Improved sustainable maintenance for mid-water coral nursery by the application of an anti-fouling agent

The ‘gardening concept’ for reef restoration focuses on coral colonies farming in mid-water nurseries before their transplantation onto denuded reef areas. Nurseries situated in a nutrient-enriched environment significantly curtail nursery time, but extend labor, as nursery construction and farmed corals must be frequently cleaned from competing fouling organisms. Mass farming of corals calls, therefore, for efficient and cheap maintenance methodologies, which we here tested by employing Aqua-guard M250, an anti-fouling agent used in the fish farming industry. We found that this anti-fouling paint, while reducing fouling organisms on nursery components during the crucial phase of coral ramets' development from nubbins and small fragments sizes to colony sizes suitable for transplantation, is not toxic to maricultured coral fragments that staged more than 2 cm away from the paint. Applying small quantities of such antifouling paint to coral nurseries, while restricting its use to nursery components that are not in direct contact with farmed coral material, reduces fouling coverage and cleaning procedures by 90%.