Global shipping is considered to be one of the most important causes of animals being abducted around the world and introduced into ecosystems that are new to them – with catastrophic consequences if these species become invasive. The Antarctic is now also at great risk, as a study by David Aldridge from the University of Cambridge and his team in »PNAS« shows. “Invasive alien species are one of the greatest threats to Antarctica’s biodiversity because the indigenous species have been isolated over the past 15 to 30 million years. They can also have an economic impact by disrupting fisheries, ”says Aldridge.
The Antarctic is now connected to at least 1,581 ports via fishing, research and tourist ships, from which the ships come or where they make a stopover. Animals can get “on board” anywhere, for example via the ballast water that is absorbed in the port or when they settle on the ship’s hull. In particular, these are various mussels, barnacles, crabs and algae, which can come from all parts of the world – including regions such as the Arctic, whose climate is similar to that of the Antarctic.
Aldridge and Co are worried about these species most: Arctic species are much more likely to survive in Antarctica than related species from the mid-latitudes or even the tropics. In addition, many cruise and research ships sail through the Arctic in the northern summer and the Antarctic in the southern summer, so that a relatively direct exchange occurs here. Fishing ships, in turn, mostly head for the same ports in a few countries. However, cruise ships only stay on site for a short time, while research and supply ships anchor significantly longer in the ports and in the Antarctic, which significantly increases the risk of being introduced.
© David Aldrigde, University of Cambridge (detail)
Shipping to the Antarctic | The Antarctic Peninsula is particularly popular, which shouldn’t come as a surprise as there are many research stations and tourist destinations there. Overall, the shipping traffic and thus the connection to the rest of the world is much stronger than the scientists had expected.
Because of its relatively strong isolation from the strong circumpolar currents for millions of years, a very special animal world was able to develop in the Antarctic. In contrast, some species groups such as shallow water crabs are missing. If these are introduced, they can impair ecosystems: shallow water crabs, for example, are predatory, while the Antarctic species lack the appropriate antidotes to these animals.