Approximately 10 000 penguins were contaminated by the spill, the worst in the history of South Africa, when it washed ashore onto both Dassen and Robben Islands.

Most of the oiled penguins were taken to the South African National Foundation for the Conservation of Coastal Birds (SANCCOB). Just over a month later, the first batch of cleaned penguins were released with flipper bands for monitoring purposes. Four years later, 2 907 or 71% of the more than 4 000 penguins which were banded and released have been seen again. Some of the birds have been sighted a number of times since their release.

One such example is penguin S24611 which was released from Silwerstroomstrand in 1994 and was seen three times on Robben Island between October and December 1996, once with a mate.

On June 2 1998, it was found oiled on Robben Island, following the Cape Town Harbour spill, and was taken to SANCCOB for its second cleaning in four years. It was re-released on June 29 from Melkbosstrand about ten kilometres from Robben Island, and wasted little time in returning to the Island, where it was seen two days later with its mate and two small, feathered chicks," said Mr Phil Whittington who maintains the database of sightings at the Avian Demography Unit.

He has urged members of the public to make contact with the South African Bird Ringing Unit (SAFRING), based at UCT if they find a dead penguin or any other bird with a ring giving the date, place and possible cause of death.