Spawn collected from critically endangered pillar coral by scuba divers this August has enabled the non-profit Reef Renewal Foundation Bonaire (RRFB) to use its breeding programme to raise young corals on the southern Caribbean diving island for the first time.
Pillar coral (Dendrogyra cylindrus) has been devastated by disease and bleaching in recent years, says the RRFB, with only a handful of colonies remaining on Bonaire. Too rare to reproduce naturally any more, human restoration projects represent one of its only chances of survival.
Divers use collection nets placed above spawning colonies to collect gametes in collection tubes. These are transferred into underwater nurseries, where their growth is carefully monitored until they can be safely returned to the reef.
Pillar coral is highly sensitive to ocean change and often the first coral to show signs of stress, says RRFB.
The devastating spread of stony coral tissue loss disease (SCTLD) and consecutive marine heatwaves have left colonies too far apart to reproduce naturally, and pillar coral already faces functional extinction in Florida and elsewhere in the Caribbean.
“Helping pillar corals reproduce here is more than just a milestone for us – it’s a lifeline for a species that is vanishing from Bonaire’s reefs,” says RRFB lead restoration technician Cheyenna de Wit.
Two recent landmark studies are said to show that heat tolerance can be passed from parent corals to their offspring, and that young, lab-reared corals show greater resilience to bleaching than wild colonies.
The RRFB says it is applying its research-backed techniques at scale – as well as pillar coral, its team has just produced 56,000 staghorn-coral larvae, and earlier this year raised more than 26,000 young grooved brain corals.
Working around the island in co-operation with 17 of its dive-operators and a team of volunteers, RRFB has so far outplanted corals covering an area of more than 1.3 hectares.
Supported by the local government office and Dutch fisheries ministry via the Nos ta Biba di Naturalesa (We Live From Nature) project, it is also part of a collaborative effort with SECORE International and FUNDEMAR to test new coral-breeding technologies across the Caribbean.
