How to regrow a coral reef in two years instead of a century

Some of the most wonderful discoveries are serendipitous, and so it is with the story of how a revolutionary technique to speed up regeneration of coral reefs was discovered. It involves the insights of a marine biologist who lived in Belize and knew its reefs well, and the accidental discovery by another biologist that staghorn coral accidentally broken in his laboratory tank had regrown in a week by itself.

Placencia Lagoon, Fragments of Hope

Micro-fragmenting has been a game changer for marine biologists worldwide. It dramatically speeds up coral tissue regeneration. Where it would take at least a century for coral to reach maturity in nature, microfragmenting allows coral to become mature in two years.. The full-grown coral are also sexually mature, which would otherwise take at least 75 years. It is a discovery as amazing as the realization that tropical forests could be regrown in their complexity – something else we didn’t think could be done.

Marine biologist Lisa Carne began to wonder about regrowing coral after seeing the terrible devastation Hurricane Iris had wrought on Belize’s coral reefs in 2001. It was something that no one then thought was possible – that live, broken coral could be transplanted, in order to save coral reef systems and with it, the livelihoods of whole communities. And it led to a most spectacular result – the reconstruction of what is now the world’s largest barrier reef.

Belize’s barrier reef system was declared a World Heritage site by UNESCO in 1996. It includes more than one thousand islands, the famed Blue Hole, and 1,400 species of flora and fauna. The reef generates about 15% of the country’s GDP through tourism and fishing. Laughing Bird Caye National Park alone was recently valued at US$4.5million a year.

The first time Lisa visited Belize in 1994, she swam with wild dolphins for more than an hour, and she fell in love with Placencia. When she moved to Belize in 1995, she worked as a volunteer research assistant at Carrie Bow Caye, the Smithsonian field station at Placencia. Assisting researchers who were working on sponges, corals, and mangroves, she saw the impact of coral bleaching at first hand.

In 2001, Hurricane Iris devastated southern Belize, causing US$250 million in damages. The fishing village of Placencia and Laughing Bird Caye National Park were decimated by tidal surges that reached 14 feet in height. The villagers lost homes, farms, fishing grounds, and livelihoods. The hurricane damaged the Belize Barrier Reef, a UNESCO World Heritage site, and the fishermen realized that when the coral died, the fish disappeared.

While conducting reef research on Ambergris Caye in 2002, Lisa began to wonder about the possibility of coral transplanting after noticing pieces of Elkhorn coral that had broken from the reef were still alive. In 2006, PACT funded her transplanting experiment, and in 2009, with funding from the World Wildlife Fund, the Caribbean Community Climate Change Center and the World Bank, she launched the coral nursery project at Laughing Bird Caye National Park. 

“The idea of transplanting coral to Laughing Bird Caye was dismissed by many, saying there was only rubble left, the donor reef site was too far, and disease or bleaching might kill them. People did not think there was a need, until 2006 when the Caribbean acroporids (hard coral) were listed by the U.S. as an endangered species,” Lisa told UNDP in 2019.

Fragments of Hope is basically a ‘coral nurseries’ project that focuses on the most endangered corals, she said in a 2011 interview. “We’re focusing on the Acroporids family that’s the (Elkhorn, Staghorn, and hybrid) the most important reef-building corals and the fastest growing corals and branching corals.”  

New micro-fragments are grown directly in shallow inlets of the reef..”Small coral cuttings of staghorn, elkhorn, and brain coral, no bigger than a pinkie finger, are placed on ‘cookies’, made from Portland cement, sand and water. Marine epoxy or crazy glue are used to glue coral in place. These are laid out on underwater coral nursery tables, like cookies cooling on baking racks. The ocean’s current and fish clean the algae and debris from the growing coral.”

Now considered the Caribbean’s most successful reef restoration projects, Fragments of Hope has planted over 100,000 coral fragments in three different marine protected areas. They use various  methods, including rope nurseries – long strands of rope strung between steel frames buried in the seafloor. 

“At Laughing Bird Caye, we’ve been able to quantify that since Hurricane Iris we had less than six percent live coral cover in the shallow reefs. And through our work in just seven years or so, we have now increased that coral coverage to well over 50 percent by 2017,” Lisa told UNDP. This initial work was financed from the Protected Areas Conservation Trust, which was established through a grant to Belize from the GEF.

“Today, Fragments of Hope has moved from restoring coral to replenishing reefs, a rewarding sign of decades of hard work. Fish, tourism and jobs are returning to Placencia. They’ve expanded coral replenishment work in 10 different reef sites in four different marine-protected areas in Belize. Fragments of Hope’s work means Belize is now home to the largest living barrier reef in the world, following the declining health of Australia’s Great Barrier Reef.”

It’s gratifying seeing the corals thrive and to see how much pride local residents have when they see corals that they planted are thriving years later, she says.

The organization is sharing its knowledge widely. It has hosted 15 exchange visits to teach coral replenishment with other countries in Latin America and the Caribbean, including Jamaica, Mexico, Guatemala and Honduras, and 30 Belizeans have been trained and certified in coral replenishment through the Belize Marine Conservation and Climate Adaptation Project. A manual and video detailing coral replenishment and training techniques has been produced.

(I am grateful to Future Crunch for introducing me to this amazing woman and her work in its latest newsletter. You can learn more about Fragments of Hope, and how to support its work, at its website.)


How the Belize Barrier Reef is coming back to life. Optimist Daily, May 24, 2022.