Baie de Bouéni Wildlife Reserve: Mapping the Coastal Ecosystems of Mayotte, France

Although Baie de Bouéni has long been part of the coastal landscape inhabited by communities in the Chirongui and Bouéni communes of south-west Mayotte, its formal recognition as a protected natural area came relatively recently. In 2007 the bay and its surrounding coastal strip were acquired by the Conservatoire du Littoral, the French national agency responsible for safeguarding outstanding shoreline and lakeside sites.

Following this acquisition, the bay gained a clear institutional identity as a conservation site. Recognition by BirdLife International as an Important Bird Area confirmed the international significance of the habitats already known locally, particularly the mangrove fringe and the intertidal mudflats that support regionally important bird populations.

The designation placed Baie de Bouéni within the evolving network of protected coastal sites across Mayotte and strengthened the territory's profile as a stronghold for mangrove and island biodiversity in the western Indian Ocean. It also marked a turning point in formal scientific attention to the Comoros' remaining mangrove stands, of which this bay holds the largest example.

The natural character of Baie de Bouéni is dominated by its mangrove ecosystem, the largest of its kind in the Comoro archipelago. The mangrove strip runs for several kilometres along the bay's eastern shore and reaches several hundred metres inland in places, forming a near-continuous green fringe between the water and the land. At least seven species of mangrove tree have been recorded for Mayotte within this habitat, contributing to an unusually diverse mangal for a small island group.

Behind the mangroves lie extensive intertidal mudflats that emerge at low tide and provide rich feeding grounds for coastal birds, crustaceans, and other invertebrates. This combination of mangrove cover and tidal flats creates a transitional zone where marine and terrestrial influences overlap almost continuously along the shoreline. The small islet of Chissioua Karoni adds a further dimension, providing hard substrate habitat distinct from the muddy coastal fringe.

Beyond the shore itself, the bay's catchment reaches into the surrounding volcanic uplands. Drainage from the slopes of Mont Bénara and Mont Choungui feeds the coastal system with freshwater and nutrients, reinforcing the productivity of the mangroves and mudflats. Altogether, the bay stands as a compact but ecologically rich mosaic of coastal habitats within the broader island ecosystem of Mayotte.

The wildlife profile of Baie de Bouéni is closely tied to its mangrove and intertidal habitats. The bay has been identified by BirdLife International as an Important Bird Area precisely because these habitats support bird populations of regional and global conservation concern.

Among the species associated with the bay are the Malagasy pond heron, a heron of regional significance whose populations depend on wetland and mangrove-rich coastlines; the Mayotte drongo, an island-associated forest bird; the Mayotte white-eye and the Mayotte sunbird, two of the bird species characteristic of Mayotte's woodland and coastal habitats; and the red-headed fody, a small passerine whose range includes the western Indian Ocean islands. Together these species point to the bay's role as both a mangrove specialist site and a stronghold for island-endemic birds.

The bay also supports a colony of crabier blanc, a white heron species, within its mangroves, highlighting the site's relevance for waterbirds as well as forest-associated species. Beyond birds, the area is home to the endangered and endemic Robert Mertens's day gecko, a reptile found only in limited parts of Mayotte and dependent on intact coastal habitat. This combination of endemic birdlife, waterbirds, and an endemic reptile gives the bay a distinctive place in the regional wildlife network of the Comoros.

Baie de Bouéni holds a clear conservation profile that extends well beyond its local shoreline. It contains the largest remaining mangrove belt in the Comoros, an ecosystem that has declined sharply on many islands worldwide, and therefore serves as a regional refuge for mangrove biodiversity in the western Indian Ocean.

The bay's formal protection began in 2007, when the site was acquired and brought under the management of the Conservatoire du Littoral, the French national agency dedicated to safeguarding outstanding coastline and lakeshore areas across France and its overseas territories. This designation ensured that the mangrove fringe, intertidal flats, and surrounding coastal lands would be managed with conservation as a primary objective.

Recognition as an Important Bird Area by BirdLife International gave the bay an international conservation identity and underlined its role in supporting threatened and endemic bird populations, as well as the endangered Robert Mertens's day gecko. In practical terms, the bay functions as a reference site for mangrove and coastal bird conservation in the Comoros, anchoring efforts to monitor, protect, and potentially restore mangrove habitat across the archipelago.

The bay lies within a region of Mayotte with a long-standing coastal human presence. The communes of Chirongui, on the south-eastern side of the bay, and Bouéni, to the east, both border the inlet and give the bay its name. These communities are part of Mayotte's broader Mahoran cultural landscape, in which fishing, small-scale agriculture, and coastal settlement have shaped the relationship between people and the sea for generations.

From Mont Choungui and other vantage points around the bay, villages such as Tsimkoura and Chirongui are visible along the shoreline, illustrating how closely the inhabited landscape and the mangrove-lined coast are interwoven. The bay itself, together with the small islet of Chissioua Karoni, forms part of the local geographic identity and is a familiar feature in the everyday surroundings of nearby communities.

The single most defining feature of Baie de Bouéni is its mangrove belt, the largest in the Comoros, which forms a continuous coastal strip along the bay and supports a rich mosaic of associated habitats. The bay's intertidal mudflats add a second layer of ecological value, exposing rich feeding grounds for waterbirds at low tide.

Equally striking is the visual setting, in which the curving bay sits between two of Mayotte's most prominent volcanoes, Mont Bénara and Mont Choungui, with the small islet of Chissioua Karoni lying near its centre. The combination of formal protection since 2007 under the Conservatoire du Littoral, international recognition as an Important Bird Area, and the presence of an endemic gecko species gives the site a tightly defined and internationally significant conservation identity.

As a coastal and mangrove-dominated site, Baie de Bouéni is best appreciated when conditions allow clear views across the bay and active bird presence along the shoreline. The dry season months, broadly aligned with the cooler and less humid period in the southern hemisphere winter, generally offer calmer seas, better visibility from the surrounding volcanic viewpoints such as Mont Choungui, and easier walking on exposed mudflats and beaches.

The wetter and warmer months bring heavier seas and reduced visibility but can also be a time of greater waterbird activity around the mangroves. Birdwatchers and naturalists may find the transitional shoulder periods particularly rewarding, when bird populations are active and weather is not yet at its most extreme. The bay is an outdoor site, and conditions can shift quickly, so visitors typically prefer clear, dry days for both panoramic views from the surrounding peaks and shoreline exploration.