(CN) – Rapid shifts in the ocean caused by fishing and climate change threaten the endangered African penguin, whose natural instincts lead it to seek food in regions that are now resource-poor and filled with predators.
Juvenile African penguins typically search large stretches of ocean for certain signs that suggest there is plenty of prey nearby.
But in a study published Thursday in the journal Current Biology, researchers detail how changing dynamics sparked by fishing and climate change are causing the birds to hunt for food in areas with minimal prey – and a variety of predators.
“There were once reliable cues for prey-rich waters, but climate change and industrial fishing have depleted forage fish stocks in this system,” first author Richard Sherley said.
This “ecological trap” results from small changes in the salinity and temperature of the waters in the area known as the Benguela ecosystem has forced anchovies and sardines to move their distribution hundreds of miles to the east.
“Juvenile African penguins look for areas of low sea temperatures and high chlorophyll-a, which indicates the presence of plankton and therefore the fish which feed on it,” Sherley said.
The team worked with government scientists from South Africa and Namibia to deploy satellite trackers on 54 juvenile penguins from eight colonies spanning the species’ breeding distribution.
Using the data from the satellite trackers, the scientists found that the combined impact of commercial fishing and environmental changes off western South Africa has significantly reduced prey populations.
“Our results support suspending fishing when prey biomass drops below certain levels, and suggest that mitigating marine ecological traps will require major conservation action,” Sherley said.
The African penguin – previously known as the jackass penguin – is listed as endangered by the International Union for Conservation of Nature, which says the species is “undergoing a very rapid population decline” that shows “no sign of reversing.”