The northwestern Mediterranean — specifically the corridor between Valencia and Genoa that includes the Pelagos sanctuary — hosts roughly two-thirds of the Mediterranean's fin whales and more than a fifth of its sperm whales. In July 2023, the International Maritime Organization designated it a particularly sensitive sea area (PSSA) and recommended vessels over 300 gross tonnes slow to 10–13 knots. Vessels travelling above 15 knots almost always kill cetaceans on impact. Below 10 knots, strikes are unlikely to be fatal. The voluntary recommendation has been largely ignored. Guardian analysis of Global Fishing Watch data found ships with IMO identification numbers spent more than 280,000 hours travelling at 15 knots or above through the PSSA in 2025. More than 6,000 hours were logged above 25 knots — deep into the range where collision is both more likely and universally lethal. The concentration is extreme: just seven vessels — four Baleària fast ferries and three Grimaldi cruise ferries — accounted for 70% of hours above 25 knots. Seven Grimaldi cruise ferries alone represented about 8% of all vessel-hours above 15 knots in the entire PSSA. Six captains — five current, one former — from Grimaldi Group and Moby Lines told the Guardian their companies have introduced no measures to encourage slow steaming since the PSSA designation. One Grimaldi captain was blunt: as long as the rule is voluntary, no one will comply. The commercial logic is unyielding. Fast ferries carrying tourists operate on fixed schedules at 25 knots. Slowing down means restructuring the entire service, adding ships, or losing passengers to airlines. Thomas Folegot, CEO of maritime tech firm Quiet-Oceans, confirmed the asymmetry: container ships could cut speeds modestly, but for ferry operators, meaningful compliance threatens the business model. The companies responded predictably. Grimaldi and Moby Lines did not respond at all. Corsica Ferries cited crew training, whale-alert tools, and instructions to captains to navigate with caution — then noted that reduced speeds actually impaired captains' ability to avoid whales appearing suddenly, a claim that inverts the established physics of the problem. Baleària cited real-time monitoring systems and noted none of its fast ferries had recorded a collision with cetaceans — an assertion undercut by the International Whaling Commission's finding that most strikes go unrecorded. There are modest positive signals buried in the data. Total hours above 15 knots fell 11% between 2022 and 2025. Hours above 25 knots dropped by roughly a third. But Veson Nautical's associate director Olivia Watkins attributed these declines primarily to altered shipping routes, not to PSSA compliance. The voluntary recommendation, in her assessment, is unlikely to be a significant cause. The structural problem is clear. A voluntary speed recommendation in a habitat where a handful of commercial operators have overwhelming economic incentives to ignore it produces exactly the outcome you'd predict: near-universal non-compliance among the highest-speed actors and marginal changes from everyone else. Simone Panigada, president of the Tethys Research Institute, says the transition from voluntary to mandatory rules is overdue. The IWC has recorded six incidents since July 2023 — five near-misses and one collision — but acknowledges these represent a tiny fraction of actual events. The 20-year question is whether the Mediterranean's sperm and fin whale populations can survive a regulatory regime built on corporate goodwill. The scientific consensus is that they cannot. Slowing vessels is the most effective mitigation strategy when rerouting isn't possible, and neither rerouting nor slowing is happening at scale. Every year of voluntary compliance that produces non-compliance is a year subtracted from these populations' viability.
