If African penguins are facing extinction‚ we only have ourselves to blame.
According to alarming new research‚ juveniles heading off on their maiden swims from the Western Cape are falling into an “ecological trap”.
They are responding to cues — such as the chemicals plankton release and the temperature of the water — that for centuries have steered them towards food but are now plunging them into starvation.
These cues are “trapping juvenile penguins in areas with hardly any food” say the scientists‚ whose report is published in Current Biology.
It is estimated that only 20% of the juveniles are surviving their first year‚ and this ecological trap is the main cause.
This is the first known ocean “ecological trap”‚ which occurs when a once-reliable environmental cue prompts an animal to do something harmful because of human interference.
“Humans have broken the system‚” says Richard Sherley‚ a marine ecologist with the University of Exeter Environmental and Sustainability Institute.
The underlying causes include higher ocean temperatures‚ changes in salinity and overfishing‚ all of which have driven the fish penguins eat to an area the birds do not instinctively find.
This study is the best evidence so far of an ecological trap in the ocean‚ said Rob Hale‚ an ecologist with the University of Melbourne.
Adult members of the endangered species have adapted to the trap and shifted their hunting patterns. And Sherley and his colleagues used satellites to track juvenile penguins from the Namibia and Eastern Cape‚ and found that the eastern penguins have been unaffected by the trap because sardines and anchovy have moved closer to them.
Western Cape penguins have been worst affected. The population has declined 80% in the last 15 years‚ from 40 000 breeding pairs to 5 000 or 6 000‚ and Sherley said extinction could be a likely outcome.
To quantify the impact of the trap‚ researchers created models to estimate the size of the penguin population if juveniles swam towards the fish-rich waters to the east.
“The modelling suggests that the Western Cape population would be roughly double what it is now‚” Sherley said. “That’s quite a clear demographic impact.”
Humans are to blame for death march of the penguins‚ say scientists
If African penguins are facing extinction‚ we only have ourselves to blame.
According to alarming new research‚ juveniles heading off on their maiden swims from the Western Cape are falling into an “ecological trap”.
They are responding to cues — such as the chemicals plankton release and the temperature of the water — that for centuries have steered them towards food but are now plunging them into starvation.
These cues are “trapping juvenile penguins in areas with hardly any food” say the scientists‚ whose report is published in Current Biology.
It is estimated that only 20% of the juveniles are surviving their first year‚ and this ecological trap is the main cause.
This is the first known ocean “ecological trap”‚ which occurs when a once-reliable environmental cue prompts an animal to do something harmful because of human interference.
“Humans have broken the system‚” says Richard Sherley‚ a marine ecologist with the University of Exeter Environmental and Sustainability Institute.
The underlying causes include higher ocean temperatures‚ changes in salinity and overfishing‚ all of which have driven the fish penguins eat to an area the birds do not instinctively find.
This study is the best evidence so far of an ecological trap in the ocean‚ said Rob Hale‚ an ecologist with the University of Melbourne.
Adult members of the endangered species have adapted to the trap and shifted their hunting patterns. And Sherley and his colleagues used satellites to track juvenile penguins from the Namibia and Eastern Cape‚ and found that the eastern penguins have been unaffected by the trap because sardines and anchovy have moved closer to them.
Western Cape penguins have been worst affected. The population has declined 80% in the last 15 years‚ from 40 000 breeding pairs to 5 000 or 6 000‚ and Sherley said extinction could be a likely outcome.
To quantify the impact of the trap‚ researchers created models to estimate the size of the penguin population if juveniles swam towards the fish-rich waters to the east.
“The modelling suggests that the Western Cape population would be roughly double what it is now‚” Sherley said. “That’s quite a clear demographic impact.”
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