Sierra Leone River Estuary (6834)
Sierra Leone, Africa
Site overview
KBA status: confirmed
Year of last assessment: 2015
National site name: Sierra Leone River Estuary
Central coordinates: Latitude: 8.6167, Longitude: -13.0500
System: freshwater, marine, terrestrial
Elevation (m): 0 to 75
Area of KBA (km2): 558.23228
Protected area coverage (%): 75.84
KBA classification: Regional
Legacy site: Yes
Site details
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).
Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance that was identified using previously established criteria and thresholds for the identification of Important Bird and Biodiversity Areas (IBAs) and for which available data indicate that it does not meet global KBA criteria and thresholds set out in the Global Standard. KBA identified in the CEPF Ecosystem Profile of the Guinea Forests of West Africa Hotspot (2015). Taxonomy, nomenclature and threat status follow the 2013 IUCN Red List.
Additional 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.
Habitats
Land use: agriculture | fisheries/aquaculture | urban/industrial/transport
| IUCN Habitat | Coverage % | Habitat detail |
|---|---|---|
| Marine Intertidal | 3 | |
| Marine Coastal/Supratidal | 1 | |
| Forest | 90 | |
| Artificial - Terrestrial | 2 | |
| Wetlands(Inland) | 2 | |
| Marine Neritic | 2 |
Threats
Summary of threats to biodiversity at KBA: There is no official protection for this site. However, there are legal restrictions against fishing activities by large trawlers. Only artisanal fishing by small (2–8 man) canoes with nets or fishing line is permitted. Legislation also exists on the size of the net mesh that can be used, but there is little enforcement. Mangroves along the banks and creeks are being cleared for small-scale farming and they are also cut down and sold for firewood. Dumping of untreated waste from industries in the Freetown area and oil spillage from tankers unloading at the main port threaten the wildlife in the estuary. Although threat levels are thought to be generally low at present, conservation action is needed.
| Threat level 1 | Threat level 2 | Threat level 3 | Timing |
|---|---|---|---|
| Biological resource use | Fishing & harvesting aquatic resources | Unintentional effects: subsistence/small scale (species being assessed is not the target) [harvest] | Ongoing |
| Pollution | Domestic & urban waste water | Type Unknown/Unrecorded | Ongoing |
| Residential & commercial development | Housing & urban areas | Ongoing |
Additional information
References: Schwarz (1992), Taylor and Rose (1994), Tye and Tye (1987).