The Biology and Population Status of Marine Turtles in the North Pacific Ocean
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NOAA Technical Memorandum NMFS SEPTEMBER 1993 THE BIOLOGY AND POPULATION STATUS OF MARINE TURTLES IN THE NORTH PACIFIC OCEAN Karen L. Eckert NOM-TM-NMFS-S W FSC-186 U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Marine Fisheries Service Southwest Fisheries Science Center NOAA Technical Memorandum NMFS The National Oceanic and Atmospheric Administration (NOAA), organized in 1 970, has evolved into an agency which establishes national policies and manages and conserves our oceanic, coastal, and atmospheric resources. An organizational element within NOAA, the Office of Fisheries is responsible for fisheries policy and the direction of the National Marine Fisheries Service (NMFS). In addition to its formal publications, the NMFS uses the NOAA Technical Memorandum series to issue informal scientific and technical publications when complete formal review and editorial processing are not appropriate or feasible. Documents within this series, however, reflect sound professional work and may be referenced in the formal scientific and technical literature. NOMTechnical Memorandum NMFS This TM sorb ir used fu documntalian and timely communicplbn of pdiminary msulh, interin raport., u special purposa infodim:and have not received conplda fad review. editorial control, u ddbdediting. SEPTEMBER 1993 THE BIOLOGY AND POPULATION STATUS OF MARINE TURTLES IN THE NORTH PACIFIC OCEAN Karen L. Eckert, Ph.D. Executive Director, WIDECAST Prepared for Honolulu Laboratory, SWFSC National Marine Fisheries Service, NOAA 2570 Dole Street 3 Honolulu, Hawaii 96822-2396 NOAA-TM-NMFS-SWFSC-186 U.S. DEPARTMENT OF COMMERCE Ronald H. Brown, Secretary National Oceanic and Atmospheric Administration D. James Baker, Under Secretary for Oceans and Atmosphere National Marine Fisheries Service Nancy Foster, Acting Assistant Administrator for Fisheries iii PREFACE In recent years considerable international attention has been directed toward high-seas driftnet fisheries in the North Pacific Transition Zone and their impacts on living marine resources. Among the many species affected are marine turtles whose populations are sufficiently depleted to warrant listing as protected species under U.S. and international laws. To provide a foundation for assessing impacts of the driftnet fisheries on marine turtles, the Honolulu Laboratory commissioned this study to review available background information. The aim was to assemble and summarize current data on the biology and conservation status of turtles in the North Pacific, and to cover a wide spectrum of sources, including unpublished reports and personal accounts. Soon after the completion of this study, the countries involved in high-seas driftnet fishing agreed to a moratorium on the use of large-scale driftnets sponsored by the United Nations. Nevertheless, this compendium remains a valuable source of information. It will be of particular value in programs to assess other sources of risk to turtle populations in the North Pacific, develop recovery plans, and monitor population recovery. Opinions expressed in this paper are those of the author and are not necessarily shared by the National Marine Fisheries Service. Jerry A. Wetherall George H. Balazs 20 July 1993 iV TABLE OF CONTENTS List of Abbreviations ....................vii Objectives and Scope of Work .................2 Importance of North Pacific Sea Turtles to Human Populations: Exploitation. Trade. Use. Cultural Values and Traditions ...2 Canada ...........................2 United States of America ..................3 United States Outlying Territories in the North Pacific . 4 Mexico ...........................8 Japan .......................... 10 Korea .......................... 12 China .......................... 13 Taiwan .......................... 14 VietNam ......................... 15 Kampuchea ........................ 16 Thailand ......................... 17 Malaysia ......................... 18 Philippines ....................... 20 Federated States of Micronesia .............. 22 Republic of the Marshall Islands ............. 24 Kiribati ......................... 25 Status of North Pacific Sea Turtle Populations Under Conservation and Wildlife Protection Laws .......... 26 National Legislation ................... 26 Canada .......................... 27 United States of America ................ 27 United States Outlying Territories in the North Pacific 29 Mexico ......................... 30 Japan ......................... 31 Korea ......................... 32 China ......................... 32 Taiwan ......................... 33 VietNam ........................ 34 Kampuchea ....................... 34 Thailand ........................ 34 Malaysia ........................35 Philippines ...................... 37 Federated States of Micronesia ............. 38 Republic of the Marshall Islands ............ 38 Kiribati ........................ 38 Regional and International Treaties and Agreements .... 39 Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) ....... 40 Convention on Nature Protection and Wildlife Preservation in the Western Hemisphere ........ 40 ASEAN Agreement on the Conservation of Nature and Natural Resources ................ 40 V Convention for the Protection of the Natural Resources and Environment of the South Pacific Region ..... 41 International Convention for the Prevention of Pollution of the Sea by Oil ............. 42 Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter ........ 42 International Convention for the Prevention of Pollution From Ships (MARPOL) ............ 42 Protocol of 1978 Relating to the International Convention for the Prevention of Pollution From Ships (London Convention. or MARPOL) ............ 43 Biological Review Loggerhead Sea Turtle. Caretta caretta .......... 43 Taxonomy ........................ 43 Morphology ....................... 43 Population Units .................... 44 Nesting Habits and Areas ................ 45 Insular and Pelagic Range ............... 47 Growth ......................... 49 Conservation Status .................. 49 Life Cycle Overview .................. 50 Green Sea Turtle (complex). Chelonia mydas ........ 52 Taxonomy ........................ 52 Morphology ....................... 53 Population Units .................... 54 Nesting Habits and Areas ................ 55 Insular and Pelagic Range ............... 62 Growth ......................... 65 Conservation Status .................. 66 Life Cycle Overview .................. 66 Leatherback Sea Turtle. Dermochelys coriacea ....... 70 Taxonomy ........................ 70 Morphology ....................... 70 Population Units .................... 71 Nesting Habits and Areas ................ 71 Insular and Pelagic Range ............... 73 Growth ......................... 76 Conservation Status .................. 77 Life Cycle Overview .................. 77 Hawksbill Sea Turtle. Eretmochelys imbricata ....... 79 Taxonomy ........................ 79 Morphology ....................... 79 Population Units .................... 80 Nesting Habits and Areas ................ 80 Insular and Pelagic Range ............... 84 Growth ......................... a7 Conservation Status .................. 88 Life Cycle Overview .................. 88 Olive Ridley Sea Turtle. Lepidochelys olivacea ...... 91 Taxonomy ........................ 91 Morphology ....................... 91 Population Units .................... 92 vi Nesting Habits and Areas ................ 93 Insular and Pelagic Range ............... 94 Growth ......................... 97 Conservation status .................. 97 Life Cycle Overview .................. 98 Factors Important to Assessing Impacts of High-Seas Driftnet Fisheries ................101 Likelihood of Survival Following Entanglement in Driftnets Based on Experience with Trawls and Other Fishing Gear . 101 Ability of Sea Turtles to Survive Prolonged Submergence 101 Effects of Handling ..................103 Research and Monitoring Needs for Improved Impact Assessment 104 Basic Biology ......................104 Population Dynamics and Stock Monitoring .........106 Pelagic Distribution and Ecology ............. 107 Acknowledgments ....................... 108 Literature Cited ...................... 109 Table1 ........................... 153 Figure1 .......................... 155 vii LIST OF ABBREVIATIONS BCS Baja California Sur CCL Curved carapace length CITES Convention on International Trade in Endangered Species COSEWIC Committee on the Status of Endangered Wildlife in Canada DAWR Division of Aquatic and Wildlife Resources, Government of Guam EEZ Exclusive Economic Zone ESA U.S. Endangered Species Act of 1973, as amended ETP Eastern Tropical Pacific FSM Federated States of Micronesia FWS U.S. Fish and Wildlife Service GAC/BEECS Genetic Analysis Core, Biotechnologies for the Ecological, Evolutionary and.Conservation Sciences (University of Florida) GBR Great Barrier Reef, Australia HSWRI Hubbs-Sea World Research Institute IUCN World Conservation Union MMDC Micronesian Mariculture Demonstration Center, Palau mtDNA Mitochondrial DNA NMFS U.S. National Marine Fisheries Service NPWS National Parks and Wildlife Service, Government of Australia NWMMSN Northwest Marine Mammal Stranding Network SCL Straight-line carapace length SPREP South Pacific Regional Environment Programme TAMU Texas A&M University viii TED Turtle excluder device UNAM Universidad Nacional Autonoma de Mexico UNEP United Nations Environment Programme