The site comprises the coastal fringe of the large bay in south-west Mayotte. It extends from Poroani village (in the north) to Karoni hamlet, including the largest extent of mangrove on Mayotte (and indeed the Comoro archipelago), the landward strip adjacent to it, and also some intertidal mud. The strip is about 13 km long, and the mangrove belt reaches a maximum thickness of about 800 m. The landward side is cultivated with bananas and coconut, with a woodland of large trees (especially Heritiera sp. and Erythrina sp.) bordering the coast. The coastal plain is almost flat for up to 1.5 km inland. The towns of Chirongui and Tsimkoura lie a few hundred metres inland on this strip.
See Box and Table 2 for key species. Most of the forest-living birds of Mayotte occur. Of special importance at this site is the small population in the south (around Chirongui) of the restricted-range species Foudia eminentissima, which is otherwise poorly represented in the site inventory for Mayotte. Other species rare or absent from inland sites on Mayotte include the herons Ardeola idae and Butorides striatus and most shorebirds. In addition to the species listed, the threatened Ardea humbloti may occur as an occasional visitor.
Non-bird biodiversity: Threatened ecosystem: mangrove (largest area in Comoro archipelago). Reptiles: Phelsuma robertmertensii. No other data specific to this site.
BirdLife International (2019) Important Bird Areas factsheet: Bouéni Bay Mangroves. Downloaded from http://www.birdlife.org on 24/08/2019.