Fewer Penguins in Antarctic!
PureSilver67: Fewer penguins survive warming Antarctic climate Two of the most well-known penguin species in Antarctica -- chinstraps and Adelies -- are under pressure because a warmer climate has cut deeply into their main food source, shrimp-like creatures called krill. Fewer of the juvenile penguins survive what scientists call their "transition to independence" because there isn't enough krill to go around, according to a study published on Monday in the Proceedings of the National Academic of Sciences. The study found only 10 percent of young penguins survive the first independent trip back to their colonies from their winter habitat, said lead author Wayne Trivelpiece, a sea bird expert at the National Oceanic and Atmospheric Administration's Antarctic Ecosystem Research Division. When the study began, back in the mid-1970s, the chances that a two-to-four-year-old penguin would survive the trip was about 50 percent, Trivelpiece said in a telephone interview. "What's changed is young penguins surviving their transition to independence," he said. "They're no longer able to do that anywhere near the way they used to do, and we think that's directly related to the fact that there's 80 percent less krill out there now." Initially, scientists figured one of these two penguin species might actually benefit from climate change, since Adelies love ice and chinstraps avoid it. They theorized that the chinstrap penguins might flourish with less ice and more of the open water they favour. But this latest research suggests it is less a question of vanishing penguin habitat -- though this is also occurring -- than it is a matter of vanishing habitat for krill.
(Source: http://www.reuters.com/article/2011/04/11/us-climate-penguins-idUSTRE73A7M*******11 )
How very sad. Amazing isn't it. We've killed so many whales and yet our "farming" of krill for other uses has dimished their levels so much it's still affecting other animals in the ecosystem and so far away from the general population.
People have no clue and many don't care.
ohnonotthatguy: Maybe more predators (Sharks,Orca's)in the area that alone will diminish the penguin population.
PureSilver67: Thanks for your response.
The article actually talks about the decrease being due to a decrease in the amount of krill. Both parents and young are having a hard time finding enough krill to eat apparently.
Sharks don't inhabit Antarctic waters (at least as far as I'm aware - someone can correct me if I'm wrong). An increase in Orcas it could be, I don't think they have been actively hunted by any human population. I think Leopard seals are the main predators of penguin in the Antarctic.
gnsha: Wow. I was surprised to hear (years ago) that most species of penguins are actually not polar, so it makes these guys even more exceptional. How sad.
And something trivia(l): Are there really no sharks in the Antarctic? Weird but I think that you are right. The north subpolar has Greenland and frilled sharks, as well as dogfish, I think. If there *are* sharks down there, they probly are weird deep kinds....hmmm....I wonder why that is?
PureSilver67: That's right gnsha - most penguins are not of the poles and in fact there are none inhabiting the Arctic .. polar bears hunt seals.
As for sharks - mixed results on Google - I think it's because it's too cold. I know that Great Whites inhabit the colder waters of Australia i.e. they do not go further north on the East Coast than around Fraser Island and about the same longitude on the West Coast, but Antarctic waters are much colder (hmm of course) and sharks are well, cold blooded. And while checking for this reply, I realised that the penguins eat krill and squid - not fish, which are also cold blooded. So the answer is: Antarctic waters are too cold for cold blooded creatures.
Life in the Freezer is a great documentary about the Antarctic by Sir David Attenborough
Sir Loin: The reason or reduction in penguin numbers is Antarctica is getting colder and sea ice is increasing rapidly so penguin parents are unable to reach open waters to fish for their chicks. Sea ice has increased by 15 million sq km in the last couple of decades. Adelie penguins have been worst affected so far as their nesting grounds are furthest inland and there have been catastrophic chick failures the last 2 nesting seasons.