Biology and conservation of sea turtles in Baja California, Mexico Item Type text; Dissertation-Reproduction (electronic) Authors Nichols, Wallace J. Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 10/10/2021 22:51:32 Link to Item http://hdl.handle.net/10150/280439 NOTE TO USERS Page(s) missing in number only; text follows. The manuscript was microfilmed as received. 145 Page(s) duplicate in number only; text follows. The manuscript was microfilmed as received. 462 This reproduction is the best copy available. ® UMI BIOLOGY AND CONSERVATION OF SEA TURTLES IN BAJA CALIFORNIA, MEXICO by Wallace J. Nichols Copyright © Wallace J. Nichols 2003 A Dissertation Submitted to the Faculty of the SCHOOL OF RENEWABLE NATURAL RESOURCES In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY WITH A MAJOR IN WILDLIFE ECOLOGY In the Graduate College THE UNIVERSITY OF ARIZONA 2 003 UMI Number: 3108937 Copyright 2003 by Nichols, Wallace J. All rights reserved. INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. UMI UMI Microform 3108937 Copyright 2004 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 2 THE UNIVERSITY OF ARIZONA ® GRADUATE COLLEGE As members of the Final Examination Committee, we certify that we have read the dissertation prepared by Wallace J. Nichols entitled BIOLOGY AND CONSERVATION OF SEA TURTLES IN BAJA CALIFORNIA, MEXICO and recommend that it be accepted as fulfilling the dissertation ^ f T. c DOCTOR OF PHILOSOPHY requirement for the Degree of ^ Date ) ^ ' K!in/oo Date V \i j2iv| esTp Date Final approval and acceptance of this dissertation is contingent upon the candidate's submission of the final copy of the dissertation to the Graduate College. I hereby certify that I have read this dissertation prepared under my direction and recommend that it be accepted as fulfilling the dissertation requirement. Dissertation Director Date ' 3 STATEMENT BY AUTHOR This dissertation has been submitted in partial fulfillment of requirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library. Brief quotations from this dissertation are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his or her judgment the proposed use of the material is in the interests of scholarship. In all other instances, however, permission must be obtained from the author SIGNED: 4 ACKNOWLEDGEMENTS In my first meeting as a graduate student I sat on one side of a large rectangular table in Room 1 in the basement of the Biological Sciences East Building at the University of Arizona. Facing me were an ichthyologist (Dr. Donald Thomson), a wildhfe ecologist (Dr. Cecil Schwalbe), and an emeritus sea turtle biologist (Dr. John Hendrickson). After presenting my proposal to study the biology and conservation of sea turtles in Baja California for my doctoral research I was surprised by their response. "There really aren't enough turtles left to accomplish your goals in a reasonable amount of time," I was told. With that we set out on what has become nearly a decade of sea turtle research, conservation and education that has reached south to Central America and west to the waters off Japan. Since that day my advisors have provided enthusiastic research advice, constructive criticism and professional guidance as my efforts have been seemingly guided by the wind. I first thank all of them, and especially my friend and colleague Jeff Seminoff, for their encouragement and friendships. In the field, especially during the first months of research, the help of many experienced fishermen probably saved my life. Left to my own devices it is likely that I'd be tangled in a mass of turtle net adrift on the sea, somewhere between Mexico and Japan. I cannot adequately explain the patience of the men who assisted this project. Mil gracias to all of the fishermen who have taught me, and who have opened their boats, homes, kitchens, and minds to me. Antonio and Bety Resendiz have been wonderful colleagues to work with, but also role models and friends. Their commitment to the conservation of marine resources in Bahia de los Angeles sets a standard few can meet but all aspire to. A large, diverse group of people, friends, family, organizations and foundations has contributed in many ways this work. To all of them I owe my confidence in and commitment to the belief that in learning and education lie the restoration and conservation of much of the world's biological diversity, wilderness, and natural resources. As there are literally thousands of names to mention, and at the risk of leaving one out I'll simply say, thank you. 5 TABLE OF CONTENTS LIST OF TABLES 11 LIST OF FIGURES 15 ABSTRACT 20 GENERAL INTRODUCTION 22 Organization of the Project 24 Organization of the Dissertation 28 Description of the Region 30 Description of Main Study Areas 36 LITERATURE CITED 39 TABLES AND FIGURES 44 CHAPTER 1. ASPECTS OF SEA TURTLE LIFE HISTORY IN BAJA CALIFORNIA, MEXICO ABSTRACT 52 INTRODUCTION 53 IDENTIFICATION OF THE FIVE SPECIES OF SEA TURTLE INHABITING BAJA CALIFORNIA WATERS 55 SPECIES-SPECIFIC LIFE HISTORY CHARACTERISTICS 60 Green turtle, Chelonia mvdas 60 Loggerhead turtle. Caretta caretta 74 Olive ridlev turtle. Levidochelys olivacea 83 Hawksbill turtle. Eretmochehs imbricata 89 6 TABLE OF CONTENTS—Continued Leatherback turtle. Dermochelys coriacea 97 SUMMARY 102 LITERATURE CITED 103 TABLES & FIGURES 115 CHAPTER 2. FROM BLACK STEER TO SACRED COW: fflSTORIC AND CONTEMPORARY SEA TURTLE USE IN BAJA CALIFORNIA, MEXICO ABSTRACT 135 INTRODUCTION & fflSTORY OF SEA TURTLE FISHERIES 137 MODERN SEA TURTLE FISHERIES 143 HISTORY OF SEA TURTLE CONSERVATION 146 THE CULTURAL CONTEXT OF SEA TURTLES 151 PROBLEMS IN BAJA CALIFORNIA SEA TURTLE CONSERVATION EFFORTS 154 RECOMMENDATION & POTENTIAL SOLUTIONS 158 SUMMARY 161 LITERATURE CITED 163 TABLES & FIGURES 169 CHAPTER 3. STRANDINGS, INCIDENTAL TAKE, AND HUNTING: MORTALITY PATTERNS OF SEA TURTLES ALONG THE BAJA CALIFORNIA PENINSULA, MEXICO (1994-1999). ABSTRACT 175 INTRODUCTION 176 METHODS 180 RESULTS 186 7 TABLE OF CONTENTS— DISCUSSION 190 Incidental Capture of Sea Turtles in Baia California Fisheries 191 Directed Capture and Domestic Use of Sea Turtles 194 Other Causes of Sea Turtle Mortality 201 Mortality Synopsis by Species 205 SUMMARY 209 RECOMMENDATIONS 211 LITERATURE CITED 213 TABLES & FIGURES 223 CHAPTER 4. TRANSPACIFIC MIGRATION OF A LOGGERHEAD TURTLE MONITORED BY SATELLITE TELEMETRY ABSTRACT 239 INTRODUCTION 240 METHODS 243 RESULTS 245 DISCUSSION 247 Swimming speeds of migrating turtles 248 Migration path 249 Nayjgational cues 251 Conseryation implications 253 LITERATURE CITED 255 8 TABLE OF CONTENTS—Continued TABLES & FIGURES 265 CHAPTER 5. HOMING MIGRATIONS OF EAST PACIFIC GREEN TURTLES (CHELONIA MYDAS) INVESTIGATED BY SATELLITE TELEMETRY ABSTRACT 270 INTRODUCTION 272 METHODS 275 RESULTS 278 DISCUSSION 284 Homing migrations 284 Station-keeping movements 286 Swimming speeds 288 Conservation implications 290 LITERATURE CITED 293 TABLES «& FIGURES 299 CHAPTER 6. ORIGINS OF GREEN TURTLES, CHELONIA MYDAS, FORAGING IN THE WATERS OF THE BAJA CALIFORNIA PENINSULA, MEXICO ABSTRACT 313 INTRODUCTION 315 METHODS 321 RESULTS AND DISCUSSION 324 LITERATURE CITED 330 TABLES & FIGURES 339 9 TABLE OF CONTEmS—Continued CHAPTER 7. WHAT IS A BLACK TURTLE? THE EAST PACIFIC GREEN TURTLE PROBLEM ABSTRACT 348 INTRODUCTION 350 NOMENCLATURE AND TAXONOMY 353 GENETICS 355 MORPHOLOGY 357 WAR GAMES: TOWARDS AN APOLITICAL SEA TURTLE 369 THE REAL EAST PACIFIC GREEN TURTLE PROBLEM 376 CONCLUSIONS 381 LITERATURE CITED 385 TABLES & FIGURES 394 CHAPTER 8. TOWARDS A CONSERVATION MOSAIC: A CASE STUDY OF SEA TURTLE PROTECTION IN BAJA CALIFORNIA, MEXICO ABSTRACT 404 INTRODUCTION 406 THE SEA TURTLE CASE STUDY 410 THE COMMUNITY-BASED RESEARCH APPROACH 414 COMBINING SCIENTIFIC AND LOCAL RESEARCH KNOWLEDGE 417 EDUCATION, BROADLY DEFINED 420 SEA TURTLE RESERVES AND PROTECTED AREAS 423 GLOBALLY RELEVANT LOCAL ACTION 426 10 TABLE OF CONTENTS—Continued ENFORCEMENT BY COMMITTEE 428 MONITORING 432 SIGNS OF SUCCESS 434 CONCLUSIONS AND RECOMMENDATIONS 438 LITERATURE CITED 441 TABLES & FIGURES 452 CHAPTER 9. RESEARCH SUMMARY AND CONSERVATION RECOMMENDATIONS SUMMARY 458 RECOMMENDATIONS 461 APPENDIX A: ACRONYMS AND ABBREVIATIONS 462 APPENDIX B: RESEARCH PERMIT NUMBERS 464 APPENDIX C: INTERVIEW & SURVEY QUESTIONS 465 APPENDIX D: PARTIAL RESULTS OF MEDIA/OUTREACH CAMPAIGN (1996-2000) FOR SEA TURTLES IN BAJA CALIFORNIA 469 11 LIST OF TABLES INTRODUCTION Table 1. Shrimp production for northwestern Mexico relative to total national production for 1997/1998 44 Table 2. Marine protected areas of the Baja California peninsula and Gulf of California region 45 CHAPTER 1. ASPECTS OF SEA TURTLE LIFE fflSTORY IN BAJA CALIFORNIA, MEXICO Table 1. Scientific, English and Spanish names for sea turtles occurring in Baja California waters 115 Table 2. Simplified key to the sea turtle species of Baja California waters 116 Table 3.