Sandwich Harbour is a natural lagoon which lies on the Namib desert coast, c.55 km south of Walvis Bay. One of Namibia’s four Ramsar Sites, and the country’s only marine reserve, Sandwich was once a natural harbour for whalers and fish processors who could gain access to fresh water here. Owing to dynamic geomorphological change, its sandbars and lagoons shift constantly with winter storms and longshore currents.Two main sections of this wetland are recognized: the northern freshwater wetland, much reduced in size since the early 1970s when it covered c.2 km², and the southern mudflats, a 20 km² area of sand and mudflats inundated daily by the tides. The northern wetland is now a thin sliver, mainly of reedbed Phragmites, fed by a massive freshwater aquifer beneath the high dunes of the Namib sand-sea. This potable water slowly seeps through the wetland and there supports lush but dwindling stands of emergent and marginal vegetation. The wetland is protected from the Atlantic Ocean swells by a barrier beach which has moved from 1 km to within 100 m of the dunes. The southern lagoon, which leads into mudflats, is a relatively shallow water-body some 5 km long by 3 km wide. It is protected from the ocean by a western sand-spit that once reached the northern wetland but now joins the mainland some 3 km south of it.Sandwich Harbour is one of the most geomorphologically active areas along the entire Namib coast. In the late 1800s there was no barrier beach and therefore no protected wetland and an otherwise open harbour. The system continues to evolve rapidly and contrary to popular belief it is far from dead.
See Box for key species. This is the most important wetland for waterbirds in southern Africa, with counts exceeding 300,000 birds in some years. Sandwich Harbour regularly supports over 50,000 birds in summer and over 20,000 in winter. Traditionally, the northern wetland holds the highest species diversity (up to 51 species of wetland bird), while the southern mudflats hold by far the largest number of birds, dominated by terns, sandpipers, flamingos and cormorants. Shorebirds occur here at densities exceeding 7,000 birds/km², amongst the highest recorded in the world. The largest total counts at Sandwich Harbour have been 238,000 birds in January 1998 and 316,000 in January 2001.The area is vitally important for Palearctic waders and flamingos, which comprise the majority of the numbers. The area supports massive numbers of several species, including Phalacrocorax capensis, Phoenicopterus ruber and P. minor, Sterna hirundo, up to 40% of the world population of Charadrius pallidus, and tens of thousands of Calidris ferruginea and C. minuta. At times, the combined total of birds in Sandwich Harbour and Walvis Bay is so large that it constitutes half of all birds counted in southern Africa during African waterfowl counts.
Non-bird biodiversity: The dolphin Tursiops truncatus (DD) is seen in the lagoons, with pods of 10–20 animals not uncommon, while a non-breeding colony of c.10,000 Arctocephalus pusillus occupies the beach west of the mudflats. Hyaena brunnea (LR/nt) is a frequent visitor to the wetland.
Pressure/threats to key biodiversity
There have been no permanent human inhabitants at Sandwich Harbour since 1969, although remnants of a whaling station exist at the foot of the dunes and several wooden buildings belonging to earlier guano collectors and fishermen still stand. The entire area was a marine reserve, but that status was lost in 1994 through a legal oversight. Sandwich lies within the boundaries of the Namib-Naukluft Park (NA010), managed by the Ministry of Environment and Tourism. Owing to its discrete and dynamic nature it is treated as a separate IBA from the Namib-Naukluft system. Should current geomorphic processes eradicate the northern wetland, most of the freshwater vegetation would be lost and species richness would probably decrease. Any plans for the area should recognize that the southern end of the harbour supports the greatest abundance of birds, and this situation will remain, irrespective of the fate of the northern wetland. It is one of the best studied and most fascinating wetlands in Namibia, with bird counts spanning a period of 27 years and further research planned on the invertebrate fauna that presumably accounts for the high densities of waders found here.The one conservation problem is the constant illegal low flying undertaken by tour companies, which ‘buzz’ the flamingos and cormorants 5–6 times daily in order to show visitors the sights of Sandwich Harbour, particularly flushed flamingos. Height restrictions are now set at 1,000 m and more regularly enforced. The area’s history is well known and numerous artefacts, grave sites, shipwrecks and large shell middens litter this fascinating site.
BirdLife International (2022) Important Bird Areas factsheet: Sandwich Harbour. Downloaded from
http://www.birdlife.org on 07/07/2022.