How to restore coral reefs?

Coral reefs are one of the most important and valuable ecosystems on planet earth , and one that has unfortunately been most affected by climate change.

Alongside has developed a project focused on planting corals with a clear objective: to restore and recover reefs damaged by climate change. By transplanting corals in the most damaged areas, we manage to recover marine life. To this end, we plant corals of different species to create more complex ecosystems, achieving greater biodiversity. 

In the following, we will explain what coral reef reef reef culture is and what techniques exist. But before you continue reading this article, if you are unfamiliar with corals, we recommend that you first read the article What is coral?

What does coral reef restoration consist of?

Thanks to the ability of corals to reproduce asexually, scientists have been able to grow cultures from fragments of healthy corals. These fragments, like cuttings, are grown in strategic areas underwater where conditions are ideal for the corals to be stress-free and grow strong before being transplanted onto reefs.

The first step in the process consists of cultivation in the form of cuttings with coral fragments. The cultures are placed at depths of between 5 and 12 metres, in coastal areas that allow better access for the maintenance they require. These fragments are obtained from our most adult culture, which we call mother corals. There are also coral cultures that are nourished by broken fragments as a result of storms or strong waves.

There are various techniques for coral culture. Below, we explain the most commonly used coral culture techniques for reef recovery.

Rope technology

The rope technique consists of placing ropes stretched in such a way that they are elevated with respect to the seabed and where they place small fragments of coral intertwined with the rope. This technique is very effective, although it is avoided as it poses a risk to marine species such as turtles, which can become entangled in the ropes.

Coral trees

In this technique, corals are suspended by filaments in a floating tree-like structure, hence the name coral tree. This system minimises the surface area exposed to algae harmful to corals, making it a technique that requires less maintenance without the need to remove predatory algae, especially when the fragments are small.

Coral nurseries are metal structures where coral fragments rest on ceramic bases.

Before installing the nurseries, it is common for biologists to use the rope technique in different areas, extending ropes of 25/50m in length in order to observe which mini coral fragments grow the fastest and consequently the strongest and healthiest. In this way, we can install the coral nurseries in the area with the best conditions for their survival.

From coral farming to reef recovery

After a few months in culture, which can vary from 6 to 18 months depending on conditions and coral species, the fragments are ready to be transplanted onto the reefs.

The location and distribution of the corals is very important for the good development of the reefs, with a prosperous future ahead. If we transplant the fragments in areas where they hardly get any sunlight, or if we fix two corals next to each other, all the previous work will have been of little use.

Once we have strategically selected where we are going to plant the corals in order to have a greater positive impact on the marine ecosystems, it is time to fix them. With an aquatic drill the rock where the coral fragment will be fixed is drilled, and with a special cement the coral is fixed for the rest of its life.