Part of the exceptional coral reefs suffered the full impact of the cyclone. State of play.
The drama is not only human and social. It is also environmental. Catastrophic for the inhabitants of Mayotte, its fauna and its flora, Cyclone Chido also shook its lagoon and part of the exceptional coral reefs particularly suffered.
Donatien Pelourdeau, field agent for the Mayotte Marine Natural Park, comes back from a dive, the “first since Chido”towards Bambo islet (south-east of the archipelago). “There are many, many corals destroyed”he laments once back on the boat. “The expression that comes back is: pickled” et “even if we suspected it because (the outer part of the coral reef) is the most exposed, it hurts the heart”he admits to AFP.
Two to three dives per week
In thirty years, this specialist has seen “storms, but nothing to see” with what the 101st French department suffered on December 14, when Cyclone Chido devastated the Indian Ocean archipelago.
Since then, the teams from the Natural Park, headed by the French Biodiversity Office, have been diving two to three times a week. “to realize the impact of the cyclone”a first overview before the actual scientific monitoring, explains Sébastien Quaglietti, head of the Sea unit.
Some iconic underwater places in Mayotte have been hard hit, such as the Tombant des Aviateurs, or “outside the S Pass”testifies Annabelle Djeribi, deputy director of the Park. “Corals, sponges, gorgonians, there is absolutely nothing left, it’s dramatic”she laments. But “today, we cannot draw any conclusions, there are devastated places and others preserved”adds the manager cautiously.
Worse without the reef
Mayotte is surrounded by a double coral reef, a fringing reef and a barrier reef, the latter almost closing the lagoon, making it one of the largest in the world with its 1,500 km².
This specificity makes the archipelago a showcase of marine biodiversity, with 300 species of coral (there are between 800 and 900 in the world), 760 species of fish, 24 species of marine mammals and five species of turtles.
-Durant Chido, “coral reefs have played their role in protecting the land”rewinds Annabelle Djeribi. Thus during the cyclone, the “strong swell” of 9 meters outside the lagoon was “reduced to 5.5 m” inside, broken by the barrier.
Regeneration time
The reefs therefore have “suffered the full force of the impact”like mangroves, mitigating the effects of marine submersion and “retaining waste” scattered by the hurricane, according to Ms. Djeribi. Chido's effects “would have been even more devastating” if these two ecosystems “had been in poor health”says the manager who emphasizes the importance of letting them regenerate.
This attention is all the more necessary since El Niño, a cyclical natural event which impacts temperatures and causes bad weather in the areas concerned, had led to “lots of coral bleaching”what the cyclone “continued to deteriorate”notes Sébastien Quaglietti. In 2024, El Niño will cause the disappearance of 35% of reefs “and others were weakened”recalls Ms. Djeribi.
On the wildlife side, the species “mobile like fish and mammals were able to take shelter”estimates Yoan Doucet, head of the Park’s engineering department. All these specialists consider it crucial to give the marine environment time so that it can quickly reinvest its functions as a barrier and provider of food and economic resources.
Siltation
They say to themselves like this “vigilants” on the problems that already threaten it in normal times, such as siltation (20,000 tonnes of earth are dumped each year in the lagoon, due to agriculture and construction, according to Ms. Djeribi), poaching, waste. It will therefore be necessary to monitor “what will happen on land, and in particular the Mayotte reconstruction plan,” warns Mr. Doucet.
“The ecosystem will need all the energy and tranquility available» to rebuild itself, which will require “a work of the entire population in their daily activities”.
