A Southampton study found whale-shark detours would add little fuel

Routing container ships and tankers around whale shark gathering sites, or slowing them as they pass through, added less than 1 percent to fuel use on the crossings a Southampton team simulated. Phys.org reported on November 10, 2026, on a paper in Royal Society Open Science led by Ryan Reisinger at the University of Southampton. The group loaded maps of known aggregation sites into voyage-planning software already used in commercial shipping, then tried eight crossings that begin in the Persian Gulf or the Gulf of Mexico, two regions they ranked among the most dangerous for the sharks.

On journeys longer than six days, a full detour used at most 1 percent more fuel, and on journeys longer than 12 days the increase was about 0.5 percent. On shorter trips, slowing down inside the hotspot was the cheaper choice, again under 1 percent for the slower ships. Whale sharks spend nearly half their time at the surface, and the report said the population has more than halved in 75 years. Co-author Freya Womersley of the Marine Biological Association said collisions are hard to count because the animals sink. Reisinger said the same approach could be tried for whales and dolphins. The researchers also said the idea still needs better maps, forecasts, and a reason for companies to use it. The news is the fuel math on these eight simulated routes. It is not a report that any fleet has changed course.