Coral Gardening

Have you ever thought about coral gardening? Do you know what it is or why you would do it?

Coral gardening (coral propagation) is a process in which we grow corals in a nursery area, until they can grow bigger. The reasons for doing this? To replace corals that have been damaged or to rebuild coral reefs that have been destroyed by natural disaster or human activity.

Coral reefs – the heart of the ocean

Coral is amazing! The coral polyps (animals) have a symbiotic relationship with zooxanthellae (algae) that creates coral reefs. The zooxanthellae provides energy by photosynthesis while the coral polyp provides protection. Reefs provide shelter for many ocean creatures, from tiny shrimps up to large moray eels. They are like the tropical rainforests of the ocean. The coral helps to filter the water, regulate the salinity of the ocean (among other things), and is itself part of the food chain.

Why does coral get damaged?

As with all living things, there is a natural cycle where coral lives, dies and is replaced by new. There are natural predators and there is also competition between coral for space. The extra stresses on coral are largely created by mankind. Some examples of the stressors that we add:

  • sun screen
  • people standing on the reef
  • pollution
  • ghost nets

What is coral rescue?

Coral rescue is simply to take broken or damaged pieces of coral and give them another chance. When coral is broken, it doesn’t immediately die, but in many cases it drops to the ground and gets covered in sand or silt. When it gets buried it can no longer photosynthesise, and then it dies.

The most simple example of coral rescue is to pick up a broken piece of coral from the sand and then replace it on the reef in a position where it can continue to grow.

How does coral propagation help?

Coral propagation is where we take tiny fragments of coral (think seedlings here) and then place them in a nursery to grow. We do this away from the reef so that we can monitor and protect them. Once they are large enough, we can re-introduce them to the reef from which they came.

It is important here that we don’t add strangers in to the reef. We need to ensure that the coral going back is the same type of coral that is (or was) already there. Getting ‘creative’ with our gardening will result in invasive species – like lionfish in the Caribbean.

Coral starting to grow

Where and how do we grow coral?

There are lots of solutions out there to the question of where and how do we grow coral. People have developed metal frames, concrete structures, pvc pipes, electrified grids, cable ties and strings. There are almost as many ideas as there are people wanting to help.

The simple solution is to keep it natural. If we introduce man-made structures into the ocean then we risk polluting the environment we are trying to save. Plastics degrade and become micro-plastics, while concrete has a high pH which is not an ideal substrate for coral growth.

We need to make sure that we don’t damage healthy coral to get our ‘seedlings’. The aim is to take only pieces that are already broken and cultivate from those. Wherever you have human interaction with the reef, you will find broken coral with which to start.

Coral propagation

Ocean Quest / Sea Shepherd Dive

We have been working with Ocean Quest to learn safe, ethical, organic and non-destructive ways of rescuing and propagating coral. They are running a campaign with Sea Shepherd (Sea Shepherd Dive) to teach people how to rescue and propagate coral without creating any more environmental damage.

With the Ocean Quest system we use dead coral pieces as substrate. These lift our coral fragments out of the sand, without introducing anything manmade or un-natural. We attach small coral fragments to the substrate using superglue and use an activator to help harden the glue while wet. Superglue was used in Vietnam to help close wounds on soldiers, and is non-toxic to life.

We at Khao Lak Scuba Adventures are now working to set up our own coral gardening program so that we can teach our divemasters and instructors how to look after our ocean garden.