Longshore drift of sediments from south to north along the coast, driven by the Benguela Current, has led to the formation of a sandbar across what was formerly a coastal embayment just south of the rocky promontory of Cape Cross. The inner part of the embayment remains a series of saline lagoons. These receive oceanic water from seepage through the sandbar and, during extreme high tides or storms, by water washed over the sandbar. The lagoons vary in size and number depending on water-level, and are controlled by two main factors: evaporation and seawater input. Desiccation of the eastern borders of the embayment has produced sterile saltpans and flats. These salt deposits are worked commercially on a small scale. Three wooden platforms with a total area of 68,000 m² have been erected in some of the lagoons to provide roosting and breeding places for seabirds, as their guano is commercially harvested. Guano from these platforms probably serves to enrich the micro-flora and fauna of the lagoons. There is an irregular fringe of saltmarsh vegetation along the coastal edge of the lagoons. Inland of this region are the rocky gravel-plains of the Namib desert.
See Box for key species. The lagoons, and their platforms, have been known to support up to 14% of the global population of Phalacrocorax capensis (30,600 pairs), but estimates as high as 900,000 cormorants were made from aerial counts in 1974. Regular wetland counts indicate that, in addition to cormorants, these lagoons regularly support up to 11,000 other birds. In total, the lagoons and platforms regularly support over 20,000 birds, including up to 16% of the southern-African-endemic subspecies Podiceps nigricollis gurneyi and large numbers of Phoenicopterus ruber and P. minor, Charadrius pallidus, Calidris ferruginea, C. minuta, Larus dominicanus, L. hartlaubii, Sterna balaenarum, S. bergii and large flocks of S. hirundo.
Non-bird biodiversity: A massive mainland breeding colony of the Namibian near-endemic seal Arctocephalus pusillus, numbering 156,000 adults and subadults, occurs here. This is one of two populations in Namibia that are harvested commercially, mainly for pelts.
BirdLife International (2021) Important Bird Areas factsheet: Cape Cross lagoon. Downloaded from http://www.birdlife.org on 05/03/2021.