More than 60,000 African penguins at two major colonies off South Africa’s coast starved to death after sardine populations collapsed, according to a new scientific study linking the losses to climate change and overfishing.
Researchers found that more than 95% of penguins at Dassen Island and Robben Island, two of the species’ most important breeding sites, died between 2004 and 2012. The findings were published in Ostrich: Journal of African Ornithology.
African penguins undergo an annual molting period that lasts about 21 days. During this time, they stay on land and cannot feed. To survive, they must build up enough fat beforehand. When sardines, their main food source, are scarce, penguins may not store enough energy to endure the fast, researchers said.
“If food is too hard to find before they molt or immediately afterwards, they will have insufficient reserves to survive,” said study co-author Richard Sherley of the University of Exeter’s Centre for Ecology and Conservation. Researchers believe many penguins died at sea rather than on shore.
According to the study, in all but three years since 2004, sardine biomass off South Africa’s west coast remained at about 25% of its highest recorded level. Rising ocean temperatures and changes in salinity have disrupted sardine spawning. At the same time, fishing pressure has stayed high.
African penguins have declined by nearly 80% over the past 30 years. In 2024, the species was classified as critically endangered, with fewer than 10,000 breeding pairs remaining.
South Africa has banned commercial purse seine fishing around six major penguin breeding colonies. Researchers hope the move will improve the penguins’ access to food during critical life stages. Conservation efforts also include artificial nests, predator control, and rehabilitation of weakened birds.
Marine biologist Lorien Pichegru, who was not involved in the study, called the findings “extremely concerning” and warned that small fish stocks remain dangerously low.