How to read a week at sea
Most ships at sea say where they are, every few seconds, to anyone listening. Lehar draws a week of that inside India's line, 15 Oct to 21 Oct 2026, and what the radar saw that said nothing.
Vessels heard
5,703
inside India's line in the week; 2,696 fly India's flag
Fishing boats
707
among them, beside 1,852 cargo ships and carriers
Foreign fishing boats
171
flying another country's flag; 26 Chinese, 139 Sri Lankan
Hours heard
3,32,298
one position an hour, at about 1 km; the map sails each vessel along them
India's waters, drawn by the week's vessels alone
- hours heard, larger for more
- foreign fishing boats
- India's line
- a weather radar's reach
What a broadcast is
The Automatic Identification System (AIS): a radio on board that sends the vessel's position, name, number and course, picked up by other ships, by stations on shore and by satellites.
Ships of 300 gross tonnage and more on international voyages must carry one (SOLAS, chapter V). India's shipping directorate requires it on fishing boats over 20 m. Smaller boats mostly do not carry one, and are not on this map.
Open the mapWho is out there
the kind each vessel gives in its broadcast
Vessels heard each day
- Fishing
- Cargo and carriers
- Passenger
- Survey
- Other or not given
In the week, by kind
On the map: fishing boats teal (foreign ones amber), cargo coral, passenger violet, survey gold.
Foreign boats inside India's line
15 Oct to 21 Oct 2026
Foreign fishing boats, by flag
Sri Lanka1,121 hours heard inside139
China377 hours heard inside26
Indonesia24 hours heard inside3
Taiwan15 hours heard inside2
Malaysia12 hours heard inside1India's line
“The exclusive economic zone shall not extend beyond 200 nautical miles from the baselines from which the breadth of the territorial sea is measured.”
UN Convention on the Law of the Sea, article 57. Inside it the fish are India's to manage; ships of every flag may still pass.
Chinese boats
26
heard inside for 377 hours between them; 12 for under half a day, crossing
Named in the week
- PUTRI SAMUDRA AB Indonesia, drifting longlines, 10 h
Foreign boats Global Fishing Watch marks as fishing inside India's line, by the name they broadcast. Tap one on the map for its week.
A month of foreign fishing hours inside, day by day
- Sri Lanka 113 h
- Indonesia 44 h
- China 18 h
22 Sept to 21 Oct 2026. Hours Global Fishing Watch's model reads as fishing, from the way a boat moves.
Heard inside is not caught inside
A boat heard inside the line may be passing through, sheltering, or under an arrangement this map cannot see. Lehar shows where boats said they were; it does not say any broke a law.
What does not broadcast
the radar sees hulls, whether or not they speak
Radar contacts inside
24
groups of vessels the Sentinel-1 satellites' radar saw in the week that no broadcast accounts for: 930 detections
The largest, by the nearest place
- Hugli River 213 detections, 72 km out
- Vengurla Rock 327 detections, 34 km out
- Mahabalipuram 184 detections, 4 km out
- Sutrapada 138 detections, 38 km out
- Kalingapatnam 18 detections, 13 km out
- Nagayalanka 12 detections, 9 km out
Most lie within 30 km of the shore, where the small boats that carry no AIS fish. The map's Not broadcasting view rings each one.
The chokepoints
ships present on an average day, over the month
Vessel-hours heard in a box over each passage, divided by 24. The last seven days are lit; the change is against the three weeks before.
The coast that watches
Weather radars
20
India Meteorological Department radars on the coast, drawn as domes as wide as their scan. They watch rain, not ships: the dome shows how far out the coast can see weather coming.
Not for navigation or enforcement
A picture of broadcasts, a few days old. Positions can be wrong or false; a vessel can switch its radio off. Check any finding against the record before acting on it.