TURTLE HEARING CLASSIFICATION
FOR TURTLE EXCLUDER DEVICES DESIGN
ANTON YUDHANA
TURTLE HEARING CLASSIFICATION FOR TURTLE EXCLUDER DEVICES DESIGN
ANTON YUDHANA
A thesis submitted in fulfilment of the requirements for the award of the degree of Doctor of Philosophy (Electrical Engineering)
Faculty of Electrical Engineering Universiti Teknologi Malaysia
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ACKNOWLEDGEMENT
Alhamdulillah. I praise and glorify be only to Allah SWT the Almighty, the Most Beneficent, and the Most Merciful, whose blessings and guidance have helped me to be able to finish this thesis. In particular, I wish to express my sincere appreciation to my supervisor, Associate Professor Dr. Jafri Din for encouragement, guidance, critics, advices, motivation, and friendship. Without his support and interest, this thesis would not have been the same as presented here.
I am also indebted to Ministry of National Education (Depdiknas) Indonesia and Ministry of Science, Technology, and Innovation (MOSTI) Malaysia for their financial support during the term of this study. Many thanks to my colleague Mr. Sunardi, Mr.Reza Firsandaya Malik, Lam Hok Yin, Mr. Tole Sutikno, Mrs. Lina Handayani, and Mr. Ditto Prihadi. Also full thanks to Mr. Ahmad Syahril Mohd Nawi for their supports. Thanks to Turtle and Marine Ecosystem Center (TUMEC) Terengganu Malaysia for providing research infrastructure for facilities, researchers, and staff, especially Syed Abdullah and YM Raja Bidin Raja Hassan, I am grateful for their warm hospitality and for taking the time to share with me their knowledge of the turtles of Malaysia. Mr. Jamil and TUMEC staffs are thanked for assisting ABR measurements. Gratefully acknowledge to Department of Electrical Engineering Universitas Ahmad Dahlan (UAD) Yogyakarta Indonesia for the opportunity to pursue Ph.D. program at UTM. This thesis will not be completed without their full encouragement and support as a solid team.
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ABSTRACT
The process of reducing the accidental capture and subsequent mortalities of sea turtles in regional captured fisheries through the use of Turtle Excluder Device (TED) has been extremely important. The objectives of this study is to determine the hearing ability for Green Turtle (Chelonia Midas), identify the green turtle and fish behavior on various sound exposures, and determine the specification of TED using underwater sound technique. Auditory Brainstem Response system is used to identify the hearing threshold of the turtle. The measurements were performed at Turtle and Marine Ecosystem Center (TUMEC) Terengganu, Perak, and Melaka Malaysia. It was conducted at a turtle tank by employing click and tone stimulus. Turtle ages of 2 years, 5 years, 9 years, and 30 years were deployed. The measured data were analyzed in time and frequency domains. It is found that the green turtle has a hearing ability in the range of 50 Hz to 1200 Hz. The results showed that turtle hearing sensitivity is about 300 Hz to 500 Hz. Also, the measurement of ambient noise in the life habitat has been conducted. The measurements were divided into 3 different distances from the sea shore: 200 m, 400 m, and 800 m and within 3 different sea depth: 2 m, 5 m, and 10 m for each point, respectively. The frequency and maximum magnitude of ambient noise are found to increase as the depth increased. Finally, the behavior of the turtle and fish towards the emitted sound has been observed. A group of signals that dispel turtles have been determined. The types of signals are Low and High Frequency Modulation, white noise, and sinusoidal signal. These signals do not give any respond to the fish. Therefore, this information is very useful in the development of TED using sound.
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ABSTRAK
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TABLE OF CONTENTS
CHAPTER TITLE PAGE
DECLARATION ii
DEDICATION iii
ACKNOWLEDGEMENTS iv
ABSTRACT v
ABSTRAK vi
TABLE OF CONTENTS vii
LIST OF TABLES xi
LIST OF FIGURES xii
LIST OF ABREVIATIONS xv
LIST OF SYMBOLS xvii
LIST OF APPENDICES xviii
1 INTRODUCTION 1
1.1 Research Background 1
1.2 Problem Statement 2
1.3 Objectives 3
1.4 Research Scope 3
1.5 Outline 3
2 LITERATURE REVIEW 5
2.1 Introduction
2.2 Types of Sea Turtle 5
2.2.1 Green Turtle Morphology 9
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2.3 Underwater Acoustic Units of Measurement 13 2.4 The decibel Scale in Underwater Acoustics 14
2.5 Turtle Auditory System 17
2.6 Turtle and Fish Hearing Threshold 20 2.7 Turtle Excluder Devices (TED) 25
2.8 Long Line and Gill Net 28
2.9 Sound Classification 31
2.10 Fast Fourier Transform (FFT) Algorithm 33 2.11 FFT Application on Spectral Analysis 34
2.12 Summary 35
3 RESEARCH METHODOLOGY 36
3.1 Introduction 36
3.2 Design of Study 36
3.3 Research Materials and Life Specimens 37
3.3.1. Research Tank 37
3.3.2. Green Turtle 40
3.3.3. Targeted Fish 42
3.3.4. SmartEp Software 43
3.3.5. Hydrophone for Recording Underwater sound
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3.3.6. Sound Generator 46
3.3.7. Underwater Speaker 48
3.3.8. Sound Recorder Software 49
3.3.9. Matlab Software 50
3.4 Measurements Procedures 50
3.4.1 Types of Measurement 50
3.4.2 ABR Response Measurement 50 3.4.3 Seawater Quality Measurement in Life
Habitat
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3.4.4 Seawater Quality Measurement in the Research Tank
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3.4.6 Turtle and Fish Response Towards Sound 55 3.5 Spectral Analysis of The ABR Waveforms and
Sound Profile
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3.5.1 ABR Waveforms Data Extraction 56 3.5.2 Sound Calibration Method 58 3.5.3 Sound Profile Data Extraction 58 3.5.4 Program Implementation and Analysis 60
3.6 Summary 61
4 RESULTS AND DISCUSSIONS 62
4.1 Introduction 62
4.2 Turtle Auditory Brainstem Response 62
4.2.1 Turtle Age 2 years 64
4.2.2 Turtle Age 5 years 67
4.2.3 Turtle Age 9 Years 69
4.2.4 Turtle Age 30 Years 71
4.3 Seawater Profile 77
4.3.1 Life Habitat Water Quality 77
4.3.2 Portable Instrument 78
4.3.3 Fixed Instrument 79
4.4 Sound Profile 81
4.4.1 Seawater Sound Profile 81
4.4.2 Research Tank Sound Profile 83
4.5 Sound Characterization 85
4.5.1 LFM Sound Profile 85
4.5.2. Sinusoidal Sound Profile 86
4.5.3. White Noise Sound Profile 88
4.6 Turtle and Fish Response 90
4.6.1 Turtle Response 90
4.6.2 Fish Response 91
4.7. Problem Encountered 91
4.8. Key Contributions 92
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5 CONCLUSIONS AND FUTURE WORKS 93
5.1 Conclusion 93
5.2 Future Works 94
REFERENCES 95
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LIST OF TABLES
TABLE NO. TITLE PAGE
2.1 Sound speed in some medium 14
2.2 The hearing ranges of fish 20
3.1 Hydrophone C304 Technical specification 45 3.2 Underwater Speaker Lubell 3400 Technical Specification 48
4.1 Turtle’s morphology in ABR measurement 61
4.2 ABR setup for green turtles ages 2 years 62 4.3 ABR response green turtles ages 2 years 64 4.4 Water quality recorded by using portable meter in life
habitat 76
4.5 Water quality recorded by using portable meter in the tank 76 4.6 Water quality recorded by using automatic meter (Half
Day) 77
4.7 Water quality recorded by using automatic meter (Two
days) 78
4.8 Water quality recorded by using automatic meter (Three
days) 79
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LIST OF FIGURES
FIGURE NO. TITLE PAGE
2.1 Green turtle (chelonia midas) 5
2.2 The hawksbill turtle 6
2.3 The leatherback turtle 7
2.4 Lipas turtle 7
2.5 Sites of green turtle for hatchling in Malaysia Peninsula. 10 2.6 Maps of east Malaysia for egg and hatchling 11 2.7 The post breeding migration of three C.midas Female
(a,b,and C) and one C.midas (D) release from Ma’Daerah Turtle Sanctuary Terengganu Malaysia
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2.8 ABR waveforms 17
2.9 Diagrammatic representation of a Turtle Excluder Device
fitted to a trawl 25
2.9 Senangin II, research vessel, equipped with trawl net 28
2.11 Trawl net at senangin II 29
2.12 Trawl operation at Senangin II 29
2.13 Diver filming TED 30
3.1 The main site of research 36
3.2 Primary research tank with square shape 37
3.3 The second tank with round shape 37
3.4 The third tank with square shape 38
3.5 Research tank arrangement 38
3.6 Tank in cleaning 39
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3.9 The weight measurement of turtle 41
3.10 The fish in the second tank 42
3.11 SmartEp main screen 43
3.12 Hydrophone C304 44
3.13 Generated sound software 46
3.14 Speaker type Lubell 3400 47
3.15 Sound recorder using edit audio software 48
3.16 Green turtle in ABR measurement 50
3.17 Green turtle was stationed by jacket for ABR measurement 51 3.18 Quality of Seawater measurement in life habitat 52 3.19 Quality of Seawater measurement in tank 53
3.20 Sound profile in the research tank 54
3.21 Acquired ABR data analysis flow 56
3.22 Reference sound analysis software 57
3.23 Monitored signal of water in tank profile 58
3.24 Extracted monitored signal in the tank 58
3.25 Acquired sound profile analysis 59
4.1 Green turtle morphology 61
4.2 ABR signal spectral of green turtle ages of 2 years 63 4.3 Turtle ages of 2 years hearing sensitivity 65 4.4 ABR signal spectral of green turtle ages of 5 years 66 4.5 Turtle ages of 5 years hearing sensitivity 67 4.6 ABR signal spectral of green turtle ages of 9 years 68 4.7 Turtle ages of 9 years hearing sensitivity 69 4.8 ABR signal spectral of green turtle ages of 30 years 70 4.9 Turtle ages of 30 years hearing sensitivity 70 4.10 Minimum frequencies of turtle’s hearing 72
4.11 Maximum frequencies of turtle hearing 72
4.12 Green turtle’s hearing bandwidth 73
4.13 Green turtle’s hearing range 74
4.14 Hearing ranges constellation 75
4.15 Noise floor in the life habitat(distance=200m,depth=2m) 79
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4.17 LFM sound profile 83
4.18 Sinusoidal sound profile 85
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LIST OF ABBREVIATIONS
ABR - Auditory Brainstem Response AEP - Auditory evoked potentials
ANSI - American National Standard for Institute
ASCII - American Standard Code for Information Interchange ASSR - Auditory Steady State Response
AULS - Autonomous Underwater Listening Station CWT - Complex Wavelet Transform
dBnHL - dB scale relative to normal hearing level
DO - Dissolved Oxygen
EEG - Electro EnchepaloGraph EFR - envelope following response EFR - envelope following response FFT - Fast Fourier Transform
hh - Hour
IHS - Intelligent Hearing System
L - length
LFM - Low Frequency Modulation
mm - Minute
MRTF - modulation rate transfer function NMFS - National Marine Fisheries Service
NN - neural network
NOAA - National Oceanic and Atmospheric Administration NPF - Northern Prawn Fishery
PTT - push to talk
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RMSE - The Root Mean Squared Error
Sal - Salinity
sd - Stimulus Duration
SEAFDEC - South East Asian Fisheries Development Center SNR - signal to noise ratio
SpCond - Sound propagation Conductivity SPL - Sound Pressure Level
ss - Second
SSE - The Sum of Squares due to Error
Std - Standard Deviation
STFT - Short Time Fourier Transform STFT - short time Fourier Transform
T - tall
TED - Turtle Excluder Devices Temp - Temperature
TUMEC - Turtle and Marine Ecosystem Center UTM - Universiti Teknologi Malaysia
W - width
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LIST OF SYMBOLS
μ - micro
W - watt
m2 - meter square ms - mili second
re - relative
Pa - Pascal
L - liter
mg - mili gram
C - celcius
d - depth
ºC - degree celcius
Ω - ohm
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LIST OF APPENDICES
APPENDIX TITLE PAGE
A List of Author’s Publication 100
B Source Code 101
C1 First measurement Procedure 107
C2 Second measurement Procedure 108
C3 Third measurement Procedure 109
C4 Fourth measurement Procedure 110
C5 Fifth measurement Procedure 111
C6 Sixth measurement Procedure 112
C7 Seventh measurement Procedure 113
C8 Eight measurement Procedure 114
D1 ABR and sound profile recording 115
D2 ABR System Setup and resulted data 116
D3 ABR spectral in smartEp 122
E1 Sound Profile in Life Habitat (distance=100m) 124 E2 Sound Profile in Life Habitat (distance=200m) 125 E3 Sound Profile in Life Habitat (distance=400m) 127 E4 Sound Profile in Life Habitat (distance=800m) 129 E5 Noise Floor in the life habitat (distance=200m) 131 E6 Noise Floor in the life habitat (distance=400m) 132 E7 Noise Floor in the life habitat (distance=800m) 133 E8 Peak of Magnitude for Life Habitat Noise Floor 134
F1 Sound Characterization Measurement 135
F2 Turtle response towards sound 136
CHAPTER 1
INTRODUCTION
1.1 Research Background
Sea turtles are important marine animals, not only under CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) agreement but also traditional living resources in the ASEAN region. Most of the ASEAN member countries have established national programs on the conservation and enhancement of sea turtles. However, information on research, conservation and enhancement of these animals in the region is rather fragmented.
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Fisheries Regulation 1990 was aimed to prevent turtle extinction when this regulation had caused stingray fish production got decrease. The stingray fish is quite popular in Malaysia and it is in line with the food industry variety. The demand of this fish is increase in Malaysia. Recreational and sport fishing stingray is also point of interest for tourism industry in Malaysia. The other benefit, its skin had commercial values in exotic leather wear and very rare to found any of the stingray skin wallets in Malaysia.
Meanwhile, the usage of gill net by fisheries had been monitored by local authority because of many fisheries still used it in illegal fishing. The Turtle and Marine Ecosystem Center (TUMEC) has been reported that in 2006 under Fisheries Department they had confiscated more 20 gill nets in the inspection in Terengganu reported by (http://web10.bernama.com/maritime/news). Fishermen still used the gill net in the zone A that has much stingray population there. Plenty of fishes had been collected, but incidentals capture of sea turtles in fishing gear is another major problem. One interesting point to note is that hook and long lines do not seem to be catching turtles within Malaysian territorial waters, although they are known to take turtles in offshore areas. It is clear that prohibition is not really effective.
1.2 Problem Statements
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1.3 Objectives
The main purpose of this research is proposed Turtle Excluder Devices (TED) using Sound technique. The proposed TED designed begin by conducted some basic objectives of research step. The following objectives are:
• To determine the hearing ability for green turtle.
• To identify the green turtle behavior on various sound exposures.
• To determine the specification of TED using underwater sound technique.
1.4 Research Scope
In order to achieve the research objectives, the following scopes will be covered:
• Measurement of turtle hearing threshold using Auditory Brainstem Response (ABR) System.
• Measurement of underwater sound profile. • Green turtle ABR data analysis.
• Investigation of sound profile in sea water.
• Measurement of the green turtle behavior on specific sound exposures.
1.5 Outline
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Chapter 2 begins by discussed on the types of sea turtles with green turtle morphology, evolutionary trends and conservation and green turtle distribution in Malaysia. Then, in the following section are discussed on underwater acoustic units of measurement, the decibel scale in underwater acoustics, turtle auditory system, turtle and fish hearing threshold, TED, long line and gill net, sound classification, Fast Fourier Transform (FFT) algorithm. Finally, FFT application on spectral analysis is discussed.
Chapter 3 presents the research methodology. This chapter begins by discuss design of study, research materials and life specimens, measurements procedures, spectral analysis of the ABR waveforms and sound profile.
Chapter 4 presents the results and discussion. The results consist of turtle auditory brainstem response, seawater profile, sound profile, sound characterization, turtle and fish response, and problem encountered. Finally, the contributions of the research are given.
