On the recurrence of coral bleaching and recovery in North Bay, Port Blair, Andaman and Nicobar Islands

Abstract

Coral cover, live-form categories, bleaching and their recovery were monitored in North Bay, South Andaman during pre- and post-tsunami periods. The reef is a fringing type, with a total coral cover of 313,382 m2. The total live and dead coral percentages recorded prior to tsunami were 29.4% and 27%, respectively. A patchy bleaching of 7.5% was recorded in month of April-May 2005. However, the coral reef started to recover quickly, and as much as 4.7% of recovery was recorded, and 2.8% of the bleached coral failed to recover. No significant variations in the physicochemical parameters were recorded prior to and post-tsunami. A sudden change in the water column height due the land subduction caused by the mega earthquake on 26 December 2004 was evident. The sudden change in depth and light penetration might have exerted a stress in the corals, leading to expulsion of zooxanthellae from the gastrodermal layer of cells, causing the bleaching phenomena.