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Location Namibia, Karas
Central coordinates 15o 12.00' East  27o 1.00' South
IBA criteria A1, A4i, A4ii, A4iii
Area 80 ha
Altitude 0 - 5m
Year of IBA assessment 2001

Site description Possession Island is located 1.6 km from the Diamond Coast of south-western Namibia, just south of Elizabeth Bay, c.40 km south of Lüderitz. This rectangular island is the largest of Namibia’s guano islands. It extends 4 km from north to south and is at most 1 km wide. Low rainfall (less than 10 mm per year) and frequent storms inhibit vegetation growth, and isolated bushes are scattered around otherwise barren and somewhat sandy ground. Old diamond diggings have broken much of the sandy surface. The island still holds a main jetty and the remains of a small village. Like the other guano islands it was stripped of its guano cap in the 1840s and has never regained it. It is permanently manned to keep seals from settling on the island.

Key Biodiversity See Box for key species. As Possession Island is the largest of the Namibian coastal islands, it has the potential to hold the most seabirds. This honour, however, goes to Ichaboe (IBA NA016) which is 14 times smaller than Possession. Despite the relatively low seabird densities, Possession Island is a vitally important coastal seabird breeding island, supporting over 20,000 seabirds in total. Important species include decreasing numbers of Spheniscus demersus, Morus capensis, Phalacrocorax capensis, P. coronatus and P. neglectus (10 pairs). Some of these breeding seabirds have been in decline since the island was first surveyed in 1956. Numbers of Spheniscus demersus decreased by 92% and numbers of Morus capensis by 68% over the next 40 years. While some colonies have disappeared altogether, others remain at much-reduced densities. Single pairs are unusual, scattered haphazardly over barren portions of the island. Large areas which were once occupied by breeding birds, now stand unused. This is the only island breeding site of the normally mainland-breeding Sterna balaenarum. Small colonies of Sterna balaenarum, that once bred between dunes on the adjacent mainland, have largely disappeared since the early 1970s. Sterna bergii are said to have nested on the island, but now no longer do. Haematopus moquini are common on the island.

Non-bird biodiversity: Of great significance was the birth of a calf of Eubalaena australis (LR/cd) in Elizabeth Bay in 1996, the first breeding record of this whale on the Namibian coast for over 100 years.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
African Penguin Spheniscus demersus resident  300-900 breeding pairs  A1  Endangered 
Cape Gannet Morus capensis resident  800-3,000 breeding pairs  A1, A4ii  Vulnerable 
Cape Gannet Morus capensis winter  2,000-10,000 individuals  A1, A4ii  Vulnerable 
Cape Cormorant Phalacrocorax capensis resident  2,000-4,000 breeding pairs  A1, A4i  Endangered 
Cape Cormorant Phalacrocorax capensis winter  5,704 individuals  A1, A4i  Endangered 
Bank Cormorant Phalacrocorax neglectus breeding  10 breeding pairs  A1  Endangered 
Crowned Cormorant Microcarbo coronatus resident  20-280 breeding pairs  A1, A4i  Near Threatened 
Crowned Cormorant Microcarbo coronatus winter  50-500 individuals  A1, A4i  Near Threatened 
African Oystercatcher Haematopus moquini resident  66 breeding pairs  A1, A4i  Near Threatened 
African Oystercatcher Haematopus moquini winter  200-300 individuals  A1, A4i  Near Threatened 
Kelp Gull Larus dominicanus winter  2,864 individuals  A4i  Least Concern 
A4iii Species group - seabirds winter  10,000-19,999 individuals  unknown  A4iii   
A4iii Species group - seabirds breeding  10,000-19,999 individuals  unknown  A4iii   

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Namibia Islands Marine Protected Area 955,525 protected area contains site 80  

Land use

Land-use Extent (% of site)
nature conservation and research -

References Cooper et al. (1980), Cordes et al. (1999), Crawford et al. (1982, 1989), Hockey (1982), Noli-Peard and Williams (1991), Pallet (1995), Rand (1963), Swart (1987, 1988), Williams (1993).

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Possession Island. Downloaded from on 23/10/2016

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