Starfish threaten the Coral Triangle

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A group of reefs known as the Coral Triangle are under threat from an outbreak of Crown of Thorns Starfish.

The Wildlife Conservation Society and the ARC Centre of Excellence for Coral Reef Studies conducted surveys on the Coral Triangle, a name given to the coral reefs located in the Sulu and Sulawesi seas between Indonesia, Malaysia and the Philippines.

The reefs are highly diverse, and home to around 450 species of coral, and a large variety of reef fish. Unfortunately, they have become a target of destructive fishing methods, including the use of cyanide and dynamite, which were witnessed by the scientists during the surveys.

However, Dr Andrew Baird, of the ARC Centre of Excellence for Coral Reef Studies, believes that the main cause of damage to the corals was the Crown of Thorns Starfish, rather than these destructive fishing practices.

Crown of Thorns starfish by Albert Kok, Creative Commons.

The Crown of Thorns Starfish, Acanthaster planci, is a corallivore, and well-known for the damage it can inflict upon reefs. It predates upon coral polyps, over which it extends its stomach, releasing enzymes to liquefy the coral tissue for digestion.

The researchers witnessed a number of active outbreaks of this coral predator during their surveys, most notably in the reefs of Halmahera, Indonesia. Poor water quality is believed to be responsible for the outbreaks.

This is clearly a complex human environment and effective management of the marine resources must address the needs of communities. It will also be vitally important to understand the causes of conflict among communities and address them, Dr Stuart Campbell, Program Leader for the Wildlife Conservation Society's' Marine Program in Indonesia, told Science Daily.

Some good news from the study, however, is that there was little to suggest that the reefs have been much affected by climate change, reported Dr. Baird.

Tasrif Kartawijaya, of the World Conservation Society, also reported that the reef fish assemblages are still in very good shape. Because of this, the researchers believe that these reefs have the capacity to recover if we can address the current threats.