The development and survival of an important group of marine invertebrates known as sea hares is under threat from increasing boat noise in the world’s oceans, according to a new study by researchers from the UK and France. While previous studies have shown that marine noise can affect animal movement and communication, with unknown ecological consequences, scientists from the Universities of Bristol and Exeter and the École Pratique des Hautes Études (EPHE) CRIOBE in France have demonstrated that boat noise stops embryonic development and increases larval mortality in sea hares.