Relevance to agencies and industry of effects of sound on populations of marine mammals

Background/Question/Methods and Results/Conclusions

Sound in the oceans is generated by a variety of natural and anthropogenic sources, and may affect marine life at multiple levels from behavioral disruption to population level effects. Recent observations of marine mammal strandings coincident with loud, anthropogenic sounds have focused attention on the potential effects of such sounds on individual whales and populations. All federal agencies engaged in living marine resources research and conservation and/or management are required under federal law to evaluate potential adverse environmental effects from their own activities or private sector activities they regulate. Numerous scientific and government panels and task forces have called for directed behavioral response studies to identify the causal link between sound exposure and behavioral responses that could lead to strandings.  Recent federally funded behavioral response studies are designed to obtain direct measurements of responses to simulated sonar and other sound exposure that indicate onset of behavioral disruption in different contexts. Ultimately, the goal of BRS studies is to provide a scientific basis for estimating risk and supporting and/or improving environmental assessments and science-based mitigation measures for future operations. There is a need, however, to differentiate between disturbance resulting in minor behavioral changes and the disruption of biologically significant activities, including but not limited to, migration, breeding, care of young, predator avoidance or defense, and feeding. In 2005, the National Resource Council (NRC) set out to clarify the term ‘biologically significant’. In the broadest sense, any action or activity becomes biologically significant in an individual animal when it affects the ability of the animal to grow, survive, and reproduce. Developments since the committee issued its report, and advances in research that were not considered explicitly by the committee, made it possible to transform this conceptual framework into a more formal model structure. The scientific work presented in the symposium represents a substantial advance in understanding of the population-level effects of multiple sources of disturbance, including sound, on marine mammals. In this presentation, we will explore the motivations for exploring effects of anthropogenic sound on marine mammals and examine the implications for government agencies and, potentially, industry.