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Report on Coral Bleaching in the Bar Reef Marine Sanctuary

26/03/2005

Report on

Coral Bleaching in the Bar Reef Marine Sanctuary
Observed on 26th March 2005 Sri Lanka
By
Arjan Rajasuriya
National Aquatic Resources Research and Development Agency
Sri Lanka

Minor coral bleaching was observed on the 26th March 2005 among the reef crests of shallow coral banks of the Bar Reef Marine Sanctuary. The depth varied between 1 and 2m. Below is a table of the species affected and the degree to which they were bleached. It was noted that all the colonies of affected species were not bleached.

Species affected Level of bleaching
Leptoria phrygia Partial bleaching (mainly on upper surfaces of colonies)
Favia pallida Partial bleaching (mainly on upper surfaces of colonies)
Favia favus Partial bleaching (mainly on upper surfaces of colonies)
Platygyra daedalea Partial bleaching (mainly on upper surfaces of colonies)
Hydnophora microconos Partial bleaching (mainly on upper surfaces of colonies)
Symphyllia radians Partial bleaching
Pocillopora damicornis Some branch tips only
Acropora muricata (formally A. formosa) 2 small colonies totally bleached
Montipora foliosa Edges of whorls bleached


In this location there are many table corals (Acropora cytherea) that have come up after the 1998 coral bleaching event, which destroyed almost all corals in these shallow coral patches. No signs of bleaching were observed on Acropora cytherea. 2 small colonies of Acropora muricata about 25 cm high were completely bleached. Bleached massive coral colonies were relatively small (about 30 cm across or less). Partial bleaching was observed on massive corals.

In the latter half of March 2005 the temperature on land was relatively high with humidity 90% or higher. The sea surface temperature was not measured where the bleaching was observed.

Since 31st of March 2005 the weather on the west coast has changed to pre-monsoon. This means that there is SW winds and rain. If the rainy weather continues it might save the corals from further bleaching.

Minor coral bleaching was reported from SL last year too, from Trincomalee in the East coast and Rumassala reef in the south.

 
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