Juvenile African penguins stuck in ecological trap
Research indicates that juvenile African penguins continuously forage in areas of low food availability due to climate change and overfishing. The research conducted by an international group of scientists over the span of three years, highlights alarming results for the already endangered African penguin species, the only penguin endemic to the African continent.
Conducted between 2011 and 2013 by Dr Richard Sherley from the University of Exeter and a team of scientists from South Africa, Namibia and the United Kingdom, the study looked at the initial journey of 54 African penguin fledglings, including 14 rescued chicks that were hand-reared at SANCCOB. Penguins were tracked for the first few weeks of their lives out at sea using satellite transmitters.
The study revealed that the juvenile penguins used three main areas for finding food: Swakopmund in central Namibia, an area north of St Helena Bay along the West Coast of South Africa, and a third area around Cape Agulhas on South Africa’s south coast. Only birds from the Eastern Cape foraged east of Cape Agulhas whilst birds from the West Coast foraged north of Cape Town and into Namibian waters.
All three areas were historically rich in fish availability, including sardine and pilchards. Dr Katrin Ludynia, Research Manager at SANCCOB and co-author of the study explains, “Young penguins mistakenly select poor quality habitat because once useful cues (cold water and high primary production) remain intact in the face of underlying environmental change. One would expect to find abundant fish stocks in these areas but due to the combination of climate change and high fishing pressure over the past decade, fish is scarce along the West Coast.” This explains the low chances of juvenile penguins surviving their first year at sea, observed previously in other studies.
Owing to the rapid decline in population numbers, the African penguin was reclassified as endangered in 2010 and today, it is estimated that less than 2% of its historic population remain in the wild (less than 23 000 breeding pairs). Modelling exercises, presented in the current study, showed that with sufficient food in these areas, the African penguin population on the West Coast of South Africa would be twice the size it is now.
The study highlights that various conservation measures need to be implemented at different levels in order to save the endangered African penguin species. Apart from protecting critical breeding colonies and hand-rearing abandoned African penguin chicks, fish stocks have to be better protected in order for these birds to actually survive their first years at sea.