Jan 17, 2022 9:00 AM

Global Ship Traffic Could Imperil the Antarctic’s Biosecurity

Vessels from more than 1,500 ports have visited the region since 2014. Each one is a threat to introduce invasive species.

Right now, the Antarctic and the waters around it are surprisingly free of invasive species. According to new research, however, that situation might change in the not-too-distant future, thanks to a shocking level of connectivity with ports across the world. Ships can accidentally carry a large array of marine life, which can in turn colonize new places (like the world’s polar south), outcompete native life, and generally wreak havoc on an ecosystem. New research has traced the paths of the various research vessels, tourist ships, and fishing boats that chug along through the icy waters of the Antarctic.

According to Arlie McCarthy, a researcher in the University of Cambridge’s Department of Zoology and the British Antarctic Survey, these watercraft all carry with them a risk of unwanted visitors. And the visitors may have more chances to relocate than we once thought.

“We know from other cold areas in the world, including the Arctic, that things growing on the hulls of ships absolutely do get transported from place to place, and it is one of the major sources of marine introductions around the world,” McCarthy told Ars. “We also know that ships going into Antarctica do have things growing on them. What we didn’t know until this point was good detail on where those ships go.”

McCarthy's research suggests that there are 1,581 ports around the world with connections to the Antarctic. These are ports from which at least one ship traveled to the region, defined as south of -60 degrees latitude, as set by the Antarctic Treaty. To determine this, she and her team looked at shipping data from Lloyd’s List Intelligence, an old and reliable source of maritime data, port call data, and raw satellite data. It allowed her to track ship activity from between 2014 and 2018.

“They are connected in some way to Antarctica,” McCarthy said, referring to the ports. This means that myriad species such as crabs, barnacles, and algae from a huge number of places could end up in the area. As global shipping increases—and as researchers and tourists continue to head into these waters—the odds of invasive species taking hold grows as well. There’s also a concern about the movement of some species from the North to the South Pole, potentially on tourist or research ships. Species from the Arctic would likely be adapted to cold and could thrive in the chilly Antarctic better than species brought in from somewhere south of the equator.

Antarctic waters are mostly free of invasive marine species—there are some invasive grasses and insects—and the ocean is more isolated than many other oceans. That's due largely to the neighboring Southern Ocean, which has currents that circle around Antarctica. They’re particularly strong and form a kind of barrier. “Anything coming on ocean currents from oceans farther north, they can be deflected away from Antarctica rather than actually crossing into the Southern Ocean. They stop most things that come in on water currents,” McCarthy said, adding that seals and whales are capable of traversing these currents, even as mussels, barnacles, and algae are often blocked.

Because the region is so cold, many of the organisms that call it home are living more or less at the edge of what is physiologically possible. There is less food than elsewhere, and many of the creatures have adapted very specialized behaviors to survive, so invasive species could cause more damage than they do in a place where there is more food and warmth. For instance, some Antarctic lifeforms have developed polar gigantism, meaning that they grow large, live slow, and die old. Smaller, faster, and quicker-reproducing species from elsewhere—assuming they can survive in the Antarctic—may outcompete the original inhabitants.

As climate change continues to warm Antarctica, the polar zone could become more agreeable for various species that would otherwise simply die in the cold. Competition from new species would add stress on many Antarctic species that are vulnerable to warming temperatures anyway, McCarthy said. Further, the naturally warmer parts of the area—the Antarctic Peninsula, for instance—are already the places where ships go more often (there are more research stations there, and they're more appealing to tourists), and they’re warming faster than the rest of the region. “The combination of climate change and ship activity … are really the two parts of the puzzle needed to allow invasive species to establish in Antarctica.”

These potential marine invasive species also pose an economic threat. There are two main industries that operate in the Antarctic: fishing and tourism. It’s mostly unknown how much invasive species would impact them, McCarthy said. But invasive species can come with pathogens that could kill fish and/or krill, hurting those businesses. If penguins were also impacted, directly or indirectly, tourism could also see a hit.

There are already some biosecurity measures protecting the Antarctic from invasion, but there's room for improvement. The area is governed through the Antarctic Treaty system, which includes more than 50 nations that have agreed to try to keep the zone free of nonnative species. But, McCarthy said, there aren’t many regulations about the fouling of ships' hulls. In New Zealand, a ship needs to show that it doesn’t have any barnacles or other wayward lifeforms on its hull in order to get into the country. But regulations are relatively lax going into the Antarctic, and McCarthy said that strengthening the rules could be a challenge. “It would take quite a lot of international cooperation,” she said.

Knowing where ships went and what critters they may have come into contact with prior to entering the Antarctic may aid in biosecurity, she said. The team also identified ports where biosecurity measures could be implemented to get the best results and various hot spots within the Antarctic where monitoring programs should be established.

This story originally appeared on Ars Technica.