Two of the primary reasons behind dwindling populations of endangered young penguins in Africa are climate change and overfishing, researchers have showed through a study published in journal Current Biology.
A team of researchers from University of Exeter and University of Cape Town found that because of overfishing and climate change, young penguins in the region are getting confused about where to find food. They describes a dire predicament for African penguins, whose young population is projected to be down 50 per cent in some of the most affected areas of coastal Namibia and South Africa.
Researchers found that the juvenile African penguins are foraging for food in the wrong places. When young penguins leave their colonies for the first time and travel long distances, searching the ocean for signs that an area has plenty of fish and the smaller creatures they feed on, called plankton. These signs include areas of low sea temperatures and high chlorophyll-a,which indicates plankton is near, and likely also the sardines and anchovies that feed on it.
While these were reliable cues for prey-rich waters, that’s not the case anymore because of climate change and industrial fishing that have caused massive declines in fish stocks over the last few years. It was found during the study that these signals are effectively leading the young penguins to places where these fish are scarce.
Using satellites, researchers tracked newly fledged African penguins from eight sites across their breeding range. They found that many penguins were getting trapped in the Benguela Current Large Marine Ecosystem (BCLME), an area that stretches from southern Angola to Cape Point in South Africa’s Western Cape. The region has suffered from decades of overfishing and environmental changes, reducing the number of fish. While the penguins are still moving to places where the plankton are abundant, the fish stocks are scare at those places. Young penguins that wind up there often starve to death.
“Their breeding numbers are about 50 per cent lower than they would be if they found their way to other waters, where the human impact has been less severe,” said the study. Scientists are considering the possibility of transporting young penguins to areas where food is more abundant.