Antarctica’s pristine ecosystem at risk from invasive species hitching a ride on ships, warn Cambridge researchers
They have shown how the movements of ships entering Antarctic waters connects them to all areas of the globe, thanks to fishing, tourism, research and supply ships.
They found 1,581 ports with links to Antarctica and warn all represent a potential source of non-native species such as mussels, barnacles, crabs and algae attached to ships’ hulls, in a process termed ‘biofouling’.
Prof David Aldridge, in the Department of Zoology at Cambridge, senior author of the study in the journal PNAS, said: “Invasive, non-native species are one of the biggest threats to Antarctica’s biodiversity - its native species have been isolated for the last 15-30 million years. They may also have economic impacts, via the disruption of fisheries.
Pole-to-pole movements are of particular concern. Cold-adapted species could journey on tourist or research ships that spend the summer in the Arctic before travelling across the Atlantic for the Antarctic summer season.
“The species that grow on the hull of a ship are determined by where it has been. We found that fishing boats operating in Antarctic waters visit quite a restricted network of ports, but the tourist and supply ships travel across the world,” said Arlie McCarthy, a researcher in the Department of Zoology and the British Antarctic Survey, and first author of the report.
Research vessels stay at Antarctic ports longer than tourism vessels, but fishing and supply ships stay even longer - increasing the likelihood of non-native species being introduced.
Isolated Antarctic wildlife has not evolved to tolerate many groups of species. Should mussels be accidentally introduced, for example, they would have no competitors, while shallow-water crabs would introduce a new form of predation not encountered before.
Large krill fisheries in the southern oceans could also be affected by invasive species arriving on ships.
Krill is a key component of the fish food used in the global aquaculture industry and krill oil is sold as a dietary supplement.
Arlie added: “We were surprised to find that Antarctica is much more globally connected than was previously thought. Our results show that biosecurity measures need to be implemented at a wider range of locations than they currently are.
“There are strict regulations in place for preventing non-native species getting into Antarctica, but the success of these relies on having the information to inform management decisions. We hope our findings will improve the ability to detect invasive species before they become a problem.”
The Southern Ocean is the only global marine region without any known invasive species so far.
“Biosecurity measures to protect Antarctica, such as cleaning ships’ hulls, are currently focused on a small group of recognised ‘gateway ports’.
“With these new findings, we call for improved biosecurity protocols and environmental protection measures to protect Antarctic waters from non-native species, particularly as ocean temperatures continue to rise due to climate change,” said Prof Lloyd Peck, a researcher at the British Antarctic Survey, who was also involved in the study.
This research was funded by a Whitten Studentship, the General Sir John Monash Foundation and the Natural Environment Research Council (NERC).