Millions of Adélie penguins call Antarctica home
Scientists have their best estimate yet of how many Adélie penguins live in East Antarctica, numbering almost six million, 3.6 million more than previously estimated.
The new research by a team of Australian, French and Japanese scientists used aerial and ground surveys, tagging and resighting data, and automated camera images over several breeding seasons.
The researchers focused on a 5000 kilometre stretch of coastline in East Antarctica, estimating 5.9 million birds and extrapolating that out to likely global estimate of 14-16 million birds.
Australian Antarctic Division seabird ecologist, Dr Louise Emmerson, said up until now population estimates only took into account breeding pairs and did not include non-breeding birds.
“Non-breeding birds are harder to count because they are out foraging at sea, rather than nesting in colonies on land,” Dr Emmerson said.
“However, our study in East Antarctica, has shown that non-breeding Adélie penguins may be as, or more, abundant than the breeders.
“These birds are an important reservoir of future breeders and estimating their numbers ensures we better understand the entire population’s foraging needs.”
The research has implications for both terrestrial and marine conservation, with more birds potentially interacting with human activities on the continent and in the Southern Ocean than previously thought.
Lead author of the study seabird ecologist, Dr Colin Southwell, said the rocky, ice-free areas preferred by the penguins for nesting is also a region preferred for research stations due to ease of resupply.
“There are currently nine permanently occupied research stations in the ice-free areas of East Antarctica and we found over one million birds, or 29% of the population, breed within 10 km of a station, and 44% within 20 km of a station,” Dr Southwell said.
“Of the 16 Antarctic Specially Protected Areas in the study region, eight contain breeding Adélie penguins, encompassing about 10% of the breeding age population.
“By identifying significant penguin breeding populations near stations we can better identify which areas may need enhanced protection into the future,” Dr Southwell said.
The research also estimates the amount of prey (krill and fish) needed to support the Adélie penguin population.
“An estimated 193 500 tonnes of krill and 18 800 tonnes of fish are eaten during the breeding season by Adélie penguins breeding in East Antarctica,” Dr Emmerson said.
This information will be used by the Commission for the Conservation of Antarctic Marine Living Resources to set sustainable krill fishery catch limits.
Adélie penguin population
Seabird Ecologist - Dr Louise Emmerson
The purpose of this work was to bring together various elements of research to try and identify what pressures or threats there were on the Antarctic breeding seabirds. For this work, we were particularly focusing on the terrestrial environment where the birds were breeding, as well as the marine environment where the birds were foraging.
We used a long term 25-year mark re-sight program to try and estimate how many non-breeders there were in the population, and how this number related to the number of breeders.
So we estimate that the total population, which comprises of the breeders and the non-breeders, is around 5.9 million birds in East Antarctica. When we extrapolate that out to the entire continent, that's between 14 to 16 million birds.
In East Antarctica, the Adélie penguins are primarily eating krill but they also eat some fish as well, and we're trying to understand exactly how much of that has any overlap with potential fishing industry.
There were a lot of breeding Adélie penguins within very close proximity to the Antarctic stations. The Adélie penguins are trying to find locations to breed, which are ice-free and they're very close to open water. Our results can be used to identify areas which may need enhanced protection in the future.