A Preliminary Assessment of the Sea Turtles and Sea Turtle Habitats of Saipan, Commonwealth of the Northern Mariana Islands
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A PRELIMINARY ASSESSMENT OF THE SEA TURTLES AND SEA TURTLE HABITATS OF SAIPAN, COMMONWEALTH OF THE NORTHERN MARIANA ISLANDS A Report Prepared for the National Marine Fisheries Service, Honolulu, Hawaii November 1999 by Steven P. Kolinski Hawaii Institute of Marine Biology I Department of Zoology, University ofHawaii, Honolulu, Hawaii Denise Parker Joint Institute for Marine and Atmospheric Research, Honolulu, Hawaii Larry Itibus llo Division ofFish and Wildlife, Saipan, CNMI Joseph K. Ruak Division of Fish and Wildlife, Saipan, CNt\-fl CONTENTS EXECUTIVE SUMMARY................................................................. 1 1. IN'TRODUCTION....................................................................... 2 2. ~1L1J])1{ ~~)l........................................................................... 2 3. 1VI~1rll()])~ .•.•.•.....•.....•.....•....•••..•..•••.•••.•.•••••••.•.•••••.•••.•.•••..•••...• 4 3.1 Terrestrial Sur-veys ........................................................... 4 3.2 Aquatic Surv-eys ............................................................... 4 3.2.1 Sea Turtle Assessments ............................................ 4 3.2.2 Tag and Release Efforts ............................................ 5 3.2.3 Assessment of Potential Sea Turtle Forage.................... 5 4. ~~1J~1r5;................................................................................. 6 4.1 Sea Turtle Nesting Activity................................................... 6 4.2 Sea Turtles in Nearshore Environments................................... 6 4.3 Tag and Release Efforts in Nearshore Environments................... 8 4.4 Potential Sea Turtle Forage in Nearshore Environments.............. 9 5. DISCUSSION.............................................................................. 9 5.1 Nesting Grounds - Breeding Population................................... 9 5.2 Nearshore Environments- Resident Population......................... 9 5.3 Recommendations.............................................................. 13 ACKNOWLEDGEMENTS................................................................. 14 ~~ltlE~<:~es;................................................................................ l!i AJ»J»~NDIC:~5;................................................................................. 19 Appendix 1. Site Descriptions, Accessibility, Sources of Information, And Raw Data....................................................... 19 Pun tan Laggua to Pun tan Makpe, North Saipan.. .. .. ... .. .. ... 20 Banzai Cliff, North Saipan.. .. .. .... .. .... ..... .... ..... .... .. .. .. .. .. 23 Grotto, Puntan I Maddok, East Saipan..... ..... .•. .. ... .. ... ... 25 Bird Island (Isleta Maigo Fahang), East Saipan. ... .... ... .. ... .. ... 27 Kingfisher Golf Course, Sabanan Fiiang, East Saipan. ... ........ .. 29 Forbidden Island, Unai Hakmang and Puntan Hakmang, East Sai pan.......................................................................... 32 Laulau Bay Golf Course, Laulau Bay, East Saipan.................. 35 Unai Laulau, Laulau Bay, ~ast Saipan................................. 37 North Naftan, East Saipan. ... ...................... ...................... 38 Central Naftan, East Saipan.. ................................... ... ..... 41 Pun tan Agingan, South Saipan.......................... ................ 44 Agingan to Puntan Naftan, South Saipan............................... 46 Coral Ocean Point Golf Course, Agingan, South Saipan ............ · 48 Coral Ocean Point Golf Course, Proximal Puntan Obyan, South S:.1ipan. .. .. .. .... .. ..... ... .. ... ........ ......... ............... .............. 50 Puntan Naftan, South Saipan.............................................. 52 Puntan Makpe to Tanapag Lagoon Entrance, West Saipan........ 54 Tanapag Lagoon Seagrass Pastures, West Saipan.................... 56 Tanapag Lagoon Entrance Towards Puntan Flores, West Saipan.. .. .. .. .. .. .. .. ... .. .. ..... ... .. .. ... .. ... .. .. .. .. 57 Red Buoy No. 10 and Charlie Dock, West Saipan.................... 59 Puntan Muchot Patch Reefs, Garapan, West Saipan............... 61 Preliminary Survey, Outer ReefMatix, Balisa Area, Garapan West Saipan........ .. .. .. .. .. .. .. .•• . ...•...... .. .. .. .. 62 Outer Reef Matrix, Balisa Area, Garapan, West Saipan............ 64 Chalan Kanoa to San Antonio, Outer Reef, West Saipan........... 67 Pun tan Susupi to Puntan Afetna, Outer Platform Chalan Kanoa, West Saipan........................................................ 69 Appendix 2. Maps of Turtle Distributions..................................... 70 Map I: Saipan Geographic Divisions.................................. 71 Map 2: Distribution of North Saipan Turtle Observations....... 72 Map 3: Distribution of East Saipan Turtle Observations ... ~..... 73 Map 4: Distribution of South Saipan Turtle Observations........ 74 Map 5: Distribution of West Saipan Turtle Observations......... 75 TABLES Table 1: Known Turtle Nesting Activity on Saipan Beaches During the 1999 Nesting Season........................................................................ 6 Table 2: Observations of Green Turtles, Chelonia mydas.. •.. ..•... .. ..••. ... ........ 7 Table 3: Turtle Capture Attempts in Selected West Saipan Feeding and Resting Areas........................................................................ 8 Table 4: Morphometric Measurements of Immature Chelonia mydas. .... .. .. .. 8 Table 5: Saipan Marine Plants and Algae which are Listed by Hirth (1997) as Green Turtle Forage................................................................. 10 FIGURES Figure 1: Map of Saipan, CNMI..... .. .. .. .. ... .. .. ....... .. .. .... ... ... .. .. .. ... .... 3 Figure 2: Estimate Number of Green Turtles Observed Categorized by Size and Location................................................................................ 8 ii EXECUTIVE SUMMARY A preliminary assessment of the sea turtles and sea turtle habitats in nearshore environments of Saipan, Commonwealth of the Northern Mariana Islands, was conducted from 15 to 29 August 1999. A total of 169 individual Chelonia mydas were estimated to have been observed via 238 sightings over 28 surveys covering roughly 54% of Saipan's outer reef and· shoreline perimeter. No other sea turtle species were observed. Sixty percent of the turtles were classified as juveniles, 22% as juvenile/adults, and 12% appeared to be of adult size. A disproportionate number ofturtles (60%) were located along relatively uninhabited east coast sites where access to humans is limited, but topographically complex benthos and a variety of food resources is apparent. Two species of seagrass and at least 26 species of algae noted as turtle forage in other regions of the world were identified at Saipan in this and previous. surveys.· Two turtles were captured, tagged and released. Turtle nest activity was ·limited, ·with 15· ·crawls and 6 nests recorded throughout the 1999 nesting season. · J ~d. !T ' ", Continued monitoring of both resident and breeding sea turtles is essential to determining the status and dynamics of these populations. Four east coast and one·wesf·survey:sites stood out as candidate areas for capturing and tagging large numbers ofturtles'giveh appropriate methods and oceanic conditions. Additional sites in west lagoon seagrass feediri'g• pastures are noted for potential use of tangle net methods in tag and release efforts. lt'isltecommended that visual surveys continue, and that a tag and release program, focusing on both research and management, be initiated, incorporating community . involvement• aS. a.':. nieans? to extend a conservation ethic regarding sea turtles within this region. ·· · · ,.. ·• ·· : :1 · !H' ' :~ ,:i' ' 1. INTRODUCTION Four species of sea turtles, Chelonia mydas, Eretmochelys imbricata, Dermochelys coriacea, and Lepidochelys olivacea have been reported to inhabit or transverse nearshore waters of the Commonwealth of the Northern Mariana Islands (CNMI) (National Marine Fisheries Service and U.S. Fish and Wildlife Service 1998a, 1998b and 1998c, Pritchard 1982). All four are listed as Endangered worldwide by the International Union for the Conservation of Nature and Natural Resources (Groombridge 1982), and appear on Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). As the Northern Mariana Islands are politically a Commonwealth of the United States, these species gain protective status under the U.S. Endangered Species Act of 1973. Unfortunately, however, there is a near absence of documentation which adequately reflects past or present sea turtle numbers and activities within the region (Pritchard 1977, 1982, Pacific Basin Environmental Consultants, Inc. 1984, Johannes 1986, Wiles et al. 1989, Rodda et al. 1991, Eckert 1993, McCoy 1997, but see Pultz et al. In Press), thus it is impossible to gauge the status and reaction of turtle populations relative to human activities in the area and the protection purportedly provided by domestic and international law. Recent interest in renewing traditional practices involving sea turtles as a means of expressing and maintaining Carolinian culture (McCoy 1997, see also McCoy 1974, 1982, Lessa 1983, and Alkire 1989), in combination with an almost complete absence of documented information reflecting sea turtle population size and status, created the need for a rapid assessment of sea turtle numbers, sizes, activities, locations and habitat characteristics along the shores of Saipan.