With an estimated 20 percent of the world’s coral reefs already destroyed, the symmetrical brain coral faces many of the threats affecting coral reefs globally (5) (6). Worldwide there is increasing pressure on coastal resources resulting from human population growth and development. There has been a significant increase in domestic and agricultural waste in the oceans, poor land-use practices that result in an increase in sediment running on to the reefs, and over-fishing, which can have ‘knock-on’ effects on the reef (5). However, the major threat to corals is global climate change, with the expected rise in ocean temperatures increasing the risk of coral ‘bleaching’, in which the stressed coral expels its zooxanthellae, often resulting in the death of the coral. Climate change may also lead to more frequent, severe storms, which can damage reefs, and rising carbon dioxide levels may make the ocean increasingly acidic. Such stresses can also make corals more susceptible to disease, parasites and predators, such as the crown of thorns sea star (Acanthaster planci) (5) (6) (7).
Despite the wealth of threats that the symmetrical brain coral faces, it is still relatively common throughout its range, and is thought to be the most abundant of all the Diploria corals. However, of all the Diploria species, it is also thought to be the most susceptible to black band disease and white plague, both of which are caused by infectious bacteria and can cause partial or total mortality of colonies, and as a consequence of this, some local declines in the species’ population have been observed (1). The number of outbreaks of these diseases has increased dramatically in recent years, and is most frequent in reefs already affected by pollution and degradation (1) (8).