Arctic & Antarctica
British Antarctic Survey research ship 'Ernest Shackleton' at Antarctica. Credit: Lloyd Peck

ANT - Invasive species 'hitchhiking' on tourist and research ships threaten Antarctica's unique ecosystems

Marine life hitching a ride on ocean-crossing ships poses a threat to Antarctica's pristine ecosystems, with the potential for invasive species to arrive from almost anywhere across the globe, say the authors of a new study.

New research by the University of Cambridge and the British Antarctic Survey has traced the global movements of all ships entering Antarctic waters. It reveals that Antarctica is connected to all regions of the globe via an extensive network of ship activity. Fishing, tourism, research and supply ships are exposing Antarctica to invasive, non-native species that threaten the stability of its pristine environment.

The study is published today in the journal PNAS.

The researchers identified 1,581 ports with links to Antarctica, and say that all could be a potential source of non-native species. The species—including mussels, barnacles, crabs and algae—attach themselves to ships' hulls, in a process termed 'biofouling'. The finding suggests that they could arrive in Antarctic waters from almost anywhere across the globe.

"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," said Professor David Aldridge in the Department of Zoology at the University of Cambridge, senior author of the report.

Invasive species 'hitchhiking' on tourist and research ships threaten Antarctica's unique ecosystems
Stalked and acorn barnacles, green algae and caprellid amphipods (small marine crustaceans) on a ship that visited Antarctica and the Arctic. Credit: Arlie McCarthy

The scientists say they are particularly concerned about the movement of species from pole to pole. These species are already cold-adapted, and may make the journey on tourist or research ships that spend the summer in the Arctic before traveling 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 University of Cambridge's Department of Zoology and the British Antarctic Survey, and first author of the report.

Research vessels were found to stay at Antarctic ports for longer durations than tourism vessels. Fishing and supply ships stay for even longer, on average. Previous research has shown that longer stays increase the likelihood of non-native species being introduced.

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