|Central coordinates||15o 12.00' East 27o 1.00' South|
|IBA criteria||A1, A4i, A4ii, A4iii|
|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.
|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 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||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 http://www.birdlife.org on 23/10/2016
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