When Europeans retreated into their homes to observe strict stay-at-home rules to contain the coronavirus, dolphins and whales on the Mediterranean coast basked and thrived in a hitherto unknown calm. But the return of tourists, noisy boats and heavy sea transport with the end of lockdowns in France and other Mediterranean littoral countries has signalled the return of danger and harm caused by human activity for underwater creatures. Nowhere is this more true then in the crystalline waters outside France’s second biggest city of Marseille, a nature reserve important for wildlife but also thronged with day-trippers in the summer season. “As soon as the pleasure boaters came back, we saw footage that really annoyed us,” said Marion Leclerc from the conservationist organisation Souffleurs d’Ecume (Sea Foam Blowers).In one video, three teenagers jump from a boat close to a finback whale while wearing snorkelling masks, which is dangerous for both animal and human, said Leclerc. “We’re speaking of an animal that weighs 70 tons,” she lamented.“Many forget that the Mediterranean is also a home, where animals rest, feed and reproduce,” Leclerc said. The Mediterranean Sea is home to more than 10,000 species, despite only amounting to 1 percent of the Earth’s oceans. But the sea which separates Africa from Europe draws 25 percent of marine traffic. Heavy traffic increases the risk of fatal collision with the sea mammals.“It’s the first cause of non-natural mortality for big cetaceans,” said Leclerc. Reduce speedOut of the 87 marine mammals in the world registered by the UN, 21 have been spotted in the Mediterranean. Most of them are considered at risk of extinction.On a bright summer’s morning, a group of fifty striped dolphins splash around an inflatable blue speedboat off La Ciotat bay a short boat ride from Marseille.“We need to reduce our speed and place ourselves parallel to their trajectory to avoid cutting their path. They come and play if they want to,” said Laurene Trudelle, at the helm of the boat belonging to the scientific research group GIS3M. The lockdown brought maritime traffic to an almost complete standstill, giving dolphins and whales the opportunity to explore areas from which they are normally kept at bay by tourists.