The Sounds of Restored Coral Reefs

New research by the University of Exeter and the University of Bristol in the U.K. has found that coral reefs off the coast of Indonesia are coming back to life, and the evidence is in the sounds of the restored ecosystems beaming with life.

This is particularly encouraging news for the local communities and teams involved in the Mars Assisted Reef Restoration System (MARRS) driving restoration efforts in the area. Not only do findings show coral reefs are being restored but coral restoration is also helping entire ecosystems develop and function again.

"Restoration projects can be successful at growing coral, but that’s only part of the ecosystem," said lead author Dr. Tim Lamont, of the University of Exeter and the MARRS project.

"This study provides exciting evidence that restoration really works for the other reef creatures too – by listening to the reefs, we’ve documented the return of a diverse range of animals", Dr. Lamont added.

Using 2018 and 2019 recordings to monitor how reef communities grow, scientists found the diversity of the soundscape they recorded was similar to the one of existing healthy reefs. The teams also recorded considerably more fish sounds across healthy and restored areas than on degraded reefs.

Professor David Smith, Chief Marine Scientist for Mars, Incorporated, added: "When the soundscape comes back like this, the reef has a better chance of becoming self-sustaining because those sounds attract more animals that maintain and diversify reef populations."

The MARRS project is one of the world’s largest coral reef restoration programs. It uses three-foot-wide, star-shaped, steel structures, known as reef stars, which are coated with sand and tied with live coral fragments.

These stars are connected together underwater in a web and anchored to the sea floor to provide a stable platform for corals to grow, and habitat for marine species to thrive. The stars are positioned directly on top of barren coral rubble fields caused by historically destructive fishing techniques and which have shown no previous sign of recovery, turning them back into flourishing reefs.

The first network of stars was built between two island communities in Sulawesi, Indonesia, and the project is now expanding off the coast of Mexico, off Australia’s Great Barrier Reef and in the Maldives. Since 2018, coral cover has increased from 5% to 55% at key restoration sites.

Teams plans to restore coral reefs measuring more than 185,000 square meters—roughly the size of 148 Olympic swimming pools— at key sites around the world.

This project is part of our commitment to supporting Sustainable Development Goal 14, Life Below Water - a call to action to conserve and sustainably use the oceans, seas, and marine resources for sustainable development.