• Each habitat or MRU has different physical and biological characteristics;
• Each indicator species or groups of species react differently depending on audi-
tory capabilities (e.g., low frequency, mid-frequency, or high frequency), sound
source frequency, and sound levels;
• Sound propagation in shallow waters, e.g., in the North Sea, differs from prop-
agation in deep waters, e.g., Mediterranean Sea.
Quality of noise data in registries: Ideally, a complete dataset of the source event
should be available for determining the sound levels using propagation modelling
(source type, source level, location, duration). In addition to the mandatory data
reported to noise registries, additional data, e.g., frequency distributions, speci?ed
source level, and measured levels, would signi?cantly improve the quality of the
noise propagation modelling. Irrespectively, the quantity and quality of available
noise data should be evaluated carefully prior to an assessment.
Selection of Habitat/Area of Assessment: Habitat or area relevant for assessment
should be de?ned with respect to environmental (bathymetry, topography, currents)
and biological (species spectrum, occurrence) characteristics. For regulatory pur-
poses, the selection of administrative sectors could be a suitable choice, which
allows Member States to regulate and monitor activities and to de?ne measures to
achieve GES, if required.
Information on geographical, geological, and hydrographic data for habitats or
MRUs: Hydrographic and geological information is important for the quality of the
• All data available
(geological,
hydrographic,
bathymetry)
• Only geographical data
available
• Numerical models
(shallow / deep water)
• Empirical models (with
cut-off frequency)
• Analytical models (10 /
15 / 20 Log R)
• Simple Dipolmodel (half
space)
• (Effect Ranges)
• Complete information
(SL, location, duration, ..)
• Only mandatory
information of noise
registry (Noise classes,
etc.)
• Species auditory
capabilities
• LF, MF, HF
• Knowledge about
threshold values?
• Regional dependent
• Shallow water
• Deep water
• 2d, 3d
1. Range of
interest
2. Quality of
Noise Data
3.
Information
on Habitats
and MRUs
4.
Propagation
modelling
Fig. 2 Decision scheme for the selection of appropriate propagation models as proposed in Müller
et al. (2021)
EU Marine Strategy Framework Directive-Compatible Approaches for. . . 9
