World’s largest coral is 300 years old and was discovered by accident

In the south-west Pacific, off the coast of one of the tropical Solomon Islands, a giant structure beneath the water’s surface has just been identified as the world’s largest known coral.

Visiting the remote site in mid-October, a team of scientists and film-makers from National Geographic thought the object was so large, it must be the remains of a shipwreck.

But when underwater cinematographer Manu San Félix jumped into the water to take a closer look, he was astonished by what he saw.

“I remember perfectly just jumping and looking down, and I was surprised,” he told reporters during a briefing. Instead of a shipwreck, San Félix had stumbled upon the largest coral ever discovered. “It is enormous,” he said. “The size is close to the size of a cathedral.”

The coral, which lies a few hundred metres off the eastern coast of Malaulalo Island, has been identified as the species Pavona clavus. It measures 34 metres wide by 32 metres long, making it larger than a blue whale, and is thought to be 300 years old.

The discovery was a “happy accident”, says Enric Sala of National Geographic’s Pristine Seas project, which aims to inspire governments to protect ocean ecosystems through exploration and research. It is by far the largest single coral colony ever discovered, easily beating the previous record holder – a giant Porites colony found in American Samoa in 2019, which was 22.4 metres in diameter and 8 metres in height.

Over the past two years, record-breaking ocean temperatures have triggered a wave of coral bleaching events across the world. But while other reefs around the Solomon Islands are showing signs of bleaching, Sala says the huge P. clavus coral is looking healthy. It is a vital habitat for ocean life, he says, providing shelter and food for fish, shrimp, worms and crabs. “It’s like a big patch of old growth forest.”

But the coral isn’t immune from ecological threats, from local pollution and overfishing to global climate change. Sala says he would like to see more marine protected areas (MPAs) established to shield marine life from local pollution, alongside global action to tackle climate change. “Protecting the reef cannot make the water cooler, cannot prevent the warming of the ocean,” he says. “We need to fix that, we need to reduce carbon emissions. But MPAs can help us buy time by making the reefs more resilient.”