Nature Notes – Fauna of the beaches

by Amy Schoeman

While the entire length of the Namibian coast forms the western fringe of the Namib Desert, it is surprisingly rich in fauna. A great many species of birds find their sustenance in the rich plankton and pelagic resources of the Benguela Current, while the beaches are kept clean by ghost crabs, jackal and hyaena.

Self-appointed health officials of the coast are black-backed jackals, Canis mesomelas, which patrol up and down the beaches keeping them clean of dead seals, birds and fish. They are attractive and colourful animals with their bright rufous coats and the broad conspicuous dark mantle down their backs. In competition for the refuse and carrion cast up by the tides are brown hyaena, Hyaena brunnea, dark-brown shaggy creatures with thick manes along their backs. They are seldom seen as they are strictly nocturnal, but make their presence known at night by the resonant ‘wah-wah-wah’ of their distinctive call.

Other scavengers of the coast are the ghost crabs, Ocypode africana and O. cursor, fair-weather creatures that make their appearance in large numbers when the sun is shining. At the slightest provocation they scuttle frenetically towards the sea, sometimes in large squadrons. They live in holes about 20 cm under the sand, and feed mainly on carrion and young mussels.

In contrast to the so-called barrenness of the desert is the immense richness of the adjacent ocean. The cold Benguela Current flows up Africa’s south-western coast from Antarctica, laden with oxygen and a rich variety of zoo- and phytoplankton. This plankton is driven close to the shore by the west winds, where the upwelling of the current causes it to rise to the surface. Exposed to the energy of the sun, a plankton ‘bloom’ is produced that feeds large schools of pilchards and anchovies, on which seals, cormorants, gannets and many other marine creatures feed.

The most numerous of the coastal birds are the cormorants, also the main producers of guano. Cormorants need up to 15 per cent of their body weight in food per day, and when they breed, up to 20 per cent. To gain the optimal use of the rich pelagic resources, they synchronise their breeding with the wind regimes. Small flocks of Damara terns are another common sight. These tiny birds lay their eggs about one kilometre inland on the open gravel plains in small holes scooped in the sand, in the same way as seagulls. Gull species include Sabine’s gull, the greyheaded gull and the blackheaded gull. Lesser and greater flamingos frequent coastal lagoons and waterholes, as do white pelicans.

There are several colonies of Cape fur seals, Arctocephalus pusillus, along the coast, the largest of which is at Cape Cross. As awkward as these animals look on land, as graceful and agile they are when cavorting in the Atlantic waves. They breed at 16 sites along Namibia’s coast, the biggest one being at Cape Cross, where as many as 350 000 can be seen at one time.

This article appeared in the Dec ‘04/ Jan ‘05 edition of Travel News Namibia.