Page 2/2 - Posted February 17, 2012
Researchers to focus on chinstrap penguin population declines
Both scientists made separate expeditions to the Antarctic Peninsula this season, the 18th of the Antarctic Site Inventory, which now includes 142 sites. The current research is partly funded by the NSF’s Office of Polar Programs .
Most of Oceanites’ fieldwork is opportunity-based, hitching rides aboard tourist vessels during the Antarctic summer. This year, Naveen and his team were able to raise additional funds and charter the yacht Pelagic. They spent 12 days at Deception Island, home to world’s largest chinstrap colony at a location called Baily Head.
“Deception Island has never been counted like that in one season, let alone in a 12-day period. We’re pretty excited about the results,” Naveen said.
The manuscript describing their findings is still in the works, but Lynch said the numbers will shock those scientists familiar with the Baily Head colony.
“We have found a complete collapse of the penguin colony there,” she said. “I was there this year, and it’s like a ghost town.”
Meanwhile, this season Lynch worked aboard the research vessel Laurence M. Gould , one of two science vessels in the U.S. Antarctic Program , which is managed by the NSF. She was able to visit several islands where she saw visible signs of change.
“We spend a lot of time chasing ghosts and going to a lot of empty colonies now,” she said.
Photo Credit: ©Thomas Mueller
A sound recorder installed by the Oceanites/Antarctic Site Inventory team at Baily Head, Deception Island.
The chinstrap story has been largely ignored until recently, according to Lynch. She and Naveen want to focus more attention to their plight. This year they installed a sound-recording device at the Baily Head colony that captures 20 minutes of sound per day. The scientists will be able to hear when the chinstraps return to their colony in the summer to begin breeding — and even when the eggs begin to hatch.
“There’s some natural wobble every year when the peak of egg laying occurs. The better and better we get at understanding that date and refining our data, we reduce the error in our analyses,” Naveen explained.
A second device was set up at another location on Cuverville Island, with a large gentoo population. “It’s just another tool that we have in the arsenal. We’ll be testing it out over the next few years to see if it is useful to us, and we’re optimistic,” Naveen said.
Another very useful tool has been high-resolution satellite imagery. Lynch and Naveen predict the technology will eventually lend itself to monitoring penguin colonies around the entire Antarctic. [See related article — Eyes in the sky: Scientists use satellites to track health of seal, penguin populations in Antarctica.]
For instance, counts from satellite pictures matched up closely with previous Oceanites estimates for the Adélie population breeding on Paulet Island in the Weddell Sea, and a more recent analysis shows a near perfect match between satellite image-based estimates and ground counts for chinstraps breeding at Baily Head.
“We’re very clear now that for some of these large colonies, this is the way to go to measure change, to see if the colonies are expanding or shrinking,” Naveen said. “The satellite stuff is going to be pretty amazing.”
Predictions about what might happen to the penguins of the Antarctic Peninsula are a little harder to come by. The current population trends will likely continue, assuming the region’s climate and ecosystem trends also follow their current trajectories.
Regional extinction may be a possibility, unless the penguins can change their behavior. Naveen noted that previous studies of tissue samples of eggs from ancient penguin colonies in the Antarctic Peninsula region show that Adélies once ate a diet similar to gentoos, one more rich in fish.
Human pressures through whaling 200 years ago removed a major predator from the peninsula ecosystem for decades, presumably creating a surplus of krill. Now the whale populations are bouncing back, and krill are fished commercially for products like omega-3 nutrition supplements. Throw in climate change, and there appears to be less krill to go around.
A switch to a less krill-centric diet may help. But a research cruise in 2010 in search of silverfish, a sardine-sized fish favored by penguins, found little evidence that they were still available around the peninsula region — another possible casualty of climate warming. [See previous article — Fishy business: Climate change may be to blame for disappearance of Antarctic silverfish.]
Naveen sees a lesson here: Can species adapt quick enough to a multitude of changes driven by climate change?
“We’re going to see more and more of that around the globe. What’s happening in the peninsula may be giving us some clues as to what we who live in more temperate climates may be facing in the future,” he said.