Automated Monitoring Technologies for Real-Time Marine Mammal Detection

Active sonar training and testing is necessary to ensure well-trained, combat-ready maritime forces; however, in-water transmission of sonar has the potential to cause harm to marine mammals. Timely information on marine mammal presence in, or near, sonar training areas can be used to minimize the risk of harming these animals. Defence Research and Development Canada (DRDC) has investigated a variety of acoustic technologies to facilitate real-time marine mammal monitoring. A combination of fixed and autonomous systems was considered. Fixed automated monitoring capabilities included a moored surface buoy with a volumetric hydrophone and a network of acoustic volumetric and vertical line arrays. Mobile passive acoustic monitoring (PAM) systems included an underwater glider with a single hydrophone and an uncrewed surface vehicle with a towed line array. Each system is capable of onboard real-time detection and species-level classification, which generates an alert to be telemetered to a shore-based station. Alerts may be used to alter when or where active sonar training and testing occurs. Advantages and disadvantages of each type of passive monitoring system considered were weighed to provide recommendations on the effectiveness of each system and to assess which type of system is best suited for a particular monitoring requirement.