Shell ships: Antarctic species threatened by crabs and barnacles clinging to ships
Invasive species from around the world are hitchhiking on ships visiting Antarctic waters, bringing with them a threat to native species.
Fishing, research, supply and tourist vessels from 1,581 ports connected to Antarctica could carry seaweed, barnacles, crabs and mussels. These species attach themselves to the hulls of ships in a process called “biofouling” that exposes the once pristine continent to visitors from around the world.
“Invasive non-native species are one of the greatest threats to Antarctica’s biodiversity – its native species have been isolated over the last 15 to 30 million years. They can also have economic impacts, via the disruption to fishing,” said Professor David Aldridge of the University of Cambridge.
Aldridge is co-author of a new report on the threat of maritime traffic in Antarctica, published in the online journal PNAS.
Of particular concern are species in the North Pole region, which are already adapted to a cold climate, which hitchhike on research or tourist vessels that spend time in the Arctic before heading to Antarctica for the antipodal summer season.
“The species that grow on a ship’s hull are determined by where it has been. We found that fishing vessels operating in Antarctic waters visit a fairly small network of ports, but tourist vessels and supplies are traveling around the world,” said study co-author Arlie McCarthy of the University of Cambridge and the British Antarctic Survey.
Research vessels stay longer in Antarctic waters, according to the report, than ships on sightseeing excursions. But fishing and supply ships stay even longer. Researchers had previously found that the longer the stay, the more likely invasive species were to take hold.
Because Antarctica is so remote, many native species have not developed a tolerance for non-native species. Mussels attached to ship hulls, for example, have no Antarctic competitors if introduced, and shallow-water crabs would pose a new predatory threat that native species have not encountered.
“We were surprised to find that Antarctica is much more globally connected than previously thought. Our results show that biosecurity measures need to be implemented in more places than ‘They currently aren’t,” McCarthy said. Although there are strict regulations intended to ban invasive species, McCarthy said their success “rely on having information to inform management decisions.”
The researchers hope the study can help detect non-native species before they become problematic.
The study used port call data and satellite observations from 2014 to 2018, which showed the ships most often sailed from southern South America, northern and western Europe. from the Pacific Ocean to Antarctic waters. The Southern Ocean surrounding the icy continent is Earth’s most isolated marine environment, supporting a fragile and unique ecosystem of plants and animals. So far, there are no known invasive species. But the additional shipping traffic increases the likelihood of accidental introduction of non-native plants and animals.
Invasive species can endanger krill fisheries in the Southern Ocean. Krill are tiny shrimp-like crustaceans that are found at the bottom of the food chain and are eaten by species ranging from baleen whales and penguins to fish and squid. They are also important for human nutrition as they are used in fish feed in aquaculture and in the pharmaceutical industry. A drop in krill biomass could starve filter feeders like the gigantic blue whale.
“Biosecurity measures to protect Antarctica, such as cleaning ship hulls, are currently focused on a small group of recognized ‘ports of entry’. With these new findings, we call for improved biosecurity protocols and environmental safeguards to protect Antarctic waters from non-native species, especially as ocean temperatures continue to rise due to climate change. climate,” said British Antarctic Survey researcher Lloyd Peck.
Edited by Richard Pretorius and Kristen Butler