Malgas Island carpeted by breeding Cape gannets
Malgas Island (33°03'S, 17°55'E), lies about 800 m from the
mainland, it is located at the northern entrance of Saldanha
Bay in the Benguela upwelling system.It is a small island, about
8.3 ha, almost rectangular and fairly flat, with the highest
point raising about 9 m above sea level. Parts of the island
consist of smooth rock and big boulders, though there are patches
of shallow soil, guano, sand and shell fragments.
Most of the central areas of the island are occupied by nesting
Cape Gannets, whereas other nesting seabirds are mostly confined
to the periphery. One exception is the
Kelp Gull Larus dominicanus
that have managed
to establish themselves in the very centre of the island, although
in low numbers. The few rocky outcrops in the midst of the gannets'
nesting ground are used both by Crowned and Cape Cormorants.
Crowned cormorant create these turret nest structures by adding
new nests on top of old ones. This species breeds all year round at Malgas Island
The breeding seabirds include Bank Cormorants Phalacrocorax neglectus,
Cape Cormorants P. capensis and Crowned Cormorants P. coronatus,
Kelp Gulls and
Hartlaub's Gulls L. hartlaubii,
African Penguins Spheniscus demersus.
The scarce vegetation consists mostly of low herbs that grow
during winter but there is almost no vegetation during summer.
There are no terrestrial mammals on Malgas Island. The table
below lists the biodiversity of the island.
The African Black Oystercatcher is a conspicuous
resident at Malgas Island
The paucity of the flora and fauna found at Malgas Island can be traced
to its history. Malgas, as well as all the other coastal islands
of southern Africa are part of the continental plate, and during
the Pleistocene glaciations (12 000 years ago) were part
of the mainland. About 2000 years ago the sea level was at least
3 m higher than at present, during this time most islands, including
Malgas, were either completely covered by water (appearing only
at low tide) or were frequently awash by high seas during storms
at spring tide. Clearly, most terrestrial flora and fauna was
completely eradicated from the islands. Other factor that has
a negative effect on the island's biodiversity are the seabirds
themselves. The high density of gannets literally covers everything
in guano, which, in spite of its famous fertilizing qualities,
is in itself quite inert.
Human impact on the nesting areas includes removal of the guano
cap in 1845, construction of low retaining walls, paths for
guano collectors and several buildings at the eastern side of
the island, where the landing jetty is also found.