Site description This site is the drowned estuary of the Rokel or Seli river. It is bounded to the north by a coastal plain indented by creeks, and to the south by the mountainous Western Area peninsula. At the point of entry into the Atlantic Ocean, the estuary widens to about 11 km and abruptly deepens along its southern shore to form a natural harbour (the third-largest in the world). The estuary is lined by 110 ha of mud and sand foreshore, backed by mangrove, and 1,800 ha of intertidal mudflat and muddy sandflats. The predominant mangrove tree species are Rhizophora sp., Avicennia africana, Laguncularia sp. and Conocarpus sp., and these cover a total of 34,234 ha (19% of the total area of mangrove in Sierra Leone).
Key Biodiversity See Box for key species. A total of 36 wader species have been recorded in the estuary and numbers are known to exceed 20,000 regularly. This is one of the four major sites for wintering waders in the country. Concentrations are usually found along the banks of the Bunce river and Aberdeen Creek, where mangrove provides suitable roosting sites, as well as breeding habitat for such species as Butorides striatus. Less common migrant Palearctic waders (less than 500 individuals) found include Arenaria interpres, Numenius arquata, Tringa stagnatilis and Calidris temminckii.
Non-bird biodiversity: None known to BirdLife International.