First invasive species found in the Antarctic

The first official invasive species has been found in the Antarctic. It was long thought the freezing cold temperatures, barrier-type currents and remote location would protect the Antarctic from invasive species. That has now changed following the discovery of juvenile mussels in the waters of Fildes Bay on King George Island.

Laval University marine biologist Paulina Bruning revealed in a paper published by Nature that the juvenile mussels on specimens from the region were being examined in the Quebec university’s laboratory. There are no native species of mussels in the Antarctic, where the waters were thought to be too cold.

The bivalves have been identified as blue mussels from Patagonia. The mussels are not migratory and currents discount the theory they survived the 805 km journey from their native location. The only logical explanation is the bivalves were transported by ship on the hull or in the ballast tanks of ships and were spawned by adults.

The research paper notes that the early stage of the bivalves growth appears to have been achieved locally. Early stages of development have been achieved elsewhere in similar water temperatures. If the juveniles survived to adulthood, they could establish a colony in the region. This is would be a difficult step for the mussels to achieve given the nature of their lifecycle. It has been observed that mussel invasions elsewhere failed to survive the initial colonisation.

Should the colony survive and grow, it could provide a beachhead for other species, altering the local ecosystem significantly. Further research is being undertaken to establish the presence of the mussel colony.

The paper notes that the presence of the mussels raises questions on the factors behind the discovery – the activity of ships in the region and global warming. Shipping traffic in the region has increased, led by scientific research and adventure tourism and cruises. Under the IMO Ballast Water Management Convention, commercial shipping will have ballast water treatment technology to comply with the Antarctic Treaty. There is not an international biosecurity measure to cover hull fouling risks in the Antarctic.

The second factor is climate change. Antarctic waters are persistently below 2°C and this is a major physiological barrier to invasive species. The paper notes research indicating the waters of the Southern Ocean are warming and “more and more species will be able to establish and those that establish will have greater and greater impacts.”

The presence of the tiny bivalves does not represent the main risk to the Antarctic but the paper notes their presence “provides a glimpse of ’invasions future’: the vector has been identified, the pathways have been described and at least one of the environmental filters has failed.”