Military training in the Canadian Pacific: Taking aim at critical habitat or sufficient mitigation of noise pollution impacts?

The Canadian Department of National Defence (DND) has approved the resumption of military activities within 'Whiskey Hotel', a 330 km2 area in the Strait of Juan de Fuca that overlaps the critical habitat of endangered Southern Resident Killer Whales in the northeast Pacific Ocean. Multiple Canadian and United States defense organizations use the area for training. The renewal of small-arms training follows a three-year cessation selfimposed by DND to allow a third-party consultant to investigate the risk in-air and underwater training noises pose to marine mammals. Here, we summarize the findings and limitations of the commissioned report and discuss the broader implications for mitigating aquatic noise pollution. The report evaluated the potential for marine mammals to experience injury, behavioral disturbances, and acoustic masking, and proposed mitigation measures (e.g., avoidance zones) to limit impacts. However, the narrow scope of the commissioned report prevented the investigation of the potential effects on non-mammalian taxa and the inclusion of vessel noise generated during training. Resuming military activities within the habitats of imperiled species is contentious among stakeholders. Nevertheless, the DND's approach to examining noise pollution employs at least two of the precautionary principle's four components, and their decision to commission a third-party investigation and implement mitigation strategies represents a framework rarely applied when evaluating the impacts of pollutants. The importance of this approach is magnified given the absence of federal underwater noise regulations, the pending development of Canada's Ocean Noise Strategy, and multiple nations seeking to balance industrial and military activities with environmental stewardship.