Largest Ever Coral is the Size of a Football Pitch

Citizen scientists have discovered the largest coral that has ever been seen. The 111 metre long, 3,973 square metre Pavona clavus was discovered by a mother and daughter as they surveyed coral reefs on Australia’s Great Barrier Reef as part of the Great Reef Census. The football pitch-sized coral colony is thought to be 1000 years old. 

The coral was first encountered by Sophie Kalkowski-Pope, Marine Operations Coordinator at Citizens of the Reef, and her mother, Jan Pope, before being verified and mapped through coordinated in-water measurements, surface-based photogrammetry, and three-dimensional spatial modelling. 

“I knew right from the minute we dropped in that it was something special,” said Sophie Kalkowski-Pope. “My mum and I dive from our family boat, and taking part in the Great Reef Census has given us the opportunity to really explore the full scale of what was there,” 

“When I got in the water, I’d never seen coral growing like this before,” said Jan Pope, who first encountered the coral alongside her daughter. “It looked like a meadow of coral. It just went on and on.”  

Large individual Pavona coral colonies are typically measured in the 30–35 metre range.

The Great Reef Census

The Great Reef Census was designed for large-scale spatial reconnaissance, which enables reef surveying at a huge scale. “The Great Reef Census helps us to locate the most important sources of reef recovery, helping scientists and managers better target their protection,” said Prof. Pete Mumby from the Marine Spatial Ecology Lab at the University of Queensland. 

This approach is now being adopted by major reef initiatives around the world. The Great Reef Census brings together tourism operators, Traditional Owners, research teams, recreational vessels, divers, snorkellers and community participants to collect reef imagery across vast areas of the Great Barrier Reef. 

More than 100 vessels take part, generating broad-scale data that helps reef managers prioritise where limited resources and protection efforts are directed. 

“To drive conservation at the scale now required for reefs around the world, we need to engage local reef communities, leading scientists, and people power to target the best places for intervention and conservation impact”, said Andy Ridley, CEO of Citizens of the Reef. 

“The Great Reef Census was developed to complement existing monitoring programs by gathering large-scale data. This is made possible by people already out on the water, like Sophie and Jan, and thousands of citizen scientists around the world.” 

By combining in-water image capture with AI and structured analysis by citizen scientists, Citizens of the Reef turns community participation into reef data that can be used by reef managers and scientists. 

Following the initial sighting, a team coordinated by Citizens of the Reef worked to verify the coral’s dimensions using multiple independent methods. Manual underwater measurements were combined with high-resolution imagery captured from surface-based platforms, with the resulting data used to generate a detailed 3D model. 

The spatial modelling was undertaken in collaboration with the Queensland University of Technology Centre for Robotics, alongside imagery capture supported by Biopixel, enabling precise measurement for long-term monitoring of the site. 

“The benefit of this kind of spatial data is that we can take measurements at very high resolution,” said Serena Mou, Research Engineer at the QUT Centre for Robotics. “It also means we can return in future months and years and make direct, one-to-one comparisons to understand how the coral changes over time.” 

The site is characterised by strong tidal currents and low cyclonic wave exposure compared to many parts of the Great Barrier Reef. These environmental conditions are now being examined by scientists, as part of ongoing monitoring, to better understand the context in which such large coral structures can persist. 

Alongside its analysis through the Great Reef Census, the coral is being considered by reef scientists and Traditional Owners to help contextualise its ecological and cultural significance. Data collected through the Census is used to identify areas of high ecological value, including reefs that play an important role in supporting surrounding reef systems through coral spawning and larval dispersal. 

Researchers emphasise that the discovery of an exceptionally large coral colony should not be interpreted as evidence that reefs are recovering or that climate impacts are diminishing. Rather, it highlights the uneven ways reef systems respond to environmental pressures, and the importance of identifying, understanding and protecting remaining strongholds across vast reef systems. 

“Discoveries like this are significant because the reef still holds so many unknowns, and we don’t know what we stand to lose,” said Sophie Kalkowski-Pope. “I think this shows why reef conservation efforts like the Great Reef Census matter now more than ever.” 

To reduce the risk of unintended impacts, exact location details are being withheld, imagery has been reviewed to prevent site identification, and relevant management authorities have been informed to support long-term stewardship of the site. 

Citizens of the Reef 

The Great Reef Census is a Citizens of the Reef project in partnership with The University of Queensland, Great Barrier Reef Marine Park Authority, Dell Technologies, the Walt Disney Company, Mars, the Australian Institute of Marine Science and James Cook University. The project would not be possible without support from Cotton On Foundation, Prior Family Foundation, the Queensland Government’s Department of the Environment, Tourism, Science and Innovation, the Australian Government’s National Environment Science Program, the Reef and Rainforest Research Centre, The Special Group and Mindshare. 

For more information, visit citizensgbr.org.