Telecom infrastructure at the ocean floor is being harnessed as a powerful conservation tool for vulnerable marine mammalsA hidden network of underwater fibre optic cables could offer unprecedented new insights into the lives of some of the world’s most threatened and elusive sea creatures. That’s the hope of researchers from the University of Washington, US, who have laid 1.25 miles of cable across Puget Sound, just south of the Canadian border, to eavesdrop on the region’s endangered southern resident orcas. The technique, known as distributed acoustic sensing (DAS), works by firing laser pulses through the fibre optic cables and analysing tiny disturbances caused by vibrations and sound. It’s already been used to monitor earthquakes and in recent years has proved adept in detecting marine mammals.