Hot spots of unseen fishing vessels

TLDR

Illegal, unreported, and unregulated fishing costs up to US$25 billion annually, depletes marine life, and is linked to human rights abuses, yet automatic identification system (AIS) tracking—though powerful—can be disabled, undermining surveillance. The study presents a global dataset of AIS disabling in commercial fisheries, revealing that such disabling obscures more than 6 % (over 4.9 million hours) of vessel activity. By compiling and analyzing this dataset, the authors mapped disabling events worldwide, identifying hotspots near the exclusive economic zones of Argentina, West Africa, and the Northwest Pacific, particularly around transshipment sites and contested boundaries. These findings link disabling to efforts to hide from competitors and pirates, providing actionable information to improve fisheries management.

Abstract

Illegal, unreported, and unregulated (IUU) fishing incurs an annual cost of up to US$25 billion in economic losses, results in substantial losses of aquatic life, and has been linked to human rights violations. Vessel tracking data from the automatic identification system (AIS) are powerful tools for combating IUU, yet AIS transponders can be disabled, reducing its efficacy as a surveillance tool. We present a global dataset of AIS disabling in commercial fisheries, which obscures up to 6% (>4.9 M hours) of vessel activity. Disabling hot spots were located near the exclusive economic zones (EEZs) of Argentina and West African nations and in the Northwest Pacific, all regions of IUU concern. Disabling was highest near transshipment hot spots and near EEZ boundaries, particularly contested ones. We also found links between disabling and location hiding from competitors and pirates. These inferences on where and why activities are obscured provide valuable information to improve fisheries management.