Marine non-native species in the Southern Ocean and Antarctica

The Antarctic Circumpolar Current reduces the oceanographic transport of organisms from adjacent temperate ecosystems southward. Additionally, the extreme environmental conditions in the Antarctic marine environment, in particular south of the Antarctic Polar Front, limit the survival of non-native marine species (NNMS). In a changing climate with increasing water temperatures and declining sea ice, however, the establishment and potentially harmful impacts of NNMS will become more likely. Biofouling on ships and, to a lesser extent, ballast water have been identified as the main anthropogenic transport vectors of NNMS to Antarctica. Shipping activity by tourism, fisheries, and research vessels has increased 5 to 10-fold since the 1960s, posing a risk for NNMS introductions. Coastal sites subject to high visitation levels could serve as entry points and stepping stones for NNMS, especially those that already experience higher water temperatures such as Port Foster (Deception Island). While there are international and Antarctic-specific agreements and guidelines that aim to reduce the introduction of NNMS via ship ballast water, fewer binding agreements focus on biofouling and the resulting deposit of species in the Antarctic near-shore environment. Generally, once an NNMS is established, there is little scope for its removal from the Antarctic marine environment. Therefore, an emphasis on enhanced quarantine measures and monitoring could help the ATCM respond to projected increases in NNMS introductions to avoid their establishment in the first place.