Scientists have identified ‘opportunity sites’ for protecting marine mammals from ocean noise in the coastal waters of British Columbia. The team from SMRU, Oceans Initiative, Curtin University, and Cornell University has highlighted the importance of protecting habitats that experience low levels of shipping noise. Like many fish and invertebrates, marine mammals rely on sound for essential life functions including communication, foraging, mating, and navigation. Anthropogenic ocean noise is on the rise and can disrupt these behaviours – resulting in changes in individual behaviour and having potential consequences at the population level. These effects are especially important to consider in the conservation and management plans of endangered species where population sizes are small and habitat preferences are typically limited.
In many instances, areas have been identified where acoustically sensitive species are susceptible to ocean noise and mitigation strategies are subsequently prioritized. The authors suggest another complementary strategy: to prioritize the protection of currently quiet areas with high animal densities. Mitigation measures (for example, the quieting of ship propellers) often take a long time to be implemented. This strategy offers the opportunity to protect more pristine habitat until those measures start to have a positive impact on the underwater soundscape in high noise areas.
Maps of overlapping marine mammal densities and shipping noise were created to identify these opportunity sites for ten marine mammal species in coastal British Columbia (harbour porpoise, Northern Resident killer whale, Dall’s porpoise, Pacific white-sided dolphin, minke whale, humpback whale, fin whale, Northern elephant seal, steller sea lion, and harbour seal). The Salish Sea has high levels of ocean noise and not surprisingly, did not offer any opportunity sites for any these species. The southeastern coast of Haida Gwaii, on the other hand, presented the highest availability of opportunity sites for all study species. The north and northeastern coast of Haida Gwaii was also highlighted as a potential opportunity site for Northern Resident killer whales, minke whales, and Dall’s porpoise.