- 19 December 2014 by Penny Sarchet
A take-off in tourism could open the door to new bird diseases (Image: Frans Lanting/National Geographic Creative)
For those who go, it's the trip of a lifetime – and it wouldn't be complete without a selfie with penguins. But growing tourism to the Antarctic, in combination with its warming climate, could be placing penguins at a risk of infectious diseases.
Antarctic species are believed to have weaker immune systems due to their long isolation from the world's common pathogens. Humans only started visiting Antartica roughly 200 years ago.
Antarctica is no longer a stranger to human contact: more than 37,000 people visited the continent in the 2013-14 season as part of a growing tourist industry, compared with an estimated 8000 just twenty years earlier. An additional 4400 researchers can be accommodated simultaneously in Antarctica during peak months.
"The effects of both a growing tourism industry and research presence will not be without consequences," says Wray Grimaldi of the University of Otago in Dunedin, New Zealand. "Penguins are highly susceptible to infectious diseases." She bases that on a survey by her team of penguin diseases in captivity, reaching as far back as 1947. It found reports of Salmonella, E. coli, West Nile virus and Avian pox virus infections, among others.
The team also found evidence of a number of mass penguin mortality events across the Antarctic since 1969. A number of infectious agents are implicated, including Avian pox, which killed more than 400 gentoo penguins in 2006, and caused 60 per cent mortality rates throughout another outbreak in 2008.
Grimaldi says disease agents may have arrived in Antarctica via migrating birds like skuas or giant petrels, although some pathogenic bacteria could have been introduced by humans. There isn't enough evidence to test either possibility, she says.
Yet, as the climate warms, more birds are expected to visit Antarctic regions, bringing their pathogens with them, while diseases borne by other animals could expand their ranges southwards.
But Norman Ratcliffe of the British Antarctic Survey in Cambridge, UK, says there is not a lot of evidence that wild penguin populations have been significantly affected by disease, adding that the Antarctic's tourism industry has been very active for 20 years and takes appropriate precautions.
"The tour companies are quite careful to make sure everyone cleans their boots before they go ashore," he says. "They don't allow any animal products to be taken ashore."
Grimaldi warns that climate change could help drive the emergence of new penguin diseases in Antarctica. Claire Christian of the Antarctic and Southern Ocean Coalition, a group of environmental NGOs, agrees.
"Climate change may result in a number of stressors that make it more difficult for penguin populations to deal with disease," she says. In addition to prompting the arrival of new pathogens or species carrying pathogens, warming temperatures could have a negative impact on food sources like krill, which might leave the penguins less able to fight off illness, she adds.
"A coordinated monitoring system needs to be in place," argues Grimaldi. "That way, responses can be directed by science." Christian agrees, but she says research alone is not enough – the countries that are signatories to the Antarctic Treaty also need to cooperate in implementing protective and precautionary measures.
Journal reference: Polar Biology, DOI: 10.1007/s00300-014-1632-5