French navy's MICA centre in Brest tracks 750 ships stranded by Iran's Hormuz blockade

In a basement in Brest, a dozen French navy personnel scour screens at the Maritime Information Cooperation and Awareness Centre (MICA) for blinking lights signalling movement near the Strait of Hormuz. Since the Iran war began in late February, the centre has been the principal channel through which the French navy keeps merchant captains alive in the Gulf. When MICA detects bombardment, it pushes an encrypted alert within a 50-nautical-mile radius — a wide net relative to a strait that narrows to 29 nautical miles at its choke point. “We share the nature of the event, its context and exact position,” Commanding Officer Thomas Scalabre told AFP. Crews receiving the alert can turn off transponders or steer away from debris.

The blockade — twin Iranian and US — has left more than 750 civilian ships marooned on the Gulf side of a passageway that, before the war, carried a fifth of the world's crude oil and liquefied natural gas. Only a handful have been allowed out in recent weeks. MICA serves 85 maritime transport companies including the French line CMA CGM and Denmark's Maersk; its screens stitch together satellite imagery, transponder pings and reports relayed by crews at sea.

Scalabre says the centre has logged around 40 security incidents in the theatre, of which 24 were direct Iranian attacks on commercial vessels since 28 February, some of them fatal. Tehran also claims to have laid sea mines in the main part of the waterway. “What matters is the psychological effect. No one will take the risk of venturing there,” he said. The Revolutionary Guards' rules for transit, he added, “remain very unclear and are constantly shifting,” with no obvious logic in how the IRGC selects targets: “There isn't necessarily any logic in the IRGC's targeting policy. We've seen many different nationalities and types of vessels” being attacked.

On 18 April, IRGC gunboats opened fire on the India-flagged tanker Sanmar Herald without prior radio contact, security intelligence firm Vanguard Tech reported — even though New Delhi, alongside China, Russia, Iraq and Pakistan, is treated by Tehran as a friend. In his office, Scalabre showed AFP an image of a swarm of speedboats encircling and seizing a vessel, the IRGC's so-called “mosquito fleet.” Even when Iran has formally authorised a transit, he said, “the IRGC's mosquito fleet can emerge to block their way.” The Guards, he added, “sometimes carry out indiscriminate attacks, whether the country is considered friendly or not.”

France and the United Kingdom have pledged to assemble a peaceful coalition to reopen the strait once the conflict ends, but the centre's work goes on against a backdrop of stalled peace talks and an estimated 20,000 seafarers stranded across Gulf cargo ships, per reporting from 27 April. “For Tehran, controlling the Strait of Hormuz remains one of its trump cards to exert pressure and negotiate” a way out of the conflict, Scalabre said. Beyond the Middle East, MICA also monitors Yemeni rebel missile and drone strikes in the Red Sea, piracy off Somalia and drug smuggling — but Hormuz dominates its screens.