Marine Mammals and Noise: A Sound Approach to Research and Management


Title: Marine Mammals and Noise: A Sound Approach to Research and Management
Publication Date:
March 01, 2007
Pages: 370

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Marine Mammal Commission (2007). Marine Mammals and Noise: A Sound Approach to Research and Management. Report by Marine Mammal Commission. pp 370.

Human activities are increasing the level of sound in the oceans, causing widespread concern about potential effects on marine mammals and marine ecosystems. Major human sources of sound include seismic surveys for oil and gas exploration and scientific research; commercial shipping for transportation of goods; and sonar systems for military purposes, fishing, and research. Sound also is important to marine mammals for communication, individual recognition, predator avoidance, prey capture, orientation, navigation, mate selection, and mother-offspring bonding. Potential effects of anthropogenic sounds on marine mammals include physical injury, physiological dysfunction (for example, temporary or permanent loss of hearing sensitivity), behavioral modification (for example, changes in foraging or habitat-use patterns, separation of mother-calf pairs), and masking (that is, inability to detect important sounds due to increased background noise). For individual animals, such effects and their secondary consequences may vary in significance from negligible to fatal—the worst outcome being documented in a small number of cases. The implications for conservation of marine mammal populations are undetermined.


In the late 1960s and early 1970s Congress provided a framework for protecting marine mammals and marine ecosystems when it passed a suite of environmental laws including the Marine Mammal Protection Act (MMPA), Endangered Species Act (ESA), and National Environmental Policy Act (NEPA). The MMPA provides a general prohibition on activities that take marine mammals, with limited exceptions for scientific research, commercial fisheries, subsistence harvest by Alaska Natives, activities that take marine mammals incidentally but that have a negligible impact on their populations, and military activities deemed essential for national defense. The ESA prohibits the taking of marine mammals listed as endangered or threatened, also with some exceptions. The NEPA requires that major federal actions that would have a significant impact on the environment—including those involving anthropogenic sound—be assessed to inform decision-makers about the consequences of such actions and alternatives to minimize impacts. With respect to sound effects, the management framework has been of limited effectiveness largely because of the considerable uncertainty regarding those effects, inadequate attention to management of certain sound producers, inadequate monitoring and mitigation methods to characterize and avoid or minimize effects, and implementation strategies that have proven to be less than optimal.


To address these matters, in 2004 Congress directed the Marine Mammal Commission to “fund an international conference or series of conferences to share findings, survey acoustic ‘threats’ to marine mammals, and develop means of reducing those threats while maintaining the oceans as a global highway of international commerce” (Public Law 108-7). The Commission convened an Advisory Committee on Acoustic Impacts on Marine Mammals and sponsored a series of meetings and workshops to gather information necessary to carry out the directive and prepare this report.


Important progress has been made toward understanding sound and its potential effects on marine mammals. The research effort has been led by the U.S. Navy with significant contributions by the Minerals Management Service, National Oceanic and Atmospheric Administration, National Science Foundation, several industry groups, and scientists from the academic community and private sector. In addition, the National Research Council has conducted four reviews of the sound issue, providing important recommendations for future research to address remaining uncertainties.


Despite these commendable efforts, the effects of anthropogenic sound on marine mammals remain uncertain and, as yet, the significance of sound as a risk factor cannot be assessed reliably. Other human-related risk factors appear to be at least as great a threat to marine mammals as is human-generated sound. For example, all known marine mammal mortalities caused to date by anthropogenic sound involve a limited number of species and are at least an order of magnitude less than the number of cetaceans killed annually in direct fisheries bycatch. However, because our ability to observe potential sound effects is limited, the documented level of mortality may be a poor indicator of actual effects. The 2005 National Research Council report indicated that “...sound may represent only a second-order effect on the conservation of marine mammal populations; on the other hand, what we have observed so far may be only the first early warnings or ‘tip of the iceberg’....” We can be certain that the need to address this issue will increase over time as the Nation’s human population continues to grow and concentrate in coastal areas and as commercial vessel traffic, oil and gas exploration and production, military exercises, and other ocean-related human activities—both anticipated and unforeseen—expand with that growth.


The challenge facing the concerned community of decision-makers, managers, scientists, sound producers, and conservationists is to gain an understanding of the effects of sound in the oceans and to manage those effects in a judicious manner. Doing so will require recognition of remaining uncertainties and provision of a suitable buffer to ensure marine mammal conservation, while also endeavoring to avoid or minimize unnecessary constraints on human activities that introduce sound into the oceans. The major unresolved elements of this issue are as follows:


  • Uncertainty regarding the risks to marine mammals and marine ecosystems. Risk assessment requires research to identify and characterize sounds that may be hazardous to marine mammals, determine their level of exposure, assess their responses to such exposure, characterize the significance of those responses for both individual animals and their populations, and manage the resulting risks of adverse effects. Such assessment must address individual sound effects, cumulative effects of multiple sound exposures over space and time, and the combined influence of sound and other risk factors for marine mammals and marine ecosystems.
  • Inadequate monitoring and mitigation measures. Existing monitoring and mitigation methods are not adequate for detecting the presence of marine mammals and discerning the impacts of sound exposure. More effective monitoring and mitigation measures are needed to determine whether (1) harmful effects occur, (2) such effects are biologically significant, and (3) measures taken to mitigate impacts are necessary and effective.
  • Regulatory inconsistencies. The requirements and procedures for obtaining authorizations to take marine mammals differ among and within various groups of sound producers—for example, commercial shippers, fishermen and aquaculture operators, the military, the oil and gas industry, and the academic community. Even when the same provisions apply, implementation and enforcement are inconsistent. The current framework is not well suited for managing some activities, such as commercial shipping, which is a major source of ocean noise and which may result in the taking of marine mammals. Some modification of existing regulations and statutes is necessary to ensure that, where feasible, all sound producers are subject to consistent standards.


Delays in issuing research permits and take authorizations also have been identified as a significant element of the sound issue. The Commission believes that such delays result from inadequate implementation of the relevant statutes and regulations and could best be resolved with increased management resources and improved procedures rather than statutory and regulatory changes.


The two cornerstones of a national approach to the sound issue should be an expanded research program to improve our understanding and a more effective, comprehensive management approach to ensure marine mammal conservation while minimizing unnecessary constraints on sound-producing activities. With that in mind, the Marine Mammal Commission makes the following recommendations.


Recommendation 1: Establish a coordinated national research program on the effects of anthropogenic sound on marine mammals and the marine environment


Congress should establish a research program to improve understanding of anthropogenic sound, its biologically significant effects on marine mammals and marine ecosystems, and effective means for mitigating and monitoring those effects.


Administration—The research program should be guided by an interagency coordinating committee with representatives from the Navy, Minerals Management Service, National Oceanic and Atmospheric Administration, Fish and Wildlife Service, U.S. Geological Survey, National Science Foundation, Marine Mammal Commission, and any other agencies with related responsibilities or interest in this issue. As the agency responsible for oversight of marine mammal research and management in the United States, the Marine Mammal Commission is the most appropriate agency to chair the committee and would be pleased to do so. The initial charge to the committee should be preparation of a research plan to study anthropogenic sound and its effects on marine mammals. To address other significant threats to marine mammals and marine ecosystems the committee should be granted the flexibility to expand or modify its membership, scope, and activities once the initial sound research plan is completed and critical uncertainties are being addressed through well-designed research projects. This administrative recommendation satisfies Congress’s mandate to the Commission to provide guidance on research and management related to the sound issue, but also maintains consistency with the Commission’s larger statutory mandate to be attentive to all factors that threaten marine mammals and the ecosystems upon which they depend.


Program Direction—Direction for the research program should be described in a comprehensive five- to ten-year plan focusing on (1) improving understanding of sound in the marine environment; (2) characterizing sound effects on marine life, including marine mammals, at the individual, population, and ecosystem levels; (3) evaluating existing prevention, mitigation, and monitoring measures and (4) developing more effective management measures. The plan should—


  • identify the critical uncertainties and establish research priorities,
  • describe the scope, time, equipment/infrastructure, logistics, and funding needed for the research,
  • specify lead and cooperating agencies for each task and their funding and other responsibilities,
  • be updated regularly to incorporate new findings and information,
  • ensure peer-review and prompt publication of research and monitoring results,
  • be open to public review and comment, and
  • promote public education and training of scientists and students.


Funding and Resources—In view of the variety of research topics to be addressed, the difficulty of working in the marine environment, and the extensive infrastructure required, a substantial investment is needed. The research caucus that participated in the Commission’s Advisory Committee process recommended that new funding be provided to participating agencies with the amount increasing over three or four years to an annual level of $25 million. This amount presumably represents the required minimum investment in basic research but does not include the substantial logistical and regulatory compliance costs associated with that research (for example, applying for authorizations, completing environmental assessments, processing such materials by permitting agencies). Although intermediate levels of new funding (that is, less than $25 million) may be appropriate initially, the best basis for establishing long-term funding levels will be a comprehensive, integrated, and focused research plan.


Funding for the sound research program should not be taken from other areas of marine mammal research. Rather, the national sound research program should be funded with additional appropriations as necessary to undertake the cooperative long-term research program recommended by the interagency coordinating committee. Affected industries and others with related interests, expertise, and specialized equipment and logistic capabilities should be invited to participate in or contribute to implementation of the long-term program plan.


Recommendation 2: Establish consistent standards for the regulation of sound in the marine environment


With two exceptions, the Commission finds no basis for different regulatory treatment of the various sources of anthropogenic sound that are likely to take marine mammals incidentally. Those exceptions are commercial shipping, which is addressed under recommendation 7, and Department of Defense activities that are necessary for national defense and may be exempted in accordance with section 101(f) of the MMPA.


Congress should provide the National Marine Fisheries Service and the Fish and Wildlife Service authority to regulate all anthropogenic sound sources in the marine environment. In particular, Congress should require assessment of the effects of fishery and aquaculture activities as an objective of the national sound research program described under recommendation 1 and grant the National Marine Fisheries Service the authority and responsibility to regulate those effects.


Recommendation 3: Ensure that all sound producers comply with statutory and regulatory requirements


Requirements for authorization to take marine mammals incidentally should be applied consistently to all sound producers. For example, the Navy should obtain authorizations for taking marine mammals incidental to its various exercises and operations, and the oil and gas industry should obtain authorizations for all of its operations unless they meet the standards for exception. Similarly, the potential for disturbance by whale-watching vessels as well as small watercraft should be evaluated to determine if regulation is needed to avoid harmful sound-related effects. Congress should advise the National Marine Fisheries Service and the Fish and Wildlife Service that sound producers in U.S. waters and U.S. sound producers (including those receiving funding from U.S. sources) on the high seas are required to obtain necessary taking authorizations if their activities have the potential to kill, injure, or harass marine mammals. Congress also should advise the Services to take action necessary to ensure that authorizations are obtained when any taking is likely.


Congress should amend the MMPA to make incidental take authorizations under section 101(a)(5) available to all sound producers operating in U.S. waters, regardless of nationality, provided that the substantive requirements (for example, the negligible impact standard) remain in place. As reflected in recommendation 7, such an amendment, by itself, is unlikely to solve the problem of how best to authorize the taking of marine mammals incidental to commercial shipping.


Recommendation 4: Retain mitigation and monitoring as requirements of the authorization and compliance process and designate the evaluation of existing measures and development of more effective measures as high priorities for the national research program


Although the effectiveness of existing mitigation, monitoring, and reporting measures is a matter of debate, those measures are vital to validating assumptions regarding the nature and significance of sound effects and improving our ability to manage sound-producing activities. Measures should—


  • minimize unnecessary sound production—for example, preclude repetitious seismic surveys of the same area when a single, comprehensive survey will suffice to provide the information needed by the oil and gas industry;
  • promote sound-reducing technologies—for example, encourage the seismic industry to develop airgun arrays that direct virtually all of their energy straight down and inform ship-builders of the need for ship-quieting technologies that will reduce marine noise as well as improve sound conditions on those ships. Note that this latter example should be accompanied by a research program to ensure that quieter ships do not result in an increase in ship/whale collisions;
  • implement temporal and spatial measures to avoid sound-producing activities in seasons and areas that are especially important in the life history of marine mammals; and
  • use the assets of sound producers to enhance mitigation, monitoring, and reporting of sound effects—for example, use the variety of Navy range assets to study marine mammal responses to different types and levels of sound.


In view of the limited value of current mitigation and monitoring measures, Congress should require that the evaluation of existing methods and development of more effective methods be identified as high priorities of the national research program.


Recommendation 5: Require the National Marine Fisheries Service and the Fish and Wildlife Service to develop a management system that accounts for the cumulative effects of sublethal exposure to anthropogenic sound and other human impacts on marine mammals


Successful conservation strategies for marine mammals must take into account the full impact of human activities on them. The full impact is a function not only of direct mortality but also of sublethal effects (for example, changes in stress level, condition, health) that, when combined, may significantly influence individual reproduction or survival, the factors that ultimately determine a population’s status. Such sublethal effects are a major concern regarding human-generated sound in the marine environment, and a management system is needed to account for them.


The potential biological removal (PBR) system has been used effectively to account for incidental mortality of marine mammals in commercial fisheries. Whether this system can be extended to account for the sublethal effects of other risk factors, including sound (National Research Council 2005), or would serve better as a model for a separate management system is not clear. Nonetheless, any comprehensive and effective management strategy must account for sublethal as well as lethal effects. With that in mind, Congress should require the Services to develop a management system that accounts for the cumulative effects on marine mammals of sublethal exposure to anthropogenic sound as well as all other human impacts.


Recommendation 6: Direct the National Marine Fisheries Service and the Fish and Wildlife Service to streamline their implementation of permitting and authorization processes for research on sound effects and for activities that may take marine mammals incidentally


Permitting and authorization processes could be streamlined without statutory or regulatory changes by combining analyses required under different statutes, conducting programmatic analyses to provide large-scale consideration of proposed actions, and invoking use of categorical exclusions where analyses are not required. Congress should advise the National Marine Fisheries Service and the Fish and Wildlife Service to implement options for streamlining environmental analyses to avoid delays in processing applications for take authorizations and research permits.


Recommendation 7: Promote U.S. leadership in international matters related to anthropogenic sound in the marine environment


The United States has an important opportunity to lead international efforts to address the effects of anthropogenic sound in the oceans. Such leadership is needed to promote research and sharing of information and to coordinate management strategies for regional and global sound-related issues. All the major sources of anthropogenic sound in the oceans are active on a global basis (that is, commercial shipping, seismic surveys and research, military and other sonar). Any comprehensive research and management approach must recognize that sound effects extend beyond national waters. Coordination of military exercises using sonar, development of ship-quieting technologies for commercial ships, and incorporation of ambient noise assessment into developing ocean observing systems are examples of activities requiring international leadership.


Shipping appears to pose a particularly difficult challenge. The vast majority of the commercial shipping fleet is registered outside the United States, and most shipping noise originates in international waters. Thus, it would be best to work within the international treaty structure to develop an appropriate framework for addressing this issue. Congress should direct the Department of State to consult with the interagency national research program on sound recommended earlier, the National Oceanic and Atmospheric Administration, the Department of Justice, the Marine Mammal Commission, and any other affected agencies to determine what shipping-related proposals should be made to the International Maritime Organization.



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