Larval propagation: an innovative technique to scale-up Bonaire’s coral reef restoration

The crescent shaped island of Bonaire has been a pioneer in coral restoration, as its economy is mainly dependant on coral reef tourism. In 1979 it was one of the first places to establish a marine protected area (MPA), and The Bonaire National Marine Park (BNMP) is one of the oldest marine reserves in the world.

Although some reefs in this Caribbean island feature significant populations of some coral species, they may be effectively extinct if they can’t reproduce through sexual reproduction.

Since 2019, Reef Renewal Foundation Bonaire (RRFB), under its mission of helping to protect, replenish and restore the biodiverse coral of the island, has developed larval propagation to produce millions of genetically unique coral offspring.

In its visit to the island in October 2022, BEST 2.0+ engaged with Francesca Virdis, Chief Operating Officer at RRFB and lead of a project that has received funding from this European financial mechanism to assist the recovery of deteriorated coral reef areas in Bonaire. A riveting conversation revealed some of the work that this project is carrying out to contribute to the conservation of the island’s biodiversity and its ecosystem services, such as reef growth and coastal protection.

BEST 2.0+: What are the challenges around marine protection and conservation in the Caribbean?

FV: Balancing nature, culture, and development might be the biggest challenge for Caribbean islands. Support for the local economy is needed, which often translates into over-tourism and overdevelopment. The coral reef around Bonaire is one of the healthiest in the Caribbean. However, research shows that a large part is no longer in good shape. The reefs close to human activities appear to be the most affected due to overfishing, pollution and coastal development.

BEST 2.0+: How does RRFB’s larval propagation project fit into this narrative?

FV: In the face of climate change and increasing human pressure on nature, coral reefs need our help to become more resilient. Their capacity to adapt to complex environments is potentially hidden within the coral’s genetic diversity. Although Bonaire’s coral reef still features significant populations of coral species, the healthy colonies may be too far apart to reproduce successfully through sexual reproduction alone, limiting the formation of new genetic strains. Assisting the copy of ecologically important coral species through the larval propagation method is critical for recovering the degraded populations.

BEST 2.0+: Your project’s outstanding efforts in engaging an invested community of volunteers have paid off. Give us a flavour of how this has been achieved.

FV: Knowledge sharing is key to scaling up and impacting the reef. A significant part of the project directly involves the community in restoration efforts. Trained residents and visiting tourists provide RRFB with the additional workforce needed. Local divers are also an essential part of the programme, i.e. through presentations and volunteer training, they are the first contact the public to get involved in the project.

BEST 2.0+: What has been the project’s most notable achievement to date?

FV: RRFB’s outplanted corals on the reef have been spawning for years. When corals spawn, it indicates that they are healthy, have reached sexual maturity, and have started reproducing and colonising adjacent areas. This year, we collected the released gamete (eggs and sperms) from our restored sites, assisting the fertilisation and producing new coral strains that returned to our nursery system. This has increased our coral stock’s genetic diversity and resulted in fully integrating our coral production techniques, larval propagation and fragmentation.

@ Paul Selvaggio

BEST 2.0+: What would you wish to have as a legacy of this work?

FV: I wish our legacy would be about tangible results that can be witnessed underwater. In terms of Bonaire corals thriving, offering shelter and new reef habitat, and contributing to the conservation of its biodiversity and ecosystem services. A wonder of nature for people and future generations to enjoy.

Check out their beautifully produced video: “From Polyp to Reef: Reinvigorating Bonaire’s Coral Sanctuaries” to get a good insight into this project.