This is how a coral nursery starts....

"This is how a coral nursery starts - a tiny "nubbin" is carefully clipped from the parent coral, and secured or suspended into the elevating nursery. The gold is healthy tissue while the white is bare skeleton exposed in the clipping. This fishing line has 50 such nubbins and there are two of them = 100 corals." - Andrew Ross, Seascape Caribbean

Coral nubbins suspended by fishing line between floating buoys, Round Hill Reef, Jamaica