On Dec. 25 in the East China Sea, hundreds of fishing vessels suddenly formed a mysterious line across the water, dropping anchor as if creating a deliberate barrier. Then, just as quickly, they dispersed.
The New York Times called it a possible military exercise. I wasn’t convinced — so I turned to the data.
What I found with Global Fishing Watch data did not solve the mystery, but it did help provide some context. An animation of all the fishing vessels in the East China Sea during those two weeks in December shows that only a small fraction of the total Chinese fleet were used to form that line. In fact, most vessels were returning to port at this time.
We also see lines of vessels forming in different places on March 15, April 13 — and most recently on Jan. 11, 2026.
In each case, it appears like vessels are being restricted from traveling east. A video of activity for the whole year shows these events, as well as other extremely interesting activity over the year. We see almost the entire fleet head home to celebrate the Lunar New Year, and we see the fleet observing the the summer moratorium (when most types of fishing are prohibited). You can also see boundaries between fishing grounds that are used by different fishing fleets in the region.
