Specialists working aboard a research vessel in the southwest Pacific Ocean have just found what is believed to be the world’s largest coral, marking a “significant scientific, 300-year-old discovery” that could uncover the secrets to surviving the centuries.

Discovered in the Three Sisters island group by members of the National Geographic Pristine Seas team, this “mega coral” measures in at 34 metres wide, 32 metres long, and 5.5 metres high. Its circumference of 183 metres makes it longer than the average blue whale – the world’s largest mammal. 

This large coral is a gigantic organism, a complex network of coral polyps – tiny individual creatures – that is believed to have grown over a span of three centuries. In contrast to a coral reef – which is a network of many coral colonies – this structure is a standalone coral that has grown, uninterrupted, for hundreds of years.

Made during the team’s scientific exploration of the Solomon Islands, the discovery has been likened to “finding the world’s tallest tree.” The coral itself is described as “mostly brown with splashes of bright yellows, blues, and reds” and “covered with ripples of waves, mirroring the ocean’s surface.” The coral in question is of the species Pavona clavus and where it is situated it provides essential habitat, shelter, and breeding grounds for an array of species, from shrimp and crabs to fish.

“Just when we think there is nothing left to discover on planet earth, we find a massive coral made of nearly one billion little polyps, pulsing with life and colour,” said Enric Sala, National Geographic Explorer in Residence and founder of Pristine Seas. “This is a significant scientific discovery, like finding the world’s tallest tree.

“But there is cause for alarm. Despite its remote location, this coral is not safe from global warming and other human threats.”

To the naked eye the coral may look like an immense rock just below the surface of the ocean, but this coral is so large, it can be seen from space. In fact, when team members initially spotted the structure, it was first believed to be remnants of a shipwreck, due to its size. It was the Pristine Seas’ underwater cinematographer, Manu San Félix who dove down for a closer look to discover it was, in fact, an exceptionally large Pavona Clavus.

Despite its size, the coral has never been documented with even the local community reporting they did not know it was there.

“The ocean provides for our livelihoods and has contributed so much to our national economy and communities,” said Solomon Islands Prime Minister, Jeremiah Manele. “Our survival depends on healthy coral reefs, so this exciting discovery underlines the importance of protecting and sustaining them for future generations.”

Corals are known for being havens for marine life. Pavona clavus’ dome-like shape shelters juvenile reef fish, crabs, and other reef invertebrates that local communities rely on for food. The polyps that form this enormous coral come from larvae that settled on the seafloor and multiplied into millions of other genetically identical polyps over the centuries.

“Large adult coral colonies like this contribute significantly to the recovery of coral reef ecosystems due to their high reproductive potential,” said Eric Brown, a coral scientist for the Pristine Seas expedition to the Solomon Islands. 

Brown, who is one of the world’s premier coral scientists, had identified and measured the previous record-holding coral, located in American Samoa.

“While the nearby shallow reefs were degraded due to warmer seas, witnessing this large healthy coral oasis in slightly deeper waters is a beacon of hope.”

Discovery of the mega coral comes in the same week that researchers at the IUCN delivered an important warning to world leaders at COP29 that 44% of reef-building coral species now face extinction. This is a dramatic update to data collated when the survey was last conducted in 2008 to find, at the time, that one third of coral species were ‘critically endangered.’

Despite the threats they face, coral is among the least protected of marine life. Research indicates that only 8.4% of the ocean is protected to some degree. If we are to achieve the goals of protecting 30% of the ocean by 2030, we will need to rapidly create and implement around 190,000 small marine protected areas in coastal regions and 300 large marine protected areas in remote areas by the end of this decade.

“It is a natural monument that has seen the arrival of the first Europeans to these waters,” said San Félix, who was the first to spot the record-breaking coral. “Illustrious figures of humanity have coexisted with this colony: Newton, Darwin, Curie, Gandhi, Einstein… and it has survived them. It now stores information on how to survive throughout the centuries.

“The genetic code of these simple polyps is an enormous encyclopedia that has written how to survive multiple climatic conditions, and until now, it does so in the face of ocean warming.”

Solomon Islands hosts the second largest coral diversity on the planet, boasting more than 490 known species, both hard and soft. It’s also home to one of the world’s most active underwater volcanoes, Kavachi.

In mid-October, 18 scientists and filmmakers from National Geographic Pristine Seas embarked on an expedition to study ocean health in parts of the Solomon Islands. The expedition is using cutting-edge technology to better understand the country’s marine ecosystem in the hopes of advancing ocean conservation.

Click here for more from the Oceanographic Newsroom.