Coral disease prevalence in the Palk Bay, Southeastern India - with special emphasis to black band

Present study consists the details related to the nature of coral disease in nine locations from Vethalai to Rameswaram north in the Palk Bay. Among the overall corals 21% were affected by disease. Six disease types were documented. Black Band Disease (BBD) is high with 9.8% followed by white band (5.5%), white spot (2.2%), pink spot (1.9%), white plague (1.1%) and yellow band (0.6%). Eight coral genera were found to be affected wherein Acropora and Porites showed severe damage and the high prevalence of diseases. The coral genus, Porites was found to be affected by four different types of diseases. BBD affected colonies were tagged and photographed at regular intervals to quantify the progression rate in two coral genera, Acropora and Platygyra and the disease progression rate was 3 cm per month. White band disease was widespread and was found to affect exclusively Acropora sp. Corals like Symphylia sp. and Cyphastrea sp. in the Palk Bay were comparatively not affected by diseases. Total heterotrophic bacteria and pathogenic microbial forms in the reef environment were also examined in the present study.