Principles of Marine Bioacoustics (eBook)

Whitlow W.L. Au and Mardi C. Hastings have been involved with scientific acoustic research on marine animals for many years and their total combined span of time in this field extends over 5 decades.

Preface 7
Contents 9
Part I: Principles and Methodology 17
1 18
Introduction 18
1.1 What Is Marine Bioacoustics? 18
1.2 Introduction to Underwater Acoustics 20
1.2.1 Derivation of the Wave Equation 22
1.2.2 A Simple Harmonic Solution to the One-Dimensional Wave Equation 26
1.2.3 Particle Displacement and Velocity 27
1.2.4 Acoustic Intensity and Acoustic Impedance 28
1.2.5 The Decibel and Sound Pressure Level 29
1.2.6 Spherical Spreading Transmission Loss 33
1.3 Appendix: Some Mathematics 34
1.3.1 Introduction to Complex Variables 34
1.3.2 Arithmetic Operations of Complex Numbers 36
1.3.3 Wave Equation in Different Coordinate Systems 37
References 40
2 41
Measurement and Generation of Underwater Sounds 41
2.1 Electroacoustic Transducers 41
2.2 Sensitivity and Frequency Response of Piezoelectric Elements 42
2.2.1 Equivalent Circuit and Resonance 45
2.2.2 Resonance of Different Shaped Elements 49
2.2.3 Measurement of Resonant Frequency 51
2.3 Hydrophone Sensitivity Using Piezoelectric Parameters 52
2.4 Piezoelectric Polymer Material 54
2.5 Transducer Configuration 56
2.6 Projection of Low-Frequency Sound 59
2.7 Calibration of Transducers 60
2.7.1 Calibration with a Calibrated Hydrophone 62
2.7.2 Spherical Reciprocity Parameter 65
2.7.3 Three-Transducer Spherical Wave Reciprocity Calibration 66
2.7.4 Two-Transducer Reciprocity and Self-Reciprocity 68
References 69
3 71
Transducer Properties and Utilization 71
3.1 Near and Far Acoustic Fields 71
3.2 Directivity Pattern of Simple Transducers 76
3.2.1 Beam Pattern of a Thin Cylindrical Transducer 76
3.2.2 Beam Pattern of a Circular Piston 79
3.2.3 Beam Pattern of a Rectangular Piston 82
3.3 Linear Transducer Arrays 83
3.3.1 Beam Pattern of a Dipole Array 83
3.3.2 Beam Pattern of an N-element Array 84
3.3.3 Product Theorem 89
3.3.4 Electrically Steered Beam 90
3.3.5 Multibeam Sonar 94
3.3.6 Directivity Index 97
References 99
4 100
Acoustic Propagation 100
4.1 Basic Principles 100
4.1.1 Plane Waves and Acoustic Impedance 100
4.1.1 Surface and Bottom Reflections 102
4.1.1 Absorption and Refraction 105
4.2 Propagation of Sound in the Ocean 107
4.2.1 Ray Theory 108
4.2.2 Lloyd Mirror Effect 113
4.2.3 Propagation of Sound in the Deep Ocean 116
4.2.3.1 Mixed Surface Layer 117
4.2.3.2 The Deep Sound Channel 120
4.2.3.3 The Arctic Sound Channel 123
4.3 Propagation in Shallow Water 125
4.3.1 Ocean Acoustics Software 127
4.4 Sound Fields in Tanks 127
4.5 Sound Fields in Small Tanks 130
References 133
5 134
Signal Recording and Data Acquisition 134
5.1 Measurement of Underwater Sounds 134
5.2 Underwater Acoustic Noise 136
5.2.1 Ambient Noise in the Deep Ocean 137
5.2.2 Ambient Noise in Shallow Waters 139
5.2.3 The Effects of Rain on the Ambient Noise 140
5.2.4 Noise Caused by Ice 140
5.2.5 Other Sources of Acoustic Noise 141
5.3 Electronic Noise 142
5.4 The Sonar Equation 145
5.4.1 Active Form of the Sonar Equation 146
5.4.2 Passive Form of the Sonar Equation 147
5.5 Recordings of Sounds on Magnetic Tape 148
5.5.1 Linear Analog Magnetic Tape Recorders 148
5.5.2 Helical Scan Tape Recorders 151
5.5.3 Digital Audio Tape (DAT) 153
5.5.4 Digital Audio Recorders 154
5.6 Principles of Digital Data Acquisition: A/D Conversion 155
5.6.1 Sampling 156
5.6.2 Binary Representation 159
5.6.3 Analog-to-Digital (A/D) Conversion 160
5.6.4 Data Acquisition Systems 163
5.7 Localization with Hydrophone Arrays 168
5.7.1 The Hyperbola 168
5.7.2 Sound Localization in a Plane 169
5.7.3 Sound Localization in Three-Dimensional Space 172
5.7.4 Linear Equation Approach 173
5.7.4.1 Three Hydrophone in a Line 173
5.7.4.2 Four Hydrophones in a Plane 175
5.7.4.3 Five-Hydrophone Array 178
5.7.5 Two-Hydrophone Method of Cato 179
5.7.6 One-Hydrophone Localization 181
5.7.6.1 Using Direct and Surface Reflections Arrivals 181
5.7.6.2 Using the Direct, Surface, and Bottom Arrivals 182
5.7.7 Measurement of Time of Arrival Differences 183
References 187
6 189
Fourier Analysis 189
6.1 The Time and Frequency Domains 189
6.2 Foundation of Fourier Analysis: The Fourier Series 190
6.2.1 Even and Odd Functions 191
6.2.2 Discrete Spectra from Fourier Series 192
6.2.3 Exponential Form of the Fourier Series 195
6.3 Fourier Transform 196
6.3.1 The Impulse or Delta Function 198
6.3.2 Fourier Transformation of Cosine and Sine Functions 199
6.3.3 Negative Frequency in Fourier Transform 201
6.3.4 More Fourier Transform Examples 201
6.4 Properties of the Fourier Transform 205
6.4.1 Addition or Linearity Theorem 205
6.4.2 Time and Frequency Scaling 206
6.4.3 Time and Frequency Shifting 206
6.4.4 Modulation Theorem 207
6.4.5 Convolution Theorem 208
6.4.6 Correlation Theorem 211
6.4.7 Rayleigh-Parseval Theorem 212
6.5 The Discrete Fourier Transform and Fast Fourier Transform 213
6.5.1 The Discrete Fourier Transform 213
6.5.2 The Fast Fourier Transform 215
6.5.3 DFT Leakage 219
6.5.4 FFT Windows 220
6.5.5 Digital Convolution 222
6.6 Some Signal Processing Applications 227
6.6.1 Beamforming 227
6.6.2 Measuring Ambient Underwater Noise 228
6.6.3 Time Difference of Arrival Measurements 230
6.6.4 Reduction of Noise 231
6.6.5 Ceptrum Analysis: Removal of Multi-paths 234
6.6.6 Digital Equalization of Planar Transducers 235
References 238
7 239
Auditory Systems of Marine Animals 239
7.1 Structure of the Human Ear 239
7.1.3 The Middle Ear 240
7.1.3 The Inner Ear 243
7.1.3 Auditory Nervous System 250
7.1.3 The Central Auditory Nervous System 253
7.2 The Cetacean Ear 256
7.2.1 Middle Ear 264
7.2.2 The Inner Ear 267
7.3 The Pinniped Ear 274
7.3.1 The Outer Ear 275
7.3.2 The Middle Ear 276
7.3.3 The Inner Ear 278
7.4 The Sirean Ear 278
7.5 Ears in Fishes 280
7.5.1 Structure of the Inner Ear 280
7.5.2 Frequency Discrimination 284
7.5.3 Auxiliary Structures and Acoustic Pathways to the Ear 285
References 290
8 295
Experimental Psychological and Electrophysiological Methodology 295
8.1 Psychoacoustics Procedures 295
8.1.1 Stimulus Control and Operant Conditioning 296
8.1.2 Yes/No Response Paradigms in Detection Experiments 297
8.1.2.1 Binary Decision Matrix for Yes/No Detection Experiments 298
8.1.2.2 Receiver-Operating Characteristics Curve 299
8.1.2.3 The Forced Choice Procedure 302
8.1.3 Psychoacoustics Testing Procedures 305
8.1.4 Signal Detection Theory 307
8.1.4.1 Weakness of Classical Psychophysical Threshold 307
8.1.4.2 Elements of Signal Detection Theory 309
8.1.4.3 Applying SDT to Marine Mammals 314
8.2 Psychoacoustics Discrimination Experiments 316
8.2.1 Relative Magnitude Difference 317
8.2.2 Standard Versus Non-Standard Stimuli 318
8.2.3 Same-Different Stimuli 319
8.2.4 Matching-to-Sample 320
8.2.5 Probe Technique in Echolocation 323
8.3 Psychoacoustics Techniques for Fish Hearing 324
8.4 Electrophysiological Techniques for Marine Mammals 327
8.4.1 Auditory Evoked Potentials Caused by Brief Signals 328
8.4.2 Envelope-Following Responses 334
8.5 Electrophysiological Techniques for Fishes 340
References 342
Part II: Acoustics of Marine Animals 347
9 348
Hearing in Marine Animals 348
9.1 Hearing in Dolphins 348
9.1.1 Hearing Sensitivity 348
9.1.1.1 Sensitivity to Continuous Tones 348
9.1.1.2 Sensitivity to Pulse Tones 353
9.1.1.3 Hearing at Depth 354
9.1.1.4 Temporary Threshold Shift 356
9.2 Spectral Analysis Sensitivity 358
9.2.1 Critical Ratio 358
9.2.2 Critical Bandwidth 361
9.2.2.1 Masking by a Pure Tone 362
9.2.3 Frequency Discrimination 364
9.3 Directional Hearing Capability 366
9.3.1 Receiving Beam Patterns 366
9.3.2 Directivity Index 371
9.3.3 Sound Localization 374
9.4 Hearing in Pinnipeds 377
9.4.1 Hearing Sensitivity 378
9.4.1.1 Hearing at Depth 383
9.4.2 Spectral Analysis Sensitivity 384
9.4.2.1 Critical Ratio 384
9.4.2.2 Critical Bandwidth 386
9.4.2.3 Frequency Discrimination 387
9.4.3 Intensity Discrimination 388
9.4.4 Sound Localization 388
9.5 Hearing in Manatees 394
9.6 Hearing in Fishes 395
9.6.1 Influence of the Lateral Line at Low Frequencies 396
9.6.2 Hearing Sensitivity 398
9.6.2.1 Pressure vs. Particle Motion 399
9.6.2.2 Temporary Threshold Shift 400
9.6.2.3 Hair Cell Damage 401
9.6.3 Spectral and Temporal Analysis 404
9.6.4 Directional Hearing 404
References 406
10 412
Emission of Social Sounds by Marine Animals 412
10.1 Social Sound Emissions by Odontocetes 416
10.1.2 Whistles 419
10.1.2 Social Sounds: Signature Whistles 430
10.1.2 Burst Pulses 436
10.1.2 Geographic Difference and Dialect 448
10.2 Sound Emissions by Mysticete Whales 455
10.2.1 Songs of Mysticete Whales 456
10.2.2 Calls of Mysticete Whales 470
10.3 Underwater Vocalization of Pinnipeds 480
10.3.1 Underwater Vocalization of Phocids 480
10.3.2 Underwater Vocalization of Otariids 487
10.4 Underwater Vocalization of Sirenians 491
10.5 Sound Production by Fishes 492
10.6 Sound Production by Snapping Shrimp 496
References 501
11 511
Echolocation in Marine Mammals 511
11.1 The Dolphin Transmission System 512
11.1.1 Echolocation Signals of Dolphins Capable of Whistling 513
11.1.2 Echolocation Signal of Dolphins That Do Not Whistle 517
11.1.3 Some Properties of Echolocation Signals 519
11.1.3.1 Transmission Beam Pattern 519
11.1.3.2 Click Intervals 521
11.1.3.3 Click Source Levels 522
11.2 Target Detection Capabilities 524
11.2.1 Target Detection in Noise 525
11.2.2 Target Detection in Reverberation 531
11.3 Target Discrimination Capabilities 537
11.3.1 Range Resolution Capabilities 537
11.3.2 Target Structure Discrimination 538
11.3.2.1 Thickness and Material Composition of Plates 538
11.3.2.2 Structure and Material Composition of Hollow Cylinders 539
11.3.2.3 Wall Thickness of Cylinders 544
11.3.3 Shape Discrimination by Echolocating Dolphins 548
11.3.3.1 Planar Targets 548
11.3.3.2 Spheres and Cylinders 549
11.3.3.3 Cylinders and Cubes 549
11.3.4 Multidimensional Discrimination 551
11.4 Sperm Whale Echolocation 553
11.5 Pinniped Echolocation 560
11.6 Baleen Whale Echolocation 565
References 569
12 575
Some Signal Processing Techniques 575
12.1 Some Useful Signal Processing Concepts 575
12.1.1 The Envelope Function 575
12.1.2 Matched Filtering 577
12.1.3 Center Frequency and RMS Bandwidth 578
12.1.4 Accuracy in Target Range Determination 580
12.1.5 Range Resolution 582
12.1.6 Wideband Ambiguity Function 584
12.1.7 Time-Bandwidth Product 587
12.2 Mammalian Auditory System Modeled as an Energy Detector 589
12.2.1 Urkowitz Energy Detection Model 589
12.2.2 Application of Urkowitz Model 592
12.3 Signal Processing Models for Signal Recognition 593
12.3.1 Energy Detection in a Filter Bank 594
12.3.2 Measure of Feature Recognition 596
12.3.3 Time Domain Highlight Features 597
12.3.4 Spectrogram Correlation Model 600
12.3.5 Comparative Evaluation of Target Recognition Models 602
12.4 Artificial Neural Network and Signal Recognition 604
12.4.1 Backpropagation Network 606
12.4.2 Counterpropagation Network 608
12.4.3 Application to Cetacean Social Signals 610
12.4.3.1 Discrimination of Bowhead Whale Sounds 610
12.4.3.2 Categorizing False Killer Whale Sounds 612
12.4.3.3 Detection of Beluga Phonation in Noise 614
12.4.4 Application to Dolphin Sonar Discrimination 614
12.5 Concluding Remarks 627
References 627
13 631
Some Instrumentation for Marine Bioacoustics Research 631
13.1 Some Instrumentation for Marine Mammal Acoustics 632
13.1.2 The Bioacoustic Probe: Acoustic Recording Tag 632
13.1.2 Digital Acoustic Recording Tag: D-Tag 635
13.1.2 Other Odontocete Tags 638
13.2 Special Techniques to Localize and Track Vocalizing Marine Mammals 639
13.2.1 Radio Synchronization of Hydrophone Stations 639
13.2.2 GPS Technique of Hydrophone Position 640
13.2.3 Broadband Measurement of Dolphin Social Sounds 640
13.2.4 Measurement of Echolocation Signals: Wild Dolphins 644
13.2.5 Dolphin Phantom Echo Sonar Experiment 649
13.3 Some Instrumentation for Fish Acoustic Research 651
13.3.1 Acoustic Tags Satellite Tag, Chat Tag, Pop-up Satellite Tag 651
13.3.2 Active Acoustic Mooring 654
13.3.3 Active Impedance Control 657
13.3.4 Non-Invasive Ultrasonic Measurement System 659
13.4 General Instrumentation 662
13.4.1 Autonomous Acoustic Recorder - Bottom Resting 662
13.4.2 Cornell Pop-Ups 663
13.4.3 HIMB/PIFSC Ecological Acoustic Recorder (EAR) 665
13.4.4 Scripps HARP 666
13.5 Concluding Remarks 667
References 668
Index 670