Alaska’s ship traffic boosts hull biofouling area by 50%, raising invasive species risk
A study of nearly 30,000 commercial vessels arriving in Alaska from 2012-2022 found that wetted surface area grew 50%, mainly due to passenger ships, heightening the chance of non-indigenous marine species hitchhiking on hulls.
The analysis, published in Frontiers in Marine Science, tracked commercial ship traffic to Alaskan ports over an 11-year span, covering bulkers, container ships, general cargo, passenger vessels, tankers and RoRo ships. Vessel arrivals increased 23%, but the total wetted surface area (WSA) expanded 50%, from 39.9 sq km in 2012 to 59.7 sq km in 2022, largely because of a surge in large passenger vessels that contributed over half of the total WSA.
Passenger ships also had the greatest per-arrival WSA and the highest relative probability of moving non-indigenous species, aided by frequent trips and connections to ecologically similar ports. Traffic patterns varied by region, with the North American Pacific Fjordland receiving the most arrivals and the Gulf of Alaska seeing many tankers, while container ships dominated the Aleutian Islands. The study highlighted additional risk factors such as short port stays, long intervals since dry-docking, and environmental similarity between departure and arrival ports, noting that climate change could further amplify invasion potential.
Why it matters
Growing hull biofouling in Alaska raises the chance of invasive marine species establishing, threatening local ecosystems and fisheries.
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