Assessing Invasive Species Risks Amid Shipping Growth and Ballast Water

A new study published in Nature Sustainability warns that growing global shipping could accelerate biological invasions faster than ballast-water rules can contain them. Ships take on seawater for stability and discharge it when cargo changes, unintentionally transporting plankton, larvae, bacteria and other organisms across oceans. If released into suitable habitats, some may survive and spread, disrupting food webs, fisheries and coastal economies. The research links projected maritime trade growth with the real-world performance of ballast-treatment systems and finds that even widespread treatment may not offset ecological effects. Depending on shipping growth and compliance, future introduction risk could rise from 94% to 900% above a 2018 baseline, reaching nine times in the extreme scenario.