More than 60,000 penguins in colonies off the coast of South Africa have starved to death as a result of disappearing sardines, a new paper has found.

More than 95% of the African penguins in two of the most important breeding colonies, on Dassen Island and Robben Island, died between 2004 and 2012. The breeding penguins probably starved to death during the moulting period, according to the paper, which said the climate crisis and overfishing were driving declines.

The losses that researchers recorded in those colonies were not isolated, said the paper, which was published in Ostrich: Journal of African Ornithology. “These declines are mirrored elsewhere,” said Dr Richard Sherley, from the Centre for Ecology and Conservation at the University of Exeter. The African penguin species has undergone a population decline of nearly 80% in 30 years.