email a friend
printable version
Location Sierra Leone, Western Area
Central coordinates 13o 3.00' West  8o 37.00' North
IBA criteria A4i, A4iii
Area 295,000 ha
Altitude 0 - 75m
Year of IBA assessment 2001

Conservation Society of Sierra Leone

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.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Great White Egret Ardea alba winter  500 individuals  A4i  Least Concern 
Charadrius alexandrinus winter  2,100 individuals  A4i  Not Recognised 
Grey Plover Pluvialis squatarola winter  2,300 individuals  A4i  Least Concern 
Common Ringed Plover Charadrius hiaticula winter  8,600 individuals  A4i  Least Concern 
Common Redshank Tringa totanus winter  4,000 individuals  A4i  Least Concern 
Sanderling Calidris alba winter  2,900 individuals  A4i  Least Concern 
Curlew Sandpiper Calidris ferruginea winter  9,500 individuals  A4i  Near Threatened 
A4iii Species group - waterbirds winter  20,000-49,999 individuals  unknown  A4iii   

IBA Monitoring

2013 high not assessed low

Biological resource use fishing & harvesting aquatic resources - unintentional effects: subsistence/small scale happening now majority/most of area/population (50-90%) moderate to rapid deterioration high
Pollution domestic & urban waste water - type unknown/unrecorded happening now some of area/population (10-49%) slow but significant deterioration medium
Residential and commercial development housing and urban areas happening now some of area/population (10-49%) very rapid to severe deterioration high

Little/none of site covered (<10%)  A management plan exists but it is out of date or not comprehensive  Some limited conservation initiatives are in place  low 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Sierra Leone River Estuary Wetlands of International Importance (Ramsar) 295,000 is identical to site 295,000  


IUCN habitat Habitat detail Extent (% of site)
Wetlands (inland) Coastal lagoons; Estuarine waters; Intertidal mud, sand or salt flats; Mangroves; Rivers & streams; Sand dunes and beaches - riverine  8%
Artificial - terrestrial   2%
Forest   90%

Land use

Land-use Extent (% of site)
agriculture -
fisheries/aquaculture -
urban/industrial/transport -

References Schwarz (1992), Taylor and Rose (1994), Tye and Tye (1987).

Contribute  Please click here to help BirdLife conserve the world's birds - your data for this IBA and others are vital for helping protect the environment.

Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Sierra Leone River Estuary. Downloaded from on 27/10/2016

To provide new information to update this factsheet or to correct any errors, please email BirdLife