Marine turtles are critical members of marine ecosystems. Green turtles are important for maintaining healthy seagrass beds and coral reefs. Without constant grazing, seagrass beds become overgrown, obstructing currents, shading the bottom, or decomposing. Seagrass beds are nurseries for a number of species of commercial fish and crustaceans, including shrimp.
On coral reefs, green turtles crop algae that can compete with corals. Hawksbill turtles control the population of sponges in coral reefs, which can easily out-compete corals for the same space. Through selective foraging, hawksbill turtles are able to impact the overall reef diversity. Leatherback turtles eat large quantities amounts of jellyfish, keeping their populations under control. Jellyfish prey on larval fish, many species of which are economically important to humans. Loggerhead turtles recirculate sediments on the seabed and distribute nutrients while they search for, and feed on, crustaceans and molluscs. On the beach, unhatched eggs, trapped hatchlings, and egg shells provide nutrients for beach vegetation, which secures the sand via root development. The loss of beach vegetation leads to erosion, minimizing sea turtle nesting habitat, and reducing coastal resilience.
These same, ecologically important, marine turtles are threatened through ongoing egg harvests, poaching of adults by foreign fishing fleets, and as by-catch in shrimp and fish trawl fisheries. In 2007 MRF estimated bycatch of turtles from the Sabah shrimp fleets alone at several thousand turtles each year.
The conservation of sea turtles is thus a key priority in the SSME. Sulu-Sulawesi turtles are recognised at both National and Regional levels, and even globally: turtles are similarly a priority under the Indian Ocean and Southeast Asia Memorandum of Understanding on the Conservation of Sea Turtles and their Habitats (IOSEA MoU), the Coral Reef Triangle (CTI) Regional Action Plan, and the Association of Southeast Asian Nations (ASEAN) Sea Turtle MoU. At the National level sea turtles are completely protected in all three countries bordering the SSME. The Convention on International Trade in Endangered Species of Flora and Fauna (CITES) lists marine turtles occurring in the Turtle Islands Heritage Protected Area (TIHPA) on Appendix I, while the World Conservation Union (IUCN) lists the green turtle as Endangered, and the hawksbill as Critically Endangered.
But tailored conservation action relies on a thorough understanding of turtle population biology and ecology. One needs to know where turtles are in order to protect them. One needs to know where they go as they disperse from nesting beaches, and where they grow up. One needs to understand the relationship between nesting adults and developing populations, in order to understand the linkages among the various stocks.
This project entails four inter-linked components to further the understanding of the biology and ecology of sea turtles in the SSME, upon which National policy decisions and the expansion of the Tri-National Network of Protected Areas may be based. Each component addresses critical biological and reproductive traits of turtles that have previously not been studied in the SSME, and together they form a cohesive research programme which complements National projects within the Sulu Sulawesi Tri-National Sea Turtle Corridor initiative.
- Laparoscopy of adult turtles at the TIHPA
Using laparoscopy, this project sub-component aims to provide recruitment rate information for marine turtles at the Turtle Islands Heritage Protected Area, where nothing is known about the influx of new young females to the breeding population;
- Laparoscopy and genetic studies of juvenile foraging populations
This project sub-component aims to provide, again through laparoscopy but linked to genetic studies, population structure data (sex ratios in the wild, age-class structure, and genetic origin) which can be used for effective marine turtle conservation in the SSME;
- Satellite tracking of post nesting females to identify foraging grounds
This project component will determine migration paths of marine turtles and linkages between foraging and nesting populations within the important Sulu-Sulawesi biogeographic region; and
- Determining temporal habitat use in key foraging grounds in the SSME
This project component will highlight when turtles use different habitats via aerial surveys– allowing for potential future development of time-area closure management practices, and for determining habitat impacts such as fisheries, poaching and industrial development.
The project has been funded via a grant by the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) Philippines.