At least 6% of global fishing ‘probably illegal’ as ships turn off tracking devices

Global mapping reveals hotspots for untracked vessels in west Africa, the coast of Argentina and the north-west Pacific

Up to 6% of global fishing activity is hidden because commercial vessels disable their tracking systems, a practice that can be used to hide illegal fishing, according to a new study.

Ships use automatic identification systems (AIS), tracking beacons that enable them to be located on global shipping maps. Researchers applied a machine learning algorithm to a dataset of fishing vessel activity compiled by the non-profit Global Fishing Watch, which included more than 3.7bn AIS messages from fishing vessels between 2017 and 2019.