I have been involved in considering criteria and guidelines concerning the potential effects of anthropogenic sound on fishes (and more recently invertebrates).
The following paragraphs summarizes each of these papers, and gives links to the full documents.
For copyright reasons, we cannot always provide copies of the full papers on the website, but those interested are welcome to send an email and we would be glad to provide copies. (All images on these pages are copyright by either Drs. Hawkins or Popper.)
Popper, A.N., Hawkins, A.D., Fay, R.R., Mann, D., Bartol, S., Carlson, T., Coombs, S., Ellison, W.T., Gentry, R., Halvorsen, M.B., Løkkeborg, S., Rogers, P., Southall, B.L., Zeddies, D., Tavolga, W.N. (2014) Sound Exposure Guidelines for Fishes and Sea Turtles: A Technical Report prepared by ANSI-Accredited Standards Committee S3/SC1 and registered with ANSI. ASA S3/SC1.4 TR-2014. Springer and ASA Press, Cham, Switzerland. Link
Much of our recent work ties back to this 2014 working group report prepared under the auspices of the American National Standards Institute. The authors of the report (shown at left) met multiple times over several years to develop a set of interim criteria for fishes and turtles. The group were clear in pointing out that the interim criteria would likely change as more data were obtained. A critical component of this work product was the recognition that it would not be possible to have separate criteria for all fish species or all possible anthropogenic sources. Instead, the team proposed “group'ing” fishes into several different categories based on hearing structures, and to limit sound sources to several basic types.
Significantly, the guidance provided in this document is now being used, at least informally, in many places around the world.
Abstract: This Technical Report presents the outcome of a Working Group that was established to determine broadly applicable sound exposure guidelines for fishes and sea turtles. After consideration of the diversity of fish and sea turtles, guidelines were developed for broad groups of animals, defined by the way they detect sound. Different sound sources were considered in terms of their acoustic characteristics and appropriate metrics defined for measurement of the received levels. The resultant sound exposure guidelines are presented in a set of tables. In some cases numerical guidelines are provided, expressed in appropriate metrics. When there were insufficient data to support numerical values, the relative likelihood of effects occurring was evaluated, although the actual likelihood of effects depends on the received level. These sound exposure guidelines, which are based on the best scientific information at the time of writing, should be treated as interim. The expectation is that with more research the guidelines can be refined and more cells in the tables completed. Recommendations are put forward defining the research requirements of highest priority for extending these interim exposure guidelines.
Hawkins, A. D., Pembroke, A., and Popper, A. N. (2015). Information gaps in understanding the effects of noise on fishes and invertebrates. Reviews in Fish Biology and Fisheries. 25:39-64. Link
This paper was based on a workshop convened in 2012 by the U.S. Bureau of Ocean Energy Management (BOEM). The basis for the workshop, and our paper, was that there was (and, for that matter, still is) that it is almost impossible to arrive at clear conclusions on the nature and levels of man-made sound that have potential to cause adverse effects upon fishes and invertebrates. In order to develop a better understanding of effects of man-made sound, this paper identifies the most critical information needs and data gaps on the effects of various sounds on fishes, invertebrates, and fisheries, resulting from the use of sound-generating devices. It highlights the major issues and discusses the information currently available on each of the critical information needs and data gaps. The paper then identifies the main critical questions concerning the effects of man-made sounds on aquatic life for which answers are not readily available and articulates the types of information needed to fulfill each of these needs for information—the key information gaps. Finally, a list of priorities for research and development is presented.
Hawkins, A. D. and Popper, A. N. (2017). A sound approach to assessing the impact of underwater noise on marine fishes and invertebrates. ICES Journal of Marine Science, 74:635-651 . Link
Abstract: Increasing attention is being paid to the ecological consequences of underwater noise generated by human activities such as shipping and maritime industries including, but not limited to, oil and gas exploration and extraction, sonar systems, dredging and the construction of offshore renewable energy devices. There is particular concern over the extension of these activities into previously undeveloped areas of the oceans, including Polar Regions and areas of coral reef habitat. Most of the concern by regulators and others has focused upon effects upon marine mammals and other protected species. However, examining the impacts upon the overall ecology of affected habitats is also important as it may be dominated by effects upon the far larger biomasses of fishes and invertebrates, which do not have the same degree of legal protection. Many of these assessments of the impact of noise on fishes and invertebrates have overlooked important issues, including the sensitivity of a substantial proportion of these species to particle motion rather than sound pressure. Attempts have been made to establish sound exposure criteria setting regulatory limits to the levels of noise in terms of effects upon mortality levels, injury to tissues, hearing abilities, behaviour and physiology. However, such criteria have almost exclusively been developed for marine mammals. Criteria for fishes and invertebrates have often had to be assumed, or they have been derived from poorly designed and controlled studies. Moreover, the metrics employed to describe sounds from different sources have often been inappropriate, especially for fishes and invertebrates, as they have been based on sound pressure rather than particle motion.
Potential effects of a sound at different distances from a source. Note, the actual distances will depend on the source level, and the distance from any given source that some effect may “drop out” will likely vary as a result of numerous factors including the species of fish and perhaps even its size.
In addition, the sound propagation models employed to assess the distances over which effects might occur have seldom been validated by actual measurements and are especially poor at dealing with transmission under shallow water conditions, close to or within the seabed, or at the surface. Finally, impacts on fish and invertebrate populations are often unknown and remain unassessed. This paper considers the problems of assessing the impact of noise upon fishes and invertebrates and the assessment procedures that need to be implemented to protect these animals and the marine ecosystems of which they form an integral part. The paper also suggests directions for future research and planning that, if implemented, will provide for a far better scientific and regulatory basis for dealing with effects of noise on aquatic life.
Popper, A. N. and Hawkins, A. D. (2019). An overview of fish bioacoustics and the impacts of anthropogenic sounds on fishes. Journal of Fish Biology, 94:692-713. Link
We were invited to write the paper described here by the Fisheries Society of the British Isles as a way to help educate fish biologists and others about anthropogenic sound and fish bioacoustics. In addition to the paper, we were also invited to develop a short briefing report on the topic for a lay audience that might include fishers, regulators, and the public. This is a four-page PDF that can be found here.
This paper reviews the potential effects of anthropogenic sounds upon fishes, the resulting consequences for populations and ecosystems, and the need to develop sound exposure criteria and relevant regulations. However, assuming that many readers may not have a background in fish bioacoustics, the paper first provides information on underwater acoustics, with a focus on introducing the very important concept of particle motion – the primary acoustic stimulus for all fishes (including elasmobranchs). The paper then provides background material on fish hearing, sound production, and acoustic behavior. This is followed by an overview of what is known about effects of anthropogenic sounds on fishes and considers the current guidelines and criteria being used world-wide to assess potential effects on fishes.
Most importantly, the paper provides the most complete summary of the information on the impacts of anthropogenic noise on fishes already available. It is also made clear that there are currently so many information gaps that it is almost impossible to reach clear conclusions on the nature and levels of anthropogenic sounds that have potential to cause changes in animal behavior, or even result in physical harm. Further research is required on the responses of a range of fish species to different sound sources, under different conditions. There is a need both to examine the immediate effects of sound exposure, and also the longer-term effects, in terms of fitness, and likely impacts upon populations.
Popper, A. N., Hawkins, A. D., and Halvorsen, M. C. (2019). Anthropogenic sound and fishes. A Report Prepared for the Washington State Department of Transportation, Olympia, WA. Link
This report was written with a goal of obtaining the best scientific data available to determine potential effects on fishes exposed to elevated levels of underwater sound produced by impulsive underwater sources in the aquatic environment, especially impact pile driving. The report evaluates research and literature that have been published since the 2008 interim criteria were proposed by the Fisheries Hydroacoustics Working Group (FHWG). Thus, the report includes a review and evaluation of literature and research on the effects of underwater sound on fishes, focusing on the effects of impulsive sound produced by impact pile driving. The primary intent of this review is to serve as a “white paper” which is a succinct source of information. The report also includes the evaluation of the existing literature (2005 to present) and a summary of knowledge of the injurious and sub-injurious response of fishes exposed to elevated levels of underwater sound, produced during impulse sound events such as impact pile driving and blasting.
Hawkins, A. D., Johnson, C., Popper, A. N. (2020). Setting of sound exposure criteria for fishes. The Journal of the Acoustical Society of America, 147:1762-1777. Download Publication
Each of the authors of this paper has, in various ways, been engaged with studying, thinking about, and assisting with regulatory activities associated with the potential effects of anthropogenic sound upon fishes. Over this period, we have realized that there are still major gaps in information concerning the potential effects of sound on fishes. There are also major problems in the way that this topic has been considered and discussed. Indeed, we have been particularly “bothered” by the fact that many critically important words and ideas that are central to any discussion of the effects of anthropogenic sound on fish are used in diverse ways by various investigators, regulators, and agencies. Indeed, one can almost analogize the diversity of use to that described for the Tower of Babel (Genesis 11:1-9), which emphasized the diversity of human languages. Thus, in discussing the effects of anthropogenic sounds, people often use the same words, but with very different meanings that are often not clear to others. This makes developing a common understanding of ideas, and seeking appropriate solutions, exceptionally challenging.
The other issue that we often encounter is that there is a broad lack of understanding of how to set rigorous sound exposure criteria for fishes, as well as a diversity of ideas about how this should be done. There have been many different and often incompatible approaches to collecting the data needed to develop such criteria. And, as a consequence, it is hard to use much of the current data in setting criteria. As a result, there is a strong potential for different criteria to be established for the same effects.
The purpose of this paper is to provide a common foundation for developing sound exposure criteria for fishes for use by researchers, regulators, and other interested parties, but not to provide final answers. To lay that foundation, we recommend specific definitions for critical concepts and discuss how they should be used. We are not suggesting, however, that our recommendations end the discussion of these concepts. Instead, our goal is to get our colleagues in the research and regulatory communities around the world moving towards a dialogue that results in a common understanding. [Adapted from paper introduction.]
Abstract: Underwater sounds from human sources can have detrimental effects upon aquatic animals, including fishes. It is important to establish sound exposure criteria for fishes, setting out those levels of sound from different sources that have detrimental effects upon them, in order to support current and future protective regulations. This paper considers the gaps in information that must be resolved in order to establish reasonable sound exposure criteria for fishes. The vulnerability of fishes is affected by the characteristics of underwater sounds, which must be taken into account when evaluating effects. The effects that need to be considered include death and injuries, physiological effects and changes in behavior. Strong emphasis in assessing the effects of sounds upon fishes has been placed upon their hearing abilities. However, although hearing has to be taken into account, other actual effects also have to be considered. In this paper we consider the information gaps that must be filled for the development of future guidelines and criteria.
Variation in goldfish hearing data from different studies. The data illustrate the need for some standardization in the way in which fish hearing thresholds are determined. The variation, as discussed in the paper, is likely related to the acoustics of different setups, the methodology used to obtain thresholds, and many other differences in the studies.
Popper, A. N., Hawkins, A. D., Sand, O., and Sisneros, J. A. (2019). Examining the hearing abilities of fishes. The Journal of the Acoustical Society of America, 146, 948-955. Download publication
Because sound is so important to fishes, knowledge of their hearing capabilities is imperative for determining whether human activities, particularly in terms of noise pollution, have an impact on hearing and thus on fish behavior. It is important, therefore, to determine those levels of different sounds that particular species are able to respond to, and those levels that they cannot detect, in order to evaluate the significance of different sounds to fishes and to determine the distances over which sounds can be detected. It is also important to have a far better understanding of how fishes detect and process sounds.
A key point that led to our thinking for this paper derives from the observation that many investigators (including the authors) have measured hearing by fishes using a wide range of techniques and approaches (see figure at left). Most of this work has focused on measuring hearing sensitivity by determining hearing thresholds – defined as the lowest sound levels an animal can detect and respond to at particular frequencies. There have been far fewer studies of other, albeit very important, questions, such as whether, how, and how well, fishes can discriminate between sounds (e.g., frequency, intensity, temporal patterns), detect signals in the presence of sounds that mask them, and determine the direction to a sound source.
The purpose of this paper is two-fold. First, we discuss the basis for the variation in data, and point out what we see as the major issues resulting from having unreliable data. Second, we present, as investigators who have focused on fish hearing for many decades, some initial thoughts on what and how future scientific work should be carried out to investigate fish hearing for both basic science and applied purposes. Our hope is that these suggestions may provide a basis for future discussions and approaches on how experiments should be done.
Popper, A. N., Hawkins, A. D. and Thomsen, F. (2020). Taking the animals’ perspective regarding underwater anthropogenic sound. Trends in Ecology and Evolution. Link
Abstract: There is increasing concern about the effects of man-made sounds on aquatic life. While these concerns lead to regulation and mitigation, there are few data upon which to base environmental management, especially for fishes and invertebrates. We argue that regulation and mitigation should always be developed by looking at potential effects from the perspectives of the animals and ecosystems exposed to the sounds. We contend that there is currently a need for far more data upon which to base regulation and mitigation, and that future studies should be directed at the most important questions. This will require a process whereby regulators and researchers come together to identify and implement a strategy that links key science and regulatory questions.
![Representative sound sources that produce anthropogenic sounds and the animals that are potentially affected. Note that sounds may be both in water (from boats, seismic air guns, construction work) on the bottom, and in the substrate. Moreover, while most sounds arise from in-water operations, it is well known that sounds on land, such as from auto traffic, may get into the water through the substrate [e.g., 35]. Thus, the underwater acoustic environment, especially near-shore, can be very complex. Figure © 2020 Anthony D. Hawkins, all rights reserved.](https://images.squarespace-cdn.com/content/v1/5ea05edf0db95a1ffa37498b/1590246511007-6NX54COBUBEZERT0H2R6/Figure+1.png)
Representative sound sources that produce anthropogenic sounds and the animals that are potentially affected. Note that sounds may be both in water (from boats, seismic air guns, construction work) on the bottom, and in the substrate. Moreover, while most sounds arise from in-water operations, it is well known that sounds on land, such as from auto traffic, may get into the water through the substrate [e.g., 35]. Thus, the underwater acoustic environment, especially near-shore, can be very complex. Figure © 2020 Anthony D. Hawkins, all rights reserved.
Popper, A.N., L. Hice-Dunton, K.A. Williams, and E. Jenkins. 2021. Workgroup report on sound and vibration effects on fishes and aquatic invertebrates for the State of the Science Workshop on Wildlife and Offshore Wind Energy 2020: Cumulative Impacts. Report to the New York State Energy Research and Development Authority (NYSERDA). Albany, NY. 20 pp. Link
This work has now been published as a peer-reviewed article in JASA. Link
There are substantial gaps in knowledge regarding both the bioacoustics and the responses of animals to sound associated with pre-construction, construction, and operations of offshore wind energy development. In association with the 2020 State of the Science Workshop on Wildlife and Offshore Wind Energy, hosted by the New York State Energy Research and Development Authority, a workgroup identified studies for the next five years that would help stakeholders better understand potential cumulative biological impacts to fishes and aquatic invertebrates as the offshore wind industry develops. The workgroup focused on potential impacts of sound and vibration and identified seven short-term priorities. Priorities include a mix of primary research and other types of coordination efforts. Key research needs include the examination of animal displacement and other behavioral responses to sound, as well as hearing sensitivity studies focused on particle motion and substrate vibration as well as sound pressure. Other needs include the identification of priority taxa on which to focus research, standardization of methods, development of a long-term highly instrumented field site, and an examination of sound mitigation options for fishes and invertebrates.
Major sources of sound and vibration from offshore wind farms during the pre-construction (left), construction (center), and operational (right) periods (not to scale). Sounds emitted from each source are indicated with red lines. Acoustic energy put into the substrate as a result of seismic airguns and the pounding of piles during construction can emanate back into the water at considerable distances from the sources themselves (Popper and Hastings, 2009; Hawkins et al., 2021) (Color online) (Figure copyright © 2021 Iain Stenhouse/Biodiversity Research Institute, all rights reserved.)