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Perfectly formed and harmoniously tuned to their environment, corals perform a unique and vital role in the ocean ecosystem. Coral reefs are home to 25% of all marine life and form the nurseries for about a quarter of the ocean's fish.


Fiji - Detail of Soft coral, close up. rel= © Cat HOLLOWAY / WWF

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Key Facts
Common name
Common Name

Corals

Population

How many?

There are 798 coral species worldwide

Latin name

Scientific Name

Order: Scleractinia (stony) and Alcyonacea (soft)

Endangered

Status

Overall decline in habitat, some species critically endangered

A spectacular underwater kingdom

All coral reefs began life as a single polyp - a tiny, sea anemone-like soft marine animal - which attached to a hard surface. Stony coral species live as colonies and exude calcium carbonate, which forms an external skeleton. As the polyps grow and die, these stony corals create vast reefs.

There are 3 basic kinds of coral reefs: fringing reefs, barrier reefs, and atolls. Fringing reefs grow in shallow waters close to the coast. Barrier reefs are separated from land by a lagoon, growing parallel to the coast and forming a large and continuous reef. Atolls are ring-shaped reefs that develop near the sea surface on underwater islands or islands that sink, or subside.

Like their jelly fish and sea anemone relatives, coral polyps have stinging tentacles that they use to catch food. During the day, these tentacles are usually tucked away, out of reach of hungry fish and other marine animals. But at night they unfold to catch their prey, mainly plankton - small plants and animals floating in the currents.

The Jewel in the Crown
In the Indo-Pacific region is the coral triangle, a magical underwater tapestry created by the collision of tropical light, warm sea temperatures and oceanic currents. It is home to 75% of all known coral species.

Corals showing signs of bleaching. New Caledonia, France. 
© Roger LeGUEN / WWF
Corals showing signs of bleaching. New Caledonia, France.
© Roger LeGUEN / WWF

What are the main threats to coral?

Despite surviving for thousands of years, the impact of man's activity seriously threatens the future viability of many coral reefs. The main identified problems are:
Destructive fishing practices
Overfishing
Pollution
Sedimentation
Coral mining
Careless tourism
Climate change

One of the major threats to the health of corals around the world is climate change.

Other significant problems include loss of natural habitat and increases in human activity which disturb the natural structure of the corals.

Priority species

Coral is a WWF priority species. WWF treats priority species as one of the most ecologically, economically and/or culturally important species on our planet. And so we are working to ensure such species can live and thrive in their natural habitats.

What is WWF doing?

WWF works to protect areas rich in corals. It has been exploring and protecting the Coral Triangle for some 20 years. It helps create policies to ensure responsible environmental management of the area, raise awareness, and promote the sharing of skills for better stewardship of the Coral Triangle's amazing marine world



How you can help

Did you know?

The zooxanthellae algae which live symbiotically inside the coral polyp give the corals their amazing colours.
Properly managed coral reefs can yield an average 15 tonnes of fish and other seafood per sq km per year (source WRI)