50,000 corals grown in ocean nurseries – a giant leap for Seychelles |10 April 2025
50,000 corals grown in ocean nurseries between 2021-2025 (Photo: Contributed)
Nature Seychelles is excited to share a huge milestone in its coral reef restoration in the Cousin Island Special Reserve.
Between April 2021 and April 2025, the NGO’s Reef Rescuers team, with the help of volunteer scientific divers from around the world, has grown 50,000 coral fragments in underwater nurseries at Cousin Island.
This has been achieved under the Coral Reef Restoration Project, funded by the Adaptation Fund through the UNDP and the Seychelles government. This is a regional collaboration between Seychelles and Mauritius to restore coral reefs using both ocean and land-based nurseries.
“Nature Seychelles has now met the targeted number of corals in underwater nurseries under this donor-funded project,” says Dr Nirmal Shah, Nature Seychelles chief executive.
“Our team has worked extra hard to reach here. We started this project during the Covid-19 pandemic and faced other challenges such as the theft of our boat and boat engines. These are critical for the project, and it delayed months of operations where underwater activities to collect and stock corals for the nurseries stalled,” he added.
Coral reefs face many problems, most notably the catastrophic and widespread climate change-induced coral bleaching. The nursery and its care are essential for reef restoration, as they prepare coral fragments for reintroduction to the reef. The Reef Rescuers built nine underwater rope nurseries holding different species of corals, including Acropora and Pocillopora species commonly used due to their occurrence.
Corals of opportunity, which are fragments that have broken off the reef due to wave action or storms, along with harvested corals from nearby healthy donor sites, were collected. After collection, they were transported above water in large tubs, fragmented further, and attached to ropes. These ropes were then placed onto pre-constructed nursery structures.
“The nurseries are made of low-cost materials you can find locally in hardware stores such as ropes, metal bars, PVC pipes, and jerry cans used for suspension,” says Dr Luca Saponari, the team leader, adding that the construction of nurseries is both delicate and physically demanding, and is usually done in ideal sea conditions.
It can take up to a year for corals to reach a suitable size for transplantation, so coral nursing is a continuous task. The coral fragments are monitored as they grow for size, survival, health conditions, diseases, predation, and bleaching. Dead fragments have to be removed and replaced with new fragments.
The nurseries also need to be constantly cleaned to prevent competition with algae and other bio-fuelling organisms. If not removed these organisms can encroach on the coral itself potentially causing extensive tissue loss and even death. Toothbrushes, table knives, and scrubbing brushes are used for cleaning. But cleaning is no easy feat with each rope holding around 100 corals.
“Cleaning becomes particularly challenging during the south east monsoon, which creates optimal conditions for plankton and algae growth. Extra effort is required, but the nurseries are often inaccessible due to rough weather,” Luca said.
“It has taken many years of hard work, but we are thrilled to share this milestone,” Dr Shah concluded.
The accompanying photos after following in action.