Seal Island

Overview

Seal Island in False Bay consists essentially of a huge granite rock 2 ha in area, with no beaches or vegetation. It lies almost centrally in the northern part of False Bay, 5.7 km offshore. A radio mast, built on the island during World War II, was a conspicuous landmark in the bay until it was blown over in a winter storm in 1970. All that remains of this is some rusty, twisted metal. There are also ruins of some huts and a few structures from the sealing and guano-collection era. Some rock inscriptions made by sealers in the 1930s are still evident. Guano collection ceased in 1949.

About 100 years ago (ie about 1880), the great voyage of the HMS Challenger brought the naturalist Moseley to the Cape. The following extract from his notes brings out the changes that have taken place since then - or at least one of them. "I paid a visit to an island in False Bay, called Seal Island. It is a mere shelving rock, on which it is only possible to land on very favourable occasions. The whole place is a rookery of the Jackass Penguin".

Nowadays, this island supports the largest Cape Fur Seal Arctocephalus pusillus colony in the Western Cape; up to 75 000 seals occur. The growth of the population of seals was held in check by a quota system until the early 1980s. The market for fur seal products crashed in 1983 and seal harvesting no longer occurs on Seal Island. As a result, the seal population has increased dramatically in recent decades. The seals attract Great White Sharks Charcharadon charcharius, and an ecotourism industry to view the sharks is slowly developing.

Seal Island continues to support a small population of African Penguins. The penguins have been provided with artificial nest sites, and this has increased their breeding success. In spite of the increasing seal population, the number of penguins has remained stable since the 1980s, and about 80 pairs breed each year.

Other bird species which breed regularly on the island are Whitebreasted Cormorants and Bank Cormorants. Cape Cormorants bred for the first time in 2000; there were 30 nesting pairs. A handful of Cape Wagtails almost certainly breed on the island. There are a few Turnstones in summer, but no African Black Oystercatchers.

Cape Gannets bred on the island in the 17th century, but it is not documented when this colony folded. Kelp Gulls last bred in the 1950s. They remain common scavengers on the island, though.

Cape Town Green Map
updated 03/2012 by Cape Town Green Map