Mesopelagic predator-prey interactions revealed by joint passive and active acoustic observations

The ocean’s mesopelagic zone is one of the Earth’s largest habitats and contains large numbers of animals, playing important roles in aquatic food webs—notably as food for many marine mammal species. While these communities have been observed for decades on echosounders as sound scattering layers (SSLs), their ecological dynamics remain poorly understood. Using a broadband (0-128 kHz) hydrophone and an upward-looking echosounder (38 kHz) at a...