Top 10 coral species at most risk of extinction

10 of the world’s most at risk coral species have been identified by the EDGE Coral Reefs project, as conservationists unveil plans to save coral reefs from extinction.

The elkhorn coral Acropora palmata has undergone a 95 percent decline in many shallow Caribbean reefs in the past three decades.

Led by scientists from the Zoological Society of London, the EDGE (evolutionary distinct and globally endangered) Coral Reefs project is aiming to preserve and protect the world’s most important species of coral from the increasing threats they face.

The entire surface of the distinctive pearl bubble coral (Physogyra lichtensteini) is covered in vesicles, which retract when the coral is disturbed.

Focal coral reef species
Among the 10 species chosen to kick start the project are the pearl bubble coral, a colonial species that forms massive colonies with many small, bubble-like vesicles, and the mushroom coral Heliofungia actiniformis, which lives as a solitary polyp with many long tentacles that provide shelter to a variety of marine organism, including the colourful clown fish.

Coral reefs are under pressure from a variety of threats including overfishing, pollution, rising sea temperatures due to climate change, and increased ocean acidity, both of which can lead to coral bleaching. When a coral is bleached it expels its symbiotic algae, known as zooxanthellae, meaning the coral cannot photosynthesise and so cannot feed.

“Coral reefs are threatened with functional extinction in the next 20-50 years, due predominantly to global climate change. 2010 seems set to have been one of the worst years for coral bleaching.” Catherine Head, co-ordinator of the EDGE Coral Reefs project.

Endemic to the Chagos Archipelago, the peculiar Ctenella chagius is able to extend its stomach onto the living tissues of an adjacent coral and kill it.

Conservationists intend to focus their efforts on the ‘coral triangle’ around the Philippines, the West Indian Ocean around the Mozambique Channel, and in the Caribbean Channel. They plan to provide local conservationists with the training and equipment needed to carry out the research, with initial projects lasting two years.
Importance of coral reefs
The project will temporarily increase the resilience of coral reefs to environmental change, but conservationists concede that part of the solution in the future must involve the designation of more of the ocean as marine protected areas. With coral reefs – the rainforests of the oceans – being the planet’s most diverse marine ecosystem, and harbouring up to a third of all marine life, it is vital that coral reefs flourish in the future.