Assessment of the extent of bleaching and recovery rates of corals in Diego Suarez Bay, Northern Madagascar

摘要

When combined with anthropogenic stresses, coral bleaching is considered to be a major threat to coral reefs worldwide. Coral bleaching is most widely caused by elevated sea temperatures, solar radiation and a combination of these stresses. Published records from as far back as the nineteenth century display an almost exponential increase in both the scale and severity of bleaching events. The 1998 bleaching event in the Indian Ocean was the most extensive and severe bleaching event that has been documented to date. The reefs within Diego Suarez Bay in northern Madagascar are influenced by anthropogenic stresses including eutrophication, overfishing and sedimentation. In regions subject to such stresses, bleaching is often high with low rates of coral recovery. Thus the extent to which these corals are able to survive and recover will be dependant on the magnitude of these external factors. This paper presents the findings of a study into the health of reefs in Diego Suarez Bay Suarez following the 2005-bleaching event and compares the recovery of corals subjected to varying levels and types of physical and anthropogenic stress. The extent of the bleaching and recovery of corals across five study sites was assessed, relative to both coral community structure and biophysical fluctuations.