How does coral reproduce?

It all starts with a coral larva called a planula. To create a reef, coral has two methods of reproduction:

• Sexual reproduction: Once a year, according to the lunar cycle, corals release male and female gametes that lead to the development of larvae. These are carried by the current through a pelagic phase before settling on a suitable support. They develop into a coral polyp, carrying a new genetic make-up.
• Asexual reproduction (budding): To develop and form a coral reef, the polyp clones itself. An outgrowth will give rise to a new polyp, a genetic replica of the parent polyp.

Little by little, the coral forms a colony comprising thousands or even millions of individuals. A reef is therefore made up of several colonies of coral.

In the natural environment, after storms, corals can break off and try to attach themselves to a new support in order to develop. This random method of propagation in the natural environment is practised in a reasoned way with a high success rate in Nausicaá's aquariological reserves, using the cutting technique.

This technique involves taking a piece of coral from a mother plant and attaching it to a support so that it can grow. Again, this is cloning. Nausicaá's aquarists have mastered this technique and breed all the corals on display.

Highly threatened by climate change, corals are experiencing bleaching episodes that can lead to the death of reefs. Local associations are also working to restore them through cuttings.

The Coral Planters, for example, installs artificial structures to which coral cuttings are attached. Submerged in the Maldives, these grow and help to reconstitute a rich, living ecosystem by attracting marine biodiversity once again.

Plastic artist Jérémy Gobé is developing modular structures to house coral cuttings. Tested at Nausicaá, his innovation is now installed in a natural environment in Colombia.