attenuates more rapidly than the piston model and no side lobes are present. A diffuse back beam is also present with levels about -30 dB relative to the source level. In PAM, up to 50% of detections can be from portions of the beam profile with distorted click spectra, although this drops substantially for higher detection thresholds. Simulations of the probability of acoustically detecting a harbour porpoise show that a traditional piston model can underestimate the probability of detection compared to the actual three-dimensional radiation pattern documented here. This highlights the importance of empirical 4π measurements of beam profiles of toothed whales, both to improve understanding of toothed whale biology and to inform PAM.

AB - The source properties and radiation patterns of animal vocalisations define, along with propagation and noise conditions, the active space in which these vocalisations can be detected by conspecifics, predators, prey, and by passive acoustic monitoring (PAM). This study reports the 4π (360° horizontal and vertical) beam profile of a free-swimming, trained harbour porpoise measured using a 27-element hydrophone array. The forward echolocation beam is highly directional, as predicted by a piston model, and is consistent with previous measurements. However, at off-axis angles greater than ±30°, the beam attenuates more rapidly than the piston model and no side lobes are present. A diffuse back beam is also present with levels about -30 dB relative to the source level. In PAM, up to 50% of detections can be from portions of the beam profile with distorted click spectra, although this drops substantially for higher detection thresholds. Simulations of the probability of acoustically detecting a harbour porpoise show that a traditional piston model can underestimate the probability of detection compared to the actual three-dimensional radiation pattern documented here. This highlights the importance of empirical 4π measurements of beam profiles of toothed whales, both to improve understanding of toothed whale biology and to inform PAM.

UR - http://www.scopus.com/inward/record.url?scp=85087473680&partnerID=8YFLogxK

U2 - 10.1121/10.0001376

DO - 10.1121/10.0001376

M3 - Journal article

C2 - 32611133

AN - SCOPUS:85087473680

VL - 147

JO - Acoustical Society of America. Journal

JF - Acoustical Society of America. Journal

SN - 0001-4966

IS - 6

ER -