Reef balls as a Tool for Sea Turtles Conservation Programme in Sarawak, Malaysia




James Bali


Biodiversity Conservation Department,

Protected Areas and Biodiversity Conservation,

Sarawak Forestry Corporation,

Level 11, Office Tower,

Hock Lee Centre,

Jalan Abang Abdul Rahim,

93450 Kuching,

Sarawak, Malaysia

Tel: + 6082 302315

Fax: + 6082 341550



All species of Chelonidae and Dermochelyidae were listed as Totally Protected Animal, under the Wild Life Protection Ordinance, 1998 (Amended 2003). Any person who hunts, kills, captures, sells, offers for sell or claim to be offering for sale, imports, exports, or is in possession of, any totally protected animal or any recognizable part or derivative thereof, or any nest thereof, except in accordance with the permission in writing of the Controller of Wildlife for scientific or educational purposes or for protection and conservation of such totally protected animal, shall be guilty of an offence: Penalty – imprisonment for two years and a fine of twenty five thousand Ringgit (Sarawak Government Gazzette, 2003).  In 2003, most of the functions of the Sarawak Forest Department were taken over by Sarawak Forestry Corporation (SFC). Conservation and management of sea turtles and other wildlife in Sarawak were taken over by the Protected Areas and Biodiversity Conservation Unit (PABC) of SFC.

Four species of sea turtles namely the leatherback (Demochelys coriacea), green turtle (Chelonia mydas), hawksbill (Eretmochelys imbricata) and olive ridley (Lepidochelys olivacea), nest along the sandy beaches and islands of Sarawak. Green turtles account for 99% of nesting sea turtle recorded yearly. The main sea turtle nesting sites in Sarawak are located on the Sarawak Turtle Islands (Talang-Satang National Park) consists of Talang-Talang Besar, Talang-Talang Kechil and Satang Besar. Around 1700-3000 nests recorded yearly from these three Islands. Turtle nests were also recorded at Tanjung Datu National Park, Similajau National Parks, Sematan and Miri (Bali, 1998).

In the old days the numbers of eggs harvested on the Sarawak Turtle Islands were astronomical; more than 3,000,000 were collected in 1950s. At the present time, the Sarawak turtle population is in serious trouble, suffering from over 90% exploitation of the eggs laid since 1951. In the past 50 years, Sarawak turtle population was decreased by 90% (Sarawak Forest Department, 1996). Besides over exploitation of green turtles eggs in the past, accidental catches of adult turtles in fishing gears were also a major contribution of declining of turtle population in Sarawak (Tisen and Bali, 2000). Successful conservation of sea turtle not only relies on ‘good’ legislations, protection of eggs and nesting beaches, enforcement and public awareness campaign but an adequate understanding of their temporal and spatial distributions, migratory patterns and habitat utilization. Management of sea turtles on nesting beaches have been relatively straight forward, which includes studies and observation on various aspects such as body size, clutch and eggs size, nesting behaviour, hatching success, individual nesting periodicity, sex ratio and incubation temperature. Meanwhile, huge gaps remain in the understanding of physiology and ecology of turtles while they are at sea. According to Hirth (1997), most green turtles are taken (killed) on their feeding pastures, in shallow water just off the nesting beaches (part of the nesting habitat) and on the nesting beaches. Some are incidentally caught in fishing gears. Information are required include interactions with fisheries and other threats, as well the designation of key areas to be protected or subject to management regimes. 

                                Before 1998, in Sarawak a significant numbers of adult turtles have been found dead and believed to be caught in trawler nets. Around 70 to 100 dead turtles were found stranded from Sematan to Telaga Air beach every year before 1998 (Bali et. al. 2004). Enforcement against these illegal trawlers is not effective because the trawlers can always spot the patrol boat first and fled immediately. In view of these, the Sarawak Reef Balls Project was initiated. Reef balls are commonly used worldwide as artificial reefs. The use of reef balls as a tool for turtle conservation in Sarawak is the first in the world. Sharp and rough surface, with 2 tonnes weight made reef ball a suitable tool to ripping the trawler nets that entangled on it. This will keep trawlers away from the sea turtle internesting habitats.

Reef balls were deployed randomly at areas that were identified as the internesting swimming ground for turtles during its nesting season through radio and ultrasonic telemetry study. Since 1998, 2284 units of reef balls were deployed by the Sarawak Reef Balls Working Group (SRBWG) along the coast of Sarawak (100 reef balls were sponsored by PETRONAS).

Deployment of reef balls in areas identified as internesting swimming grounds for sea turtles around Talang-Satang National Park resulted in a marked reduction in number of dead turtles reported (around 20 dead turtles annually compared to 70 to 100 before 1998). Besides that, local fishermen benefits from that project as their traditional fishing grounds are protected from illegal trawlers activities. Since then, the local fisherman has experienced an increased in catches and in size of fishes caught resulted in increased income.

Around 5000 reef balls are required to protect the critical habitats (internesting swimming areas, nesting beaches, and feeding ground) and migration routes of sea turtles along the coastline of Sarawak. Most of the budgets are required for purchasing and deployment of reef balls. Each reef ball is estimated to cost about RM 1,000 for construction only and another RM100-300 each for transportation and deployment (depend on location). Thus national and international based companies, private sectors, individuals, governmental agencies and non-governmental agencies are most welcome to sponsor for the Sarawak Reef ball Project to save the endangered sea turtles, enhancement marine ecosystem which also benefits the local fishermen in Sarawak.



Note: Sarawak Reef Balls Working Group comprises of 13 governmental agencies in Sarawak namely:

Sarawak Forestry Corporation; Department of Marine Fisheries Department Malaysia, Sarawak; Marine Police, Sarawak Contingent; Sarawak Ministry of Public Health and Environment; Sarawak Ministry of Urban Development and Tourism; Sarawak Ministry of Social Development and Urbanization, Sarawak Tourism Board; Sarawak Natural Resources and Environmental Board; Sarawak Museum Department; Sarawak Turtles’ Board; Institute of Marine Fisheries, Sarawak; and Universiti Malaysia Sarawak;