+603 2161 5948    wecare@reefcheck.org.my


What is coral bleaching?

Coral bleaching refers to a natural stress response of corals that causes them to expel their symbiotic zooxanthellae in large numbers, lose their natural colour and expose the underlying white calcium carbonate skeleton. The symbiotic zooxanthellae in coral tissue provide their host with 90% of their food source. In return, the corals provide shelter for the microscopic algae. By losing their primary source of food, bleached corals become more susceptible to disease and death.

What causes coral bleaching?

Small scale local bleaching events can be caused by a variety of factors such as pollution or sedimentation, variations in salinity, excessive amounts of ultraviolet light, and toxins (such as pesticides). However, climate change and the increase of sea water temperature are the main reasons for large-scale mass coral bleaching.

Are bleached corals dead?

Bleached corals are still alive. However, prolonged bleaching periods can cause the death of corals. Bleached corals, however, are dangerously weakened as they have lost their symbiotic zooxanthellae, which once provided up to 90% of their food. Bleached coral therefore rely 100% on active feeding to nourish themselves.

Corals that survive a bleaching event involving the loss of zooxanthellae will eventually regain normal density of zooxanthellae (recoloured) when environmental conditions improve and stresses are eliminated. 

RCM's Approach

After the mass bleaching event of 2010, RCM developed a Coral Bleaching Response plan, which was adopted by the Department of Marine Parks Malaysia (DMPM) in 2011. The plan ensures effective communications and coordination of management efforts to protect coral reefs during future bleaching events. 

The response plan has 4 major components:

1. Early warning system

By combining satellite data with a community-based monitoring network, bleaching will be reported to various authorities when it occurs. This enables the prediction and identification of possible bleaching events, which will provide information for communication to stakeholders, government agencies and the media.

 2. Ground-truthing survey

This is done by assessing and measuring the level and impact of bleaching by setting up a bleaching task force to carry out monitoring and investigation. Once data is gathered, a brief report of the preliminary results can be prepared.

3. Public awareness and communication exercise

It is important to let all stakeholders know how they can adapt to bleaching problems, and also how human activities can be managed to reduce further damage to bleached reefs.

4. Resilience building action plan

In order to give coral reefs the best chance of survival, relevant authorities will take appropriate steps to remove and reduce human stresses to the reef.

Do something about coral bleaching

If you come across any coral bleaching in Malaysia, report the location to us. Click to download the Bleaching Watch Survey Report Form. 



Reef Check Malaysia (RCM) is a non-profit organisation that was registered in 2007 to engage with the local community to raise awareness for the importance of, and threats to, coral reefs.


Subscribe to our quarterly newsletter.


Contact Us

Reef Check Malaysia
Suite 5.19-5.22, Box 606, Wisma Central, Jalan Ampang, 50450 Kuala Lumpur, Malaysia

+603 2161 5948