Underwater noise / Underwater Radiated Noise
Criteria by type of participant
Ship owners
Ports
SHIP OWNERS
Performance indicator's objective:
Reduce underwater radiated noise (URN) made by ship operations to reduce impacts to marine species, particularly marine mammals.
APPLICABILITY: Applicable only for vessels transiting in marine (salt water) environments, including brackish waters such as estuaries.
REFERENCES (and see footnotes throughout):
- Revised Guidelines For The Reduction Of Underwater Radiated Noise From Shipping To Address Adverse Impacts On Marine Life - MEPC.1/Circ.906 (22 August 2023) https://wwwcdn.imo.org/localresources/en/Documents/MEPC.1-Circ.906%20-%20Revised%20Guidelines%20For%20The%20Reduction%20Of%20Underwater%20Radiated%20NoiseFrom%20Shipping%20To%20Address...%20(Secretariat).pdf
- USDOT MARAD META UN) https://www.maritime.dot.gov/innovation/meta/vessel-generated-underwater-noise
- Ship Energy Efficiency and Underwater Radiated Noise and the related Technology Matrix - available for download from this IMO webpage: https://www.imo.org/en/About/Events/Pages/URN-Workshop-2023.aspx
- Quiet Vessel Initiative: Technology, design, and operational measures for quieter Canadian waters: https://clearseas.org/research/qvi-technology-design-operation-quieter-waters/
2026 criteria
Level 1
Monitoring of regulations
Level 2
2.1 Conduct regular hull cleaning and propeller blade maintenance. The participant must keep a record of these actions for each vessel in their fleet.
Note: Hull cleaning and propeller maintenance should at least be done during dry dock.
2.2 Determine whether the participant’s vessels transit through or have operations in sensitive areas by reviewing lists and/or maps, e.g. World Shipping Council’s Whale Chart[1]; Protecting Blue Whales and Blue Skies' Whale Atlas[2]; and ProtectedSeas’s Navigator Map[3]. Ensure that this information is communicated to each vessel.
2.3 Participate in voluntary traffic measures, like a slow-down or lateral displacement, in specific zones as identified by port, governmental authority, or regional coalition, where safe and feasible, but for at least a majority of vessel travel (measured in trips, time, distance, or however traffic is measured across such voluntary programs) across the certified fleet.
2.4 Actively participate in collecting and providing whale sighting data through a recognized application (e.g., Whale Alert, Whale Report, or Vigie marine) or a logbook reported to a recognized central database (e.g. the Coast Guard Cetacean Desk(s) in the US and/or Canada) or subject regulator.
[1] https://www.worldshipping.org/whales
[2] https://bluewhalesblueskies.org/resources/ ; https://experience.arcgis.com/experience/32bfb62f57a542c2b2e79dca732e78a1
[3] https://navigatormap.org/ ; https://map.navigatormap.org/
Level 3
Fulfill one of the following 2 criteria:
3.1 Conduct a baseline estimate, noise measurement, or risk assessment for at least one vessel. Methodologies are described in Annex 6-B and include an empirical estimate from a large data set of vessels, predictive model (Ref 1 Annex 2), tank testing, or like in 4.2 or 5.2, an opportunistic[1] or planned recording and assessment of URN.
OR
3.2 Have incorporated an applicable vessel quieting technology (as referenced in criterion 4.1) on one vessel.
AND
3.3 Develop and adopt an Underwater Radiated Noise Management plan (URNMP) in order to reduce the potential adverse effects of vessels, especially within known sensitive marine areas, as identified in Criterion 2.2.
Note: See Annex 6-A.
OR as an alternative to 3.3 for pilotage organizations:
3.4 Aboard a majority of piloted ship transits, when it is safe and operationally feasible, meet criteria 2.3 and 2.4.
[1] NOAA NCEI Passive Acoustic Data Viewer) https://www.ncei.noaa.gov/maps/passive-acoustic-data/
Level 4
Applicable for ship owners ordering/designing new vessels (keel laid up to the two years prior) or conducting retrofits of propulsion systems or other equipment that contribute significantly to underwater radiated noise (within the reporting year).
4.1 Incorporate at least one applicable vessel quieting technology during retrofits and new vessel construction.
Note: Refer to published documents like the Revised IMO Guidelines[1] Table 1, Ship underwater radiated noise technical report and matrix[2] Technical Report, Vard Report: Ship Underwater Radiated Noise[3], SNAME T&R Bulletin 6-03 Guidelines for Reducing Underwater Radiated Noise From Commercial Vessels (2025), NCE White Paper: Current Technologies and Management Practices for Reducing Underwater Radiated Noise Produced by Vessels[4], and Vancouver Fraser Port Authority: EcoAction[5].
AND, all ship owners fulfill one of the following 3 criteria:
4.2 Estimate URN levels for at least two vessels in their fleet by using a hydrophone in collaboration with a port, scientific researchers, and/or an acoustic expert to obtain reliable data.
OR
4.3 Conduct an in-depth analysis of vessel noise on at least one ship with a standard measurement methodology, such as tabulated in Appendix 1 of the Revised IMO Guidelines. Note: ANSI/ASA S12.64-2009[6] or ISO 17208[7] underwater noise standard measurement methodology should be used wherever possible.
OR Applicable only for new vessels (keel laid after January 2027)
4.4 Include an URN specification in the design/build consistent with an environmental class notation limit.
[1] Revised Guidelines For The Reduction Of Underwater Radiated Noise From Shipping To Address Adverse Impacts On Marine Life - MEPC.1/Circ.906 (22 August 2023) https://wwwcdn.imo.org/localresources/en/Documents/MEPC.1-Circ.906%20-%20Revised%20Guidelines%20For%20The%20Reduction%20Of%20Underwater%20Radiated%20NoiseFrom%20Shipping%20To%20Address...%20(Secretariat).pdf
[2] Ship underwater radiated noise technical report and matrix – MEPC 74/INF.28 (8 March 2019) https://wwwcdn.imo.org/localresources/en/MediaCentre/HotTopics/Documents/NOISE/MEPC%2074-INF.28%20-%20Ship%20underwater%20radiated%20noise%20technical%20report%20and%20matrix%20(Canada).pdf
[3] https://publications.gc.ca/collections/collection_2021/tc/T29-151-2019-eng.pdf
[4] https://www.noise-control.com/wp-content/uploads/2025/09/NCE-White-Paper-Current-Technologies-and-Management-Practices-for-Reducing-Underwater-Radiated-Noise-Produced.pdf
[5] https://www.portvancouver.com/sites/default/files/2025-12/2026%20EcoAction%20infographic-EN.pdf
[6] https://webstore.ansi.org/standards/asa/ansiasas12642009partr2019?source=blog&_gl=1*h82cvs*_gcl_au*MjkzNzg5NjUxLjE3NjE0MjU3MzU.
Level 5
Fulfill one of the following 2 criteria:
5.1 Conduct an in-depth analysis of vessel noise on at least one ship with a standard measurement methodology.
Note: ANSI/ASA S12.64-2009 or ISO 17208 underwater noise standard measurement methodology should be used where at all possible.
OR
5.2 For 15% of the vessels in their fleet, with a minimum of 3 vessels, measure URN levels by using a hydrophone in collaboration with a port, scientific researchers, and/or an acoustic expert to obtain reliable data.
AND
5.3 (Optional for 2026) Identify main noise sources and incorporate applicable vessel quieting technologies, as referenced in criterion 4.1, for each vessel’s mid-life drydock / shipyard period, if operating in a sensitive area, as identified in criterion 2.2.
AND Applicable only for ship owners of new vessels (keel laid after January 2027), fulfill one of the following three criteria:
5.4 Obtain a quiet class notation.
OR
5.5 Include an URN limit in the design/build consistent with an environmental class notation limit.
OR
5.6 For 50% of the vessels in the fleet, with a minimum of 10 vessels, measure URN levels against a URN limit consistent with a class notation or a federal or international standard. Share findings and feedback with vessel designers, shipyard(s), and/or other relevant stakeholder involved in growing the demand for and achieving quieter vessels.
PORTS
Performance indicator's objective:
Manage and mitigate underwater noise (UN) sources from ships coming in and out of the port and from regular port activities and operations, maintenance, development, and construction work to reduce impacts on marine species, particularly marine mammals.
Applicability:
Applicable only for ports located in marine (saltwater) environments, including brackish waters such as estuaries.
Notes:
- Growing evidence shows that UN can adversely impact a broad range of aquatic species like fish, benthic invertebrates, reptiles like sea turtles, etc. Based on its level and frequency, UN can have direct or indirect as well as physiological, auditory, and behavioral effects on exposed species depending on their sensitivity to noise. Given the current level of knowledge and extent of existing practical approaches to reducing UN impacts on marine mammals, ports can focus their efforts on protecting these species by applying the criteria of this performance indicator. However, they are also encouraged to consider other marine species impacted by UN. Future development may expand the scope of the indicator to include freshwater species and ports in freshwater environments.
- This indicator references the document listed below that can be found on the Members’ Section of Green Marine’s website.
- International Maritime Organization (IMO) Revised guidelines for the reduction of underwater radiated noise from shipping to address adverse impacts on marine life (MEPC.1/Circ.906) (criteria 2.1, 4.3 – See Annex 1 for examples of class notations).
2026 criteria
Level 1
Monitoring of regulations
Level 2
Fulfill 3 of the 4 following criteria:
2.1 Promote and raise awareness of tenants and ship operators calling at the port about the issue of UN and approaches to managing it by distributing the International Maritime Organization (IMO) revised guidelines along with any other pertinent information on the effects of UN on marine species and sensitive areas.
2.2 Promote the provision of marine mammal sightings data from a stewardship program with a publicly available database (in Canadian and US waters) through a logbook program or a recognized application (e.g., Whale Alert, Whale Report, and Vigie marine) to port users, pilots’ associations, and ship operators calling at the port.
2.3 Summarize current knowledge on sensitive habitats and marine species potentially impacted by UN in the area (e.g., using the World Shipping Council Whale Chart) to better understand the extent of the port’s zone of influence on the local soundscape (e.g., operations/ maintenance/construction/development zones, shipping traffic routes, anchorage sites), which may inform vessel traffic management (e.g., slowdown zones, alternative vessel routing).
2.4 Contract a trained and experienced marine mammal or protected species observer (MMO or PSO, respectively) during port-related in-water or on-land construction work (below high-water mark) that is known to increase significantly the level of noise in the soundscape and prioritize daylight periods for noisier work.
Note: Applicable for ports or port tenants engaged in construction or development work. The decision to require the services of a MMO or PSO should be based on the presence of endangered species and sensitive areas.
Level 3
3.1 Implement all applicable criteria listed at Level 2.
3.2 Develop and adopt an Underwater Noise Mitigation and Management Plan (UNMMP), which incorporates a range of noise mitigation options, best practices, and operating procedures for both acute and chronic noise-generating activities including port maintenance, construction, and development, shipping traffic, and/or anchorage sites.
Note: See Annex 6-A
AND fulfill one of the following 3 criteria:
3.3 As part of the UNMMP, establish an ambient UN monitoring program and, to understand local soundscape conditions, analyze and archive the UN data.
Note: The program must be developed in collaboration with a bioacoustician or a specialized firm and specify the objectives, methodology, location of hydrophones, and data collection frequency. If the port is planning time-limited construction, development, or operational changes, additional noise measurements should be taken using the same protocol to see how those activities change the soundscape conditions.
OR
3.4 Offer a recognition program to ship owners who introduced vessel quieting technologies on their ships and/or for vessel noise reduction best practices like hull and propeller maintenance.
OR
3.5 Participate in a regional stakeholder group with industry members (e.g., port tenants, other ports in the region, ship owners, shipyards) or an expert working group to advise and facilitate research and development, projects, or programs.
Level 4
4.1 Implement all criteria listed at Level 3.
4.2 Develop and incorporate UN reduction targets into the UNMMP in the port’s jurisdiction and/or surrounding waters based on data obtained from the ambient UN monitoring program in criterion 3.3.
Note: This strategy must include a methodology to measure progress achieved in reducing UN generated at the port and to set realistic noise reduction targets.
AND fulfill one of the following 4 criteria:
4.3 Administer an incentive program for ship owners implementing vessel noise mitigation measures (e.g., offer a discount/berthing fee reduction for ships with a class notation for UN).
OR
4.4 Establish an in-situ acoustic monitoring system with a detailed protocol to collect data on the relative source level of individual ships or on the noise level as contributed by vessel type and share this data with ship owners.
Note: This criterion is linked with criterion 4.2 from the Underwater Noise indicator for ship owners.
OR
4.5 Within the last 5 years, support/collaborate on scientific research that includes the measurement of UN from ships and/or other port-related activities.
OR
4.6 Lead or co-lead a permanent regional stakeholder group with industry members (e.g., port tenants, other ports in the region, ship owners, shipyards) as well as research and environmental groups and governmental agencies aiming to share UN-related information, raise awareness, and identify mitigation and management measures relevant at the regional level along shipping routes and in port areas. The group must meet minimally twice a year.
Level 5
5.1 Implement 4 of the 6 criteria listed at Level 4.
5.2 Demonstrate that the UN reduction targets set in criterion 4.2 are met through direct measurements.
Note: If a significant correlation is demonstrated between a proxy variable (e.g., participation rate in a vessel slowdown) and UN reduction, and if approved by Green Marine, the proxy measurement may be used in alternation with direct measurements to demonstrate that targets are on track.
5.3 Demonstrate continual improvement in implementing the UNMMP through the use of noise reduction solutions and technologies that reduce UN.
