Report of the Management and Policy Session

Lewandowski, J.1*, Sigray, P.2*, Sanders, M.3, Juretzek, C.4, Nowacek, D.5

1   Bureau of Ocean Energy Management, U.S. Department of the Interior, USA
2   KTH, Sweden
3   Transport Canada, Canada
4   Federal Maritime and Hydrographic Agency, Germany
5   Duke University Marine Laboratory, Nicholas School of the Environment, USA

* Session Chairs and Corresponding Authors; E-mail: Lewandowski, Jill K <> – Peter Sigray <>

This report can be referenced as: Lewandowski, J., Sigray, P., Sanders, M., Juretzek, C., and Nowacek, D. (2023). Report of the Management and Policy Session, OCEANOISE2023, Vilanova i la Geltrú, Barcelona, Spain, 22-26 May. Retrieved from



Getting Quieter: How can regulators best establish clear and effective noise limits?

Scientific understanding of the ecological impacts of noise events is increasingly informing decision-making frameworks, including identification of limits or thresholds for short term and chronic exposure. Today, policy makers across the globe are setting noise limits through varied approaches backed by available science and monitoring information.

Through the review of five case studies below, this session was designed to:

  • Share information on the development of example approaches;
  • Discuss lessons and best practices;
  • Identify biggest policy or science challenges in establishing limits; and,
  • Identify potential science or technical solutions and regulatory tools that may improve the effectiveness and efficacy of threshold and limit setting.

Case Studies

TG Noise Recommendations on EU threshold values for underwater noise – Peter Sigray KTH, Sweden (on behalf of Fabrizio Borsani, Institute for Environmental Protection and Research, Italy)

Reaching the European Union’s Good Environmental Status requires Member States to look at the spatial distribution, temporal extent, and levels of anthropogenic impulsive and continuous underwater noise. In addition, it requires a common methodology for setting threshold values. In 2022, recommendations on the threshold values for underwater noise were agreed. These specify that no more than 20% of a given marine area, can be exposed to continuous underwater noise over a year. Similarly, no more than 20% of a marine habitat can be exposed to impulsive noise over a given day, and no more than 10% over a year. This presentation reviews the process and rationale that led the Technical Group on underwater Noise (TGNoise) to define these threshold values.

 Update on Current Efforts to Address Underwater Vessel Noise at the International Maritime Organization (IMO) – Michelle Sanders Transport Canada, Canada

In 2023, the International Maritime Organization (IMO) met during the SDC 9 meeting to agree to a revised version of the Guidelines for the reduction of underwater noise from shipping. In addition, the re-establishment of the CG for the Review of the URN Guidelines, focusing on the identification of next steps and program of action occurred. Some important structural changes to improve usability included the following: updated application so that the guidelines apply to ships of all sizes and types, including non-commercial ships; maritime administrations included as a relevant stakeholder in helping to establish mechanisms and programs through which noise reduction efforts can be realized; reflection of the current state of knowledge in technologies to reduce URN, including further distinction on measures to be applied for new vessels versus existing vessels; and new guidance on improved voyage planning and national and international designated protected areas. New Sections included “Underwater Radiated Noise Management Planning,” energy efficiency and URN reduction, and incentivization. In addition to finalizing the revised guidelines, the committee adopted a revised workplan, which included identifying ways to implement the revised guidelines and increase awareness and update, organizing an expert workshop on potential co-benefits and trade-offs that may exist between the reduction of underwater radiated noise from ships and energy efficiency, and developing a plan of action for further work. MEPC approved the revised guidelines in July 2023 at MEPC80, with a three-year experience-building phase to assess if amendments to the guidelines are needed. 

Germany offshore wind pile driving noise received level limit – Carina Juretzek, Federal Maritime and Hydrographic Agency, Germany

Since 1997, BSH has been responsible for the approval and monitoring of wind turbines and structures in the German Exclusive Economic Zone of the North and Baltic Sea. Due to climate and energy policy requirements of the Federal Government, capacities of offshore wind energy have expanded. More than 1,000 turbines are in operation up to 35 km from the coast and up to 40 meters in depth. Germany developed an offshore wind pile driving noise received level limit through a multi-step process. Scientific knowledge was developed on species and habitats in the management areas that may be affected. Scientific knowledge was also developed on the physical characterizes of anthropogenic noise sources and the transmission into habitats. The research projects resulted in an increase in knowledge on species distribution, abundance, and habitat use. This included identification of the key species of harbour porpoises which is crucial to focus research and decision making and their main habitats, including Natura 2000 areas. This research focused on possible impacts of underwater noise on marine life, including hearing thresholds of harbour porpoises and evidence of temporary threshold shifts (TTS) in harbour porpoises. Finally, this research included the cumulative impacts due to pile driving. Through this research and development, a noise mitigation strategy could be adopted. This strategy and priority targets could be communicated to stakeholders. BSH identified that through developing and choosing a noise abatement technique, the key role of regulators comes to light, to demonstrate and assess the applicability, efficiency, and efficacy of noise mitigation measures, regarding scientific knowledge and the considerations of normative aspects of noise mitigation. The final steps of the process include to develop normative rules to monitor the effectiveness of measures, to establish/identify an administrative basis, and to implement the basis in plans and approval procedures. The BAT/BEP Experience report (ERa) on offshore-suitable noise abatement systems exemplifies the key characteristics of the German offshore wind pile driving noise received level limit.  

Proposed Underwater Noise Limits for Offshore Wind Construction in the U.S.: A Work in Progress – Jill Lewandowski, Bureau of Ocean Energy Management, USA

The United States has set a target of 30GW of offshore wind energy by 2030 which has sparked substantial interest in development along the U.S. North Atlantic coast. Here, one major issue of concern is the effects of pile driving noise on the highly endangered North Atlantic right whale (Eubalaena glacialis), a species in continued decline with approximately 350 individuals remaining. While other locations worldwide have set noise limits for high frequency cetaceans (e.g., harbor porpoise), none exist for low frequency cetaceans, like the North Atlantic right whale. Further, challenges remain in the efficacy of available quieting technology to significantly reduce low frequency noise (especially in 7 Hz to 35 kHz range). This presentation will provide the U.S. Bureau of Ocean Energy Management’s approach to setting an initial pile driving noise limit for low frequency cetaceans and seek feedback on how to strengthen this limit for projects five plus years from development.

Canada’s Efforts to Address Underwater Vessel Noise – Michelle Sanders, Transport Canada, Canada

Underwater noise is identified in Canada as a high-risk anthropogenic threat in recovery plans for the Southern Resident killer whale (SRKW) and Saint Lawrence Estuary beluga under the Species at Risk Act (SARA). SRKW is listed as Endangered in Canada and the US with only 73 individuals remaining. Main threats include acoustic and physical disturbance, availability of prey, and contaminants. The population is facing imminent threats to survival and recovery — enhanced measure are necessary to support recovery. Canada’s approach includes three tiers: operational and technical measures, domestic and international efforts, and large commercial vessels and small vessels solutions, resulting in the reduction of underwater noise and physical disturbance from vessels. Seasonal measures that apply beyond the shipping lanes, in areas of importance to the SRKW include mandatory measures, such as 400m approach distance, interim sanctuary ones, and seasonal slowdown areas. Voluntary measures include to reduce speed to less than 7 knots when within 1000 m of nearest marine mammal, to turn off fish finders and echosounders if safe to do so, and to place engine in neutral and allow animals to pass within 400 m of a killer whale. Advancing longer term actions include recognizing that operational measures will only us so far and longer-term efforts are underway, such as Quiet Vessel Initiative, IMO and TSS feasibility study, and Underwater Vessel Noise Reduction Target for use in the URN management plan. Solutions must reflect complexity of the issue and differences in vessels. Feasibility of measures must consider economic, cultural, safety, and environmental perspectives. Industry, government, ports, NGOs, and indigenous communities play an important role in identifying, analyzing, and testing potential solutions.

The IUCN Western Gray Whale Advisory Panel: Managing noise from offshore oil/gas exploration and production through a multi-stakeholder process – Doug Nowacek, Duke University Marine Lab, USA

Since 2004, the oil and gas company Sakhalin Energy and the IUCN joined forces to minimize potential risks from the company’s operations to the western gray whale population. Initially, IUCN responded to Sakhalin Energy’s request for help by convening an Independent Scientific Review Panel to evaluate the company’s planned approach for minimizing the impacts of construction activities in the vicinity of Sakhalin Island, Russia, during the 2005 open-water season. In 2006, again at the request of Sakhalin Energy, IUCN convened a longer-term panel (the Western Gray Whale Advisory Panel – WGWAP) to advise the company on a more regular basis and thus strengthen its monitoring and mitigation efforts. The WGWAP is a group of 11 leading scientists from a variety of backgrounds that provide independent review and advice on Sakhalin Energy’s operational plans and mitigation measures. The WGWAP provides a mechanism for scientifically rigorous independent assessment. Moreover, it serves as a model of how business, scientists and the conservation community can work constructively and non-confrontationally to address environmental issues.


– Bellmann M. A., Brinkmann J., May A., Wendt T., Gerlach S. & Remmers P. (2020) Underwater noise during the impulse pile-driving procedure: Influencing factors on pile-driving noise and technical possibilities to comply with noise mitigation values. Supported by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (Bundesministerium für Umwelt, Naturschutz und nukleare Sicherheit (BMU)), FKZ UM16 881500. Commissioned and managed by the Federal Maritime and Hydrographic Agency (Bundesamt für Seeschifffahrt und Hydrographie (BSH)), Order No. 10036866. Edited by the itap GmbH.
BSH Offshore wind farms: Measuring instructions for underwater sound monitoring. Current approach with annotations, Application instructions (2011).
– EU Directorate General for Environment. (2022, November 29). Zero pollution and biodiversity: First ever EU-wide limits for Underwater Noise. Environment.
– International Maritime Organization. (2023, August 22). MEPC.1/CIRC.906 – Revised guidelines for the reduction of underwater radiated noise from shipping to address adverse impacts on marine life.…%20(Secretariat).pdf
Juretzek, C.; Schmidt, B.; Boethling, M. Turning Scientific Knowledge into Regulation: Effective Measures for Noise Mitigation of Pile Driving. J. Mar. Sci. Eng. 2021, 9, 819.
– Müller, A., Maquil, T., Eigenmann R. & Juretzek, C. 2020: Classification and assessment of impulsive noise with and without noise mitigation measures – Exposure Index based on a Habitat Approach. Technical Report, R&D „Assessment approaches for underwater sound monitoring associated with offshore approval procedures, maritime spatial planning and the marine strategy framework directive – BeMo“, Order Nr. 10036955, Bundesamt für Seeschiffahrt und Hydrographie (BSH).