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Coral reefs of SW Madagascar
Satellite image of the Bay of Ranobe
The principle marine and coastal environments of south-western Madagascar are:
• Mangroves
• Estuarine mud flats
• Beaches
• Coral reefs
• Seagrasses
Of the 3,540km of reef systems surrounding the island of Madagascar the majority are found on the west coast, which has 90% of the island’s coral reefs and 98% of its mangroves. In contrast, the east coast is dominated by steeply shelving beaches and rocky shores.
The reef structures present in south-west Madagascar are emergent fringing reefs, true barrier reefs, patch reefs and submerged coral banks and shoals comprising:
• 113km of fringing reef,
• 557km of reefs around islands and inlets, and patch reefs,
• 52km of true barrier reefs (all in the Toliara region),
• 1,711km of submerged coral banks and shoals.
View satellite images of SW Madagascar at GoogleMaps
The reef systems of the south-western region are some of the most heavily documented reefs, with numerous publications in the 1960s and 1970s, most of which focus on the true barrier reef of Toliara - the Grand Recif du Toliara. The reef itself is 27km long and 3km wide.
Grand Recif du Toliara
The Toliara reef system is split by two passes caused by the river Fiherenana to the north and Onilahy to the south. Continuing north of the Fiherenana, a heavily sedimented fringing reef re-appears called the reef of Songeritelo, which develops into a barrier reef at Ifaty creating the Ifaty barrier reef and the Bay of Ranobe.
The Bay of Ranobe reef system is punctuated by two passes (South and North) and a false pass 2km south of the South pass. As the reef continues north it approaches the coast forming a fringing reef, which is broken at the Manambo River and the mangrove system of Fitsitika. To the north, the reef reappears and continues unbroken all the way to the Bay of Assassins, where it is broken by numerous inlets from Andavadoaka to Morombe and the Mangaky delta.
Overall the reef system from Toliara to Morombe creates 400km of nearly continues shallow water reef, which is one of the most extensive systems in the western Indian Ocean region.
Though these reef systems are extensive, they are under enormous pressure from human and natural factors.
