Australia’s southern Coral Sea is a global “biodiversity hotspot” for large predatory sharks, tuna and marlin and together with the Great Barrier Reef host the only known spawning aggregation of black marlin in the world. These are key findings from the first comprehensive biological and physical profile of the Coral Sea released today.

The report, Australia’s Coral Sea: A Biophysical Profile, was commissioned by the Pew Environment Group-Australia on behalf of the Protect our Coral Sea coalition[1] and was written by Dr Daniela Ceccarelli, an independent marine ecologist.



Professor Hugh Possingham, director of The Ecology Centre at the University of Queensland, said the report is an important contribution to understanding the Coral Sea ecosystem.

“The Coral Sea may be the only part of the world’s tropical ocean where a permanent marine park of the scale of the interim Conservation Zone could be established and effectively managed with a relatively small impact on users. The Coral Sea Conservation Zone was declared by the federal government in September 2009.”

Other key report findings:

• The Coral Sea has 18 reef systems (includes 49 little islands and cays and multiple small reefs) that are more vulnerable than the reefs in the Great Barrier Reef because of their isolation from one another;
• At least 28 species of whales and dolphins have been recorded in the Coral Sea, including pods of up to 400 false killer whales and 400 melon-headed whales;
• Oceanic and reef sharks have been documented in large numbers in some parts of the Coral Sea. Fifty-two species of deep-water sharks and rays have been recorded, 18 of which are known to exist only there;
• The Coral Sea is an important migratory route for many species of threatened turtles; its cays and islands provide critical habitat for endangered green turtles.

Dr Ceccarelli said that knowledge of the deeper Coral Sea ecosystems is still in its infancy. “However, early studies have revealed a great diversity of habitats, including massive canyons at least 3 kilometers deep, which produce unique ecological communities. Recent discoveries include diverse cold water coral communities and high abundances of predatory fish and sharks in the deeper reaches of coral reefs.”

“The Coral Sea offers a valuable scientific reference site, as it is close to the global centre of coral reef biodiversity – the Coral Triangle – but is not subject to the human pressures that affect much of South East Asia’s marine ecosystems”, said Dr Ceccarelli.

Dr Ceccarelli discovered that average distances travelled by tuna, marlin, swordfish and sailfish that are commonly found in the Coral Sea range from 370 to 1,482 kilometers. The scale of the Coral Sea Conservation Zone is therefore large enough to conserve wide-ranging ocean species.

“This is the chance to have a vast area with large numbers of herbivores and predators functioning over a huge scale in a way that the world once was like without humans”, said Professor Possingham.

“The report confirms that the Coral Sea is healthy and relatively intact. In light of this report, conservation groups call on the federal government to establish a very large, world-class, highly protected marine park in the Coral Sea to provide a safe haven for its spectacular marine life,” said Imogen Zethoven of the Pew Environment Group and member of the Protect our Coral Sea coalition.

[1] For groups comprising the Protect our Coral Sea coalition, see p.2

Image on home page courtesy of Mark Spencer.