Preliminary Study on Sea Turtles in Bintan Island, Riau Archipelago, Indonesia

Marine Turtle Newsletter 119:13-14, © 2008

C.K. Winata, A. Nadina & M. Rofik
Research and Development Dept., Environmental & Health Division

Six out of seven species of sea turtles in the world live in Indonesia. All of them are under the Indonesian law protection (Act. no. 5 1990 re Conservation of Nature Resource and its Ecosystem; Government Regulation no. 7 1990 re Conservation Species of Flora & Fauna) and are protected by international trade by CITES (Convention of International Trade on Endangered Species). According to local people in Bintan, one could easily find 2 nests each evening in the nesting season of 1950s. However, in recent years only few nests have been observed on the beaches. To better characterize the population, we initiated a survey along Bintan Resorts coastline with two objectives: the identification of potential nesting beaches and nesting season in Bintan Resorts; and the identification of threats at nesting sites.

Bintan is the largest island among many in the Province of Riau Archipelago, located just south of Singapore. Bintan Resorts is located at the northern part (01.17° to 01.20° N and 104.30° to 104.58° E) and comprises 23,000 hectares of area, of which 3,000 hectares have already been developed. Within the resorts, there are more than 50 kilometers of white sandy beach (Figure 1). Between 2004 and 2006, we conducted ground surveys along beaches within Bintan Resorts at least once every two weeks. Between March and October, the frequency of patrols increased to 2-3 times a week on Pasir Panjang beach (01.1833°N, 104.1942°E; site 4 in Figure 1). All turtle tracks, nests, eggs, and egg shells were recorded, following Schroeder & Murphy (1999). In some cases, we relocated freshly laid nests to 3x5 m hatchery enclosures on more protected areas of beaches, for safe incubation.

Figure 1. Map of Bintan Island, with four nesting areas identified within the Bintan Resorts Area (map source: Bintan Resorts website. used with permission).

Within the Bintan Resort, we identified four nesting beaches where both hawksbill turtle (Eretmochelys imbricata) and green turtles (Chelonia mydas) laid nests (Figure 1). Hawksbill turtles were the most common species nesting on the four beaches, with most nesting activities occurring between March and September (Figure 2). No nests were observed between November and February, which coincides with the monsoon season in Bintan. The phenology of sea turtle nesting in Bintan is similar to that reported for nearby Tembelan Island (February to May) and Johor, Malaysia (March to August) (Ali et al. 2004). Although the survey design did not allow us to fully monitor all nesting activities, it appeared that nesting density was greatest on Pasir Panjang beach.

Figure 2. Number of turtle tracks counted per month at the four nesting sites being monitored within Bintan Resorts, on Bintan Island, Indonesia.

When we began our monitoring project in 2004, we found that >90% of observed nests had been collected by local people for consumption. Given the anthropogenic pressures on sea turtle nests in the area and the logistical challenge of trying to monitor widely dispersed beaches, starting in 2005 we used hatcheries to protect some incubating eggs. In 2005, there were 550 hawksbill hatchlings produced from 5 nests in the hatchery (85% successful hatching rate) that we released to the ocean. In 2006, 1224 hawksbill hatchlings were produced in the hatchery (80% hatching rate) and released to the ocean. We invited tourists and local villagers to the hatchling releases to learn more about sea turtles and conservation. In addition, we disseminated information materials about sea turtle biology and conservation, though direct conversations and the distribution of calendars, leaflets and comic books. We noted that the percentage of turtle nests collected by locals declined to 61% in 2005 and decreased further to 33% in 2006.

We have been encouraged by our efforts that we can not only protect sea turtle nests on Bintan but also raise awareness of sea turtle conservation in local villages. We anticipate that we will be able to more actively engage local people in our project, thereby increasing its effectiveness.

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Acknowledgements: We thank to Professor C.H. Diong for supervising and sharing valuable advice. Our sincere thanks to Douglas Hykle, M. Halim and W. Andyana for their inputs, Alang-alang Sea Sport Centre who helped in logistics and in checking turtle tracks, Ranan Samanya for supervising our projects. This study would not be possible without a PT. Bintan Resort Cakrawala grant.

ALI, A., Z. TALIB, M.M. ISA, S.A. RAZAK & N.A. ZAKARIA. 2004. A Guide to set up and manage sea turtles hatcheries in the Southeast Asian region. Marine Fishery Resources Development and Management Department - Southeast Asian Fisheries Development Centre. 60pp.

SCHROEDER, B. & S. MURPHY. 1999. Population surveys (ground and aerial) on nesting beaches. In: K. L. Eckert, K.A. Bjorndal, F.A. Abreu-Grobois & M. Donnelly (Eds) Research and Management Techniques for the Conservation of Sea Turtles. IUCN/SSC Marine Turtle Specialist Group Publication No. 4, pp. 45-55.