Layers
Minimum length100 m
< 40 m40–120120–220> 220
Minimum length100 m
< 40 m40–120120–220> 220

Matching links dark detections to the vessels that could be behind them: ships that switched AIS off or loitered nearby, could reach the spot in time, and have the same length and course.

Open an optical detection and press “Find candidates”. The timeline jumps to that day, every detection around it on the same pass is analysed, and candidates are assigned to all of them at once.

DARK VESSEL OBSERVER

midwatch
Not evidence

This map is an analytical tool. Nothing on it is proof of wrongdoing, and it does not accuse any vessel, company or person: a missing AIS signal, a reused identity or a suggested candidate is a lead for further checks, not a finding. Data is shown with a delay — weeks for satellite detections, days for AIS-derived layers — and nothing here is published in real time. It is meant for research, journalism and analysis.

What it is

The map takes open data from Global Fishing Watch — vessel detections on Sentinel-2 images, AIS presence, vessel identities and AIS events — and reworks it for investigations of the large shadow fleet: tankers and cargo ships that sail without AIS, under borrowed identities, or under sanctions.

Functions

  • Optical detections — ships seen on Sentinel-2 that GFW could not match to AIS, coloured by length; heading and speed from the wake.
  • Double-check — removes known structures, islands, land, repeated spots, image seams and shapes that are not hulls.
  • Find candidates — for a chosen detection, ranks vessels that switched AIS off or loitered nearby by whether they could get there in time, their length and beam as reported on AIS, and their course; sanctioned vessels weigh more, and neighbours on the same pass are taken into account.
  • Timeline — sets the period; the ring counts what is in view.

False detections

Not every optical detection is a ship. Wind turbines, platforms, rocks, small islands, clouds, foam, image seams and berthed ships in ports still get through, especially near coasts. Each is checked against fixed-structure maps (55,324 structures), islands and reefs, land cover and the image itself, and rejected detections are hidden; work on removing the rest continues. Treat a single detection with caution, and open the image before drawing any conclusion.

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