Offshore Encounters

Satellite data reveals meet-ups on the high seas

fishermen overload of products on the refrigerator

Transshipment often takes place at sea, far from the oversight of authorities. By allowing operators to avoid trips back to port for fuel and offloading, this transfer of catch between vessels helps distant water fishing fleets operate more efficiently across vast stretches of ocean. However, limitations in effective monitoring and controls leave opportunities for dishonest actors to manipulate data about their fishing practices, or simply not report the full extent of their catch. Using machine learning and satellite data, Global Fishing Watch is shedding new light on this historically opaque activity.

The transshipment challenge 

A lack of transparency around inter-vessel transfers can lead to illegal, unreported and unregulated fishing and other crimes, including drug and weapons trafficking and forced labor. Insufficient data and inaccurate reporting of catch can result in skewed stock assessments that impact conservation and management across valuable fisheries. These gaps can also impede traceability efforts, since illegally caught fish is often mixed with legal catch. 

Machine learning solutions 

To better understand transshipment at sea, Global Fishing Watch applies its machine learning technology to analyze tens of millions of global position system data points broadcast by fishing and carrier vessels every day. By studying vessel positions and behaviors, users are able to identify when and where vessels meet up at sea. Global Fishing Watch publishes these events to support those seeking to verify transshipment activities—helping to reduce opportunities for unauthorized transfers of fish products and identify when activity is not being adequately reported.

Research Lead

Contributing Team



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