Appendix D
Research Recommendations from Previous NRC Reports (1994, 2000)

RECOMMENDATIONS—NRC (1994) LOW-FREQUENCY SOUND AND MARINE MAMMALS: CURRENT KNOWLEDGE AND RESEARCH NEEDS

Limitations of Current Knowledge

Data on the effects of low-frequency sounds on marine mammals are scarce. Although we do have some knowledge about the behavior and reactions of certain marine mammals in response to sound, as well as about the hearing capabilities of a few species, the data are extremely limited and cannot constitute the basis for informed prediction or evaluation of the effects of intense low-frequency sounds on any marine species.

Changes in the Proposed Regulatory Structure

It is the committee’s judgment that the regulatory system governing marine mammal “taking” by research actively discourages and delays the acquisition of scientific knowledge that would benefit conservation of marine mammals, their food sources, and their ecosystems. The committee thus proposes several alternatives for reducing unnecessary regulatory barriers and facilitating valuable research while maintaining all necessary protection for marine mammals.Continued progress has been made on many of the recommendations made in previous reports (NRC, 1994; 2000) but further progress is needed in order to obtain the base of data needed to fully understand the impact(s) of sound on marine mammals and other marine organisms.



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Appendix D Research Recommendations from Previous NRC Reports (1994, 2000) RECOMMENDATIONS—NRC (1994) LOW-FREQUENCY SOUND AND MARINE MAMMALS: CURRENT KNOWLEDGE AND RESEARCH NEEDS Limitations of Current Knowledge Data on the effects of low-frequency sounds on marine mammals are scarce. Although we do have some knowledge about the behavior and reactions of certain marine mammals in response to sound, as well as about the hearing capabilities of a few species, the data are extremely limited and cannot constitute the basis for informed prediction or evaluation of the effects of intense low-frequency sounds on any marine species. Changes in the Proposed Regulatory Structure It is the committee’s judgment that the regulatory system governing marine mammal “taking” by research actively discourages and delays the acquisition of scientific knowledge that would benefit conservation of marine mammals, their food sources, and their ecosystems. The committee thus proposes several alternatives for reducing unnecessary regulatory barriers and facilitating valuable research while maintaining all necessary protection for marine mammals.Continued progress has been made on many of the recommendations made in previous reports (NRC, 1994; 2000) but further progress is needed in order to obtain the base of data needed to fully understand the impact(s) of sound on marine mammals and other marine organisms.

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Topics for Future Research Aims of research should be: To determine the normal behaviors of marine mammals in the wild and their behavioral responses to human-made acoustic signals. To determine how marine mammals utilize natural sounds for communication and for maintaining their normal behavioral repertoire. To determine the responses of free-ranging marine mammals to human-made acoustic stimuli, including repeated exposure to the same individuals. How is the use of natural sounds altered by the presence of human-made sounds? To determine how different sound types and levels affect migration and other movement patterns of marine mammals. To determine the responses of deep-diving marine mammals to low-frequency sounds whose characteristics (source level, frequency, bandwidth, duty cycle) duplicate or approximate those produced by acoustic oceanographers. To determine the structure and capabilities of the auditory system in marine mammals. To determine basic hearing capabilities of various species of marine mammals. To determine hearing capabilities of larger marine mammals that are not amenable to laboratory study. To determine audiometric data on multiple animals in order to understand intraspecific variance in hearing capabilities. Determine sound-pressure levels that produce temporary and permanent hearing loss in marine mammals. To determine morphology and sound conduction paths of the auditory system in various marine mammals. To determine whether low-frequency sounds affect the behavior and physiology of organisms that serve as part of the food chain for marine mammals. To develop tools that can enhance observation and data gathering regarding marine mammal behavior or that can protect the animals from intense human-made sounds. To develop tags that can be used for long-term observations of marine mammals, including studies on physiological condition, location (in three dimensions), sound exposure levels, and acoustic behavior. To develop means of using in-place acoustic monitoring devices to study marine mammal movement and behavior on an ocean basin scale and of following individuals or groups of animals for extended periods and distances. To develop procedures for rapid determinations of hearing capabilities

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(and perhaps other physiological studies) on beached or ensnared marine mammals. To investigate the possibility of protecting marine mammals from some of the adverse effects of intense, low-frequency sounds by capitalizing on any normal avoidance reactions these animals might have to certain sounds. RECOMMENDATIONS—NRC (2000) MARINE MAMMALS AND LOW-FREQUENCY SOUND Future Research and Observations Priority Studies Recommendations: The committee supports the recommendation of NRC (1994) that there is a need for planned experiments designed to relate the behavior of specific animals to the received level of sound to which they are being exposed. Very few studies have succeeded in this aim. Because studies of ocean acoustics and marine mammal behavior are very challenging, successful experiments will require a closer collaboration between biologists and acousticians than has been the case in the past for many field studies. Success will also require continued refinement of techniques for making acoustic and visual observations, such as methods for locating vocalizing marine mammals and development of tags that can monitor received levels at the tagged animal. To move beyond requiring extensive study of each sound source and each area in which it may be operated, a coordinated plan should be developed to explore how sound characteristics affect the responses of a representative set of marine mammal species in several biological contexts (e.g., feeding, migrating, and breeding). Research should be focused on studies of representative species using standard signal types, measuring a standard set of biological parameters, based on hearing type (Ketten, 1994), taxonomic group, and behavioral ecology (at least one species per group; reprinted as Box 4-1 in this report). This could allow the development of mathematical models that predict the levels and types of noise that pose a risk of injury to marine mammals. Such models could be used to predict in multidimensional space where TTS is likely (a “TTS potential region”) as a threshold of potential risk and to determine measures of behavioral disruption for different species groups. Observations should include both trained and wild animals. The results of such research could provide the necessary background for future environmental impact statements, regulations, and permitting processes. The uncertainty in predictions of received sound levels hinders the application of models of marine mammal responses to sound and will require three complementary approaches: (1) development of better acoustic propagation models; (2) development of better observing systems to gather the data needed in models; and when the first two are not feasible,

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(3) development of better systems to observe ambient sound in the ocean and transient noise pollution events. Any research that includes relatively loud sound sources should monitor sound levels around the source site to gather data to calibrate their acoustic propagation models. Acoustic studies focused on topics other than marine mammals should try to keep sound sources away from marine mammal “hotspots,” even if this complicates logistics, increases costs, and/or decreases the efficiency of the experiments. Studies of wild marine mammals should include careful determination of their locations, coupled with improved sampling and modeling of acoustic propagation to estimate received sound levels accurately. Alternatively, acoustic data loggers could be mounted on individual animals to record (1) the sounds (and their levels) to which the animals are exposed; (2) their vertical and horizontal movements; and (3) the sounds produced by the animals, including physiological sounds such as breathing and heartbeats. A central theme of this report is that the task of developing predictive models of acoustic conditions that would harm marine mammals could be simplified by partitioning research among a small number of species that are representative in their hearing capabilities and sensitivities of larger groups of marine mammals. Box 4.1 (this report) describes the priority species groups, signal characteristics, and biological response parameters that should be investigated. Richardson et al. (1995) summarized studies of marine mammal responses to human-generated sounds, particularly those associated with oil exploration and shipping. Some of these studies reported a significant difference between levels of pulsed versus more continuous sounds required to evoke a response in whales. To evoke the same level of response in migrating gray whales, a pulsed air-gun sound required levels 50 dB higher than a diverse array of low-frequency continuous sources. This result is unexpected based on human hearing capabilities. How do marine mammals respond to signals with durations between the pulsed air-gun noise (pulses separated by 7 to 15 s) and more continuous sounds? Another important question is: How do marine mammals respond when the received level is the same from two sources at different distances? This would help to discriminate whether marine mammals generally respond to received level (as was the case in the Phase II LFA study), estimated range to source, the gradient of acoustic energy over distance, and/or other sound characteristics. Response to Stranded Marine Mammals Recommendations: The concept of Stranded Whale Auditory Test (SWAT) teams recommended in NRC (1994) and NRDC (1999) should be implemented by funding trained scientists and associating them with strand-

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ing networks. The Office of Naval Research (ONR) partially funded a small effort to support the activities of a SWAT team, but the hardware and field methods are not yet adequate for wide testing. The ONR program manager (R. Gisiner) estimates that a considerable, but not unreasonable, amount of hardware and software design and testing will be needed (about one to two years of effort) before a system capable of regular operation under the SWAT team approach is feasible. However, this activity should be expanded to at least two teams, one on the East Coast and one on the West Coast of the United States. The teams should be responsible for (1) necropsy of suspected/possible marine mammal victims of sound injury (to be able to show whether sound caused the injuries or deaths) and (2) testing of hearing on stranded or entangled live animals. There is a need to expand the pool of individuals capable of doing this kind of work and capable of relating ear anatomy to function. An immediate need is for funding a specialist in evoked potential audiometry to develop improved methods applicable to large whales. A post-doctoral fellowship might be the most economical way to achieve this goal. The National Marine Fisheries Service (NMFS) and/or ONR should include funding for such work in the next budget cycle. Alternative possibilities for studying hearing in animals that are not kept in captivity also should be explored, such as placing a tag with electrodes on the head of a free-swimming whale and playing sound to the animal in a quiet environment. Multiagency Research Support Recommendations: If government funding shortages and priorities continue to constrain budgets for marine mammal research in the foreseeable future, management of sound in the ocean should remain conservative (and should incorporate management of all sources of human-generated noise in the sea, including industrial sources), in the absence of required knowledge. If government regulators need better information on which to base decisions, they should take such steps as necessary to provide increased funding for marine mammal research and to improve the ways that needed research is identified, funded, and conducted. Acquiring better information is often complicated because the regulatory parts of agencies like NMFS and the Fish and Wildlife Service (FWS) are separated from research, and funded research may not necessarily match research needed by regulators. It is imperative that the research and regulatory arms of NMFS and FWS maintain good linkages within these two agencies and that priority is given to research needed by regulators in each agency. Government agencies with basic science missions (e.g., National Science Foundation [NSF] and National Institutes of Health [NIH]) should fund marine mammal research at the levels needed to answer fundamental questions about hearing anatomy and physiology. Mission agencies with responsi-

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bilities related to marine mammals (e.g., ONR, National Oceanic and Atmospheric Administration [NOAA], Minerals Management Service (MMS), U.S. Geological Survey [USGS]) should also fund basic research (notwithstanding ONR’s limitations under the Mansfield Amendment), in the spirit of the recommendation of NRC (1992) that “federal agencies with marine-related missions find mechanisms to guarantee the continuing vitality of the underlying basic science on which they depend.” Such research should receive the same level of peer review as other basic research and be competitive with such programs for funding. Because marine mammal research is quite expensive, multiagency funding may be necessary to spread the costs. Alternatively, multiple parts of the same agency may need to cooperate in order to provide sufficient funds. Multidisciplinary Research Teams and Peer Review Recommendation: Consideration should be given to establishing a multiinvestigator program to study the effects of sound on marine mammals, funded by consortia of government agencies, nongovernmental organizations, shipping, and hydrocarbon exploration and production industries. These consortia should include individuals, organizations, and companies in nations that share marine mammal stocks and sound-producing activities with the United States (e.g., Canada, Mexico, nations of the North Atlantic Treaty Organization). Such consortia could be initiated through a workshop to bring together the interested communities. The design and implementation of auditory research on marine mammals ideally should be an interdisciplinary enterprise. Valuable contributions can be made by physical acousticians on the choice of sound stimuli to be used, by electronics experts on the choice and calibration of transducers for presenting the stimuli, by marine biologists on the choice of species and/or the best season and location for testing, by psychoacousticians on the testing procedures, and by statisticians on initial design and eventual data analysis and presentation. Without collaboration among specialists within these various disciplines, there is a greater probability that expensive and time-consuming projects will contain errors that preclude an unambiguous interpretation of the results. These projects are sufficiently complex that one or two individuals cannot reasonably be expected to have the full range of knowledge necessary for success. The logistical difficulties, permitting issues, and expense of such research demand advanced planning in all these areas. If such a research program is established, it should use a public Request for Proposal (RFP) process that results in proposals from more than one research team and is modeled after the peer-review processes used by NSF and NIH. Conversely, some research should continue to be funded through the less conservative ONR model, which provides program managers with

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greater latitude to fund more innovative science. A spectrum of funding styles is useful. The RFP should be well advertised to encourage ideas and proposals from a wide range of researchers and institutions (including foreign participants), rather than relying on a set of traditional investigators. The goal of the process should be to optimize the selection of hypotheses, methods, and design and to identify the best performer(s) (e.g., best track record in previous work) for the proposed work. It is to the advantage of the sponsors to implement programs of broad-based peer review for such proposals. Future research on marine mammals unquestionably would profit from a broad-based review of the plans developed by multidisciplinary teams and evaluated by a peer-review process that is objective and independent. Such a review should determine whether the investigative team did the following adequately: identified basic problem(s); established specific hypotheses to be tested, with appropriate methods for data reduction, data presentation, and statistical analysis; identified optimal experimental methods and test conditions (including geographic location of study); and evaluated the power of the proposed experimental design. Because long research projects often need to adjust to experience gained in field programs and learning about what kinds of observations are practical and achievable, it is important to provide advice from an outside review team later in the life of a project. Sponsors of research need to be aware that studies funded and led by one special interest are vulnerable to concerns about conflict of interest. For example, research on the effects of smoking funded by NIH is likely to be perceived to be more objective than research conducted by the tobacco industry. Concern for peer review, efficiency, and independence argues for having an agency such as NSF take the lead in managing an interagency research program on the effects of noise on marine mammals. Agencies that fund such applied research should ensure that adequate funding for analysis and plans for peer review are in place before a research award is made. Analysis might be speeded by employing a larger team for analysis and involving this team in planning the observations to make them as easy as possible to analyze later. Although publication in peer-reviewed journals is the standard by which most research is judged, applied research output from projects like the Marine Mammals Research Project (MMRP) is not necessarily suitable for publication in available academic journals and the results may need to be used for regulatory decisions within a shorter amount of time than the normal journal paper cycle. Timely peer review of such studies might be better accomplished by conducting a mail

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and/or panel review of results by an independent group established specifically for this purpose. Population-Level Audiograms Recommendations: Federal agencies should sponsor studies on the hearing abilities of both free-swimming and stranded animals. Population-level audiograms of many individuals (such as are performed for humans; see Yost and Killion, 1997) are necessary for establishing the baseline of hearing capabilities and normal hearing loss in marine mammals, as also recommended in NRC (1994). Stranded animals should be assessed to determine if their hearing is “normal.” Data are needed to provide comparisons that would allow an evaluation of how common hearing deficits may be among stranded animals. The development of population-level audiograms will require the perfection and wide use of auditory evoked potential techniques, to eliminate the need to train all tested animals. However, if the cost and techniques limit widespread auditory evoked potential measurements of captive animals, a good sample of multiple animals (different ages and both genders) of the same species should be tested. National Captive Marine Mammal Research Facility Recommendations: If the studies described in Chapter 3 and Box 5.1 (NRC, 2000) are of sufficient priority to reduce uncertainties in the regulation of human-generated sound in the ocean, federal agencies should establish a national facility for the study of marine mammal hearing and behavior. The committee believes that such a facility might be established at relatively little incremental cost by enhancement of an existing Navy facility. The facility for captive marine mammal research would have animals for “hire” by investigators funded for peer-reviewed research. Offset funds would come from individual grants and researchers, but the funding base for such a facility should not be provided solely by such offsets. Allocation of space, animals, and facility resources should be determined by a broad-based review board on the basis of the quality and significance of the proposed research. An additional virtue of establishing a national captive marine mammal research facility is that the total number of marine mammals removed from the wild would be minimized. Investigators could apply for support for short- or long-term study of the animals at this facility, from the range of agencies funding marine mammal research, at costs that would not have to include long-term maintenance of the animals. Such a facility should include the capability to work with trained animals in the open ocean. The Navy’s Marine Mammal Program facility in San Diego keeps marine mammals and already has trained animals and exper-

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tise in maintaining them. Its role potentially could be expanded to provide a more widely accessible national facility, including unclassified research. If such a facility is operated by the Navy, it will be necessary to ensure that research data are not restricted from publication. Establishment of a facility to promote field studies could also enable research recommended in this report, but such a facility would be more expensive and a lower priority than a national facility for research on trained, captive animals. Regulatory Reform Recommendations: Congress should change the Marine Mammal Protection Act (MMPA) and/or NOAA should change the implementing legislation of the MMPA to allow incidental take authorization based solely on negligible impact on the population. Research should be undertaken to allow the definition of Level A harassment to be related to the TTS produced in a species, when known. Level B harassment should be limited to meaningful disruption of biologically significant activities that could affect demographically important variables such as reproduction and longevity. Comprehensive Monitoring and Regulation of Sound in the Ocean Recommendations: Noise monitoring is important and acoustic hotspots should be identified. Fortunately, ambient noise data exist for a variety of locations, which could provide time series and baselines for additional monitoring. Existing data should be identified and made accessible through a single easy-to-access source. Like marine mammal research programs, funding for noise monitoring should be awarded based on responses to a request for proposals and careful evaluation of the costs and benefits of the proposed systems. The opening of the existing IUSS for whale research was important for demonstrating the power of bottom-mounted hydrophone arrays, but the IUSS may or may not provide the best system for the acoustic monitoring tasks envisioned here, given that it was designed for an entirely different purpose. The first step in comprehensive monitoring and regulation of sound in the ocean should be to attempt to characterize the existing ambient sound field in the ocean and to characterize the sources that contribute to it. Monitoring of baseline sound levels should be carried out, particularly in critical habitats of acoustically sensitive or vulnerable species or in habitats critical to specific life stages, such as breeding and calving areas. Protection of marine mammals from subtle or long-term effects of harassment cannot be achieved through regulation of individual “takes.” An alternative habitat-oriented approach is required to protect marine mammals from the cumulative impacts of noise pollution, chemical pollution, physical habitat loss, and fishing. Such an approach requires monitoring of the status of

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marine mammal populations along with the quality of critical habitats, including the acoustic quality. Account should be taken of the populations involved; it is sensible to protect more rigorously species that are more endangered (e.g., northern right whales, Eubalaena glacialis) than those that are less at risk. Basic research regarding what is significant about critical habitats and what factors have population-level effects—for example, food supply, water quality, and noise levels and characteristics— will prove much more effective for protecting marine mammals than merely attempting to regulate individual human activities that may potentially cause changes in the behavior of an individual marine mammal. NMFS regulations should encompass the entirety of noise pollution and other threats to marine mammals.