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