The Coral Sea provides essential habitat for an abundance of species including critically endangered hawksbill and endangered green turtles, 25 species of whales and dolphins, and 27 species of seabird.
It is one of the last places on Earth where populations of sharks, tuna, and billfish (e.g. swordfish and marlin) have not yet been severely depleted.
Underwater landscape
The underwater landscape of the Coral Sea is highly varied, with reefs, lagoons, islets and cays, plateaus, canyons, and underwater mountains. Ocean-going species use the scattered reefs, cays and underwater mountains as habitats for feeding, resting, breeding and as nursery ground.
Smaller fish also gather in these habitats, seeking refuge from the vast expanse of open ocean; and where prey fish gather, top predators such as sharks also lurk.
Endemic species
It contains endemic species: species that are not found anywhere else on the planet. The majority of reefs in the Coral Sea lie on the Queensland Plateau. This area contains about 440 species of demersal fish (fish that feed on or near the seafloor), of which 70 are not found anywhere else on the planet.
Marine life that is distinct from the Great Barrier Reef
The seafloor flora and fauna of Coral Sea reefs, lagoons, islets and cays is different from that of the GBR: there is less hard coral and a greater proportion of sponges and coloured algae. Some areas are dominated by large and spectacular sponge gardens.
The hydroid fauna of the Coral Sea (starfish, brittle stars, feather stars,sea cucumbers, etc) is considered to be remarkably rich; the mollusk fauna moderately rich (745 species of mollusks have been found on one cay alone: North East Herald Cay).
Although there are fewer species of reef fish than in the GBR, the fish assemblages are distinct from those in the GBR. A total of 372 species of fish were found at the Coringa-Herald nature reserve.
A source of life for the Great Barrier Reef
The oceanic currents flowing west from Vanuatu replenish the biological communities that grow on the emergent reefs of the Coral Sea. In turn, these communities are important sources of recruitment for the Great Barrier Reef, as the dominant ocean current hits the continental shelf and splits in two: a north current flows through the far northern section of the GBR, and the East Australian Current flows south through the GBR and beyond.
Undisturbed habitat for nesting green turtles
The green turtle regularly nests on the undisturbed islets of the Coringa-Herald and Lihou Reef National Nature Reserves. The hawksbill turtle uses these islets and reefs for foraging and occasionally for nesting.
Five other species of turtle are found in the Coral Sea: the loggerhead, olive ridley, hawksbill, flatback and leatherback turtle.
Internationally significant populations of breeding seabirds
Fourteen species of seabird nest and forage on Coral Sea cays, including regionally important populations of red-footed Booby, least frigate bird and greater frigate bird.
A regionally important area for the east coast humpback whale
Where the iconic East Australian Current (EAC) forms
The EAC is the dominant influence on the surface waters along the eastern Australian coastline. Its warm waters enhance the biological productivity of this vast area.
It brings aggregations of marine life that otherwise wouldn't be there and therefore plays a very important ecological role. For example: tropical coral larvae are transported by the EAC from the Great Barrier Reef and Coral Sea reefs to subtropical reefs in southeast Queensland and northern New South Wales as far south as the Solitary Islands near Coffs Harbour.
A critical link
The Coral Sea is a critical link between the western Pacific and the Great Barrier Reef and further on to the Coral Triangle of Southeast Asia. It provides many of the necessary stepping stones to enable genetic exchanges between species via ocean currents that transport spores, larvae, and migratory animals.
I was lucky enough to spend an unforgettable 5 weeks in the Coral Sea recently for work. Imagine long sandy beaches, brilliant blue water, amazing diving...
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