A Guardian investigation has found that despite a recommendation to slow down, leading shipping companies continue to travel above advised speeds in a key habitat for cetaceans
Marine biologist Alice Barbarioli waits with her camera trained on the horizon. A few minutes earlier, the hydrophone beneath the Pelagos research vessel detected codas – the sequence of clicks sperm whales use to communicate.
The sperm whale reveals its head and dorsal fin as those onboard the vessel in the Pelagos sanctuary, a conservation area established to protect marine mammals in the north-western Mediterranean, rush to take photos and note the rhythm of its breathing. After a few minutes, the animal arches its back, and begins to head back into the depths of the sea. They wait to catch a glimpse of its tail.
Barbarioli, the lead researcher of the citizen-science expedition, organised by the Tethys Research Institute, immediately notices an injury on its left fluke: “Given how precise the mark is, it’s probably the result of a [vessel] collision,” she says.
Collisions have long been recognised as a leading human-induced cause of death for the Mediterranean’s endangered sperm and fin whales. Now, a Guardian investigation using data from the maritime intelligence firm Veson Nautical, has found that large passenger and cargo vessels operated by four companies – the Grimaldi Group, Corsica Ferries, Baleària and Moby Lines – have frequently travelled through a protected habitat that includes the Pelagos sanctuary at 15 knots (17mph) or above – speeds that almost always kill cetaceans in cases of a collision. Strikes are unlikely to kill when a vessel is travelling below 10 knots.
View image in fullscreenA sperm whale’s tail fin rises from the sea in the Pelagos sanctuary. Photograph: Lorenzo Gordigiani/Tethys Research InstituteSlowing vessels is the most effective mitigation strategy when rerouteing isn’t possible, according to conservation NGO Oceancare.
The sea between Valencia and Genoa, which includes the Pelagos sanctuary, is a key cetacean habitat, home to about two-thirds of the Mediterranean’s fin whales and more than a fifth of its sperm whales. In July 2023, the International Maritime Organization (IMO) created the north-western Mediterranean Sea particularly sensitive sea area (PSSA). In a voluntary speed recommendation (VSR), it advised vessels weighing 300 gross tonnes and above to sail at 10 to 13 knots in the area to reduce the risk of fatal collisions.
Despite the IMO’s recommendation, the Guardian, using additional data from Global Fishing Watch, found that ships with IMO identification numbers spent more than 280,000 hours travelling at 15 knots and above through the PSSA in 2025. The data also showed that ships spent more than 6,000 hours travelling above 25 knots. It builds on previous analysis that found the voluntary recommendations were largely ineffective.
Map of Mediterranean Sea showing the Pelagos sanctuary for whales and cetaceansIn 2022 and 2025, ferries owned by the Grimaldi Group, including Cruise Roma – at more than 250 metres, the world’s longest cruise ferry – dominated the top-20 list of vessels spending the most time at 15 knots or above in the habitat.
Speeding remained concentrated among a few operators in the PSSA in 2025, with just seven vessels – four Baleària fast ferries and three Grimaldi cruise ferries – responsible for 70% of the hours spent above 25 knot. Seven Grimaldi cruise ferries amounted to about 8% of all hours recorded for all vessels at 15 knots or above in 2025.
The Guardian spoke to six captains – five current and one former – who have sailed in the PSSA since its designation. The seafarers, still or previously at the helm of ships owned by Grimaldi Group and Moby Lines, say their companies have not introduced measures to encourage slow steaming after the IMO’s VSR.
View image in fullscreenA Grimaldi Group ferry in the Mediterranean Sea off Italy, one of the companies found to travel above recommended speed limits. Photograph: Diriye Amey/Alamy“As long as it’s only a recommendation, nobody will reduce speed,” says one Grimaldi captain. “It would mean overhauling the whole commercial system. The ferries in the area travel at 25 [knots], especially the ones carrying tourists. They have schedules to follow.”
Grimaldi and Moby Lines were contacted for comment but did not respond.
Thomas Folegot, the CEO of maritime tech company Quiet-Oceans, says that while slow-moving container vessels could stand to slightly cut speeds in the PSSA, it was far more challenging for ferries: “For their business, it’s a killer. [Passengers] will fly to Corsica.”
Quiet-Oceans and Oceancare’s analysis found that 80% of the journeys by merchant ships in the PSSA in 2023 were at speeds above 10 knots.
Simone Panigada, president of the Tethys Research Institute and chair of a scientific committee dedicated to the conservation of cetaceans, says it is time to “move, progressively, from voluntary to mandatory” rules on reducing collision risk.
“A binding framework would create more level conditions for all operators, encouraging compliance among shipping companies and ensuring the adoption of these measures doesn’t rest solely on individual corporate decisions,” he says.
The International Whaling Commission (IWC) told the Guardian it has recorded six incidents since July 2023 in the PSSA: five near-miss events and one collision. It believes most strikes go unrecorded.
While the annual time spent travelling through the PSSA above the key threshold of 15 knots remained high in 2025, it represented an 11% reduction compared with 2022. The time above 25 knots also fell by about a third between 2022 and 2025.
View image in fullscreenA fin whale breaks the surface – the area stretching from Valencia to Genoa, which includes the Pelagos sanctuary, is home to about two-thirds of the Mediterranean’s fin whales. Photograph: N Pierantonio/Tethys Research InstituteThese overall declines are probably caused by factors including altered shipping routes, says Olivia Watkins, associate director at Veson Nautical, who adds: “The PSSA recommendation is unlikely to be a significant cause of the year-on-year decline in the data results.”
Wei-Jun Mun, director of public policy at the World Shipping Council, says the industry is committed to PSSA’s protective measures, while noting slower navigation involved “commercial trade-offs and operational concerns”, including having to add ships to a service for schedule reliability.
How decoding beluga whales’ chitchat may save them – and teach us more about ourselvesRead moreA spokesperson for Corsica Ferries says the company supports Mediterranean marine megafauna research and ship-strike mitigation through measures including continuous monitoring, crew training and the development of whale alert tools. Researchers from programmes including conservation project Life Conceptu Maris monitor wildlife using its ships, it says.
The company says it instructs captains to navigate with particular caution through the PSSA, and to lower speeds to 10 to 13 knots, “while seeking to avoid possible negative impacts of reduced speeds”, including on manoeuvrability. It says its captains have reported a reduced capacity to avoid cetaceans that appear suddenly when navigating at reduced speeds.
A spokesperson for Baleària says it is “committed to the conservation of marine biodiversity” and actively working to mitigate the risk of collisions, including through crew training and the use of real-time monitoring systems to allow captains to adjust speed and course where necessary. Baleària says none of its fast ferries had recorded a collision with cetaceans.
Baleària adds that it participates in marine conservation programmes, including the Life Conceptu Maris and Life Intemares initiatives.