Results of the 2001 census of African penguins Spheniscus demersus in South Africa: first measures of the impact of the Treasure oil spill on the breeding population

The Treasure, a bulk ore carrier, sank between Dassen and Robben islands on 23 June 2000. Subsequently, more than 19 000 African penguins Spheniscus demersus were oiled. A further 19 500 unoiled penguins were caught at Dassen and Robben islands and relocated to Cape Recife in the Eastern Cape to prevent them from becoming oiled. Despite concerns about the negative impacts of the incident on the penguin breeding population, especially on Dassen and Robben islands, the number of penguin breeding pairs in South Africa increased by 14% between 2000 and 2001. The increase appears to be related to an abundance of the two most important prey items of the African penguin, anchovy Engraulis capensis and sardine Sardinops sagax, in 2001. A larger proportion of clean penguins that were relocated to Port Elizabeth bred in 2001 than penguins that were oiled and cleaned. The results highlight the importance of oiling and rehabilitation and availability of food, especially of anchovy and sardine, for the future conservation of the African penguin.