Report of the Round Table Session

Dekeling, R.1*, Hatch, L.2*, Erkman, A.3, de Jong, C.4, Mather, Y.5, Tasker, M.6, Turina, F.7, and Young, J.8


1 Ministry of Infrastructure and the Environment, The Netherlands
2 NOAA Office of National Marine Sanctuaries, USA
3 Rijkswaterstaat, The Netherlands
4 TNO, The Netherlands
5 Underwater Group, dstl Naval Systems, UK
7 National Park Service, USA
8 CSA Ocean Science, USA

* Session Chairs and Corresponding Authors; E-mail:


This report can be referenced as:

Dekeling, R., Hatch, L., Erkman, A., de Jong, C., Mather, Y., Tasker, M., Turina, F., and Young, J. (2015). Report of the Regulation Session, oceanoise2017, Vilanova i la Geltrú, Barcelona, Spain, 10-15 May. (Editors Michel André & Peter Sigray). Retrieved from


The Future of Ocean Noise Regulation


Current developments in US and Europe show the intent of regulators to broaden the scale of underwater noise impact assessments. This is the case for the US NOAA Ocean Noise Strategy and the European Marine Strategy Framework Directive. In these broader scale assessments, regulators will aim to determine whether the scale of sound generating activities and anthropogenic sound levels require further action, at a larger scale/or in a wider region. If such a need for further action is identified, this wider scale (for the EU: a regional sea approach) may require a new approach to regulation other than presently used regimes.

In the topic session on regulation during the OceaNoise 2015 conference, scientists and experts of different sectors shared their view on this future regulation, including whether current approaches could work sufficiently and where changes needed to be made to the present approach to regulation. These representatives further considered how different sectors should contribute. Selected experts provided different facts and views, after which a plenary discussion was held with the panel. This paper provides an overview of the most important considerations mentioned in this discussion.

Main issues that were identified in presentations and panel discussion

The need for development of an international management framework was identified, and many different aspects of such a framework were named, including:

  • Increased monitoring and management information requirements (internationally harmonized or even joint monitoring systems)
  • International agreement on thresholds for concern
  • Methodology to determine whether thresholds would actually be reached (including improved sound modelling techniques and tools)
  • Mechanisms to determine how to share and to restrict amount of permissible sound would need to be developed, e.g.
    • cap and trade schemes
    • tax incentives and tax credits (technology and research)
    • noise reduction certification (e.g. ‘Green Ships).

Progress is being made in understanding the distribution of underwater anthropogenic sound in European waters, mostly driven by the Marine Strategy Framework Directive (MSFD), for example the noise register under development between OSPAR, HELCOM and ICES. Examples of tools and methodologies that will bring us further to assess impacts of sound over larger timescales, over larger areas and across activities were shown. European navies will contribute to the data collection and make available information on activities, enabling assessment of the relative impact and cumulative effects of different activities across multiple sectors. In the United States, tools that aim to protect habitats and ecosystems are increasingly being used by management authorities to address the acoustic conditions of places of importance to the marine animals. The National Oceanic and Atmospheric Administration (NOAA) has been promoting this more comprehensive approach to protecting the species and resources in its trust (including marine mammals and endangered species and their habitats, as well as habitats that sustain commercial fisheries and protected areas, like marine sanctuaries) through the development of an agency-wide Ocean Noise Strategy. The effort seeks to guide accumulated agency management and science activity associated with individual taxa or noise-producing activities, towards the goals of the US National Ocean Policy, which highlights the use of marine planning to address cross-sectoral environmental implications with regions.

The use of sound budgets (or noise budgets) was discussed and there were examples (e.g. experience of the US National Park Service) that using a sound budget associated with permissible biological effects for different sectors that have historical use rights, which could work better than traditional source-based threshold approaches, leading to less litigation and better acceptance of measures taken to protect natural environments; also in EU, use of budget is now investigated, e.g. in the Netherlands, use of budgets is now under development- the aim is that sound budgets will allow individual sectors or actors to be flexible and make choices themselves- if they use silent equipment, they can have more activities, if they are too noisy it will be limited. Sound budgets can and need to be tuned to specific conditions, e.g. they can be made season-dependent, but we need to learn a how noise producing activities should be distributed within a budget. Additionally, it is important that permissible effect thresholds address ecosystem oriented targets rather than remaining limited to specific impacts to target populations. Some mitigation approaches designed to reduce specific effects may have other adverse effects on the ecosystem (e.g. reducing the peak impulsive sound levels, but distributing energy over time thus leading to increased potential for masking). A wide assessment is needed before decisions are made.

For industry, we should realize that it is willing to take measures and invest, and that for this sector it may be more important that regulation is consistent, because the timescale of large projects makes it difficult if regulation is altered significantly during the course of a project. At the same time, sometimes we are able to make significant changes over relatively short periods, for example novel noise reduction techniques for wind farm construction have been developed and used within the last few years.

Apart from the technical challenges, there are non-technical challenges that need to be overcome -and these may be more complex-, but if we want new approaches to regulation to be successful it would help if different stakeholders concerned would agree on principles that could support a more trustworthy, transparent and productive dialogue:

  • Accept that all human activities in the oceans create a footprint of some fashion
  • In general, limitation of the amount of anthropogenic underwater sound would be better
  • Ocean noise should be managed on an ecosystem scale considering all sources
  • Noise has been accepted by society as a pollutant and should be managed as such
  • Judicial action is often divisive and all parties concerned should look for alternative methods to find consensus between different views and values

Legislators and environmental managers need to take account of many societal interests. Supporting economic development and use of ecosystem services (Blue Growth) is essential. Measures designed to protect the environment should be cost-effective – a requirement specified in EU legislation (the MSFD). It is for this reason that cooperation, building trust and acknowledging of all interests is essential to make future frameworks for management of anthropogenic sound successful. Research should continue in order to understand the effects of anthropogenic sound on marine ecosystems and their components, particularly in understanding the loss of underwater ‘acoustic space’. Balancing the need to protect the acoustic conditions of places that support acoustically sensitive and active marine species with the ever-increasing uses of the offshore environment is a key challenge facing international coastal and ocean managers.


Some remaining open issues mentioned during the discussion

  • Information on which aspect of a sound signal is causing which effect (both for impulsive and for ambient noise) for which species
  • Information on threshold values at which anthropogenic sound causes behavioural effects in specific species
  • Further development of techniques to quantify the population consequences of acoustic disturbance.
  • Application of Population Sensitivity Analyses to study the effects of underwater noise on fish and other lesser known taxa
  • Cost-benefit analysis of sound reduction techniques
  • For the application of noise budgets a better understanding is needed on how the temporal distribution within such a budget would influence the scale of impact. Would it be better to have spread activities generating noise over longer periods or would it be better to concentrate these in short periods?