Behavior of Marine Fishes: Capture Processes and Conservation Challenges

Contributors ix

Preface xi
Clement S. Wardle

Introduction xiii
Pingguo He

Part One: Locomotion and Sensory Capabilities in Marine Fish 3

Chapter 1 Swimming in Marine Fish 5
John J. Videler and Pingguo He

1.1 Introduction 5

1.2 The Swimming Apparatus 5

1.3 Swimming-Related Adaptations 8

1.4 Styles of Swimming 12

1.5 Interactions between Fish and Water: Fish Wakes 13

1.6 Energy Required for Swimming 14

1.7 Swimming Speeds and Endurance 18

1.8 Concluding Remarks 19

Chapter 2 Fish Vision and Its Role in Fish Capture 25
Takafumi Arimoto, Christopher W. Glass, and Xiumei Zhang

2.1 Introduction 25

2.2 Structure of the Fish Eye 25

2.3 Visual Function 27

2.4 Visual Capacity: Visual Acuity, Separable Angle, and Maximum Sighting Distance 32

2.5 Color and Appearance of Fishing Gear Underwater 35

2.6 Fish Vision and Its Application in Fish Capture 36

2.7 Concluding Remarks 40

Chapter 3 Hearing in Marine Fish and Its Application in Fisheries 45
Hong Young Yan, Kazuhiko Anraku, and Ricardo P. Babaran

3.1 Introduction 45

3.2 Properties of Underwater Sound and Vibration 45

3.3 Underwater Sound Sources and Their Characteristics 47

3.4 General Morphology and Functions of Inner Ears and Ancillary Structures 48

3.5 Responses of Fish to Sound and Its Application in Fisheries 53

3.6 Concluding Remarks 60

Part Two: Fish Behavior near Fishing Gears during Capture Processes 65

Chapter 4 Fish Behavior near Bottom Trawls 67
Paul D. Winger, Steve Eayrs, and Christopher W. Glass

4.1 Introduction 67

4.2 Trawl Gear and Trawl Fisheries 67

4.3 Fish Behavior in the Pretrawl Zone (Zone 1) 69

4.4 Fi sh Behavior between Trawl Doors and in the Net Mouth (Zone 2) 75

4.5 Fish Behavior inside the Trawl Net and the Codend (Zone 3) 82

4.6 Factors Infl uencing Fish Behavior near Trawls 89

4.7 Concluding Remarks 95

Chapter 5 Fish Behavior in Relation to Longlines 105
Svein Løkkeborg, Anders Fernö, and Odd-Børre Humborstad

5.1 Introduction 105

5.2 Worldwide Longline Fisheries 106

5.3 Description of the Gear 108

5.4 Chemoreception and Food Search—The Basis for Bait Fishing 110

5.5 Interactions between the Fish and the Longline Gear 114

5.6 Conservation Challenges and Potential Solutions 123

5.7 Concluding Remarks 130

5.8 Future Challenges 132

Chapter 6 Fish Pots: Fish Behavior, Capture Processes, and Conservation Issues 143
Bjarti Thomsen, Odd-Børre Humborstad, and Dag M. Furevik

6.1 Introduction 143

6.2 Worldwide Use of Fish Pots 143

6.3 Fish Behavior in Relation to Pots 146

6.4 Conservation Challenges and Solutions 150

6.5 Concluding Remarks 154

Chapter 7 Large-scale Fish Traps: Gear Design, Fish Behavior, and Conservation Challenges 159
Pingguo He and Yoshihiro Inoue

7.1 Introduction 159

7.2 Trap Fisheries and Trap Designs 159

7.3 Fish Behavior in and around Traps 165

7.4 Fish Behavior and Trap Designs 170

7.5 Size and Species Selectivity and Mortality of Escapees and Discards 172

7.6 Conservation Issues and Mitigation Measures in Trap Fisheries 174

7.7 Concluding Remarks 178

Chapter 8 Fish Behavior near Gillnets: Capture Processes, and Influencing Factors 183
Pingguo He and Michael Pol

8.1 Introduction 183

8.2 Capture Mechanisms, Gear Designs, and Fishing Efficiency 184

8.3 Size Selectivity of Gillnets 187

8.4 Fish Behavior and Gillnet Fishing 189

8.5 Measures to Reduce Bycatch and Discards in Gillnets 192

8.6 Interaction of Marine Mammals, Seabirds, and Sea Turtles with Gillnets 195

8.7 Derelict Gillnets: Ghost Fishing Problems and Solutions 197

8.8 Concluding Remarks 198

Chapter 9 Electric Senses of Fish and Their Application in Marine Fisheries 205
Hans Polet

9.1 Introduction 205

9.2 Properties of an Electric Field in Water 206

9.3 The Electric Field 209

9.4 Application in Marine Fisheries 219

9.5 Conservation Issues 228

9.6 Concluding Remarks 231

Part Three: Contemporary Issues in Capture and Conservation in Marine Fisheries 237

Chapter 10 Technical Measures to Reduce Bycatch and Discards in Trawl Fisheries 239
Norman Graham

10.1 Introduction 239

10.2 Bycatch and Discard in World Fisheries 240

10.3 Cause of Bycatch and Discard 242

10.4 Technical Measures to Reduce Bycatch and Discard 242

10.5 Implementation of Discard Reduction Measures in Trawl Fisheries 257

10.6 Discussion 258

10.7 Concluding Remarks 259

Chapter 11 Mortality of Animals that Escape Fishing Gears or Are Discarded after Capture: Approaches to Reduce Mortality 265
Petri Suuronen and Daniel L. Erickson

11.1 Introduction 265

11.2 Mortality of Discards and Escapees 266

11.3 Assessment of Mortality 269

11.4 Factors Causing Stress, Injury, and Mortality 276

11.5 Measures to Improve Survival 283

11.6 Concluding Remarks 286

Chapter 12 Effect of Trawling on the Seabed and Mitigation Measures to Reduce Impact 295
Pingguo He and Paul D. Winger

12.1 Introduction 295

12.2 Review of Recent Studies on the Seabed Impact of Trawling 295

12.3 Description of Trawls and Their Operation 296

12.4 Pelagic and Semipelagic Trawls 299

12.5 Groundgear Modifi cations 301

12.6 Trawl Door Considerations 305

12.7 Other Trawl Gear Components 306

12.8 Beam Trawls 309

12.9 Concluding Remarks 310

Chapter 13 Measures to Reduce Interactions of Marine Megafauna with Fishing Operations 315
Dominic Rihan

13.1 Introduction 315

13.2 Species and Fisheries Involved 316

13.3 Extent of Bycatch 318

13.4 Nature of the Problem 320

13.5 Regulatory Frameworks 321

13.6 Potential Mitigation Measures 325

13.7 Concluding Remarks 337

Appendix

Species Names Mentioned in the Text 343

Index 347