Sound transmits efficiently through the ocean and many animals have evolved communications strategies that exploit sound transmission to communicate with conspecifics. Most commonly, whales and dolphins have been monitored using passive acoustic recorders that log sonograms for manual or automated species identification. To assess such changes, the extent of anthropogenic noise, and the presence of marine mammals, C-PODs and SoundTraps will be deployed in the North Channel and at least one of the other proposed STRAITS arrays (e.g., Danish Straits, Straits of Gibraltar or the Bosporus and Dardanelles Straits). Locations will be targeted to assess the soundscape across a range of habitats for a range of species and to acoustically monitor the presence of important marine life.