Restored corals give hope for reefs worldwide

Diver conducting coral restoration work
Corals can be attached to reefs piece by piece with cement, zip ties, and nails
Image: Reef Resilience Network

New technologies for coral reef restoration produce corals in five years instead of decades

The scientific community has been relatively slow to investigate coral restoration, only in the past decade have researchers begun to develop restoration strategies in earnest.

Reef-building corals come in all different shapes, colours, and sizes. To date, most restoration efforts have focused on branching coral species that grow quickly. This is because they are relatively easy to propagate, similar to how one might propagate a plant at home where cuttings from one plant are used to create new individuals.

An underwater nursery where new corals are grown
An underwater nursery where new corals are grown | Image: Coral Restoration Foundation

However, restoring the backbone of a reef requires massive, slow-growing species such as the boulder and brain corals. These species are much harder to propagate for restoration because they typically grow only a few millimetres a year and usually need to be brought into the lab to be cut.

Some brain coral
The grooved brain coral is named for its appearance. It has particularly deep grooves that resemble the brain’s folds | Image: Oceana

For several years now, scientists have been propagating dozens of arrays of genetically identical, mountainous star coral fragments. These grow and eventually come into contact, recognising each other as “self” and fuse together, essentially reskinning the dead coral skeleton with living healthy tissue. Between two and three years after outplanting, all arrays fully fused, creating whole coral colonies.

Baby mountainous star corals at different stages of growth
Baby mountainous star corals (6 weeks to 1 year old shown here, left to right) are grown in the lab at Mote Marine Laboratory and then outplanted to Florida reefs
Image: Mote Marine Laboratory

This accelerated development breakthrough of up to 50 times natural growth rates is critical to reverse decades of coral reef damage with a healthy, banalned reef. There are now more than 250 coral restoration projects involving hundreds of thousands of outplanted corals.

A coral nursery being tended to by a diver
A coral nursery | Image: Coral Reef Alliance


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