The UK has achieved the operational target for impulsive sound through the development of the Marine Noise Registry. In 2015 this was used to record impulsive sound from various activities in the Greater North Sea and the Celtic Seas.

Background

UK Target on distribution of loud, low and mid frequency impulsive sounds

This indicator is used to assess progress against the operational target set out in the Marine Strategy Part One (HM Government, 2012) which is to establish a ‘noise registry’ to record the distribution and timing of man-made impulsive sound sources measured over the frequency band 10 Hz to 10 kHz, exceeding the energy source level 186 dB re1μPa²m²s, or the zero-to-peak source level of 224 dB re1μPa²m² over the entire UK oil and gas licence block area. The UK achieved this target through developing the Marine Noise Registry which is now in use.

Key pressures and impacts

Underwater impulsive sounds are generated by certain human activities such as geophysical surveys, impact pile driving, naval sonar, acoustic deterrent devices, multi-beam echosounders, and detonation of explosives. There is considerable evidence for the effects of impulsive sound on individual marine organisms. The effects on individuals can be subtle (for example hearing sensitivity reduction, physiological stress) or obvious (such as changes in behaviour, death); however, there is uncertainty over the potential impacts on populations and ecosystems. 

Measures taken to address the impacts

Potential physical impacts of impulsive sound generated by human activities on marine life are recognised and routinely managed through activity licences which require the implementation of mitigation measures to avoid/reduce effects. The Marine Noise Registry was designed to gather data in order to monitor cumulative pressure, assess the potential for disturbance impacts, and if needed, further manage activities. If appropriate, further management measures will be set out in the update to UK Marine Strategy Part Three (HM Government, 2015) in 2021.

Further information

This assessment addresses loud, low- and mid-frequency impulsive sounds. Impulsive sound has been observed to cause temporary displacement of marine mammals (Thompson and others, 2010; Pirotta and others, 2014; Russell and others, 2016), increased physiological stress in fish (Popper and Hastings, 2009), alter behavioural and physiological responses in invertebrates (Solan and others, 2016), and could result in hearing damage to marine mammals as well as damage to other organs and potentially death (Richardson and others, 1995). There is a growing body of literature on the potential effects of sound generated from human activities on individual animals, however, obtaining direct observations of the effects at the population or ecosystem scales is challenging and the impacts are uncertain.

Assessment method

Areas that have been assessed

Progress against the UK target was assessed in sub-divisions of each UK Marine Strategy Framework Directive sub-region (the Celtic Seas and Greater North Sea).

Monitoring and assessment methods

Information about impulsive sound sources is submitted to the Marine Noise Registry on a mandatory basis where submission of data is made a condition of activity licences, and on a voluntary basis when no licence is required, for example, activities conducted by the Ministry of Defence. Pressures arising from these activities are mapped regularly and used to improve our understanding of the distribution of impulsive sound and enable the assessment of patterns/trends across UK seas over space and time.

Assessment thresholds

Impulsive sound thresholds will be established together with other countries when our understanding of impacts has been improved. 

Regional cooperation

The UK has been a key player in development, monitoring and assessment of the OSPAR ‘impulsive noise’ common indicator across the Celtic Seas and Greater North Sea OSPAR Regions, and the UK data have been used in the OSPAR Intermediate Assessment 2017

Assessment details

The Marine Noise Registry was developed to hold impulsive sound data for seven different impulsive sound generating activities:

  1. seismic survey
  2. sub-bottom profiling
  3. impact pile driving
  4. unclassified Ministry of Defence (MoD) activity
  5. detonation of explosives
  6. acoustic deterrent devices
  7. multi-beam echosounders (≤12 kHz) 

The Marine Noise Registry is a PostgreSQL database that was created in 2016 with a web-based portal, or online interface, for ease of data entry. The Marine Noise Registry online interface was designed to meet 18 criteria which relate to, for example, security and privacy, open source code, and database iterating and improving. Data were provided by industry, regulators, and the Ministry of Defence in a standard format, and the database is subject to Quality Assurance procedures. 

The Marine Noise Registry collates records in one central location so that all data can be analysed to create UK-scale maps to catalogue the distribution and duration of impulsive underwater sound activity. The maps use the blocks of the UK oil and gas licensing grid (Oil and Gas Authority, 2015), which measure 10 minutes’ latitude by 12 minutes’ longitude and are organised in quadrants, with the majority of quadrants containing 30 blocks (Figure 2). Each grid, or block, shows the number of days that loud, low and mid frequency impulsive sound (10 Hz to 10 kHz, with the exception of multi-beam echosounders ≤12 kHz) was generated over a standard time period (for example, a calendar year). The assessment unit used is referred to as a Pulse Block Day. A Pulse Block Day occurs when at least one noise event (between 10Hz and 10kHz) has occurred within a ‘block’ on a particular day. This assessment only covers impulsive noise events that occurred in 2015. Additional records will be entered as they become available. Fluctuations in activity levels are anticipated from year to year, allowing for annual patterns/trends in Pulse Block Days in future assessments which will help our understanding of impulsive sound distribution in UK seas.

If a noise event falls within a block containing <5% water, the noise event is re-allocated to an adjacent block which is connected by the same water body and contains the same water ‘type’. The <5% water rule was decided by the Marine Noise Registry Steering Group to be used as a cut-off point for how far up river sound events are to be recorded. Water ‘type’ may be coastal, transitional, both, or neither (open water; Figure 1). Transitional waters are those waters between land and sea including fjords, estuaries, lagoons, deltas and rias. They often encompass river mouths and so show the transition from freshwater to marine conditions. When calculating Pulse Block Days, it is the reallocated block that will display the days’ noise, not the original <5% water block.

It should be noted that the 2015 map only contains information on activities that have been completed. The voluntary and non-licensed nature of some submissions to the Marine Noise Registry means that some noise events will be missing from the 2015 map. There is no licence consent condition for these activities so there is no requirement to submit data to the Marine Noise Registry. Missing data are known to include:

  • all classified Ministry of Defence active sonar, active sonar check, and explosive data. Military activity is explicitly not included in the Marine Strategy Framework Directive, so the Ministry of Defence is not obliged to submit data to the Marine Noise Registry. It has decided however to submit unclassified data on a voluntary basis. Ministry of Defence data within the 2015 total Pulse Block Days map for UK seas is only partial. Data included is from May to December 2015.
  • active sonar use by non-UK military
  • unlicensed geophysical surveys (for example, some non-oil and gas surveys carried out prior to offshore construction)
  • some impact pile driving events, where there is no licensing condition to submit data to the Marine Noise Registry, for example conducted by the oil and gas industry, and coastal pile driving events categorised as band 1 or 2 by the Marine Management Organisation
  • noisy activities in Northern Ireland waters. Future assessments will include licensed activities in Northern Ireland waters but these data from 2015 were unavailable. Acoustic Deterrent Devices at fish farms, as their use is currently unlicensed.

Map of UK oil and gas blocksFigure 1. Map of UK oil and gas blocks (adapted from UK oil and gas licensing blocks) highlighting those containing <5% water (which require reassignment), and the different water types. Contains derived data from Ordnance Survey © Crown copyright. 100019741. Information adapted from data by the Environment Agency © Environment Agency copyright and/or database right 2015. Contains UK Oil and Gas Licensing Blocks © Oil and Gas Authority 2016. Not to be used for navigation. Data displayed in British National Grid coordinates.

Results

Findings from the 2012 UK Initial Assessment (HM Government, 2012) stated that “there is currently not enough evidence to provide a quantitative assessment of the current status and trends of underwater noise in UK seas due to lack of available information from monitoring studies.”

Latest findings

The UK has achieved the operational target for loud, low to mid frequency impulsive noise as set out in the UK Marine Strategy Part One (HM Government, 2012) through the development of the Marine Noise Registry, which is now active.

In 2015 the Marine Noise Registry collected monitoring data for impulsive sound generated by the following activities:

  1. seismic survey
  2. sub-bottom profilers
  3. impact pile driving
  4. detonation of explosives
  5.  unclassified Ministry of Defence activity

The Marine Noise Registry collates these records so that a UK-scale map can be produced cataloguing the distribution and duration of impulsive underwater sound (Figure 2). Figure 3 shows the location of impulsive noise generating activities in 2015.

Status assessment 

In 2015 impulsive sound, especially from seismic surveys, was found to be prevalent in the Greater North Seas, but some events were also recorded in the Celtic Seas, including the deep waters off the northwest coast of Scotland, and in the western English Channel and Irish Sea (Figures 2 and 3). Data from subsequent years are required before a comprehensive quantitative assessment of the status and trends of impulsive sound in UK seas can be completed. Further research, monitoring, and assessment is required.

No trend assessment has been possible in this assessment.

Map of the distribution and duration of impulsive underwater sound in UK seas

Figure 2. The distribution and duration of impulsive underwater sound in UK seas from data reported in 2015 (January – December). Contains JNCC information licensed under the Open Government Licence v3.0. © JNCC January. 2017. Contains derived data from Ordnance Survey © Crown copyright. 100019741 (2015). Contains Ordnance Survey data © Crown copyright and database right 2012. Contains United Kingdom Hydrographic Office data © Crown copyright 2012. Contains UK Oil and Gas Licensing Blocks © Oil and Gas Authority 2016. EEA 2017. Contains MSFD Sub-region boundary data decided on during MSFD committee meeting 2016. Contains data collated in the UK Marine Noise Registry to fulfil the UK requirement for monitoring loud, low to mid frequency impulsive noise for MSFD D.11.1. Not to be used for navigation. Data displayed using WGS84 coordinates.

 

Map of impulsive noise generating activities in UK oil and gas licensing blocks

Figure 3. Location of impulsive noise generating activities in UK oil and gas licensing blocks from data reported by industry and regulators in 2015 (January – December 2015). Contains JNCC information licensed under the Open Government Licence v3.0. © JNCC January. 2017. Contains derived data from Ordnance Survey © Crown copyright. 100019741 (2015). Contains Ordnance Survey data © Crown copyright and database right 2012. Contains United Kingdom Hydrographic Office data © Crown copyright 2012. Contains UK Oil and Gas Licensing Blocks © Oil and Gas Authority 2016. EEA 2017. Contains MSFD Sub-region boundary data decided on during MSFD committee meeting 2016. Contains data collated in the UK Marine Noise Registry to fulfil the UK requirement for monitoring loud, low to mid frequency impulsive noise for MSFD D.11.1. Not to be used for navigation. Data displayed using WGS84 coordinates.

Further information

The greatest levels of activity were reported in the northern and eastern parts of the Greater North Sea with 39% of the total oil and gas licensing blocks having between 1 and 99 Pulse Block Days, the majority resulting from seismic surveys (Figure 3). This compares with 18% of the Celtic Seas where the majority of events occurred in the deep waters off the northwest coast of Scotland due to seismic survey activity, with Pulse Block Days ranging between 1 and 10. However, some activity, such as  naval sonar and sub-bottom profiling, was also reported in the southern Celtic Seas, concentrated in the western English Channel and Irish Sea, at between 1 and 28 Pulse Block Days, the highest Pulse Block Day due to sub-bottom profiling (Figure 3). Overall, 24% of the total blocks had at least one Pulse Block Day for 2015 (Figure 1). 

Data caveats and limitations

When using and/or interpreting the results from the total Pulse Block Day map (2015; Figures 2 and 3) the following caveats and limitations should be taken into account:

  1. The maps do not show Good Environmental Status. Presently, there is no specific target to evaluate whether Good Environmental Status for Underwater Noise is being met. The outputs derived from the Marine Noise Registry data, such as maps, are illustrations of the spatial and temporal extent of impulsive sound in UK seas and will be used to help establish a baseline level as well as enable the visualisation of patterns and trends. Within this map higher Pulse Block Day count demonstrates a greater number of days on which one or more noisy activities occurred within a given area but does not indicate the specific characteristics of this sound, nor its impact on marine organisms. These data cannot therefore be used to draw conclusions as to whether Good Environmental Status has been met by the UK.
  2. Maps do not show impacts to marine species. Due to uncertainties regarding the impacts of impulsive sound on marine organisms’ vital rates, populations and ecosystems, the number of Pulse Block Days should not be interpreted as a direct measure of habitat loss and hotspots of sound should not be assumed to have greater disturbance impact on vulnerable species or on the environment as a whole.
  3. Spatial scale - oil and gas blocks. The UK Marine Noise Registry uses the UK oil and gas licensing blocks as the spatial scale for mapping impulsive sound events, and therefore does not display the exact locations of events. In addition, any impulsive sound events which fall within a licensing block that contains less than 5% water have been reallocated to a preselected adjacent UK oil and gas licensing block which is connected by the same water body and contains the same water ‘type’ (Figure 1).

Conclusions

In 2012 there was no evidence available to suggest that current levels of noise in UK waters were having an impact at the population level on cetaceans or other noise sensitive marine animals. To address the lack of evidence a Marine Noise Registry has been developed and the UK has now achieved the operational target for loud, low to mid frequency impulsive sound, as set by the UK Marine Strategy Part One (HM Government, 2012). The Marine Noise Registry collects information on the distribution and duration of impulsive sound in UK waters. It currently contains data for one year, 2015, and intends to continue collecting data into the future. This will establish a baseline for impulsive sound in UK seas, allowing for assessment of patterns and trends.

Knowledge gaps

Further evidence and research would help to better understand whether current levels of noise are having an impact on marine ecosystems and noise sensitive marine animals at a population level.

Further information

Data on sound properties, such as sound pressure level, frequency, for example, when available, are input to the Marine Noise Registry, however there is currently a medium to low level of confidence in these estimates and therefore no attempt is made in the assessment to categorise pressure by these properties. This does not limit the assessment significantly given that the magnitude and significance of effects on marine organisms is not solely dependent on these characteristics of sound and can vary due to other sound characteristics as well as the behavioural context, motivations at the time, the previous experience of exposed individuals, and how the animal interprets the sound.

The scope of this assessment is to monitor and assess human pressure on the marine environment from impulsive sound sources. Reporting across UK seas and OSPAR marine regions in subsequent years should enable a more accurate assessment of activity types resulting in impulsive sound and enable the establishment of a baseline and the evaluation of spatial and temporal patterns/trends in the distribution and intensity of impulsive sound generating activities. However, it is recognised that future work will need to address the risk of impact from impulsive sound sources on marine organisms. Some of the broader challenges facing this work were identified within the OSPAR assessment for impulsive noise and these are outlined below. 

Broader scientific knowledge gaps in assessing impact from underwater noise

The Marine Strategy Framework Directive objective is to endeavour “the introduction of energy, including underwater noise, at levels that do not adversely affect the marine environment” (European Commission, 2008; 2010). However, there is a lack of direct evidence on the effects of man-made sound at population and ecosystem scales, which confounds the definition of Good Environmental Status for the indicators on underwater noise. 

The direct observation of population and ecosystem-scale effects will require detailed long-term studies which are able to distinguish the effects of man-made sound from the effects of other human stressors or natural factors. In the meantime, studies which examine the effects of man-made sound on, for example, aspects of ecosystem functioning, such as nutrient cycling (Solan and others, 2016) or food web dynamics, such as predator-prey interactions (Simpson and others, 2016) can investigate the mechanisms by which man-made sound may affect marine ecosystems. 

A further knowledge gap is that many of the individual-based studies of the effects of man-made sound have been carried out in laboratory conditions. More field studies on the responses of animals to impulsive sound are needed (for example, DeRuiter and others, 2013; Debuscherre and others, 2015), particularly for fish and marine invertebrates, as well as investigation of the applicability of laboratory studies to wild populations. 

Some studies (for example, DeRuiter and others, 2013; Pirotta and others, 2015) have shown that sound level can be a poor predictor of behavioural responses, and that other factors, such as distance to source, may be more relevant. This issue is important for the prediction of impact, since an understanding of the mechanisms leading to disturbance is needed to make valid predictions. Studies to further investigate the mechanisms behind behavioural responses are needed to clarify the roles of these various factors (Ellison and others, 2012). 

As these examples make clear, there are now a number of approaches available for use in assessments of the effects of impulsive sound on particular species/populations. These could be investigated, in the context of Good Environmental Status for underwater noise, through their potential to aid in the development of indicators of the effects of man-made impulsive sound on the marine environment. The present indicator provides important input as a pressure layer that could, for example, be used in combination with distribution maps of species sensitive to sound. Such assessments would enable the identification of priority areas for improved spatial planning to assess and manage the effects of underwater noise.

References

Debusschere E, Hostens K, Adriaens D, Ampe B, Botteldooren D, De Boeck G, De Muynck A, Sinha AK, Vandendriessche S, Van Hoorebeke L and Vincx M (2016) 'Acoustic stress responses in juvenile sea bass Dicentrarchus labrax induced by offshore pile driving'. Environmental Pollution 208, 747-757 (viewed on 1 October 2018) 

DeRuiter SL, Southall BL, Calambokidis,J, Zimmer WM, Sadykova D, Falcone EA, Friedlaender AS, Joseph JE, Moretti D, Schorr GS and Thomas L (2013) 'First direct measurements of behavioural responses by Cuvier's beaked whales to mid-frequency active sonar' Biology letters 9(4). doi: 10.1098/rsbl.2013.0223 Viewed on 1 October 2018)

Ellison WT, Southall BL, Clark CW and Frankel AS (2012) 'A New Context-Based Approach to Assess Marine Mammal Behavioral Responses to Anthropogenic Sounds' Conservation Practice and Policy 26 (1), pages 21-28. doi: 10.1111/j.1523-1739.2011.01803.x. (viewed 1 October 2018) 

European Commission (2008) 'Directive 2008/56/EC of the European Parliament and of the Council of 17 June 2008 establishing a framework for community action in the field of marine environmental policy (Marine Strategy Framework Directive)' Official Journal of the European Union L 164, 25.6.2008, p. 19-40. (viewed 21 September 2018)

European Commission (2010) 'Commission Decision of 1 September 2010 on criteria and methodological standards on Good Environmental Status of marine waters' (notified under document C (2010) 5956) (Text with EEA Relevance) (2010/477/EU). Official Journal of the European Union L232, 2.9.2010, p. 14-24. (viewed on 5 July 2018)

HM Government (2012) 'Marine Strategy Part One: UK Initial Assessment and Good Environmental Status' December 2012. (viewed on 5 July 2018)

HM Government (2015) 'Marine Strategy Part Three: UK Programme of Measures' December 2015. (viewed on 5 July 2018) 

Pirotta E, Brookes KL, Graham IM and Thompson PM (2014) 'Variation in harbour porpoise activity in response to seismic survey noise' Biology Letters 10: 20131090. doi: 10.1098/rsbl.2013.1090. (viewed on 1 October 2018) 

Pirotta E, Merchant ND, Thompson PM, Barton TR and Lusseau D (2015) 'Quantifying the effect of boat disturbance on bottlenose dolphin foraging activity' Biological Conservation 181, 82-89. (viewed 1 October 2018) 

Popper AN and Hastings MC (2009) 'The effects of anthropogenic sources of sound on fishes' The Fisheries Society of the British Isles 75(3), 455-489. doi: 10.1111/j.1095-8649.2009.02319.x (viewed on 1 October 2018) 

Richardson WJ (1995) Documented disturbance reactions. In: Richardson WJ, Greene CRJ, Malme CI, Thompson DH, editors. Marine mammals and noise. San Diego: Academic Press. 1995; 241–324. doi: 10.1016/b978-012588440-2/50009-3 

Russell DJF, Hastie GD, Thompson D, Janik VM, Hammon PS, Scott-Hayward LAS, Matthiopoulos J, Jones EL and McConnell BJ (2016) 'Avoidance of wind farms by harbour seals is limited to pile driving activities' Journal of Applied Ecology 53(6), 1642-1652. doi: 10.1111/1365-2664.12678. (viewed on 1 October 2018)

Solan M, Hauton C, Godbold JA, Wood CL, Leighton TG and White P (2016) 'Anthropogenic sources of underwater sound can modify how sediment-dwelling invertebrates mediate ecosystem properties' Scientific reports 6. doi: 10.1038/srep20540. (viewed on 1 October 2018)

Simpson SD, Radford AN, Nedelec SL, Ferrari MC, Chivers DP, McCormick MI and Meekan MG (2016) 'Anthropogenic noise increases fish mortality by predation' Nature communications 7. doi: 10.1038/ncomms10544. (viewed on 1 October 2018)

Thompson PM, Lusseau D, Barton T, Simmons D, Rusin J and Bailey H (2010) ‘Assessing the responses of coastal cetaceans to the construction of offshore wind turbines Marine Pollution Bulletin: volume 60, pages 1200-1208 (viewed on 1 October 2018)

Acknowledgements

Assessment metadata
Assessment TypeUK Marine Strategy Framework Directive Indicator Assessment
 

D11 – Introduction of energy

 

D11.1 - Distribution in time and place of loud, low and mid frequency impulsive sounds

 

In addition to links provided in ‘References’ section above:

OSPAR Commission (2017) ‘Intermediate Assessment 2017. D11 – Introduction of energy, D11.1 – distribution in time and place of loud low and mid frequency impulsive sounds’ (viewed on 13 January 2019)

Van der Graaf AJ, Ainslie MA, André M, Brensing K, Dalen J, Dekeling RPA, Robinson S, Tasker ML, Thomsen F, Werner S (2012) ‘European Marine Strategy Framework Directive - Good Environmental Status (Marine Strategy Framework Directive GES): Report of the Technical Subgroup on Underwater noise and other forms of energy’ (viewed on 13 January 2019)

Point of contact emailmarinestrategy@defra.gov.uk
Metadata dateWednesday, August 1, 2018
TitleUK Distribution of loud, low and mid frequency impulsive sounds
Resource abstract

The UK has achieved the operational target for D11.1. as set out in the UK Marine Strategy Part One, through the development of the UK Marine Noise Registry. This has been used to record the distribution and duration of loud, low – mid frequency impulsive sound, generated by anthropogenic activities in the Greater North Sea and Celtic Seas, for 2015.

The UK Marine Strategy Framework Directive 2018 assessment concluded that data from subsequent years are required before a comprehensive quantitative assessment of the status and trends of impulsive sound in UK seas can be completed. Further research will also help to better understand whether current levels of noise are having an impact on marine ecosystems and noise sensitive marine animals at a population level.

Linkage

More details on the Marine Noise Registry Service

Conditions applying to access and use

© Crown copyright, licenced under the Open Government Licence (OGL).

Assessment Lineage

Impulsive underwater noise data were collated in the online database: UK Marine Noise Registry.

Data input to the Marine Noise Registry is required through licence condition/condition of consent. If the activity does not require licensing, but falls under the criteria for input to the Marine Noise Registry, data are requested to be submitted voluntarily.

R-code developed by JNCC was used to extract data from the MNR and produce the mapped outputs for this assessment.

The Marine Noise Registry has built-in quality checks for when data are input to the database. Most data for input to the Marine Noise Registry are extracted from other databases, of which have their own quality assurance processes in place. Raw data and outputs go through a series of quality checks before processing and publication. A record of quality assurance is maintained by and available from JNCC.

Dataset metadata
Links to datasets identifiers

https://data.gov.uk/dataset/b48f297b-9bb6-4d38-8b45-a9439f70d91c/uk-marine-noise-registry-mnr-outputs-for-2015

Dataset DOI

Marine Scotland. 2018. Contaminant and biological effect data to support MSFD Descriptor 8 1999-2015 by CSEMP Region. DOI: 10.7489/12111-1

The Metadata are “data about the content, quality, condition, and other characteristics of data” (FGDC Content Standard for Digital Geospatial Metadata Workbook, Ver 2.0, May 1, 2000).

Metadata definitions

Assessment Lineage - description of data sets and method used to obtain the results of the assessment

Dataset – The datasets included in the assessment should be accessible, and reflect the exact copies or versions of the data used in the assessment. This means that if extracts from existing data were modified, filtered, or otherwise altered, then the modified data should be separately accessible, and described by metadata (acknowledging the originators of the raw data).

Dataset metadata – information on the data sources and characteristics of data sets used in the assessment (MEDIN and INSPIRE compliance).

Digital Object Identifier (DOI) – a persistent identifier to provide a link to a dataset (or other resource) on digital networks. Please note that persistent identifiers can be created/minted, even if a dataset is not directly available online.

Indicator assessment metadata – data and information about the content, quality, condition, and other characteristics of an indicator assessment.

MEDIN discovery metadata - a list of standardized information that accompanies a marine dataset and allows other people to find out what the dataset contains, where it was collected and how they can get hold of it.

Recommended reference for this indicator assessment

Tetrienne Box1, Charlotte Findlay1, Sónia Mendes1, Julia Hunt2, Nathan Merchant3, Mark Tasker1, Jane Hawkridge1, Roweena Patel1, Paul Gilbertson1, Ulric Wilson1, Matt Debont1 and Tarquin Dorrington2 2018. UK Distribution of loud, low and mid frequency impulsive sounds. UK Marine Online Assessment Tool, available at: https://moat.cefas.co.uk/pressures-from-human-activities/underwater-noise/impulsive-noise/

1Joint Nature Conservation Committee

2Department for Environment, Food and Rural Affairs

3Centre for Environment, Fisheries and Aquaculture Science