Noise Management

Addressing the activities and threats

Co-authored by Charlotte R. Findlay, Postdoctoral Research Fellow, Zoophysiology, Department of Biology, Aarhus University


Noise pollution includes any human-created sound that propagates underwater. The primary and most widespread source of underwater noise pollution comes from motorised vessels at sea [1]. Other major sources include seismic exploration (by oil and gas industries), underwater explosions, underwater construction of nearshore and offshore marine installations, (including marine renewable energy projects), naval sonar operations, and acoustic deterrents [1,2]. Noise from human activities may be acute or chronic, varying in frequency, volume, duration, ‘rise time’ and repetition rate.

Sea Lions © Amanda Cotton

Impacts of noise on marine mammals

Marine mammals, and particularly cetaceans, with their reliance on hearing as their principal sense for navigation, detecting predators, communication and/or hunting, can be extremely vulnerable to anthropogenic noise [3,4]. Potential effects from exposure to anthropogenic noise are varied and can include hearing impairment, stress, changes in behaviour, and acoustic ‘masking’ (obscuring important natural sounds) [5,6,7].

For example, noise pollution can interfere with marine mammal behaviour, and lead to stress [8], difficulty feeding [9], disruption of nursing and resting [10], and masking of communication [11]; while acute, high-intensity sound exposure from military sonar has led to the mass-stranding and subsequent mortality of beaked whales [12]. However, the responses of cetaceans to underwater noise pollution have been shown to vary and likely depend on factors including the noise characteristics, context of exposure, and animals’ biology [13].

Regardless, repeated exposure and disturbance due to anthropogenic underwater noise has the potential to affect the energy budgets of marine mammals if they are not able to compensate for these exposures [14], which may culminate in negative impacts to an individuals’ vital rates and potential population-level consequences.

Credit: NOAA Fisheries

Management strategies to minimise the impacts of noise

*Note; many of these management strategies may fall under the partial or full jurisdiction of agencies other than MPA management.

Given that the impact of noise on marine mammal species varies between species, the type of sound and the location, a variety of strategies may be appropriate in order to reduce these impacts in different MPAs. Furthermore, due to sound travelling much further and faster in water than in air, designated acoustic buffer zones may need to be incorporated outside MPAs to reduce the impacts of noise within the MPA [15].

To incorporate management actions to protect marine mammals from underwater noise pollution, legislative responsibility must clearly fall on either MPA management and/or national or regional agencies and be enforceable. Underwater noise limits should also be invoked within the permit process.

Specific management strategies include monitoring (and if possible, maintaining) the status of a species and underwater noise, monitoring the consequences of activities, and incorporating these results into future management plans [16]. Where possible, a precautionary approach to management should be taken with respect to noise pollution alongside the practice of adaptive management in light of new available data and recommendations (the Self-Assessment Tool can aid managers to implement adaptive measures following the assessment of management plans).

Specific management regulations might involve (depending on the species and sources of noise) prohibition of certain sources of noise (such as seismic surveys or military sonar), regulations specific to seasons or important life history locations, maximum acute noise limits for marine construction and maximum allowable limits to chronic ambient noise for fixed sources. For example, current EU Marine Strategy Framework Directive (MSFD guidelines have been introduced for both impulsive and continuous noise sources, with guidelines recommending that, for continuous sources, 20% of habitat (MPA) must be below Level of Biologically Adverse Effect) [17]. An MPA may also develop strategies to reduce the impact of commercial vessel noise on marine mammals (e.g., speed reductions [18]).

Various mitigation technologies may be regulated within a protected area, including the use of alternative reduced noise technologies, and technologies that reduce the noise emitted during conventional shipping or engineering projects. Acoustic Mitigation Devices (AMD) have often been suggested to be deployed to deter cetaceans from specified areas however, research has indicated that such devices can deter marine mammals far greater distances that intended, and in some cases result in temporary or even permanent hearing impairment in some species [19, 20]. Monitoring devices can also be deployed. Acoustic hardware can be used for implementing both passive and active acoustic monitoring and noise monitoring programs. Both fixed and towed hydrophones fall into this category [21].

Case study

Stellwagen Bank National Marine Sanctuary (SBNMS), USA

A basic map of the sanctuary and sanctuary region. Map: NOAA

An increasingly recognised element of the SBNMS’ physical setting is its acoustic environment. The sanctuary is home to many soniferous species, such as whales, that NOAA manages or protects under multiple statutes, notably the ESA and the MMPA. Due to its location, the sanctuary is also a busy place for commerce and is subjected to high levels of sound-producing activities such as commercial vessel traffic.

Within the SBNMS 2023 Stellwagen Bank National Marine Sanctuary Final Management Plan and Environmental Assessment, one of 15 action plans is dedication to noise aiming to “Maintain the role of SBNMS as a sentinel site for passive acoustic monitoring in the Gulf of Maine, and as a test bed for applying these data to both long term monitoring of ecosystems and the design of methods to reduce impacts from human activities”. The SBNMS has an established acoustic research programme that has influenced regional, national and international policies for management noise impacts on marine life. Numerous management actions are included within the management plan, including standardised mitigation metrics to track the influence of vessel traffic noise, real-time glider data reporting to notify the presence of whales within the sanctuary, the use of Right Whale Listening Buoys to determine if noise is lower by slower vessels.

With these management actions, SBNMS implements 6 management strategies;

  1. Maintain low frequency monitoring station (Noise Reference Station) to assess changes over time in acoustic contributions from vessels, linked to shifts in calling baleen whales and fish, and compare to regional and national trends
  2. Maintain broadband soundscape monitoring stations (i.e., “SanctSound”), which have collected seasonal data from 2016–18, and continuous data since 2018; assess changes over time in ambient levels and contributions from marine mammals, fish, and vessels as part of regional and national ocean observing arrays.
  3. Conduct seasonal passive acoustic and telemetry enabled glider surveys to better understand distribution and behaviour of target sound-producing species in particular areas and time periods
  4. Use status and trend information and more detailed knowledge of overlap in biological and anthropogenic sources to monitor indicators of human-induced noise influence
  5. Add an acoustic monitoring station to shipwrecks to deepen understanding of the role of wrecks in supporting sanctuary biodiversity
  6. Identify and initiate additional management actions as necessary


Within this goal, high-priority strategies include the development of a cooperative marine acoustics research program, and a policy framework for investigating and mitigating noise impacts within SBNMS. Substantial innovative research has been (and continues to be) undertaken into all aspects of underwater noise and its effects on marine mammal species in the sanctuary.

Case study

International Fund for Animal Welfare (IFAW) Blue Speeds Campaign

Driving Positive Community Engagement and Public Awareness

IFAW has identified a realistic and impactful solution to make the seas safer for marine animals: reduced shipping speeds. The Blue Speeds Campaign was launched in response to the increasing threat posed by fast moving vessels on marine life, particularly whales, dolphins, and porpoises. The Blue Speeds Campaign seeks to set better legislative standards to reduce the negative impact of commercial shipping within European waters, as well as creating widespread awareness among the shipping industry and the general public about the impacts of commercial shipping on marine ecosystems.

The objectives of the Blue Speeds Campaign are to raise awareness of the importance of responsible boating practices to protect marine life; to mobilise and engage the community; to educate boaters and the public about the negative impacts of high-speed vessels on marine ecosystems; and to advocate for implementation of regulations and guidelines to mitigate the adverse effects of fast-moving boats on marine life.

Their strategies included a multi-channel awareness campaign using traditional and digital media channels; forging collaborations with shipping companies, national/international shipowners and port associations, to enable the adoption of Blue Speeds practices; using creative and compelling content to captivate the audience and convey the urgency of the issue; and finally actively advocating for policy changes and stricter regulations and industry standards by collaborating with European and national policymakers, lawmakers and working within the International Maritime Organisation (IMO)..

The lessons learned throughout this campaign are as follows: Collaboration is key – the success of the Blue Speeds Campaign highlights the importance of collaboration and partnerships with diverse stakeholders; Use compelling communication – by using compelling storytelling techniques, IFAW effectively conveyed the urgency of the matter; and finally, by advocating for policy change IFAW was successful in effecting policy change that protect marine life. Such efforts are crucial when creating long-term systemic change.

In conclusion, the IFAW Blue Speeds Campaign exemplifies a successful Community Engagement and Public Awareness (CEPA) initiative that effectively raised awareness about responsible boating practices and their impact on marine ecosystems. Through strategic partnerships, compelling content, community engagement activities, and advocacy efforts, the campaign achieved remarkable outcomes in terms of public awareness, behaviour change, and policy improvements. The campaign serves as an inspiring example for organisations and communities seeking to drive positive change in environmental conservation.

& references



Be Aware Of Noise | Ocean Noise Poses A Threat To Marine Life

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