Bleached corals on a reef off the island of Mayotte

© M.Oriot/Fonds Tara/afrol News

afrol News, 19 October - Scientists find that the corals on the Comoran island Mayotte are rapidly bleaching, which leads to a death of the reef. The situation on Mayotte was "the worst seen in the Indian Ocean," they report.

The Tara Oceans expedition is currently cruising the Indian Ocean. Onboard are also scientists from the International Union for Conservation of Nature (IUCN), studying the environmental state of the ocean.

Mayotte, a French island of the Comoran archipelago that lies to the north-west of Madagascar, was a stop-over of special interest to the expedition. Coral bleaching was first reported on the reefs of Mayotte in March this year, and the environmentalists wanted to investigate the situation.

Specialists from the Mayotte Marine Research Centre were taken onboard and the expedition assessed 34 sites around Mayotte and found that the situation was worse than expected.

"The reefs around Mayotte have experienced the worst bleaching and mortality so far recorded in the Indian Ocean with over 50 percent of corals affected by the bleaching overall and up to 30 percent coral mortality at the worst-affected sites," concluded IUCN's Dr David Obura.

The scientists see the global phenomenon of coral bleaching - which in turn can lead to the death of the reef - in connection with global warming. Especially outer clear-water reefs, such as in Mayotte, were typically worst hit.

The expedition is not to investigate the other three islands of the Comoran archipelago - Grand Comore, Anjouan and Moheli - but reefs there are expected to be similarly exposed to coral bleaching.

The Comoran reefs are among the least studied in the Indian Ocean, much due to the fact that Comoros does not have a developed tourism industry in contrast to Mayotte, Seychelles and Mauritius. It is however known that Comoran reefs already are severely damaged by decades of coral and sand mining.

"Recovery of these sites will depend on a number of critical factors," including the health of local fish populations, says IUCN researcher Dr Ameer Abdulla. "Unfortunately, many areas around Mayotte suffer from extensive fishing to the point of overfishing. A few areas, including the marine protected areas, hold healthy communities of fish. These areas will probably have the highest chance of recovery," Dr Abdulla added.

Mayotte island, which enjoys direct domestic flight connections to the French motherland, sees most of its revenues from the tourism and fisheries sectors. Both are thoroughly connected to the health of the island's coral reefs.

By staff writer

© afrol News

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