“Cues take them to what used to be productive waters, but now those waters don’t have enough fish to meet their demands,” Stephen Votier, a researcher at the University of Exeter in the U.K. and co-author of the study, told CBC News. “And that drop in the forage fish is almost certainly driven by climate and the impact of fisheries. Hence that becomes an ecological trap. They’re following cues that used to work but that no longer takes them to the right places.”
Some of the cues these young penguins may be following are given off by phytoplankton — microscopic marine plants in the water that release substances while under stress, such as when they are consumed by predators like fish.
‘There are winners and losers, and it’s probably the case that the African penguin would fall into the cat of being losers at the moment.’ – Stephen Votier, University of Exeter
The researchers found that the young penguins can’t survive in such food-scarce environments along the coast of South Africa and Namibia. Their numbers are about 50 per cent lower than if they had travelled to other areas not suffering such depletions.
These juvenile penguins are vitally important to the health of a colony as, when older penguins die, they essentially take their place. But after travelling hundreds or thousands of kilometres — a critical period for them — and find nothing, they are unable to survive, leading to the collapse of a colony.
“But I think we should remind ourselves that something can be done, in terms of the reduction of greenhouse gases. Fishing is probably a more tractable fix.”
One of the efforts that should be undertaken is to better manage fishing areas, which, Votier points out, is beneficial not only for the penguins, but for fisheries as well who need a healthy ecosystem in order to sustain a viable practice.
Votier said that in areas where fishing practices have stopped, an improvement was seen in the numbers of breeding-age penguins who feed there (though, it’s not enough to have the population recover).
He also noted that, while experience has found that ending fishing in particular areas works on a small scale, it’s unknown yet whether it would work on a larger scale.
“There are winners and losers, and it’s probably the case that the African penguin would fall into the category of being losers at the moment,” Votier said. “But there is a willingness to try to resolve that. One thing that has been quite positive is that the fish industry is engaging in this dialogue and it’s not just conservationists.
“Hopefully by identifying [causes], you have the knowledge to try do something about it, and I think this is the step in the right direction.”