The latest 90 days against the months before the attacks
Sparklines show monthly averages since 2019. Hover any chart for exact values.
Six things to know
Suez traffic fell by almost half within two months and has stayed there
How to read it: each point is one month's average number of cargo ships (or estimated cargo tonnes) crossing the canal per day. The dashed line is the January–October 2023 average, before the first attack, and the tinted area is the time since. Numbered markers are news events for context; they are not derived from the data.
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Ships went around Africa instead: the Cape of Good Hope now sees more ships than Suez did before the crisis
Schematic, not to scale. Line width is proportional to ships per day at each chokepoint. Malacca, upstream in Asia, is in the list and the chart below.
How to read it: Bab el-Mandeb is the southern entrance of the Red Sea and Suez its northern exit, so before the crisis the two lines moved together. The Cape of Good Hope is the long way round. Malacca, between the Indian Ocean and East Asia, sits upstream of the diversion: if it held steady, Asia–Europe trade kept moving and only the route changed. Tap the chips to add Gibraltar and Malacca.
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Container ships and car carriers left first; tankers and bulk carriers held on more
How to read it: each bar is the change in daily Suez transits (or estimated cargo tonnes) for one vessel type, compared with January–October 2023. A tonnage fall larger than the ship-count fall means the biggest ships of that type were the ones that left.
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A tonnage-based proxy puts canal revenue near $4bn a year, down from $10.25bn
How to read it: bars scale the Suez Canal Authority's reported 2023 revenue by PortWatch's estimate of cargo tonnes crossing the canal each year. Tolls are charged on ship tonnage, so tonnage tracks revenue better than ship counts. The 2024 diamond is the SCA's own figure, which the proxy did not use: it shows how close the proxy gets. The dashed 2026 bar is annualised from data to date.
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Egypt's ports did not lose traffic overall, and El Sokhna on the Gulf of Suez nearly tripled its port calls
How to read it: each bar is the change in a port's daily calls (or cargo tonnes) in the latest 90 days against January–October 2023, with the before → after level beside it. Colour shows the coast. A port call is a ship entering the port to load or unload; PortWatch excludes short stops for fuel or anchoring.
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Can these numbers be trusted?
The pipeline finds the Ever Given on its own
Show coverage by chokepoint and port
Where the numbers come from and how they were processed
IMF PortWatch is a platform from the International Monetary Fund and the University of Oxford that turns ship-position signals (AIS) into daily counts of ships passing 28 maritime chokepoints and calling at about 2,000 ports, with an estimate of the cargo each ship carried. It is published as open ArcGIS feature layers, which this project downloads without a key.
Glossary
- AIS
- Automatic Identification System: the position, speed and identity signal that cargo ships broadcast. Received by coastal stations and satellites.
- Transit
- A ship crossing a chokepoint's boundary. A ship is not counted again at the same chokepoint within 48 hours.
- Port call
- A ship entering a port to load or unload. Stops under 5 hours with no change in draft (bunkering, anchoring) are excluded.
- Cargo tonnes
- PortWatch's estimate of cargo on board: how deep the ship sits in the water (its payload share) times its deadweight tonnage.
- DWT
- Deadweight tonnage: the most a ship can carry, in metric tonnes.
- Baseline
- January–October 2023: the ten months before the first Houthi attack on merchant shipping (19 Nov 2023).
- SCA
- Suez Canal Authority, the canal's operator. Its published revenue anchors the proxy.
Limitations
- Estimates, not manifests. Ship counts come from AIS tracks; cargo tonnes are modelled from draft and ship size. Neither is a customs or canal-authority record.
- Five cargo types only. Container, dry bulk, general cargo, ro-ro and tanker. Passenger ships, naval vessels and small craft are not counted, and LNG carriers sit inside "tanker".
- Revenue is a proxy. It assumes revenue moves with tonnage. Toll rates, rebates and the mix of ship sizes all changed after 2023, so it is a scale estimate, not an accounting figure.
- Timing, not proof of cause. The drop lines up with the attacks, but the data cannot separate the security effect from freight rates, insurance costs or carrier network decisions.
- Noisy single days. AIS reception gaps create one-day spikes and dips, especially at the Cape. All findings use monthly or multi-month averages.
- Port boundaries are PortWatch's. Port Said may combine the east and west terminals; El Sokhna's gains may partly reflect new terminal capacity, which this data cannot see.