Passive Acoustic Monitoring of Cetaceans

368 Pages·2011·6.57 MB·English

by  Walter M. X. Zimmer

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Passive Acoustic Monitoringof Cetaceans
Passiveacousticmonitoring(PAM)isusedincreasinglybythescientificcommunityto
study, survey and census marine mammals, especially cetaceans, many of which are
easier to hear than to see. PAM is also used to support efforts to mitigate potential
negativeeffectsofhumanactivitiessuchasshiptraffic,militaryandciviliansonarand
offshoreexploration.
WalterZimmerprovidesanintegratedapproachtoPAM,combiningphysicalprinci-
ples, discussion of technical tools and application-oriented concepts of operations. In
addition, relevant information and tools necessary to assess existing and future PAM
systemsarepresented,withMATLAB®codeusedtogeneratefiguresandresultssothat
readers can reproduce data and modify code to analyse the impact of changes. This
allows the principles to be studied while discovering potential difficulties and side
effects. Aimed at graduate students and researchers, the book provides all information
and tools necessary to gain a comprehensive understanding of this interdisciplinary
subject.
Walter M.X. Zimmer holds a Ph.D. in theoretical physics from the University of
Regensburg,Germany.HeiscurrentlyaScientist intheAppliedResearchDepartment
of the NATO Undersea Research Centre (NURC) in La Spezia, Italy, and a Guest
Investigator at the Biology Department of the Woods Hole Oceanographic Institution
(WHOI),WoodsHole,MA,USA.

Passive Acoustic Monitoring
of Cetaceans
WALTER M.X. ZIMMER
NATOUnderseaResearchCentre
cambridge university press
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©WalterM.X.Zimmer2011
Thispublicationisincopyright.Subjecttostatutoryexception
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permissionofCambridgeUniversityPress.
Firstpublished2011
PrintedintheUnitedKingdomattheUniversityPress,Cambridge
AcataloguerecordforthispublicationisavailablefromtheBritishLibrary
LibraryofCongressCataloguinginPublicationdata
Zimmer,WalterM.X.,1949–
PassiveAcousticMonitoringofCetaceans/WalterMXZimmer.
p. cm
Includesbibliographicalreferencesandindex.
ISBN978-0-521-19342-9
1. Cetacea–Monitoring. 2. Cetacea–Effectofnoiseon. 3. Dolphinsounds.
4. Whalesounds. I. Title.
QL737.C4Z53 2011
599.507203–dc22
2010052636
ISBN978-0-521-19342-9Hardback
Additionalresourcesforthispublicationatwww.cambridge.org/9780521193429
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FürGiannina

Contents
Acknowledgements page x
Introduction 1
PartI Underwateracoustics(thebasics) 5
1 Principlesofunderwatersound 7
1.1 Soundasapressurewave 7
1.2 Measuringunderwatersound(thedecibelscale) 21
1.3 Soundvelocity 23
1.4 Soundpropagation 29
1.5 Signals,noiseandinterference 36
2 Cetaceansounds 39
2.1 Classificationofcetaceans 39
2.2 Classificationofcetaceansounds 40
2.3 Cetaceansoundpresentationinthetimedomain 42
2.4 Cetaceansoundsinthefrequencydomain 53
2.5 Cetaceansoundsinthetime–frequencydomain 61
2.6 Soundsourcedirectionality 86
2.7 Cetaceansourcelevels 88
2.8 OrderCetacea 89
3 Sonarequations 96
3.1 Passivesonarequations 96
3.2 Apparentsourcelevel 97
3.3 Soundpropagation 100
3.4 Noiselevel 108
3.5 Arraygain 113
3.6 Processinggain 115
3.7 Detectionthreshold 115
vii
viii Contents
PartII Signalprocessing(designingthetools) 117
4 Detectionmethods 119
4.1 Detectionofecholocationclicks 119
4.2 Datafilter 138
4.3 DetectionofFMsignalswithpulsecompression(matchedfilter) 144
4.4 Detectionofdolphinwhistles 150
5 Classificationmethods 164
5.1 Classificationbasics 164
5.2 Optimalclassification 165
5.3 Cetaceanclassification 180
6 Localizationandtracking 198
6.1 Multi-hydrophoneranging 198
6.2 Triangulation 203
6.3 Multi-pathranging 205
6.4 Rangingbyacousticmodelling 210
6.5 Measurementofarrivaltimedifference 211
6.6 Directionfinding 212
6.7 Three-dimensionaldirectionfinding 213
6.8 Two-dimensionalconstraineddirectionfinding 216
6.9 Beam-forming 218
6.10 Beampatterns 219
6.11 Tracking 226
PartIII Passiveacousticmonitoring(puttingitalltogether) 237
7 Applicationsofpassiveacousticmonitoring 239
7.1 Abundanceestimation 239
7.2 Mitigation:absenceestimation 250
7.3 Habitatandbehaviouranalysis 253
7.4 Monitoringrareandelusivespecies 256
7.5 Loggingacousticinformation 257
8 Detectionfunctions 259
8.1 Empiricaldetectionfunction 259
8.2 LMSparameterestimation 260
8.3 Sonarequation-basedmodellingofthedetectionfunction 260
8.4 Modellinganimalbehaviour 269
8.5 Modellingtheinfluenceofanimalmotion 272