In May 2019, the sustainability team at Six Senses Zil Pasyon successfully completed the first stage of its coral restoration project. The project was put in place in October 2017 on the surrounding reef of Félicité as a technique to accelerate its recovery. It is part of a larger habitat restoration plan, which continues to unroll on the island in collaboration with two local NGOs; the Ramos Marine & Island Reserve and Nature Seychelles alongside the Seychelles National Parks Authority (SNPA). During the first two years of the coral restoration project, over a thousand grown corals have been transplanted back to the reef in the marine protected area between the northern side of Félicité and Coco Island.
Coral bleaching
Over recent years, corals have been under threat due to global heating and climate crisis. Because of the sudden increase of sea surface temperatures, the corals expel the algae living in symbiosis within their cells that provide up to 90 percent of their food requirements, making them white and resulting in widespread mortality (a process called coral bleaching).
Coral reefs comprise thousands of tiny creatures, named polyps, which exude a hard exoskeleton made of calcium carbonate. This creates a complex structure offering shelter, food and protection for a wide array of organisms and affecting livelihoods, food security and economic progress of marine species. This increase in the ocean’s water temperature can be caused by El Niño Southern Oscillation (ENSO), an event intensified by climate change, which caused up to 95 percent mortality in coral reefs and reduced coral cover from 50 to 5 percent around Seychelles in 2016.
Resilient species of coral
Some types of corals manage to survive these conditions and create heat resistant strains capable of functioning in warmer waters. Based on this, the coral restoration project was born on Félicité and its objective was to plant two resilient species or coral back onto the reef in order to create a healthy and self-sustaining ecosystem.
Coral nursery
An underwater nursery was built for the corals to grow before they are transplanted on the reef. This mid-water structure of 66 x 20 feet (20 x 6 meters) consisted of 22 ropes attached to PVC pipes, anchored to the sea floor and kept afloat using jerry cans. The nursery was situated around 23 feet (seven meters) from the surface to avoid sedimentation, coral predators and to facilitate an optimal light for faster coral growth. Because of their growth, survival rates, and their resistance to the temperature anomalies in 2016, the species selected were Pocillopora grandis and Acropora abrotanoides.
Replanting results
By August of 2018, a total of 1,750 fragments were stocked in the nursery and the transplantation process started in October 2018. Grown corals were fixed onto the rocky seafloor or on old dead coral using a mix of water-resistant materials. Within three months, the team was delighted to see that the coral tissue had started to grow. The project was completed in May 2019 with 1,339 successfully transplanted corals over the 1,750 grown colonies. At the beginning of the project the sizes varied between 1.20 to 4.3 inches (three to 11 centimeters) and in the final stage some of them reached an approximate size of 15.74 inches (40 centimeters).
According to the satellite models of the National Oceanic and Atmospheric Administration (NOAA), there is a warning for a coral bleaching event in the Seychelles this year, induced by El Niño heat stress, with the highest chance of mortality occurring between May and August. Some studies declare that colonies which survived previous bleaching events have higher chances of survival and can spread their resilient characters. In the same way, transplanted corals can help recruit new juvenile corals naturally, increasing the recovery of the ecosystem, as it’s being proved in other Seychelles regions, making coral reef restoration effective for a longer period.
What’s next?
After the successful completion of this first phase, the next step will involve the monitoring of the reef’s health, and especially of the transplanted corals. The Sustainability team are now conducting surveys for the design of a new type of coral nursery, which will further enhance the restoration of the marine ecosystem surrounding the island of Félicité.
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