From the ABC 7 Weather team

Study: Climate change, whales causing penguins to starve

April 12, 2011 - 03:39 PM
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That most iconic species of cold-weather waterfowl, penguins, is in peril due to climate change and hungry whales, according to the results of a long-term study.

A penguin that apprently starved to death lies on the sand at Peruibe beach in Sao Paulo state, Brazil, in 2010. (AP Photo/Aquario Municipal de Peruibe)

That most iconic species of cold-weather waterfowl, penguins, is in dire peril due to climate change and a resurgence of hungry whales, according to the results of a long-term study.

Back in the early 80s, about half of Adelie and chinstrap penguins on the West Antarctic Peninsula returned to their breeding grounds after hatching. That number has plummeted to just 10 percent today – the implication being that the AWOL penguins have starved to death.

Biologist Wayne Trivelpiece of the National Marine Fisheries Service, a researcher in the study who has been on the penguin case since the 1970s, thinks he knows what’s killing off the birds: a lack of krill. These tiny shrimplike crustaceans are a huge food source to young penguins, and without enough of them the creatures are essentially screwed.

So what’s causing the krill implosion? Trivelpiece et al cite two prime suspects.

The first is warmer temperatures over Antarctica. The average winter on the West Antarctic Peninsula has risen by 10 degrees since about 1950. Krill feed off of algae that accumulates on sea ice, and with warmer winters causing less ice their population drops sharply – about 80 percent since the mid-1970s, the researchers say. (It’s true that Antarctic ice increased during 2010, but any growth is expected to be temporary.)

Not everything is starving around the South Pole. Whales and seals have regained a little footing in the underwater food chain since the days when they were prey for widespread human hunting. These creatures are slurping up enough krill that it might actually be harming the penguins, according to the study. Humans are eating them, too: Krill factors into several types of dietary supplements. (Mmm… krill oil.)

So will the penguins be able to revert to their historical food source, fish? Maybe not, says Trivelpiece. As he told National Geographic:

"From everything we've seen over a 30-year period, while krill has declined 80 percent, we haven't seen an increase of fish in [penguin] diets," Trivelpiece said.

"But the fish stocks have also been heavily fished out by Russian trawlers, so we don't even know how much of that prey is available to them at this point."

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