Jeanna Bryner, LiveScience Managing EditorDate: 19 June 2012
A population of chinstrap penguins is feeling the heat, with more than one-third of a breeding colony lost in the past 20 years, new research finds.
A warming planet, which is causing sea ice in Antarctica (and elsewhere) to melt, may ultimately be to blame for the plummeting penguin population, the researchers said. That's because the chinstraps' main food, shrimplike creatures called krill, depend on algae that attaches to that ice.
"Actually, in the '90s it was thought that the climate change would favor the chinstrap penguin, because this species prefers sea waters without ice, unlike the Adélie penguin, which prefers the ice pack," study researcher Andres Barbosa told LiveScience. He added that at the time, chinstraps, named for the thin black facial line from cheek to cheek, seemed to increase in numbers, with some new colonies being established.
The sea-ice decline in the winter, however, has become so big that it is now impacting krill populations, said Barbosa, of the National Museum of Natural Sciences in Madrid.
Barbosa and his colleagues tallied chinstrap penguins (Pygoscelis antarctica) in the Vapour Col colony of Deception Island, in the Antarctic's South Shetland Islands in 1991-92 and 2008-09. They photographed nests in 19 subcolonies, mainly in December when chicks were hatching.
Results, which ended up including just 12 of the subcolonies due to availability of data, showed the occupied nests had declined by 36 percent between 1991 and 2008.
Barbosa and colleagues ruled out research activity as the cause for the loss since both studied populations and those used as controls showed similar patterns of decline.
Tourism is also not a likely culprit. Deception Island, built on a volcano, is one of the most visited places in Antarctica; the 2007-08 year saw some 25,000 visitors, according to the International Association of Antarctica Tour Operators (IAATO). Meanwhile, the nearby chinstrap penguin colony of Bailey Head, which is usually visited by 2,000 to 3,500 people every season, showed a decline of about 50 percent.
Rather, a dip in the krill population may be to blame, an idea supported by the fact that Adélie penguin population (P. adeliae) in the region is also declining, while the gentoo penguin population (P. papua), which has a more variable diet, is not.
(The chinstrap, gentoo and Adélie penguins are the three pygoscelid species (in the Pygoscelis genus) that inhabit the Antarctic Peninsula, the region of the Antarctic continent where the effects of climate change are more evident, the researchers noted.)
But Barbosa says the chinstraps aren't a lost cause.
"This is an example of how the human activity far from the poles can affect the life at thousands of kilometers far from our homes," Barbosa told LiveScience. "Therefore, a more responsible use of the energy and the fossil fuels is necessary to preserve the planet and then the Antarctica."
In addition, he said, to protect the organisms that call the Antarctic home, we need to reduce human impact by reducing overfishing, tourism and even research activity.
The research was detailed online May 22 in the journal Polar Biology.
Chin StrapCredit: Andres BarbosaNamed for the thin black band of feathers that extends from ear to ear under their heads, chinstrap penguins grow to about 2.2 feet (68 centimeters) tall, with males being larger and heavier than females.
Two ChicksCredit: Andres BarbosaThe female usually lays two eggs in a shallow nest in late November, with each of the pair participating in incubation duties. The chicks hatch after about 33 to 35 days.
Deception IslandCredit: Andres BarbosaAndres Barbosa of the National Museum of Natural Sciences in Madrid and his team have been studying the chinstrap penguins of Deception Island since 1999. Its volcanic origins have shaped the island into a horseshoe shape, with the volcano's caldera at the center. The island is one of the most visited of Antarctica, drawing some 25,000 visitors in the year 2007-08.
Find the MateCredit: Andres BarbosaMonogamy between chinstrap penguin couples often persists from year to year, with pairs even using the same nesting sites in successive years. To make sure they've got the right mate, the penguins use certain mate-recognition behavior, seen here between a pair of chinstraps, which involves the penguins pumping their chests and stretching their heads upward.
Little NestsCredit: Andres BarbosaFemale chinstrap penguins form a circular platform nest with a shallow interior. The nests are roughly about 16 inches (40 cm) across and up to 6 inches (15 cm) high.
Chick HuddleCredit: Andres BarbosaTypically, fledgling occurs at about 7 to 8 weeks, with the chinstrap penguin chicks eventually forming crèches, or groups of young penguins that huddle together for warmth and protection. Then, at about 50-60 days old, once the chicks have molted, they head out to sea.
Penguin TeamCredit: Andres BarbosaThe penguin team, including Barbosa, shown here with chinstrap penguins on Deception Island.
Nest ChecksCredit: Andres BarbosaThe researchers tallied the occupied nests on the island in 1991-92 and 2008-09. Here they are checking chinstrap nests. (They also used photographic evidence for nest counts.)
Main FoodCredit: Andres BarbosaThe culprit for the decline is likely a loss of their main prey, tiny shrimplike creatures called krill. The krill eat algae that attach to the sea ice, so without sea ice the krill plummet, followed by a decline in chinstrap penguins.
Little BeaksCredit: Andres BarbosaResearchers measure the beak of a chinstrap penguin on Deception Island.Penguins PlummetCredit: Andres BarbosaThe researchers found occupied nests on the island have declined by about 36 percent between 1991 and 2008.
Sea IceCredit: Andres BarbosaSea ice around the Antarctic's Deception Island. "Actually, in the 90's it was thought that the climate change would favor the chinstrap penguin, because this species prefers sea waters without ice unlike the Adelie penguin which prefers the ice pack," study researcher Andres Barbosa told LiveScience. The sea-ice decline in the winter, however, has become so big that it is now impacting krill populations, said Barbosa, of the National Museum of Natural Sciences in Madrid.
Icy IncubationCredit: Andres BarbosaA chinstrap penguin nesting in the snow.
Saving ChinstrapsCredit: Andres BarbosaBut Barbosa says the chinstraps aren't a lost cause. "This is an example of how the human activity far from the poles can affect the live at thousands of kilometers far from our homes," Barbosa told LiveScience. "Therefore, a more responsible use of the energy and the fossil fuels is necessary to preserve the planet and then the Antarctica."
Penguin ProtectionCredit: Andres BarbosaIn addition, he said, to protect the organisms that call the Antarctic home we need to reduce human impact by reducing overfishing, tourism and even research activity. source