Although relatively common where it occurs (3), Coscinaraea monile faces many of the threats that are affecting coral reefs globally. An estimated 20 percent of the world’s coral reefs have already been destroyed (7) (8) and there is increasing pressure on coastal resources resulting from human population growth and development. Consequently, 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 onto reefs, and over-fishing, which can have ‘knock-on’ effects on the reef (7).
There are also many localised threats associated with human activity, including the use of dynamite and chemicals when attempting to collect reef fishes. Potentially, the ability of Coscinaraea species to survive colder temperatures may extend their habitat range, therefore reducing some of the pressures faced by these corals (7).
A major threat to corals worldwide 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 death. Climate change may also lead to more frequent, severe storms, which can damage reefs, while 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 starfish (Acanthaster planci) (1) (7) (8) (9).