Fig. 2: High-resolution mapping reveals detailed patterns of fishing activity not publicly tracked.

Satellite SAR detections of individual vessels during 2017–2021, matched (blue) and unmatched (red) to known vessel positions from AIS broadcast, are classified as fishing or non-fishing vessels with a deep-learning model. Most fishing vessels, usually smaller than 50 m in length, concentrate close to shore and follow bathymetric features, such as the continental shelf break and seabed canyons, or regulatory and political boundaries. Extensive areas of previously unmapped fishing activity are revealed along Northern Africa and South and Southeast Asia. The absolute number of detections in each location depends on the local vessel density and the number of satellite image acquisitions, which varies by region. Depicted numbers may represent a slightly larger area than is shown. This figure shows the level of spatial detail that is possible with our mapping approach. Extended Data Figures 3 and 4 show further examples of high-resolution fishing and non-fishing patterns publicly and not publicly tracked.