This Marine IBA is identified using both tracking data and seaward extensions around breeding colonies. It falls within the Namibia Exclusive Economic Zone (EEZ) and the Atlantic, Southeast FAO ocean region. The site covers an area of 33103 km2 and is 22 km away from the closet coastline. The depth ranges from 0 to 548 m, with a mean annual wind speed of 1.92 m/s and mean annual sea surface temperature falls between 12.4 and 17.2 °C.
13 species trigger IBA criteria at this Marine IBA. BirdLife analyses of tracking data estimates that 49126-120087 individuals of Black-browed Albatross (EN) from South Georgia are present at the site during the Non-breeding (May-Jul) life-history stage. 3543-5179 individuals of Atlantic Yellow-nosed Albatross (EN) from Gough Island are present at the site during the Non-breeding (May-Aug) life-history stage. 17700-21240 individuals of White-chinned Petrel (VU) from Iles Crozet are present at the site during the Non-breeding (Apr-Aug) life-history stage. 168480-311983 individuals of White-chinned Petrel (VU) from Iles Kerguelen are present at the site during the Non-breeding (Apr-Aug) life-history stage. Seaward extensions around breeding colonies; Mercury Island, Ichaboe Island, Lüderitz Bay islands, Possession Island, Sperrgebiet include key near-colony areas for breeding populations of Damara Tern (NT) , Great Crested Tern (LC) 1200-3705 individuals, King Gull (LC) 300-1140 individuals, Kelp Gull (LC) 1500-2400 individuals, African Penguin (EN) 8880-21945 individuals, Bank Cormorant (EN) 10122-10122 individuals, Cape Cormorant (NT) 15000-34200 individuals, Cape Gannet (VU) 25545-41310 individuals and Crowned Cormorant (NT) 320-1137 individuals.
BirdLife International (2023) Important Bird Areas factsheet: Sperrgebiet - Marine. Downloaded from http://www.birdlife.org on 08/02/2023.