El Nino-triggered coral bleaching has spread to approximately one fourth of coral reef areas across waters around Con Dao Islands off the southern province of Ba Ria-Vung Tau since March.

According to the management board of the Con Dao national park, eight major areas – including Con Son bay, Dam Tre and Hon Tre Lon seas – are suffering, and bleaching gathered the highest speed in May.

The weather phenomenon causing the water surface to become unusually warmer has so far affected up to 500 hectares of local coral reefs, with an average of between 30 and 40 percent of corals in hit areas bleached.

Bleaching makes corals stunted and particularly prone to diseases and reproduction vulnerability; in severe cases, it kills them.

Study from the board’s maritime conservation department showed that most of Porites, round-shaped Fungiidae and Poritidae corals in these locations were completely bleached and at high risk of dying. Pocillopora corals, meanwhile, mostly saw bleaching on their branches, with Algae colours still spotted on their core bodies. However, the Pocillopora corals would die eventually, if the heated condition persists.

In 1998 and 2010, bleaching also took place in Con Dao, with some coral areas unable to recover naturally.

VNA