Scientific study finds laboratory-grown corals proved resistant to bleaching during the 2023 Caribbean marine heatwave
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SECORE International’s Coral Seeding programme utilises laboratory-bred corals for reef restoration, and a new peer-reviewed study has shown that the method has proven successful in reducing Caribbean coral’s susceptibility to bleaching
Coral seeding involves the laboratory fertilisation of gametes collected from wild corals in a laboratory, breeding the resulting larvae in special enclosures in the ocean and then replanting them on damaged reefs once they have matured sufficiently.
The programme – now present in nine Caribbean nations – increases the genetic diversity of the local corals, thus improving their chances of survival through changing ocean conditions.
The new study has found that young corals bred through the seeding programme remained healthy during the marine heatwave of 2023, which proved fatal to many corals in the Caribbean Basin as a sustained increase in water temperature precipitated a mass bleaching event across the region.
Coral bleaching occurs when elevated water temperatures cause the coral’s symbiotic, nutrient-providing zooxanthellae – a type of algae – to be ejected from the coral’s polyps, returning them to their natural translucence and exposing the white coral exoskeleton beneath, giving them the appearance of being ‘bleached’.
Bleaching is survivable if temperatures return to normal or the coral acquires more heat-resistant zooxanthellae, however, as the elevated water temperatures persisted across the Caribbean during the summer of 2023, many weakened corals died.
During a routine health check of out-planted corals in Mexico, SECORE scientists found that the young corals they had grown appeared to be completely healthy amidst the other corals on the reef, which had bleached….
The study ‘Assisted sexual coral recruits show high thermal tolerance to the 2023 Caribbean mass bleaching event’ (Miller et al, 2024) is published in the peer-reviewed journal PLOS ONE.
