In charting a course for the greening of the shipping industry (Z. Wang et al. Nature 530, 275–277; 2016), we should also mitigate the scouring of seafloor biota by the massive anchors and long dragging chains dropped by a global fleet of some 68,000 ocean-going commercial vessels.
Cruise liners, too, are proliferating, with many approaching the size of supertankers. Anchoring in exotic, near-pristine locations potentially causes greater seafloor damage than it does near long-used commercial ports, which may already have been stripped by behemoths deploying anchors weighing in excess of 30 tonnes.
Ships swinging at anchor destroy seafloor animal 'forests', as well as the resources and ecosystem services they support (S. Rossi Ocean Coast. Mgmt 84, 77–85; 2013). Yet the shipping industry's environmental code of practice does not recognize anchoring as a cause of concern (International Chamber of Shipping Shipping and the Environment: A Code of Practice, 2008).
As seaborne trade grows apace (pictured), there is an urgent need to assess the risks it poses to marine biodiversity. A solution could be to define safe anchorages near ports that reduce ships' physical footprints and avoid areas of high conservation value.