Thailand's Coral Reefs Stage Impressive Comeback After Bleaching Event

Innovative "Reduce, Refrain, Rescue" policy credited with significant recovery, as marine authorities aim for further restoration

 

Thailand's Department of Marine and Coastal Resources (DMCR) has reported a major success in its efforts to combat the widespread coral bleaching event that struck in 2024. 

 

Thanks to the implementation of a proactive "Reduce, Refrain, Rescue" policy, over 60% of the affected corals have now recovered. The department is pressing ahead with plans to restore an additional 24 rai (nearly 10 acres) of reef.

 

Dr Pinsak Suraswadi, the director-general of the DMCR, provided an update on the current state of coral reefs, explaining that the significant bleaching incident in 2024 was triggered by elevated seawater temperatures and sediment build-up on the reefs.

 



 

This environmental stress caused the corals to expel their symbiotic zooxanthellae algae, leading to weakening and the characteristic white appearance. The bleaching began in mid-April 2024, affecting between 60% and 80% of corals.

 

Encouragingly, around 60% of these bleached corals have since recovered, with approximately 40% succumbing to the stress. In some areas, about 10% of the reefs showed no signs of bleaching or only minor discolouration.
  

Recent surveys indicate a positive trend. In the Andaman Sea, which experienced peak bleaching of around 55%, recovery rates now stand at 60-70%, with mortality from bleaching at 30-40%.

 

The Gulf of Thailand saw its worst bleaching in May 2024, affecting some 90% of corals. Shallow-water corals suffered the most damage and deaths, while deeper reefs were less impacted, showing a 40-60% recovery rate and 30-50% mortality.

 



 

Crucially, neither region is currently experiencing coral bleaching, a situation much better than initially feared.

 

This reduction in mortality and damage is largely attributed to the "Reduce, Refrain, Rescue" strategy championed by the Minister of Natural Resources and Environment, Dr Chalermchai Sri-on, and diligently followed by both the DMCR and the Department of National Parks, Wildlife and Plant Conservation.

 

Minister Chalermchai emphasised his continuous monitoring of the situation and his directive for relevant agencies to collaborate on addressing the bleaching.

 



 

He outlined the "Reduce, Refrain, Rescue" policy, tasking the DMCR and the Department of National Parks with its implementation.

"Reduce" measures focus on mitigating the impact of human activities, such as banning fish feeding, removing rubbish from reefs, and prohibiting the use of sunscreens containing coral-harmful substances. 

"Refrain" measures involve the temporary closure of certain tourist hotspots, including diving and snorkelling sites, to minimise potential stress on the corals. 

"Rescue" measures aim to lower mortality rates through actions like relocating some corals to more favourable environments and providing partial shade to shield them from excessive sunlight.
 

  



 

The effective management of marine areas by all relevant bodies, and significantly, the invaluable contribution of citizen scientists, volunteer divers, and marine tourists, has been instrumental in reducing coral mortality and damage.

 

This collective effort has led to a recovery exceeding the initial forecasts of marine scientists from both departments, fostering optimism for the continued health of Thailand's reefs.

 

Dr Pinsak added that the DMCR is actively implementing its 2025 coral restoration plan.

 

This includes expanding the substrate area for coral larvae settlement by 12 rai across seven provinces (Trat, Rayong, Chonburi, Prachuap Khiri Khan, Chumphon, Surat Thani, Phang Nga, Phuket), actively replanting corals across 24 rai in the same seven provinces, and nurturing 60,000 coral colonies in nurseries.

 

He stressed that the conservation and restoration of coral reefs are paramount to ensuring the long-term health of the nation's underwater ecosystems, requiring collaborative management alongside legal enforcement to bring the reefs back to their full abundance.

 

 



 

Coral Bleaching: A Symptom of Global Warming

The US National Oceanic and Atmospheric Administration (NOAA) and the International Coral Reef Initiative (ICRI) declared the fourth global mass coral bleaching event on April 15, 2024.

 

This alarming event unfolds against a backdrop of global climate change and the El Niño phenomenon, which have driven ocean temperatures to record highs, impacting coral reefs in at least 54 countries and territories since February 2023.

 

Coral bleaching occurs when ocean temperatures rise beyond the corals' tolerance levels. Greenhouse gas emissions and global climate change are the primary culprits behind this warming trend.

 

The heat causes corals to expel the colourful algae that live within their tissues. While some coral species can recover if temperatures cool, prolonged heat stress can prove fatal.

 

Earlier, on June 7, 2023, the Intergovernmental Panel on Climate Change (IPCC) in its 2022 Sixth Assessment Report indicated a very high likelihood of the world warming by 1.5 degrees Celsius within 2030-2040.

 

However, global temperatures have consistently exceeded 1.5 degrees Celsius since 2015, leading to climate instability both on land and in the deep sea, with coral reefs being particularly vulnerable.

 

The "coral bleaching" phenomenon is not confined to distant oceans; Thailand's own waters, both in the Gulf and the Andaman Sea, experienced significant bleaching events, particularly in 2024 across numerous locations.

(2025/04/23-00:00)