Marine biologists in Thailand are turning to a novel strategy in their efforts to restore declining fish populations: sinking decommissioned naval vessels and utilising them as artificial reefs. In the Gulf of Thailand, the navy deliberately submerged two warships — the HTMS Hanhak Sattru and the HTMS Suphairin (both sunk in 2023) — creating new underwater structures that are already showing promising signs of ecological benefit.
Located roughly 20 metres beneath the ocean surface, one of these wrecks now teems with marine life: snappers, yellowtail fusiliers and bannerfish navigate through former corridors, while barnacles, algae, and juvenile corals take root on ladders and decking. What sets this case apart is that it’s being scientifically monitored: the research project by Global Reef (based on Koh Tao) collected data both before and after sinking the ships — a rare opportunity in this field of study.
The key question researchers sought to answer is whether these artificial reefs simply attract fish from natural reefs (a process called “attraction”) — possibly depleting undisturbed reef populations — or whether they actually help generate new fish populations (the “production” hypothesis). Early findings from the team suggest a mixed but hopeful picture: there is “potential evidence” of attraction, but also signs that juvenile fish are arriving and maturing on the wrecks, indicating that reproduction may be occurring.
This is a noteworthy development because Southeast Asia’s coastal ecosystems are under significant pressure from warming waters, coral disease, boat damage and heavy tourism. On Koh Tao alone, more than 500,000 tourists visit annually, straining the marine environment. Meanwhile, popular species such as stingrays, groupers and bamboo sharks are endangered, increasing the urgency to find effective conservation tools.
The artificial-reef approach offers multiple potential benefits: it provides new habitats in the depths of less than 200 metres (where many fisheries still operate), it deters commercial trawling (since wreck sites are not viable for trawling), and it channels dive tourism away from natural reefs that are more vulnerable. Both Dr Rahul Mehrotra of the Aow Thai Marine Ecology Center and Global Reef’s Piers Baillie highlight the philosophical shift embodied by Thailand’s approach: “we must protect and we must understand.”
Thailand’s government has set a target to protect 30 per cent of its land and ocean ecosystems by 2030, and the collaboration between the navy, the department of marine and coastal resources, and scientific teams on this shipwreck-reef project reflects a serious commitment to that goal. The cultural dimension is also cited: conservationists say Thailand’s Buddhist traditions and the national relationship with the sea help underpin a genuine institutional interest in marine ecosystem stewardship.
However, researchers caution that artificial reefs are not a silver bullet. They stress the need for long-term monitoring and rigorous data to understand how such structures affect wider marine ecosystems — whether they boost fish productivity sustainably or simply shift fish from one habitat to another. Without this nuance, well-intentioned efforts could inadvertently weaken natural reefs or misallocate conservation resources.
For journalists, policymakers and marine-conservation practitioners alike, Thailand’s experiment with shipwrecks opens a promising line of inquiry: with the right design, deployment and oversight, intentionally submerged structures may become a valuable tool in rebuilding fish stocks and safeguarding marine biodiversity — provided they complement (rather than replace) traditional reef conservation strategies.
