N° 7 2021 
Introduction 
and scope 
Background 
Anthropogenic underwater noise impacts have become a hot topic for environmental managers and 
regulators in Europe and beyond. From a topic undertaken by a few devoted academics in the 1970s, the 
effects of noise on marine organisms such as mortality, hearing impairment, communication masking 
and behaviour disturbance have in the last couple of decades received increasing attention worldwide, 
resulting in numerous reviews including a United Nations report (see Richardson et al., 1995; Southall 
et al., 2007; Hawkins & Popper, 2016; UN, 20183). A research strategy for the effect of underwater noise 
on marine mammals was published as Position Paper N° 13 by the European Marine Board 13 years ago 
‚Boyd et al., 2008). This report defined a strategic framework for future research; provided guidance 
about prioritisation; and proposed a process of implementation. A stepwise analytical risk assessment 
framework (see Figure 1) was developed as a systematic process to assess gaps in knowledge and identify 
priority research topics in underwater noise and has been influential in informing research on this topic 
over the past decade. 
A lot has happened in the past thirteen years. Further attention 
has been brought to the impacts of underwater noise on fishes 
and invertebrates, which are not only more abundant and diverse 
than marine mammals, but also represent important components 
of the marine food web on which higher trophic levels such as 
marine mammals and humans feed. New technologies have 
allowed us to follow animals and observe their reactions while 
being exposed to noise. Frameworks and models for assessing the 
population-level consequences of noise exposure on mammals 
and fishes have been further conceptualized and tested. Methods 
to mitigate noise effects have been developed and implemented. 
Crucially, international and national policies have been drawn up 
to address underwater noise pollution. In the European Union, 
the 11% Good Environmental Status (GES) descriptor of the 
European Marine Strategy Framework Directive (MSFD) requires 
that “Introduction of energy, including underwater noise, is at 
levels that do not adversely affect the marine environment” 
and includes two indicators, considering both impulsive and 
-ontinuous sound. 
The above mentioned work led the EMB to convene a new expert 
Working Group who were tasked to follow up on the work of Boyd 
2t al., (2008). Our objectives were to: 
Update on progress related to this topic since the 2008 
EMB Position Paper; 
Raise awareness of the current knowledge and research 
gaps; 
3roaden the scope from marine mammals to all marine 
organisms; and 
Highlight the conflicts and solutions that exist relative to 
underwater noise. 
The risk assessment framework revisited 
One of the novelties of EMB Position Paper N° 13 was that it applied 
an explicit risk assessment framework that can be used to structure 
research and impact assessments in the field of underwater noise. 
This ensures that all of the information identified for environmental 
protection is addressed. This risk framework involves a stepwise 
procedure, including: (i) risk identification (referred to as ‘'hazard 
identification' in Boyd et al., 2008); (ii) exposure assessment; (iii) 
dose-response assessment; (iv) overall characterization of risk, 
all of which leads to (v) risk management and the selection of 
appropriate mitigation measures (Figure 1).