Moscow is apparently using commercial fishing trawlers to map undersea cables connecting the U.S. and Europe. According to The Telegraph , it has uncovered over 500 incidents where Russian fishing boats loitered above critical communications cables over a span of four and a half years. All the data came from Global Fishing Watch, which uses satellite data to track vessels over the open ocean. The satellite tracks of these suspicious Russian ships are then cross-referenced over nautical charts that marked the locations of undersea cables.

While the general location of most undersea cables is clearly marked on nautical charts so ships can avoid them, any operation involving undersea cables requires more accurate positioning data. The Telegraph gave three examples of Russian trawlers seemingly surveying critical infrastructure.…