Disease and stress-induced mortality of corals in Indian reefs and observations on bleaching of corals in the Andamans

A study was carried out in the Lakshadweep and Andaman islands and the Gulf of Kutch to assess the health of corals in Indian reefs. Disease, predatio n and stress were the major factors of coral mortality. Death caused by dis eases - the black band disease (BBD), the white:band disease (WBD) - necrot ic lesions, and bleaching was observed in Kavaratti and Kadamat islands of Lakshadweep. The predatory starfish, Acanthaster planci, grazing on coral p olyps was also noticed in these reefs. Large-scale silt deposition in the i ntertidal zone of Paga, Boria, Vadinar and Mangunda reefs in the gulf of Ku tch buried the coral colonies and appeared to be the main cause of coral mo rtality. A severe incidence of coral bleaching was observed during July 199 8 in some reefs in the Andamans. While more than 85% of corals near Ross is land and Marina Park exhibited partial bleaching, up to 10% were totally bl eached.