The issue of anthropogenic sound and its possible impacts on the marine environment has created unique challenges for virtually all federal agencies conducting, supporting, or assessing operations in the marine environment. These agencies are charged with regulating, supporting, and/or performing activities in the marine environment vital to our nation’s health, economy, and security across a wide scope of sectors. Sound (both intentionally produced as a tool or as a by-product of other activities) is an integral part of the activities of these agencies and of many critical human activities, including vessel operation and navigation, offshore minerals exploration, national defense, and scientific research. Federal agencies are challenged with achieving their mission goals in conducting and/or regulating these critical activities while meeting their mandated responsibilities as environmental stewards for the nation. Continuing to develop a scientific basis for determining potential impacts and the appropriate response is an urgent requirement for federal agencies, if they are to continue to achieve their primary missions for our nation in an environmentally safe manner.
There is considerable scientific uncertainty regarding the nature and magnitude of the actual impacts of anthropogenic sound on the marine environment, as well as the most appropriate and effective mitigation measures where effects have been demonstrated or are likely. Societal benefits from the full spectrum of sound-producing activities should be considered along with, and not overshadowed by, any potential negative impacts of those activities. The goal of federally-supported research in this area is to obtain mission-critical data that are used in a timely and effective manner to inform policy guidance, develop targeted mitigation measures, and develop and improve regulatory criteria.
How anthropogenic sound may affect marine life is a new field of study. What began as a simple concern that commercial shipping might affect the long-distance calls of whales (Payne and Webb, 1972) has now evolved into a more complex recognition that various anthropogenic acoustic sources have the potential to adversely affect marine life. Additionally, concerns regarding potential impacts are compromising human applications of sound for important scientific, commercial, and military purposes, particularly where scientific data are lacking or ambiguous. These concerns stem from both an increased understanding of the biological importance of sound to most marine vertebrates (particularly marine mammals and many fish) and a growing appreciation of the value of acoustics as a tool for ocean research, energy development, monitoring ocean health, resource management, military activities, and ship operations. How do we as a society reconcile our growing dependence on sound as a tool for studying, using, and conserving the marine environment with a similarly growing understanding of the potential for unintended adverse environmental consequences? How do we balance the potential negative environmental impacts from the incidental introduction of sound with the benefits of ocean-based commerce, national security, research, or transportation? And most important, how do we regulate these essential human activities in the face of significant scientific uncertainty about adverse effects? Many of these fundamental questions remain to be answered and they clearly require additional scientific data to be adequately addressed.
The most immediate response by U.S. federal agencies has focused on understanding and minimizing the potential adverse effects of their activities, or activities they support or regulate. The current status of science (in terms of exactly what level and types of sound will result in a specific effect) often results in estimates of potential adverse impacts that contain a high degree of uncertainty.
Public perception of threats and scientific analyses of risks may lead to different priorities for acoustic research. There is growing concern by scientific experts in relevant disciplines, that the public and legal focus on a very narrow range of active sources and the predictable agency responses are distorting an appropriate scientific approach to assessing the broader impacts of anthropogenic noise as a global issue (see NRC, 2000; 2003; 2005; Nowacek et al., 2007; Southall et al., 2007). This creates a growing need for both transparency and public and stakeholder outreach as agencies respond to the increasing awareness of sound as an environmental issue.
The laudable aim of minimizing acoustic effects has produced controversy, social tension, and litigation. It has also led to precautionary restrictions, considerable additional costs and delays, not the least of which has been the paradoxical effect of hindering ocean acoustic science essential to understanding not only this issue but also other important environmental issues such as the marine aspects of climate change. These anticipatory restrictions and other precautions imposed through litigative challenges have taken place against a background of considerable uncertainty as to the nature and extent of impacts from noise exposure. It is this gap, between what should and can be done with scientific confidence and what is currently being done with abundant precaution but demonstrable societal cost, which we seek to reduce through the coordinated federal research strategy depicted here. A summary of key overarching summary points is given below:
- Sound is of vital importance for most vertebrates.
- Natural and human sounds can have benign (or no) to significant effects on marine life.
- Public, media and regulatory attention has focused on known and/or potential adverse impacts of active sonar and seismic systems, but agencies must consider a wider array of sound sources.
- Existing data needed to assess and mitigate effects are limited, leading to uncertainty in determining the necessary responses (if any).
- Federal research has been largely focused on immediate needs specific to individual agencies.
- However, agencies often have common science and technology needs on this issue that could be most quickly and economically met through a coordinated program of effort.