This coastal IBA is situated in central Namibia, on the border of the Namib desert, between the harbour town of Walvis Bay and Swakopmund. It is essentially a 30 km by 0.7 km stretch of beach comprising mainly sand, with isolated rocky outcrops forming less than 5% of its length. Two small resorts occur in an otherwise uninhabited section of coast, namely Langstrand and Dolphin Strand. Rainfall here is highly variable, averaging about 15 mm per year, but precipitation from coastal fog occurs during one out of every 3 days on average. Line fishing is common along the northern sections, while swimmers and surfers are concentrated around the two resorts. The area is the focus of an intense oceanic upwelling system that begins in Lüderitz, where nutrients are brought to the surface, and algal and zooplankton blooms form as the water is swept north by the Benguela Current. Between Walvis Bay and Henties Bay inshore winds push large quantities of nutrients inland, supporting an abundance of invertebrates on the sandy and rocky shores. Invertebrate densities on both shore-types are higher than any other beach in southern Africa. Furthermore, the effect of the Pelican Point sand-spit is to refract waves around and into the bay, concentrating the nutrients still further on these shores. Little vegetation occurs, although washed-up kelp is seen on some sections and there provides a rich microhabitat for kelp flies and associated shorebirds. Associated with this beach is the only bulge along an otherwise straight beach, known as Caution Reef (or Patrysburg). This is an area of sandflats immediately behind a shingle beach, rising to a raised plateau overlooking the shore about 600 m inland. The road between Swakopmund and Walvis Bay acts as a boundary to the area c.1 km inland.
See Box for key species. This site is not only the richest shoreline in terms of shorebird density anywhere in southern Africa, but it supports the densest colony of breeding Sterna balaenarum known. Surveys 20 years ago showed the beach to hold peak shorebird numbers of 448 birds/km. Similar densities were recorded in 1996 (451 birds/km). Individual 10-km sections, including the rocky shores between Caution Reef and Swakopmund, peak even higher at 770 birds/km. Totals for this 30-km stretch of beach therefore exceed 13,000 shorebirds of c.31 species, most of which are Palearctic migrants. The most abundant waders (Charadrii) are Arenaria interpres, Calidris ferruginea, Pluvialis squatarola and Numenius phaeopus. Breeding Sterna balaenarum occur mainly at Caution Reef and breed from October through February. Densities within a 2 km² study area have exceeded 120 nesting pairs or 60 pairs/km². This is considerably higher than the modal density in Namibia of about 1 pair/km². Other birds breed further inland at lower densities. Breeding and ringing studies have continued since 1995. Large numbers of Sterna hirundo/S. paradisaea flock here, and large numbers of cormorants, which use the artificial guano platform at the southern end of this IBA, sometimes roost on the beach.
Non-bird biodiversity: In recent years the rare cetacean Caperea marginata (five records) has occurred or been stranded on these beaches, while Lagenorhynchos obscurus (DD), Tursiops truncatus (DD) and Cephalorhynchus heavisidii (DD) are frequent visitors.
Pressure/threats to key biodiversity
As of 2001, breeding Sterna balaenarum are protected on their Caution Reef breeding site, and losses due to non-hatching have dropped by about 30%, due to a barrier preventing off-road vehicles from driving over the colony and new interpretation signs for visitors. Larus dominicanus and Canis mesomelas, attracted to fishermen and their bait, have also decreased due to the protective measures, thus decreasing predation on eggs.Fishermen regularly use the same beaches as the shorebirds, but space competition is not severe. What is more important is the possibility of major developments, including casinos and hotels, proposed for the Caution Reef plains. A building on the site, or close to it, is likely to drive birds away, even though the terns tolerate a certain degree of visitor traffic. Dogs and visitors to the two resorts also disturb feeding birds in some sections of this productive beach, but the impact is relatively minor. Pollution is relatively rare away from the Walvis Bay harbour, but tankers anchored in the bay opposite Pelican Point clean their bilges, and scum from this uncontrolled source may be problematic.
BirdLife International (2021) Important Bird Areas factsheet: 30-Kilometre Beach: Walvis - Swakopmund. Downloaded from
http://www.birdlife.org on 22/09/2021.