You can learn how Global Fishing Watch works in more detail below, but essentially the system uses algorithms, which are steadily being refined, to identify and home in on fishing vessel activity amid the masses of public data flowing in vast streams from Automatic Identification System technology installed on nearly all substantial commercial vessels as a safety and tracking tool. (dotearth.blogs.nytimes.com)
According to Global Fishing Watch, the tool uses «a global feed of vessel locations extracted from Automatic Identification System (AIS) tracking data collected by satellite, revealing the movement of vessels over time. (treehugger.com)
Similar to bar codes and magnetic stripes, microchips are a form of automatic identification technology. (animals.howstuffworks.com)