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TG Noise Thematic workshop - Torrelodones, Spain 9-10 November 2017 Towards thresholds for underwater noise

Common approaches for interpretation of data obtained in (Joint) Monitoring Programmes

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EU Technical Group on Underwater Noise (EU TG-NOISE)

Thematic workshop: Towards thresholds for underwater noise


Torrelodones, Spain, 9-10 November 2017

WORKSHOP REPORT

Context

The Marine Strategy Framework Directive (MSFD) requires European Member States (MS) to develop

strategies for their marine waters that should lead to programmes of measures to achieve or maintain

Good Environmental Status (GES) in European Seas. As a first essential step in reaching good

environmental status, MS should establish monitoring programmes enabling the state of the marine

waters concerned to be assessed on a regular basis. Over recent years, significant progress has been

made with establishing joint monitoring programmes. Impulsive noise monitoring (through registers of

relevant activities) has been started for the Mediterranean Sea, Baltic Sea and North-East Atlantic

regions.

Joint ambient noise monitoring has been undertaken in the Baltic Sea (through the now-completed BIAS

project) and similar joint monitoring programmes for ambient noise are now in various stages of

development or implementation in other (sub)regions. Through these monitoring programmes more

information on the pressure will become available. Pressure is only one side of the equation; to assess

the extent to which good environmental status is achieved, it is necessary to understand how the

specific pressure is related to impacts on populations of marine animals.

The 2017 Commission Decision: introduction of thresholds

The Commission Decision of May 2017 requires EU Member States to establish threshold values to

ensure that levels of anthropogenic noise do not exceed levels that adversely affect populations of

marine animals. Member States should establish threshold values through cooperation at Union level

(but taking into account regional or subregional specificities). In the CIS Work Programme (2016-2019)

TG Noise was tasked to provide further advice to EU Member States on the development of thresholds.

In order to contribute to this process, TG Noise organised a thematic workshop titled Towards

thresholds for underwater noise. Common approaches for interpretation of data obtained in (Joint)

Monitoring Programmes. This meeting was hosted by the Spanish Ministry of Agriculture and Fisheries,

Food and Environment and took place on 9-10th November in Torrelodones, Spain.



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The workshop was co-chaired by René Dekeling and Mark Tasker (TG Noise Chairs) and was attended by

32 participants (Annex 1) including members of the research community, government experts, and

representatives from NGOs (both environmental and commercial).



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Objectives

This workshop focused on the evaluation of possible uses of the data collected by

monitoring/registration of underwater noise and to provide advice on how these data can be used to

obtain a better understanding of the environmental impacts of underwater noise. There was no attempt

to define thresholds. There are still fundamental knowledge gaps that hinder establishing concrete

thresholds, and it may take several years to establish relevant thresholds in specific (sub)regions. At this

stage, methodologies that can be used in future, common assessments need to be assessed and further

developed, and ensuring that common methods are being used at Union level is a priority.

The present workshop builds upon the results of the 2016 Hamburg thematic workshop, where

consensus was found on the main directions to better understand the effects of underwater noise and

how to develop impact indicators.

Habitat degradation

For both impulsive and increased (anthropogenic) ambient noise, the participants at the Hamburg

workshop considered that the concept of habitat degradation was worth exploring to develop indicators

of impact. Possible options that were proposed and that should be further investigated include:

• Loss of communication space (masking)

• % loss of habitat

• Habitat degradation index

Some of these approaches would be possible already, at least to some extent, if there was full input of

relevant data by Member States to noise registers and full implementation of ambient noise monitoring

programmes. The challenge is to link these indicators of effect in a meaningful way to indicators of

population impact – noting in particular that temporal scales would also need to be considered. For

example, effects such as masking would be instantaneous, but the impact would (probably) stop after

the sound source has ceased; where habitat loss (displacement) would have continue to have effects for

a period of time after the ceasing of sound outputs, and the “index of habitat degradation” would also

need a temporal “recovery” component. The choice of marine species that would be used in such

indicators also needs to be agreed – especially as there has only been research on a very narrow range

of species (despite multiple earlier recommendations from TG Noise).

The workshop was organized around 2 thematic sessions (impulsive and ambient noise) and break-out

sessions. The discussions at the workshop clearly showed that there is a need to converge to

methodologies that may be applied at European scale. TG Noise should refine the methodology with

clear proposals on methods and advice on definition of thresholds values that can be implemented by

MSs and RSCs. This task needs to be further developed in the short-term by TG Noise and is included in

its Terms of Reference.



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Thematic Sessions and Break-out sessions After a general introduction regarding the concept of thresholds, the two thematic sessions were

introduced. The workshop attendees were then divided into three break-out groups, following each of

the invited speakers’ presentations (think pieces). Each of the break-out groups were requested to focus

on main questions relating to each of the think pieces in turn. The results of the plenary discussions and

the outcomes of the break-out groups are reported below per session theme.

SESSION 1: IMPULSIVE NOISE Chair: Mark Tasker

Think piece # 1: Putting the Commission Decision into practice

Nathan Merchant, CEFAS

This presentation first gave an overview of starting points for indicators based on a recently published

paper. Indicators need to be designed such that targets/thresholds agreed at appropriate management

levels can be implemented by regulators in practice. This will require that indicators are straightforward

to communicate to regulators and stakeholders, and that the methodology does not require unrealistic

amounts of time or funding to implement. Similarly, the indicators should be aligned with existing and

emerging marine management practices, particularly approaches for marine spatial planning and

cumulative effects assessment.

A framework for the development of such indicators was presented, that combines population or

habitat data with data on pressures, within a defined management area, to produce quantified risk

maps and exposure curves which can be used as a basis for defining indicators and setting thresholds.

This methodology was demonstrated for two case studies in the North Sea (harbour porpoise, spawning

herring), based on data from the OSPAR Intermediate Assessment 2017.

Think piece # 2: Impact assessment using the Impulsive Noise Registry

Michael Ainslie, TNO

This presentation introduced a methodology to predict the spatial and temporal distribution of the

potential for behavioural disturbance. It makes use of the data used in the OSPAR Intermediate

Assessment 2017 – the distribution of (loud) sound sources contained in the impulsive noise register

(INR). This method has been used by the Dutch government in an assessment of the cumulative effects

of the construction of offshore wind farms. The main conclusion of this presentation was that tools are

available to produce sound maps using information contained in INR through acoustic modelling. This

method naturally combines different source categories (also noise mitigation) into one meaningful map.

If an assumption is made on the received level at which a specified effect may occur, e.g. disturbance, it

is possible to map the area of potential disturbance. This area of disturbance can then be combined

with distribution data of sensitive species. Modelling in a variety of contexts shows that the size of

predicted disturbed areas varies greatly, and may be larger or much smaller than the ICES sub-grid cells.



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Think piece # 3: Impact indicator for impulsive noise – German proposal

Alexander Liebschner

This presentation introduced a way to define an impact for impulsive noise by quantifying the overlap of

a species (e.g. harbour porpoise) and anthropogenic impulsive sounds exceeding specifically defined

levels (e.g. Sound Exposure Level of 140 dB) that disturb/displace individuals of that species, over

determined areas within selected periods (‘individual-disturbance-days’).

An example using grid cells was presented to demonstrate the methodology of the proposed indicator.

The logical steps are delimitation of an area (convention area, sub-region, EEZ, national waters,

ecological important areas, etc.), selection of a period (e.g. year), determination of number of

individuals in the area in the period concerned (e.g. based on existing monitoring data). Next the

number of ‘individual-days’ is calculated; then number of days different parts of the area are impacted

by disturbing anthropogenic impulsive noise is calculated, using defined thresholds; in the example

these parts of the of the area were grid cells, but they may be other forms/polygons. These figures were

combined to first calculate total individual-disturbance-days and then the intensity of impact, i.e. the

proportion/percentage of total ‘individual-days’ that are ‘individual-disturbance-days’.

Questions discussed in break-out groups:

1. Explore and list ideas for (methodologies for) an impact indicator based on the noise

registries, all indicators should have the potential to set a justifiable threshold – though the

actual threshold should not be considered at this stage

2. Consider the advantages and disadvantages of each (main) idea.

3. Specify, as far as possible, a work plan to develop each idea (or if insufficient time, the idea

most likely to be initially developed)

Key discussion outcomes:

A summary of issues identified in the breakout groups discussions is presented. There were only limited

discussions in the plenary meeting, so these results do not reflect an overall consensus of the workshop

participants.

It was observed that in general, all approaches presented in the plenary and some other methods

discussed in the break-out sessions are similar.

The ideas/methods discussed were:

1. Register sources and ‘disturbance maps’ based on exposure criteria and propagation modeling

(e.g. SEL harbour porpoises) (Michael Ainslie)

2. Threshold/ percentage of area /population / animals affected (Alexander Liebschner)

3. Combining population/habitat and pressure data in a defined management area and produce

risk maps/exposure curves (Nathan Merchant)

4. % of unit area affected (can be SAC or other unit; based on biological assessment, can involve

analysis of persistence) (Mark Tasker).

5. French approach: Consideration of the categories of the register (risk is higher for high sources;

Temporal component = % time; spatial component = % area; applied for sub-marine region)

(Florent le Courtois).



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The first four ideas (Ainslie, Merchant, Liebschner, Tasker), are all based on the principle of overlaying

the noise registry information in some format with species distribution data, in effect an exposure

assessment by comparing the distribution of sounds with that of marine life. The species data could be

absolute or relative density, or distribution range with an added measure of habitat importance/quality.

There are varying degrees of complexity and also of uncertainty associated with the approaches. An

indicator with too much uncertainty might be a weak indicator, however there are ways in which one

could incorporate uncertainty explicitly.

In relation to the pressure layer, Ainslie’s proposal is the most quantitative using noise propagation

models together with received sound levels to estimate the disturbance area around each sound

source, noting that the German method would also use sound modelling at some stage. In theory this is

more precise than the other approaches and would take into consideration environmental effects on

noise propagation but adds complexity to estimates which could result in a potentially time consuming

and expensive process. Further it should be noted that actual accuracy relies on several assumptions

and there is disagreement between the methods as to whether sound received levels should be used as

a proxy for species responses.

Some approaches (Merchant /Tasker) rely on a fixed deterrence radius that can be determined based

on empirical evidence of disturbance ranges and does not rely on noise propagation, simplifying this

element of the indicator. Another option is to use the pulse block days more directly, at least for seismic

surveys, where the survey route coordinates are not recorded in the registries. All approaches have

limitations in representing the (poorly known) disturbance effect of seismic surveys.

Most approaches can incorporate a direct measure of species abundance (e.g. for harbour porpoise),

and have the potential to link to MSFD Descriptor 1 in relation to species abundance estimates and

associated monitoring. There is however great variability and uncertainty associated with species

abundances and there could be large areas where survey effort is low. Most approaches have not

defined how to deal with animal movement and when numbers of animals against time affected is

plotted in a specific area it is not possible to distinguish between whether it is the same or different

animals disturbed for X number of days. One way around this could be to use an index of habitat quality

that would be derived from the species density surfaces. Another potential way was presented by

Germany where the unit of the indicator is porpoise/days of disturbance.

An alternative to using animal densities to weight the potential importance of areas was presented in

both UK methods where certain areas such as marine protected areas or fish sensitive areas could have

a weighting factor. These areas may have been identified based on several criteria in addition to that of

density numbers (e.g. persistency, confidence in data) and therefore it may be more important to

reduce risk to individuals in these areas.

It is important to realize that ANY approach needs to be suitable for use in management (i.e.

forecasting) and to be understood/implemented by non-specialists with limited resources.



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As described above there are pros and cons to the different approaches which need further analysis and

discussion, but it was clear that there are fundamental similarities and therefore there is potential to

merge elements of the different approaches. More discussion is needed to decide on the desirable level

of confidence for the indicator versus level of detail and complexity. The two more detailed approaches,

by Merchant and Ainslie, are more data hungry but can be modified as the scientific understanding

improves (e.g. distances of effect with/without mitigation). They also explicitly describe uncertainty but

there is scope to capture and communicate those uncertainties as part of the indicator.

Further discussion will also be needed on how the indicator could be used in management. The more

readily that one can translate the findings of the indicator into management measures the stronger the

indicator.

Finally, one of the groups discussed potential indicators in addition to those using the noise registry

information. This could include direct measurements of fish/invertebrates’ stress markers in certain

areas.



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SESSION 2: AMBIENT NOISE Chair: René Dekeling

Think piece # 1: The use of the BIAS GES tool to determine habitat degradation

Thomas Folegot, Quiet Oceans

This presentation introduced the use of BIAS soundscape tool developed by the EU LIFE project Baltic

Sea Information on the Acoustic Soundscape (BIAS) for quantifying the pressure from ship noise in the

Baltic Sea. The planning tool can be the basis for study of the impact on marine animals once thresholds

for impact are established (Nikolopoulos et al., 2016).

The soundscape tool is based on measured and modelled soundscape data and provides a number of

functions to evaluate the spatial and temporal sound characteristics within a user-defined geographical

area. The tool is based on several hundred soundscape maps covering different frequencies, depth

intervals and exceedance levels, where e.g. 5% exceedance level describes the highest SPL in an area

that occurred 5% of the time (this will give the strongest sources in the area) and 90% exceedance level

will represent SPL 90% of the time (this level will often represent the background noise level).

Two main assessment methods are implemented in the tool. Both are designed to assess the pressure

during a certain time and in a specific area. The data from these assessments can later be used to study

the impact on marine life or to establish if a threshold for impact was exceeded or not.

Think piece # 2:

Bioacoustics-Based Impact Indicator (BBII)

Michel André

This presentation introduced a relatively new bioacoustics-based approach – the Lido approach. This

method is not species dependent and does not rely on gathering new data on species sensitivity to

noise (thresholds) to be implemented. It is global (pan-European) and transversal by combining MSFD

D11.1 and MSFD D11.2 objectives to address both impulsive and tonal (continuous) sources. It does not

rely on static thresholds but on monitoring trends (changes in the soundscape) that can be assessed on

a variety of timescales (hourly/daily/weekly/seasonally/yearly). It provides the MSFD a regional noise

budget approach for GES; biological and anthropogenic activities are comparatively assessed, and it can

be based on MSFD D11.2 existing/planned monitoring stations.

Questions discussed in break-out groups:

1. Explore and list ideas for (methodologies for) an impact indicator based on the results of

ambient noise monitoring, all indicators should have the potential to set a justifiable

threshold – though the actual threshold should not be considered at this stage

2. Consider the advantages and disadvantages of each (main) idea.

3. Specify, as far as possible, a work plan to develop each idea (or if insufficient time, the idea

most likely to be initially developed)



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Key discussion outcomes:

One breakout group approached the concepts for methodology from the viewpoint that there could be

target expressed in terms of a reduction in source levels of a proportion of the global commercial fleet,

and this would lead to a relative change in risk to sensitive populations. The impact could be expressed

in terms of a percentage reduction in risk to sensitive populations selected for a management area

(which could be MS waters, an area within that, or an area including waters of several MS).

Using the BIAS methodology, the relative risk could be described in terms of x% of time exposed to

levels above level y for z% of the area, for both the current, or reference, situation and if measures that

achieved the target were implemented. The reported impact indicator R would be the expected risk

reduction achieved if the target were met e.g. R=xtarget/xno action. (R could also be expressed in terms of z

and consideration would need to be given to which was most appropriate). Although the group

considered this in the context of the BIAS methods, it was noted that relative risk estimates could also

be made using other approaches.

It is likely that for different management areas there will be different populations that are of concern,

so there could be very different values of R. Nevertheless, if a MS were to evaluate that for a population

of particular concern to that MS a certain relative reduction in risk was needed then the methodology

would allow the calculation a source level reduction target that could achieve this.

The process aims to give stakeholders the information that will be of most concern to them. The

shipping industry is given a target noise reduction for selected vessel types (and can comment on the

technical and economic implications) and environmental management agencies are given a set of

relative risk reduction values for species they have identified as of concern.

An overview of pros and cons of the two proposals were discussed, but since no detailed description of

the LIDO approach was available at the workshop this will need further analysis. Suggested issues that

were identified include:

• BIAS

Pros: Can be understood intuitively, it seems to address the right question (habitat degradation),

adaptable (e.g. level of masking and addition of more frequencies); to be used by for managers

taking into account biological effects

Cons: Where it may be easy to use at a local scale, could be difficult to apply at large spatial scales

(relevant for example for baleen whales) as it involves three variables that are difficult to investigate;

there are still fundamental uncertainties on masking, e.g. it not clear whether animals use all active

space;

• Bioacoustics-Based Impact Indicator (BBII)

Pros: According to developers it is not-species dependent (=quick implementation), large scale

possible (global, EU), existing monitoring can be used

Cons: Because the method could not be fully explained during the meeting there was discussion on

whether the concept was suitable (e.g. bioacoustics as proxy for biological activity), threshold for

S/N, spatial issues; i.e. sample area); it was not clear how complicated it is for use by MS



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Summary of comparison / discussion between the two methods:

• BIAS approach: coherent method (same logic) with the approach for impulsive noise setting

habitat degradation as central concept, and easier to understand by regulators; methodology is

reasonably developed, but the method is species dependent and there may be challenges in

selecting species and defining factors for those species

• LIDO approach: a promising approach but addresses many variables that may be more difficult to

understand by regulators;

Both approaches need to be further developed.



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SESSION 3: Conclusions and way forward

The specific aim of this workshop was to evaluate possible uses of the data collected by registration and monitoring of underwater noise and to provide advice on how these data can be used to obtain a better understanding of the environmental impacts of underwater noise. This was an early step in the process of considering if thresholds could be defined and advised upon.

During the workshop, several concepts for assessing and evaluating impulsive and ambient noise were presented. The pros and cons of these concepts were discussed, both in break out groups and later in plenary. The objective was not to recommend a single concept or method, but to review all ideas.

The overall conclusions of this workshop are as follows and need further work at the next TG meeting and/or thematic workshop in 2018:

1) To converge methodologies: TG Noise should provide WG GES proposals for methodology that can be used at European scale. If WG GES (and MSCG) agree to these proposals, TG Noise could refine the methodology with clear proposals on methods and perhaps advice on options for setting thresholds (or carrying out research aimed to provide a scientific basis for thresholds). It should be noted that MSs (potentially working through RSCs or other international organisations) will be responsible for setting threshold values;

2) When developing an EU-wide concept, TG Noise should ensure it can be readily understood and implemented by multiple regulators (incl. non-specialists);

3) Any methodology should be usable for multiple (types of) species, not only for marine mammals; The concept identified in the 2016 Hamburg workshop to address habitat has been used as basis for the discussions on methodology; this approach looks promising.

A short description of each of the methods suggested during the workshop is attached at Annex 2.

Each method is described:

• Aim/purpose of the method

• Brief description of the method and concepts (non-technical)

• Description of any pros and cons

• References and contact person

TG Noise Chairs and support contract will collate the information into one document, which will include

an overview of pros and cons, and usability of each the methods.

The workshop participants agreed that progress needs to be made during spring 2018. The first version

of a consolidated report based on round-of comments will be available early 2018. This draft document

will be sent to workshop participants and TG Noise members for comments (early 2018). TG Noise

members provide comments and additional contributions (early 2018), then an updated version will be

made based on received comments; if this document is sufficiently developed, it may be discussed with

WG GES, potentially MSCG.



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ANNEX 1 – List of Participants

Name Surname Organization

Alain Norro Royal Belgian Institute for Natural Sciences, Belgium

Albert Willemsen International Council of Marine Industry Associations - ICOMIA

Aleksander Klauson Faculty of Civil Engineering, Tallinn University of Technology, Estonia

Alexander Liebschner German Federal Agency for Nature Conservation, Germany

Andreas Müller Müller-BBM GmbH, Germany

Annemie Volckaert ARCADIS, Belgium

Antonio Novellino EMODnet Physics

Fabrizio Borsani ISPRA, Italy

Florent Le Courtois SHOM, France

Frank Thomsen Central Dredging Association, CEDA

Jorge Ureta Ministry of Agriculture, Food and Environment, Spain

Katja Klančnik Institute for Water of the Republic of Slovenia

Lindy Weilgart Oceancare

Maria Ferreira Coastal & Marine Union (EUCC), The Netherlands

Maria-Emanuela Mihailov NIMRD, Romania

Mark Tasker Joint Nature Conservation Committee, United Kingdom

Marta Martínez-Gil

Pardo de Vera Ministry of Agriculture, Food and Environment, Spain

Mathias Andersson Swedish Defence Research Agency, Sweden

Maud Casier EC DG Environment

Michael Ainslie TNO, The Netherlands

Michel André Universitat Politècnica de Catalunya, Barcelona, Spain

Nathan Merchant CEFAS, United Kingdom

Noelia Ortega Technological Naval Centre, Spain

Pablo Cervantes Technological Naval Centre, Spain

Patrick Gorringe EuroGOOS

Predrag Vukadin Institute for Oceanography & Fishery, Croatia

Ramón Miralles University Politècnica de València, Spain

René Dekeling Ministry of Infrastructure and the Environment, The Netherlands



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Name Surname Organization

Russel Leaper IFAW / Seas at Risk

Signe Jung-Madsen Ministry of Environment and Food of Denmark

Sonia Mendes Joint Nature Conservation Committee, United Kingdom

Thomas Folegot Quiet Oceans, France



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ANNEX 2 - Descriptions of Methods

For impulsive noise the following methodologies are described:

1. Marine noise budgets in practice. Cefas, UK - Nathan Merchant

2. Dutch noise propagation method- Michael Ainslie

3. German noise protection concept- Alexander Liebschner

4. Habitat loss method – Mark Tasker

5. French impulsive noise data gathering - Florent LeCourtois

For continuous (ambient) noise two approaches discussed are presented (additionally the French

approach provided after the workshop is also included as information):

6. BIAS GES tool – Mathias Anderson

7. Bioacoustics-Based Impact Indicator (BBII) – Michel André

8. D11C2: French approach on continuous noise – Florent LeCourtois

These descriptions (and the suggested pros and cons) were made by the presenters/contact persons for

these methods. Further evaluation of the methods will be published in a TG Noise report.



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1. Marine noise budgets in practice. Cefas, UK - Nathan Merchant

Aim/purpose of the methodology

This methodology is a risk-based framework which quantifies the exposure of animal populations or

habitats to noise pollution. It can be applied to derive indicators and thresholds for noise exposure,

consistent with MSFD requirements, and is suitable for both place-based approaches (e.g. marine

protected areas, designated habitats) and ecosystem-based approaches (e.g. protected/managed

populations). The methodology has been published in a high-ranking, peer-reviewed conservation

journal (Merchant et al., 2017), using data from the OSPAR Intermediate Assessment 2017.

Brief description of the methodology and concepts (non-technical)

Figure 1. Workflow for proposed assessment framework (Merchant et al., 2017).

The framework combines population or habitat data (Fig 1b) with data on pressures (Fig. 1c) within a

defined management area (Fig. 1a), to produce quantified risk maps (Fig. 1d) and exposure curves (Fig.

1e). The exposure curves introduced by this method (Merchant et al., 2017) plot the % population or

area exposed vs. the % time exposed during the assessment period. The exposure curve provides a

quantitative basis to define indicators of overall exposure to the population or habitat (Fig. 1f; see

Merchant et al., 2017 for details).

The method has been demonstrated in case studies for both harbour porpoise (Figure 2) and herring

spawning in the North Sea (Merchant et al., 2017). The framework is flexible, and can be applied to non-

gridded data, and incorporate the most appropriate animal density and noise pressure information.



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Figure 2. Case study for North Sea harbour porpoise showing seasonal risk maps (a-c) and exposure

curves (d) during 2015 (Merchant et al., 2017). (a) Spring (Mar.-May) (b) Summer (Jun.-Aug.) (c) Fall

(Sep.-Nov.) (d) Exposure curves and exposure indices (EI). Risk maps incorporate density data from Gilles

et al. (2016).

Description of their pros and cons

Pros: meets MSFD requirements; flexible and future-proof; can be applied to populations or habitats;

risk- and evidence-based. Cons: does not incorporate (though is compatible with) modelling of

population consequences.

References and Contact person

Dr Nathan Merchant, Principal Scientist, Cefas, UK: [email protected]

Merchant, N.D., Faulkner, R.C., Martinez, R., 2017. Marine Noise Budgets in Practice. Conservation

Letters http://onlinelibrary.wiley.com/doi/10.1111/conl.12420/pdf

Gilles, A. et al. (2016). Seasonal habitat-based density models for a marine top predator, the harbor

porpoise, in a dynamic environment. Ecosphere, 7, e01367. http://dx.doi.org/10.1002/ecs2.1367

mailto:[email protected]

http://onlinelibrary.wiley.com/doi/10.1111/conl.12420/pdf

http://dx.doi.org/10.1002/ecs2.1367



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2. Dutch noise propagation method. TNO, The Netherlands - Michael Ainslie


The aim of the proposed methodology is to predict the spatial and temporal distribution of the potential

for behavioural disturbance. It makes use of the data in the OSPAR Intermediate assessment 2017 –

distribution of (loud) sound sources. The approach described here is to base the method as far as

feasible on information available from the impulsive noise register (INR). It has been used by the Dutch

government in licensing the construction of offshore wind farms. At the time of writing, OSPAR had not

agreed a methodology for assessing the effects of impulsive underwater sound, nevertheless the

approach taken can be used to further explore possibilities.


Basic principles:

While there are different potential effects of underwater sound, the assumption is that disturbance

leading to temporary habitat loss is the most relevant effect and that this needs to be quantified. This

approach is also based on results of the 2016 Thematic Workshop (ref: minutes Hamburg meeting) that

quantifying habitat loss would be a likely way forward.

This methodology employs a stepwise approach to quantify the potential effects of impulsive sound on

marine animals. There are different options with this method: In its simplest form it comprises

steps 1 and 2 only; subsequent steps can be executed at a later stage where consensus exists. The

methodology links two OSPAR common indicators (impulsive underwater sound and the distribution and

abundance of cetaceans).

Step by step summary:

Step 1: Quantify underwater sound propagation

Step 2: Determine the area affected by underwater sound: effect parameters and threshold values

After this step, there is an insight in the amount of potential habitat loss (in space and time).

Options for further assessment:

Step 3: Quantify the number of affected animals (or relative part of population)

If there is no detailed information of densities, but there is information on relative population

distribution, it would be possible to make calculations on the proportion of the population that is

exposed.

Step 4: Calculate the number of ‘animal disturbance days’

Step 5: Assess the possible impact on the population

Step 6: Assess cumulative effects of multiple projects / impulsive underwater sound sources

The approach was tailored to make it compatible with the data collected in the INR. An accurate

estimate of the effects of a pressure on a population (whether cumulative or not) requires either a

qualitative or quantitative understanding of the relationship between pressures and their effects on

individual animals. Such information is available (with certain margins of error) for most of the steps



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listed. For step 5, however, translating direct effects (disturbance) into population effects is hampered by

a fundamental lack of knowledge. A temporary solution to this problem is to use a population model

(Figure).

Transparency in terms of how outcomes are determined and how they are interpreted and used to

inform management decisions, are critical to gaining international acceptance. In this approach,

transparency is ensured by showing the uncertainties at each step, and by indicating the relative

influence of these uncertainties for the outcomes. This helps to focus future research effort. Verification

of population size (whether measured or modelled) is a clear priority to make this methodology

acceptable at a regional scale.

Steps 1 and 2 are described in more detail below:

Step 1 (Quantify underwater sound propagation): The first step is to characterize underwater sound

sources according to their energy source level (or proxy). This source level is used in combination with

known local propagation conditions to determine a map of sound exposure level, SEL (or sound pressure

level, SPL).

Step 2 (Determine the area affected by underwater sound: effect parameters and threshold values): The

value of SEL (or SPL, where appropriate) is compared with a disturbance threshold. At this stage the

number of disturbance days can be calculated at each position on the map as the number of days for

which the threshold is exceeded at that position.

The information used from the INR is:

• Start and end date of activity

• Source type (seismic/ sonar/ explosion/ pile driving)

• Source characteristics:

• source level where provided (alternatively, the TG Noise source category from ‘Very low’ to ‘Very high’ may be used).

Assumptions

The two main assumptions made are that disturbance is correlated with exceedance of a SEL (or SPL)

threshold and that the duration of each disturbance is 1 day.

Description of their pros and cons

The advantages of the proposed approach (steps one and two) are:

• It uses information from the INR

• Use of acoustic modelling facilitates the calculation of effect distances

• Addresses impact

• Naturally combines different source categories into one meaningful map

• Effects of source mitigation are included

• Allows for potentially large differences in size of disturbed areas which may strongly vary, and can be larger or much smaller than the ICES sub-grid cells

• Maps provide managers with insight into spatial/temporal distribution of disturbance

• Can be used in combination with population density to estimate effect on population (eg IPCOD)

• Transparent method.

The main disadvantages are:



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• magnitude of predicted effects depends on information not available in INR (requires assumption of geographical distribution of sources within INR resolution cell)

• requires regional harmonization of propagation modelling

Contact person and references

Niels Kinneging, Alexander von Benda-Beckmann, Michael Ainslie, Floor Heinis, Christ de Jong.

Heinis, F., de Jong, C., & Rijkswaterstaat Underwater Sound Working Group (2015). Framework for

assessing ecological and cumulative effects of offshore wind farms: cumulative effects of impulsive

underwater sound on marine mammals. TNO 2015 R10335-A. Available from

https://tethys.pnnl.gov/publications/framework-

Heinis, F. (2017). Assessment methodology for impact of impulsive sound: Evaluation of available

methods and action plan for the development of a methodology for application in the MSFD. Version 1.1

- Final report 1.1. HWE.

Sander von Benda-Beckmann, Christ de Jong, Mark Prior, Bas Binnerts, Frans-Peter Lam, Michael Ainslie

(2017). Modelling sound and disturbance maps using the impulsive noise register for assessing

cumulative impact of impulsive sound. TNO 2017 R11282 | Final report

MSFD Common Implementation Strategy, Technical Group on Underwater Noise (TG-NOISE), Thematic

Workshop: Way forward to define further Indicators for Underwater Noise. 7- 8 June 2016, Bundesamt

für Seeschifffahrt und Hydrographie (BSH), Bernhard-Nocht Straße 78, 20359 Hamburg, Germany

Figure:



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3. German noise protection concept. German Federal Agency for Nature

Conservation, Germany - Alexander Liebschner


Distribution of co-occurrence of species (indicator species e.g., harbour porpoise) and anthropogenic

impulsive sounds exceeding levels that disturb/displace individuals of that species (e.g., Sound Exposure

Level of 140 dB), over determined areas within selected periods (‘individual-disturbance-days’).

The indicator reflects the quantity/intensity of the species’ spatio-temporal use of an area (‘individual-

days’) that is impaired by disturbing/displacing impulsive noise by calculating the proportion of

‘individual-days’ that are ‘individual-disturbance-days’ as well. This proportion provides a numerical

measure of the impact of impulsive noise and thus indicates the environmental status of a determined

area within a selected time period.

The indicator should help to assess the Environmental Status. The indicator so far quantifies the impact

and can be applied both for the whole area and the sub-units of it. In order to use this impact indicator

for assessing whether the environment is in a good status (GES) threshold values have to be set.

Because the indicator is rather independent from abundance/densities or sensitivity of the species there

is the need for different thresholds: The acceptable level of impact may be much higher for areas or

times with low abundance/densities of the receiver species and much lower in e.g. spawning grounds or

during periods of especially high noise sensitivity such as the reproduction phase.


Step I delimitation of an area:convention area, sub-region, EEZ, national waters, ecological important

areas, etc.

NOTE: To be able to include inhomogeneous distribution of species and/or to calculate the

extent of the surface impacted the area may be divided in reasonable sub-units such as e.g. grid cells.

Step II selection of a period: reporting period, year, season, sensitive time of the year, etc.

Step III calculation of (mean) total number of individuals in the area in the period concerned (e.g. based

on existing monitoring data)

Step IV calculation of ‘individual-days’ by multiplying the number of individuals by the length of the

period [days]

Step V identification of the number of days different parts of the area are impacted by disturbing

anthropogenic impulsive noise during the period

the threshold defining ‘disturbing’ depends on species specific sensitivity, source characteristics

(e.g., frequencies), noise level etc.

parts of the area may be grid cells, surface, etc.

Step VI a) calculation of ‘individual-disturbance-days’ by multiplying the number of individuals within

the area impacted by the duration of the impact [days], or



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b) calculation of ‘individual-disturbance-days’ by multiplying the number of individuals within

the area impacted by the length of the period [days]

Step VII calculation of the intensity of impact, i.e. the proportion/percentage of total ‘individual-days’

that are ‘individual-disturbance-days’ as well.

regarding the whole area the total number of ‘individual-disturbance-days’;

regarding the different sub-units only the ‘individual-disturbance-days’ within the respective

sub-unit.

Description of pros and cons

Pros:

• it works with indicator species (which can be different in different area), Indicator species representing usually a group of noise sensitive animals;

• it can be adjusted to any time period

• can be applied to any area or any size of area

• therefore it is very flexible Cons:

• you need monitoring data about the abundance of the indicator species (in the area)

• you need data about the noise events in the area


For further information please contact: Thomas Merck or Alexander Liebschner/ BfN/ Germany;

Email: [email protected]; [email protected];

Tel. +49 38301-122 +49 38301-163

Example how to use the Indicator:

In the following an example is presented only to demonstrate the methodology of the proposed

indicator. It does not represent an existing area or is referring to a specific species. The use of grid cells

was chosen to make the application comprehensible, but the method can also be applied for polygons.

The grid does not reflect any existing partitioning such as e.g. ICES sub-blocks.

Step I - III

Total number of individuals [N]: 1.928

78,3 71,8 69,3 66,2 79,0 66,9 72,7

17,4 69,7 77,2 73,8 53,0 50,8 49,0

15,8 10,4 10,8 73,4 53,8 63,1 85,0

6,3 6,5 18,5 18,5 71,9 60,7 68,1

4,8 7,1 7,5 10,8 36,0 62,4 68,2

6,0 7,8 8,7 4,4 22,0 59,1 66,6

0,2 0,7 1,7 4,5 6,3 15,7 69,4

number of individuals

[n]





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9.631 8.829 8.528 8.142 9.717 8.231 8.944

2.144 8.573 9.500 9.083 6.517 6.249 6.027

1.943 1.283 1.334 9.024 6.616 7.757 10.455

776 803 2.282 2.281 8.848 7.470 8.374

596 872 919 1.331 4.428 7.679 8.387

741 959 1.075 536 2.706 7.270 8.193

31 90 211 554 777 1.932 8.530

number of 'individual-days'

[n * d]

0 0 0 0 30 30 30

0 0 0 0 22 30 30

0 0 0 0 0 0 30

0 50 50 50 0 0 0

0 50 80 50 0 0 0

0 50 50 50 0 0 0

0 0 0 0 0 0 0

number of days with disturbing impulsive noise

[dd]

0 0 0 0 2.370 2.007 2.181

0 0 0 0 1166 1.524 1.470

0 0 0 0 0 0 2.550

0 327 927 927 0 0 0

0 355 598 541 0 0 0

0 390 437 218 0 0 0

0 0 0 0 0 0 0

number of 'individual-disturbance-days'

[idd = n * dd]

Selected period: 123 days [d]

Step IV

Total number of ‘individual-days’ [ID = N * d]: 237.144

Step V

Step VI

Total number of ‘individual-disturbance-days’ [IDD]: 17.988



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Step VII

Indicator value regarding the different sub-units

Indicator value regarding the whole area:7,58 [IDD / ID *100]



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4. Habitat loss assessment method (using harbour porpoise as an example) – Mark

Tasker Aim/purpose of the methodology

One of the effects of underwater anthropogenic sound (and human presence) is to deter marine animals

from using an area of sea. The method summarised here is based upon the relatively simple information

that is (should become) available within the noise registers being established as part of the

implementation of the Marine Strategy Framework Directive. The method, as outlined in Tasker (2016),

requires some limited quantification of the effects of each noise source on a receptor animal but allows

for suitable limits to be expressed in terms of time and space for the area of sea that may become

unavailable to the animal.


Available information.

The noise registers are providing a record of where underwater anthropogenic impulsive sound above

agreed thresholds of intensity and below an agreed frequency level has occurred. The spatial definition

of such records is at a minimum within blocks of 100-200 km2 (e.g. UK oil & gas licensing blocks or ICES

sub-blocks) and the temporal definition is one day. A simple activity classification (pile driving, seismic

source, explosion etc) is also available.

In order to estimate the temporal and spatial extent of “habitat loss”, an understanding of the effects of

impulsive sound sources on marine animal(s) is needed. The evidence base for most species remains

scarce and TG Noise (and its predecessors) have highlighted the importance of such research. Limited

information is known for harbour porpoises, and this is used here to illustrate the approach.

Assessment process (illustrated for harbour porpoise)

Determine Effective Deterrence Radius (EDR) for the species concerned for each impulsive sound

generating activity.

Field measurements of the distance over which harbour porpoise respond to pile driving may be

expected to vary with pile diameter, hammer energy, etc. However, piles used at Alpha Ventus were

2.5m (500kj hammer energy) compared with the larger 4m piles used at the Horns Reef I and II (900kj

hammer energy) and reaction distances were broadly similar: 15-25km (Diederichs et al. 2009; Dahne et

al. 2013) and 18-21km (Brandt et al., 2011; Tougaard et al. 2009) respectively. It is proposed that for

unmitigated pile driving, the area affected should be based on an EDR of 26 km (Tougaard et al. 2013).

This results in an area of harbour porpoise ‘habitat loss’ of approximately 2,100 km2 for the day that a

single pile driving event occurs upon. If the precise location of the event is known, then it could be used

in calculation, if not the centre of the block should be used.

For seismic surveys, the EDR based upon the work of Thompson et al. (2013) would be 10 km. In this

case, the centre of the registration rectangle(s) that the seismic survey occurred within is proposed –

again on a daily basis.

For explosions, the EDR is not researched, but a precautionary approach might be to assume the same

as for seismic surveys.

An alternative, and simpler option, would be to use pulse block days, i.e. if any pulse occurs in a block in

one day, then it is assumed that those blocks are not available for the harbour porpoise on that day. This



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approach would also lend itself more readily to management as it could use the same unit both for

recording and managing the pressure.

Calculate the effective loss of habitat per day/season/year for the assessment unit of the species

concerned.

The assessment unit might be the range of an animal, or an accepted sub-unit of that range. The unit

might also be a protected area or a specific sensitive habitat. Calculations of the area ‘lost’ within the

assessment unit can be done on a daily/seasonal or yearly basis, and are probably best expressed as a

percentage of that area, both in total extent and averages.

Consider thresholds

These could be set in a number of ways. Ideally the loss of habitat would then be translated and

expressed in terms of effects on population viability (Tougaard et al. 2013). Population level effects may

result from a reduction in carrying capacity of the habitat in the assessment area. Long-term, permanent

reduction in carrying capacity may manifest in population declines (Tougaard et al. 2013). Thresholds

could be expressed in terms of a maximum allowable ‘habitat loss’ per agreed period of time or an

average (or both).

Such indicator and potential thresholds would allow regulators to manage noisy activities by using

spatio-temporal restrictions if the proposed activities would be likely to exceed the set thresholds. This

would need to be based on information obtained from strategic plans and project specific applications.

The information obtained by the noise registries once the activities have taken place will also allow a

further check of whether those management procedures are successful.

This approach could also take account of other activities (beyond those generating impulsive noise) that

are known to displace animals. For instance, in the case of harbour porpoise, it is known that shipping

lanes that have about 10,000 or more movements per year displace porpoises from the lane area. This

could be readily incorporated into the indicator proposed here.


Pros:

• Any species can be used where there is knowledge of disturbance area or it is assumed to be approximately the area of a noise reporting grid (it seems unlikely that a widely-distributed animal with a substantially smaller disturbance area would be affected at the population scale);

• it can be adjusted to any time period;

• can be applied to any assessment area or any size of area;

• avoids need for monitoring data for species, but can use detailed relative abundance information;

• does not make assumptions about noise propagation nor require complex noise modelling. Cons:

• relatively coarse scale, may not be fully compatible with detailed assessments of environmental impact of projects

Contact: Mark Tasker, [email protected]

References



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Brandt, M.J., Diederichs, A., Betke, K., and Nehls, G. 2011. Responses of harbour porpoises to pile driving

at the Horns Rev II offshore wind farm in the Danish North Sea. Marine Ecology Progress Series, 421:

205–216.

Dähne, M., Gilles, A., Lucke, K., Peschko, V., Adler, S., Krügel, K., Sundermeyer, J., and Siebert, U. 2013.

Effects of pile-driving on harbour porpoises (Phocoena phocoena) at the first offshore wind farm in

Germany. Environmental Research Letters 8, 025002.

Diederichs A, Brandt MJ, and Nehls G 2009. Effects of construction of the transformer platform on

harbor porpoises at the offshore test field “alpha ventus.” Report to Stiftung Offshore-Windenergie,

BioConsult SH, Husum, Germany.

Tasker M.L. 2016. How might we assess and manage the effects of underwater noise on populations of

marine animals? Pp. 1139–1144 in Popper, A.N. and Hawkins, A. (eds.), The Effects of Noise on Aquatic

Life II. Advances in Experimental Medicine and Biology. Springer Science+Business Media, New York.

Thompson P.M., Brookes K.L., Graham I.M., Barton T. R., Needham K., Bradbury G. and Merchant N.D.

2013. Short-term disturbance by a commercial two-dimensional seismic survey does not lead to long-

term displacement of harbour porpoises. Proceedings of the Royal Society B: Biological Sciences. DOI:

10.1098/rspb.2013.2001

Tougaard, J., Carstensen, J., Teilmann, J., Skov, H., and Rasmussen, P. 2009. Pile driving zone of

responsiveness extends beyond 20 km for harbour porpoises (Phocoena phocoena, (L.)). Journal of the

Acoustical Society of America. 126, 11–14.

Tougaard, J., Buckland, S., Robinson, S. and Southall, B. 2013. An analysis of potential broad-scale

impacts on harbour porpoise from proposed pile driving activities in the North Sea. Report of an expert

group convened under the Habitats and Wild Birds Directive – Marine Evidence Group MB0138. 38pp.



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5. French approach impulsive noise data gathering. SHOM, France - Florent

LeCourtois


Impulsive noise sources have been identified to be responsible for population disturbance and lethal

injuries. The Good Ecological Status (GES) is defined when functional ecological zones are preserved and

noise does not induce excess mortality [1]. The methodology proposed for to evaluate descriptor 11

criterion 1 (D11C1) follows this definition.

Regarding these two risks, the aim of our evaluation is two-fold: the first one is to provide relevant

pressure indicators of D11C1 to enable a SMART (Specific, Measurable, Assignable, Realistic and Time-

related) management of the underwater noise; the second one is to use appropriate indicators as input

of the descriptor 1 to assess the impacts.

Brief description of the methodology and concepts

The impulsive noise register contains the data from impulsive source emission which have been certified

by operators. The data contain the duration (number of days), the location (in a 15’x15’ block), the

category of impulsive source and the level. The census follows the TG Noise guidelines [2].

We define three indicators: D11C1.1 concerns the temporal extent (the total number of days during a

predefined period), D11C1.2 concerns the spatial extent (the total number of blocks over an area) and

D11C1.3 concerns the distribution of emission levels [2].

Regarding these indicators, the GES is then defined depending on the risk to assess; it follows a decision

tree approach at the subregion level and over a trimester period. The GES is evaluated in regards to

temporal and spatial thresholds. The spatial extent is then assessed as a proportion of blocks where the

temporal extent exceeds a temporal threshold; the GES is achieved if this spatial extent is below the

spatial threshold. To assess the disturbance risk, the data from all certified emissions are used to

compute the extents. To assess the lethal risk, a similar decision tree is performed but only considering

high and very high level of emissions [2]. Depending on the risk, the temporal and spatial thresholds

have to be more or less restrictive: e.g. one can consider a risk of lethal injuries with a one day temporal

threshold (i.e. there is a lethal risk at the first emission). Both approaches introduce moderate risk and

high risk thresholds to adapt the of noise emission management.


Pros:

• Easy to build: already applicable using noise register data;

• Allows noise budget in time and space for marine planning;

• Thresholds are explicitly expressed as recommended by EU;

• Easy to adapt: thresholds and decision orders can be changed depending on marine unit specificities;

• Several thresholds can be applied in order to identify low, moderate and high risks and to provide relevant mitigation solutions;

• Non-specific: it does not require dedicated and accurate knowledge on the marine life. Cons:

• Thresholds are defined empirically: work in progress to report the indicators to descriptor 1.



28 | P a g e

• Propagation effects are not taken into account

Contact persons and References

Florent Le Courtois, G. Bazile Kinda, Yann Stéphan

[1] MEDDE. (2012). Arrêté du 17 décembre 2012 relatif à la définition du Bon Etat Ecologique.

Journal Officel de la République Française, 27.

[2] Dekeling, R., Tasker, M., Van der Graaf, A., Ainlie, M., Anderson, M. A., Brensing, K., … Young, J.

(2014). Monitoring Guidance for Underwater Noise in European Seas. Luxembourg: Publications Office

of the European Union.



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6. BIAS GES tool. FOI - Swedish Defence Research Agency – Mathias Anderson


Continuous noise covers large areas of the seas and has been observed to vary both temporally and

spatially. It is known that marine species often moves over large areas and utilizes specific areas during

certain times of the year. Thus, in order to estimate the Sound Pressure Level (SPL), both time (year or

month) and space (area and water depth) need to be considered, as well what frequency (63, 125, 2 000

Hz) to study. The BIAS Soundscape planning tool was developed by the EU LIFE project Baltic Sea

Information on the Acoustic Soundscape (BIAS) for the purpose of quantifying the pressure from ship

noise in the Baltic Sea. The planning tool can be the basis for study of the impact on marina animals

once, thresholds for impact are established (Nikolopoulos et al., 2016).

Brief description of the methodology and concept (non-technical)

The soundscape tool are based on measured and modelled soundscape data and provides a number of

functions to evaluate the spatial and temporal sound characteristics within a user-defined geographical

area. The tool is based on several hundred soundscape maps covering different frequencies, depth

intervals and exceedance levels, where e.g. 5% exceedance level describes the highest SPL in an area

that occurred 5% of the time (this will give the strongest sources in the area) and 90% exceedance level

will represent SPL 90% of the time (this level will often represent the background noise level).

Two main assessment methods are implemented in the tool. Both are designed to assess the pressure

during a certain time and in a specific area. The data from these assessments can later be used to study

the impact on marine life or to establish if threshold for impact was exceeded or not.

Temporal Exposure Assessment - TEA

This method gives the proportion of area for which a SPL is exceeded a certain percentage as a function

of time for the specified month of the year, centre frequency and depth interval. For example, the

percentage of an interest area where a species is residing during mating period is exposed to SPL higher

than a certain level 5% of the time (the 5% exceedance level).

Spatial Exposure Assessment - SEA

The other method will give the proportion of area for which a SPL surpass a user defined SPL threshold,

a certain percentage of time for a specified time period, centre frequency, and depth interval. This

method is used when there is a specific threshold level of interest, for example sound levels related to

masking.


The user of the tool needs to have a basic understanding of the topic underwater noise and impact in

order to define the parameters that the tool will use to calculate the desired statistics for the area and

time of interest. The highest temporal resolution is monthly averages the spatial resolution can be

decided by the user.




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Nikolopoulos A., Sigray P., Andersson M., Carlström J., Lalander E., 2016: BIAS Implementation Plan -

Monitoring and assessment guidance for continuous low frequency sound in the Baltic Sea, BIAS LIFE11

ENV/SE/841. Available from www.bias-project.eu.

Contact person: Mathias Andersson

FOI - Swedish Defence Research Agency, SE- 164 90 Stockholm, Sweden

[email protected]

http://www.bias-project.eu/




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7. Bioacoustics-Based Impact Indicator (BBII). Laboratory of Applied

Bioacoustics (LAB) of the Technical University of Catalonia, Barcelona

(UPC, Spain) – Michel André

Aim of the methodology

The Bioacoustics-Based Impact Indicator (BBII) aims at developing a decision support tool for the

continuous monitoring of ecosystem changes in the marine environment and assessment of whether

these changes were caused by the introduction of anthropogenic sound sources. It works by

automatically and continuously tracking biological and anthropogenic acoustic activities with dedicated

instruments and analysis modules. The resulting indicators allow the informed analysis of relationships

between changes in anthropogenic sound levels and changes in ecosystem health.

Brief description of the methodology and concept (non-technical)

Assessing the impact of anthropogenic noise on the marine environment requires objective data on the

sensitivity to noise of representative species. Currently, such data is scarce on most studied species

(marine mammals and fishes) and recent findings show that non-hearing specialists like invertebrates

suffer acoustic trauma when exposed to certain sounds. It will probably take decades before we can

scientifically assess species-specific thresholds for a broad spectrum of species, which would allow a

global approach to predict impact on marine fauna.

Here, we propose to use the most recent developments in bioacoustics analysis to automatically

separate and estimate the contributions to the overall noise budget in a given area, in particular (1) the

anthropogenic sources and (2) the biological sources which serves as a proxy to biological activity. This

approach assumes that a good environmental status of a given area is associated with a diversity of

biological activities, and in turn associated to the production of biological sounds. The methodology

requires the automated real-time processing of audio streams.

The automated real-time processing of audio streams is based on machine learning methods and the

post-processing to obtain the final indicators of anthropogenic and biological activity is based on

statistical methods. These indicators will inform on the composition and relative density of acoustically

active species and received levels from anthropogenic sources in the area at a fine temporal scale. Joint

analysis of these two indicators can reveal potential impact of anthropogenic sounds on ecosystem

health. Due to its ability to work continuously and with low latency, BBII is expected to be an important

decision support tool for governmental agencies, conservation NGOs, and other stakeholders.


Pros:

• Automated processing allows an accurate quantification of relative changes. Indicators can be calibrated initially by punctual direct assessment of ecosystem health with more invasive methods which could even allow quantification of absolute changes.

• Automated method can run 24/7 over the long term, therefore offering a complete picture of an ecosystem’s temporal patterns (e.g. seasonal, diurnal, tide-related)

• Monitoring acoustic stations are required to define indicators: Indicator 11.2 monitoring stations can be used

• Indicators can be defined without awaiting further data on species-specific thresholds



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Cons:

• As any proposed methodology and measurement method, the indicators must assume a certain level of uncertainty

• A given area may not be bio-acoustically active to be able to define a reference value

• Distant sources (biological and anthropogenic) might be taken into account locally

References and contact person

The BBII approach is jointly developed by the Laboratory of Applied Bioacoustics (LAB) of the Technical

University of Catalonia, Barcelona (UPC, Spain) and Quiet-Oceans (France)

Contact person: Michel André ([email protected])



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8. French approach on continuous noise. SHOM, France – Florent LeCourtois


Continuous noise sources in the oceans can cause masking of the animal communication. The Good

Ecological (GES) is defined when communication capabilities are not downgraded [1]. This definition can

be interpreted in terms of negative or null trend in the shipping noise levels. The methodology proposed

to evaluate of descriptor 11 criterion 2 (D11C2) follows this definition.

Regarding this risk, the aim of our evaluation is two-fold: the first one is to provide relevant pressure

indicators of D11C2 to enable a SMART (Specific, Measurable, Assignable, Realistic and Time-related)

management of the underwater noise; the second one is to use appropriate indicators as input of the

descriptor 1 to assess the impacts.

Brief description of the methodology and concept

Shipping is one of the dominant anthropogenic sources of underwater noise at low frequency. Our

approach is based on the modelling of the shipping noise. The modelling of the emitted and propagated

levels is explained in [2]; in addition, the model estimates the propagation uncertainties using basin-

scale scenarios of environmental mismatches.

The shipping noise is then computed in discrete meshes for 4 months (one for each season: January,

May, August and November), at several depths between 5 and 300 m, and for the one-third octave

bands centred on 63 Hz and 125 Hz. The yearly maximal levels are computed by selecting only the

maximal levels per depth and per month for each mesh. The spatial distribution of the maximal levels in

the subregion units are the indicators D11C2.1 and D11C2.2 for the one-third octave bands respectively

centred on 63 and 125 Hz.

The maps of annual maximal levels are computed for 2 years: 2012 (year of reference according to TG

Noise) [3] and 2016 (during the evaluation cycle). The difference between the 2016 and 2012 maps

leads to the spatial distribution of the trend in the maximal shipping noise levels. For each subregion

unit, the percentile values of the maximal level differences are investigated.

The spatial proportion of the positive and negative trends and the magnitude of the percentiles are

compared to the uncertainties to provide a qualitative assessment of the GES. Additional information

such as reports from the MRCC and underwater noise opportunistic measurements [4] are used to

strengthen our analysis and to reduce the uncertainties.


Pros:

• Already applicable: scientifically validated;

• Global approach: basin scale analysis;

• No biological information is required;

• Estimate the uncertainties;

• Allows marine space planning by considering ship categories [2];

• Can be easily adapted: i.e. monthly analysis, focus on a zone and at given depth, monitoring of higher frequencies…



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Cons:

• Trends are difficult to estimate in a robust way: long term monitoring of the trend is required to provide statistic robustness;

• AIS and environmental data are required;

• Measurements are required to validate and to correct the modelling (i.e. in shallower zone, at higher frequencies or when the AIS data are not comprehensive).


Florent Le Courtois, G. Bazile Kinda, Yann Stéphan

[1] MEDDE. (2012). Arrêté du 17 décembre 2012 relatif à la définition du Bon Etat Ecologique.

Journal Officiel de la République Française, 27.

[2] Le Courtois, F., Kinda, G.B., Stéphan, Y., Boutonnier, J.-M., and Sarzeaud, O. (2016). Statistical

ambient noise maps from traffic at world and basin scales. Proceedings of the Institute of Acoustics,

Cambridge (UK).

[3] Tasker, M. L., Amundin, M., Andre, M., Hawkins, A., Lang, W., Merck, T., ... & Zakharia, M. (2010).

Marine Strategy Framework Directive Task Group 11 Report Underwater noise and other forms of

energy. Report No. EUR, 24341.

[4] Kinda, G. B., Le Courtois, F., & Stéphan, Y. (2017). Ambient noise dynamics in a heavy shipping

area. Marine Pollution Bulletin, 124(1), 535-546.

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