Coral reproduction is one of the ocean’s most incredible events, and it happens right here in our waters. Most corals are broadcast spawners – both males and females release eggs and sperm into the water column at the same time, usually triggered by moon phases and water temperature.
Some coral species take a different approach called brooding. The females keep their eggs inside or on their bodies, and fertilisation happens internally. It’s a bit more protective, giving the larvae a better head start before facing the open ocean.
Once fertilised, the coral larvae drift through the water column, sometimes for days or weeks, searching for the perfect spot to settle. When it finds suitable substrate, it attaches and transforms into a primary polyp – developing a mouth, stomach, and tentacles to start feeding.
From there, the polyp begins secreting calcium carbonate to build its skeleton, creating that hard structure we recognise as coral. Over time, it grows, buds off new polyps, and eventually becomes large enough to reproduce itself, continuing the cycle.
This process is why healthy reefs like the ones we dive here in Nusa Penida’s Marine Protected Area are so important. These corals need clean water, stable temperatures, and undisturbed substrate to successfully reproduce and maintain the reef ecosystems that support thousands of marine species.
