Dusky Dolphin (eBook)

Front Cover 1
The Dusky Dolphin: Master Acrobats off Different Shores 4
Copyright Page 5
Dedication 6
Contents 8
Preface 10
About the Editors 16
Chapter 1. The Dusky Dolphins' Place in the Delphinid Family Tree 18
A STATE OF CONFUSION 19
A HISTORICAL OVERVIEW OF THE GENUS LAGENORHYNCHUS 22
TAXONOMIC HISTORY OF THE DUSKY DOLPHIN 27
EVOLUTION, MOLECULAR SYSTEMATICS, AND A NEW TAXONOMY 31
ACKNOWLEDGMENTS 36
NOTES 36
Chapter 2. Dusky Dolphin Life History and Demography 38
DUSKY DOLPHIN TAXONOMY 39
DISTRIBUTION AND ABUNDANCE 40
HABITAT CHARACTERISTICS 46
EXTERNAL CHARACTERISTICS 48
SIZE, SHAPE, AND SEXUAL DIMORPHISM 53
INTERNAL ANATOMY 53
GROWTH AND REPRODUCTION 55
ASSOCIATIONS WITH OTHER SPECIES 57
PARASITES, COMMENSALS, AND DISEASE 58
DIET AND FORAGING ECOLOGY 60
ANTHROPOGENIC THREATS 61
SOME ANSWERS AND MORE QUESTIONS 64
ACKNOWLEDGMENTS 65
Chapter 3. Dusky Dolphin Trophic Ecology: Their Role in the Food Web 66
INTRODUCTION 67
DUSKY DOLPHINS AS PREDATORS 70
DUSKY DOLPHINS AS COMPETITORS FOR FOOD RESOURCES 76
MIXED-SPECIES FORAGING ASSOCIATIONS 82
DUSKY DOLPHINS AS HOSTS IN PARASITIC RELATIONSHIPS 84
DUSKY DOLPHINS AS PREY 87
DUSKY DOLPHIN INTERACTIONS WITH HUMANS 88
ACKNOWLEDGMENTS 91
NOTE 91
Chapter 4. Acoustics of Dusky Dolphins 92
INTRODUCTION 94
WHISTLE SIGNALS 94
BURST PULSE SIGNALS 98
ECHOLOCATION SIGNALS 99
ECHOLOCATION BEHAVIOR 106
DISCUSSION AND CONCLUSIONS 110
ACKNOWLEDGMENTS 113
INTRODUCTION 118
Chapter 5. Dusky Dolphins Foraging at Night 116
METHODS 123
RESULTS 124
DISCUSSION 129
ACKNOWLEDGMENTS 131
Chapter 6. Dusky Dolphins Foraging in Daylight 132
INTRODUCTION 133
HERDING AS A MARINE FORAGING SPECIALIZATION 133
HOW DUSKY DOLPHINS COORDINATE BEHAVIORS DURING FORAGING 134
DIFFERENCES IN DUSKY DOLPHIN FORAGING BETWEEN STUDY SITES 140
HOW DOES ECOLOGY INFLUENCE DUSKY DOLPHIN FORAGING? 144
CONCLUSIONS 148
ACKNOWLEDGMENTS 149
Chapter 7. Predator Threats and Dusky Dolphin Survival Strategies 150
INTRODUCTION 151
DUSKY DOLPHINS OFF KAIKOURA, NEW ZEALAND 153
KILLER WHALES 154
SHARKS 158
DUSKY DOLPHINS—GROUP LIVING AND VOCAL REPERTOIRE 161
SUMMARY AND CONCLUSIONS 166
ACKNOWLEDGMENTS 167
Chapter 8. Mating Habits of New Zealand Dusky Dolphins 168
PROMISCUOUS MATING SYSTEM AND REPRODUCTIVE BIOLOGY 168
STUDY OBJECTIVES 169
KEEPING UP WITH THE ACTION: METHODS AND ADVANCES 170
EFFECT OF THE BREEDING SEASON ON SEXUAL BEHAVIOR 174
SOCIAL–SEXUAL ACTIVITY BY TIME OF DAY 177
SMALL MATING GROUPS 177
MATING OF THE QUICKEST: MALE–MALE COMPETITION 180
TEAM MATES TO GET MATES: ASSOCIATIONS AMONG MALES 184
FEMALE CHOICE AND FEMALE STRATEGIES 186
INTERACTIONS BETWEEN MATING GROUPS AND NURSERIES 191
PROCREATION AND RECREATION: THE ROLE OF NON-REPRODUCTIVE SEX IN DOLPHIN SOCIAL LIVES 191
SUMMARY AND CONCLUSIONS 192
ACKNOWLEDGMENTS 193
Chapter 9. Dusky Dolphin Calf Rearing 194
INTRODUCTION 194
FEMALE DUSKY DOLPHIN REPRODUCTIVE PARAMETERS 196
OVERVIEW OF INFLUENCES ON NURSERY GROUP FORMATION 197
BEHAVIORAL OBSERVATIONS 197
DANGERS IN CALF REARING 199
OPPORTUNITIES IN CALF REARING 205
SUMMARY 209
ACKNOWLEDGMENTS 210
Chapter 10. Sexual Segregation and Genetic Relatedness in New Zealand 212
GROUP COMPOSITION 213
METHODS AND RESULTS 215
GROUPING PATTERNS OFF NEW ZEALAND 222
ACKNOWLEDGMENTS 226
Chapter 11. Human Interactions with Dusky Dolphins: Harvest, Fisheries, Habitat Alteration, and Tourism 228
INTRODUCTION 229
DIRECT HARVEST OF DUSKY DOLPHINS 229
DUSKY DOLPHIN INTERACTIONS WITH FISHERIES 232
ANTHROPOGENIC CHANGES TO DUSKY DOLPHIN HABITAT 235
DUSKY DOLPHIN INTERACTIONS WITH TOURISM 242
SUMMARY AND CONCLUSIONS 259
ACKNOWLEDGMENTS 260
Chapter 12. Human Interactions with Dusky Dolphins: A Management Perspective 262
INTRODUCTION 263
MANAGEMENT FRAMEWORKS 264
CASE STUDIES OF NEW ZEALAND MANAGEMENT APPROACHES 275
CONCLUDING REMARKS 290
ACKNOWLEDGMENTS 292
Chapter 13. Dolphin Swimming and Watching: One Tourism Operator's Perspective 294
INTRODUCTION 294
THE DOLPHIN ENCOUNTER STORY 295
Chapter 14. Neglected But Not Forgotten—Southern Africa's Dusky Dolphins 308
INTRODUCTION 309
APPEARANCE 309
DISTRIBUTION AND MOVEMENTS 311
EXTERNAL COMMENSALS AND PARASITES 314
FOOD AND FEEDING 314
REPRODUCTION AND GROWTH 318
BEHAVIOR 321
CONSERVATION THREATS 323
DISCUSSION 325
ACKNOWLEDGMENTS 328
Chapter 15. Patterns of Sympatry in Lagenorhynchus and Cephalorhynchus: Dolphins in Different Habitats 330
DEFINING SYMPATRY 331
SOUTHERN HEMISPHERE DOLPHINS 332
SYMPATRIC LAGENORHYNCHUS AND CEPHALORHYNCHUS DOLPHINS IN DIFFERENT HABITATS 336
PATTERNS IN SYMPATRIC ECOLOGY 347
ACKNOWLEDGMENTS 348
Chapter 16. A Large-brained Social Animal 350
INTRODUCTION 350
CHAPTER OVERVIEW 354
THE EVOLUTIONARY PUZZLE OF LARGE BRAINS 355
LARGE-BRAINED CETACEANS 356
MANIFESTATIONS OF INTELLIGENCE IN DUSKY DOLPHINS 357
SOME MANIFESTATIONS OF INTELLIGENCE IN OTHER ANIMALS 362
THE ADAPTIVE VALUE OF LARGE BRAINS 364
AN ANSWER TO THE PUZZLE AND FURTHER QUESTIONS 367
FUTURE RESEARCH DIRECTIONS 369
ACKNOWLEDGMENTS 370
NOTES 370
Chapter 17. Social Creatures in a Changing Sea: Concluding Remarks 372
References 376
Glossary 432
A 432
B 432
C 433
D 434
E 434
F 435
G 436
H 436
I 436
J 437
L 437
M 437
N 438
O 439
P 439
R 440
S 441
T 442
U 443
V 443
W 443
Index 444
A 444
B 445
C 445
D 447
E 447
F 448
G 450
H 450
I 451
K 451
L 451
M 452
N 454
O 454
P 454
R 456
S 456
T 457
U 458
V 458
W 458
Y 458
Z 458