World’s largest coral discovered; so big it’s visible from space

A diver swims alongside the mega coral, which is made up of nearly 1 billion polyps. Manu San Félix, National Geographic Pristine Seas

Scientists have identified the world’s largest coral in the Solomon Islands, a remarkable discovery announced during a National Geographic Pristine Seas expedition. Measuring over 100 feet in length and estimated to be at least 300 years old, this coral is so massive that it can be seen from space. It is three times the size of the previous record-holder found in American Samoa and even longer than a blue whale.

Unlike coral reefs, which are made up of multiple colonies, this mega coral is a single organism that has grown continuously for centuries. Marine biologist Manu San Félix, who dove to study the coral, described it as “close to the size of a cathedral.” Initially mistaken for a shipwreck due to its vast, undulating brown appearance, the coral revealed a stunning network of vivid purples, yellows, blues, and reds upon closer inspection.

This colossal coral provides shelter to a wide range of marine life, including fish, crabs, and shrimp, while also acting as a natural record of ocean conditions over the past three centuries. Its discovery required meticulous measurement, as standard tools fell short, forcing scientists to stretch and reel tapes in a labor-intensive process.

The coral’s resilience offers a rare glimmer of hope for marine ecosystems facing mounting threats. Climate change, overfishing, pollution, and rising ocean temperatures have caused extensive coral bleaching globally, with more than 40% of warm-water reef-building species now at risk of extinction, according to the International Union for Conservation of Nature.

Despite its remote location, this mega coral is not immune to these dangers. Enric Sala, founder of Pristine Seas, called the find both inspiring and alarming, emphasizing the urgent need for action to combat climate change.

The Solomon Islands' “Coral Triangle” region, known for its biodiversity, may hold clues to coral resilience and survival. As researchers celebrate this discovery, it underscores the critical importance of protecting these vital ecosystems for future generations.