Coral Mortality in the Gulf of Mannar, Southeastern India, Due to Bleaching Caused by Elevated Sea Temperature in 2016

Intensive underwater surveys have been conducted to assess the extent of coral bleaching and subsequent mortality in the Gulf of Mannar between March and October 2016. The extent of bleaching was 23.92% ± 10.55% during the period between March and June 2016, and the live coral cover was drastically reduced to 22.69 ± 9.07% during October 2016 with a mortality of 16.17 ± 8.46%. Fast-growing coral forms, including the genera Acropora, Montipora and Pocillopora were most affected, not only by bleaching but also by severe mortality. Boulders, including the genera Porites, Favia and Favites were found to be resistant to bleaching. During the bleaching period, water temperature was between 31.2°C and 32.6°C. The current bleaching is in alignment with the third global coral bleaching event which occurred between 2014 and 2017. Management interventions, including protection and rehabilitation using the native resistant coral species will not only help in the recovery process, but also increase the live coral cover.