Recalibrating the Department of National Defence approach to active sonar impact management

Fielding a well-trained, combat-ready military, and observing Canada's responsibility as environmental stewards are at times conflicting priorities for the Department of National Defence (DND). As new low frequency sources are introduced into service, DND must review and update policies and procedures regarding the use of active sonar to minimize its impacts on marine mammals with an evidence-based approach. Risk is mitigated primarily through avoidance, which requires an understanding of marine mammal distribution in order to avoid the most sensitive species and their habitats. In parallel, a research and development program evaluates and develops technological solutions to minimize the risk of harm. By first embracing an empirical framework to assess acute and chronic impacts, DND has been able to partner with other government departments and researchers to develop technology targeted towards the residual risks to marine mammals posed by sonar operations. •Department of National Defence updated its active sonar impact management approach.•A layered risk mitigation approach has been implemented.•Primary mitigation approach is to avoid areas with known marine mammal presence.•A mix of technological solutions is being investigated to aid in mitigation.