Hold the anchovies and help penguins in peril
One of the world’s largest colony of penguins is facing a battle for survival because global warming is forcing the birds to swim up to 50 miles further in search of food.
Dee Boersma, a biology professor at the University of Washington, says that the Punta Tombo colony of Magellanic penguins on Argentina’s Atlantic Coast has shrunk by around 22 percent in the past 20 years, leaving just 200,000 breeding pairs.
The penguins already face major challenges to their survival from oil pollution and overfishing but now greater ocean variability caused by climate change has made life even tougher.
Boersma, who has been studying and tagging the community for the past two decades, says the birds are foraging for food up to 25 miles further than they were 10 years ago.
“That distance might not sound like much, but they also have to swim another 25 miles back, and they are swimming that extra 50 miles while their mates are back at the breeding grounds, sitting on a nest and starving,” she said.
Magellanic penguins make particularly devoted mates and parents with males and females sharing incubation, foraging and feeding responsibilities.
But the extra mileage is bad news for the colony’s breeding rate, with the prospects of a penguin pair successfully reproducing greatly reduced by the distance they are forced to swim for food. Changing ocean currents also mean the penguins are returning to their breeding grounds later and in poorer health.
Increased rainfall in recent years also poses a threat to the community. The penguins’ nests have flooded five times in the past quarter-century, threatening the survival of eggs and small chicks.
Boersma said the damage already done to the colony meant that the penguins were migrating further than ever in search of suitable breeding grounds and new colonies with some travelling up to 250 miles north from Punto Tomba.
Last year, hundreds of the penguins, many of them emaciated or already, dead washed up on beaches near Rio de Janeiro, more than 1,000 miles from their normal hunting grounds, according to a World Wildlife Fund study into the impact of climate change on wildlife.
Magellanic penguins are one of 17 species of the aquatic bird. Of those, 12 are currently considered endangered or at risk because of rapid population declines. Boersma said that overfishing of small fish had posed a devastating hazard to many penguin communities.
“Penguins are having trouble with food on their wintering grounds and if that happens they’re not going to come back to their breeding grounds,” she said.
“If we continue to fish down the food chain and take smaller and smaller fish like anchovies, there won’t be anything left for penguins and other wildlife that depend on these small fish for food.”
Click here to read more about the Magellanic Penguin Project. And for a World Wildlife Fund report into how climate change is threatening the birds click here (PDF).