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Coral Sea map
Map showing the location of the Coral Sea, bounded by Australia, Papua New Guinea, Solomon Islands, Vanuatu, and New Caledonia. Nearby bodies of water include the Tasman Sea, Solomon Sea, and South Pacific Ocean

The Coral Sea is a marginal sea of the South Pacific off the northeast coast of Australia.

It is bounded in the west by the east coast of Queensland, thereby including the Great Barrier Reef, in the east by Vanuatu (formerly the New Hebrides) and by New Caledonia, and in the northeast approximately by the southern extremity of the Solomon Islands. In the northwest, it reaches to the south coast of eastern New Guinea, thereby including the Gulf of Papua. It merges with the Tasman Sea in the south, with the Solomon Sea in the north and with the Pacific Ocean in the east. On the west, it is bounded by the mainland coast of Queensland, and in the northwest, it connects with the Arafura Sea through the Torres Strait.

The sea is characterised by its warm and stable climate, with frequent rains and tropical cyclones. It contains numerous islands and reefs, as well as the world's largest reef system, the Great Barrier Reef (GBR), which was declared a World Heritage Site by UNESCO in 1981. All previous oil exploration projects were terminated at the GBR in 1975, and fishing is restricted in many areas.

The reefs and islands of the Coral Sea are particularly rich in birds and aquatic life and are a popular tourist destination, both nationally and internationally. The WWF describe the Coral Sea as being one of the last complete tropical wilderness areas on earth. It has beautiful coral reefs with many different sea creatures including grey and white tip reef sharks, hammerheads, manta rays, tuna, barracuda, turtles, whales and the rare nautilus.


The Coral Sea basin was formed between 58 million and 48 million years ago when the Queensland continental shelf was uplifted, forming the Great Dividing Range, and continental blocks subsided at the same time. The sea has been an important source of coral for the Great Barrier Reef, both during its formation and after sea level lowering. The geological formation processes are still proceeding, as partly evidenced by the seismic activity.

The sea received its name because of its numerous coral formations. They include the GBR, which extends about 2,000 km (1,200 mi) along the northeast coast of Australia and includes approximately 2,900 individual reefs and 1000 islands. The Chesterfield Islands and Lihou Reef are the largest atolls of the Coral Sea.


The Australian shore of the Coral Sea is mostly composed of sand. The GBR is too far away to provide significant coral deposits, but it effectively screens the coast from the ocean waves. As a result, most land vegetation spreads down to the sea, and the coastal waters are rich in underwater vegetation, such as green algae.

The islands of the GBR contain more than 2,000 plant species. The northern islands have 300–350 plant species which tend to be woody, whereas the southern islands have 200 which are more herbaceous; the Whitsunday region is the most diverse, supporting 1,141 species. The plants are spread by birds.


Coral Outcrop Flynn Reef
Corals on Flynn Reef near Cairns
Crown of Thorns-jonhanson
Crown-of-thorns starfish
Christmas Tree Worm
Christmas Tree Worm (Spirobranchus giganteus) in Porites coral. Admiralty, Osprey Reef
Laticauda colubrina (Wakatobi)
A banded sea krait Laticauda colubrina

The sea hosts numerous species of anemones, sponges, worms (e.g. Spirobranchus giganteus shown in the photograph), gastropods, lobsters, crayfish, prawns and crabs. Red algae Lithothamnion and Porolithon colour many coral reefs purple-red and the green alga Halimeda is found throughout the sea.

Four hundred coral species, both hard corals and soft corals inhabit the reefs. The majority of these spawn gametes, breeding in mass spawning events that are triggered by the rising sea temperatures of spring and summer, the lunar cycle, and the diurnal cycle.

Reefs in the inner GBR spawn during the week after the full moon in October, while the outer reefs spawn in November and December. Its common soft corals belong to 36 genera. There are more than 1500 fish species in the reef systems. Five hundred species of marine algae or seaweed live on the reef, including thirteen species of the Halimeda genus, which deposit calcareous mounds up to 100 metres (110 yd) wide, creating mini-ecosystems on their surface which have been compared to rainforest cover.

Crown-of-thorns starfish (Acanthaster planci) is the major predator of the reefs, as it preys upon coral polyps by climbing onto them, extruding its stomach over them, and releasing digestive enzymes to absorb the liquefied tissue. An individual adult can eat up to 6 m2 of reef per year. In 2000, an outbreak of crown-of-thorns starfish contributed to a loss of 66% of live coral cover on sampled reefs. Changes in water quality and overfishing of natural predators, such as the Giant Triton, may have contributed to an increase in the number of crown-of-thorns starfish.

There are at least 30 species of whales, dolphins, and porpoises, including the dwarf minke whale, Indo-Pacific humpback dolphin, humpback whale and dugongs. Six species of sea turtles breed on the GBR – the green sea turtle, leatherback sea turtle, hawksbill turtle, loggerhead sea turtle, flatback turtle and the Olive Ridley.

More than 200 species of birds (including 22 species of seabirds and 32 species of shorebirds) visit, nest or roost on the islands and reefs, including the white-bellied sea eagle and roseate tern. Most nesting sites are on islands in the northern and southern regions of the GBR, with 1.4–1.7 million birds using the sites to breed.

Seventeen species of sea snake, including Laticauda colubrina (pictured), live on the GBR in warm waters up to 50 metres (160 ft) deep and are more common in the southern than in the northern section; none of them are endemic or endangered. The venom of many of these snakes is highly toxic; for example, Aipysurus duboisii is regarded as the world's most venomous sea snake.

There are more than 1,500 fish species Between 300 and 500 species of bryozoans live on the reef.

Saltwater crocodiles live in mangrove and salt marshes on the coast. Around 125 species of shark, stingray, skates or chimaera live on the GBR, in addition to about 5,000 species of mollusc. The latter include the giant clam and various nudibranchs and cone snails.

Human activities

The coastal areas of the Coral Sea were populated at least 40,000 years ago by prehistoric people descending through the northern islands. Those Aboriginal tribes have been dispersed and nowadays only about 70 groups live in the area around the GBR.

Navigation has long been a traditional human activity on the Coral Sea and there are 10 major ports on the Queensland coast alone. More than 3,500 ships operated in this area in 2007, making over 9,700 voyages that transported coal, sugar, iron ore, timber, oil, chemicals, cattle and other goods.

Other economic activities in the sea include fishing and exploration of petroleum deposits in the Gulf of Papua. The sea is also a popular tourism destination. In 2006–2007, tourism on the GBR contributed A$5.1 billion to the Australian economy. The tourism is mostly foreign or from remote parts of Australia, with a local contribution of about A$153 million.

In particular, about 14.6 million visits were made to the Coral Sea reefs by the Queensland residents over 12 months in 2008. Growing concerns over the environmental effects of tourism resulted in establishment in 1975 of the Great Barrier Reef Marine Park. There are also smaller state and national parks. In 1981, the Great Barrier Reef was declared a World Heritage Site by UNESCO. From the middle of 2004, approximately one-third of the GBR Marine Park is protected from species removal of any kind, including fishing, without written permission.

World War II

Coral Sea Lexington abandoning ship
Sailors abandon the USS Lexington during the Battle of the Coral Sea

In World War II the Battle of the Coral Sea was the first aircraft carrier battle fought between the United States and Australia against Japan. The battle lasted from 4 May to 8 May 1942. During that time none of the ships saw each other of fired any of their guns at each other. All the fighting was done by aircraft from the carriers. It is the largest naval battle fought near Australia. It was important because it was the first major defeat for Japan, and it stopped the Japanese from invading Port Moresby, the capital city of New Guinea. Many people regarded it as the battle that saved Australia.

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