70% to 75% of the corals planted in Mahébourg as part of a coral restoration project have died. This was following cyclones Belal and Candice. This is according to a report from the Albion Fisheries Research Centre.
This document dated February 2024 indicates that two coral nurseries located in the Grand-Port fishing reserve zone were the subject of an evaluation at the end of January. This was to assess the damage caused by the two cyclones. These two sites had been entrusted to two non-governmental organizations: Eco-Sud and Reef Conservation, as part of the “Restoring Marine Ecosystem Services by Rehabilitating Coral Reefs to Meet a Changing Climate Future” project. The project was funded by the United Nations Development Program (UNDP).
The ecological monitoring survey was carried out on the coral nurseries of Eco-Sud and Reef Conservation by officials from the Albion Fisheries Research Centre. It made it possible to observe that the tables and ropes used to hang the corals on the Mahébourg site were heavily covered with sediments of fluvial origin. This was because of the heavy rains associated with cyclones Belal and Candice. On the other hand, for the Ile-aux-Aigrettes site, the corals were particularly affected by bleaching. Coral colonies outside of coral nurseries were also massively covered in sediments of terrestrial origin.
According to the report, coral nurseries in Eco-Sud suffered approximately 70% coral mortality due to sedimentation. At the Mahébourg site, approximately 90% of the corals died due to sedimentation. On the Ile-aux-Aigrettes site, some 35% of the corals have partially died due to sedimentation and bleaching. The remaining 65% were partially bleached, but alive.
For both Reef Conservation sites, officials noted that coral nurseries recorded approximately 75% coral mortality. Some 95% of the coral fragments at the Mahébourg site died due to sedimentation. On the Ile-aux-Aigrettes site, around 25% of the corals are dead. The remaining 75% were still alive, but partially bleached.
Vasisht Seetapah: “Our coral reefs and coral farms are struggling to survive”
Asked for a reaction, Vasisht Seetapah, Acting Head of Scientific Dept of Eco-Sud, indicates that the figures put forward in the Albion Fisheries Research Center report confirm their observations. “(…) In January, we faced an unprecedented phenomenon linked to cyclone Belal. A combination of factors caused an unprecedented release of fresh water into the Grand-Port lagoon. The change in salinity was so abrupt and strong that the coral reefs in the lagoon, as well as our coral farms, struggled to survive. In fact, 63% of the corals on our farms, which totaled around 21,500 fragments before Belal, did not survive this phenomenon,” he explains. Vasisht Seetapah indicates that he made the same observation on the Trou-Capitaine and Trou-Mootoo sites, near Île-aux-Aigrettes.
Eco-Sud's Acting Head of Scientific Dept says he is halfway through the project. The goal is to reach 80,000 coral fragments transplanted by 2026 in the Blue-Bay Marine Park. The area is 1.6 ha. “However, we want to avoid repeating the same mistakes,” he says.
Thus, among the 37% of corals that survived, certain species that showed better resistance and resilience will be prioritized. They will be grown in future similar restoration sites that have been affected by the same phenomenon. “In addition, we will soon establish a new nursery site in the Blue-Bay region. It will take into account the impacts of Belal to provide increased protection,” he says.
Financing of USD 9 million
The project “Restoring marine ecosystem services by rehabilitating coral reefs to meet a changing climate future” is financed by the UNDP to the tune of almost USD 9.1 million. It targets three islands: Mauritius, Rodrigues and the Seychelles. The objective is threefold:
- Improve food security and natural disaster risk reduction through restoration of degraded reefs;
- Knowledge management and sharing, training and awareness raising to build regional capacity for sustainable reef restoration;
- The establishment of cultivation facilities and coral nurseries.
We also sought comments from Reef Conservation on the subject. An email was sent to them to this effect. At press time, we had not yet received a response.
