2. Applicability: assessment methods are well de?ned; uncertainties can be esti-
mated by each Member State and the method can be applied for setting regulatory
measures and evaluating the suf?ciency of measures.
3. Reproducibility: methods applied are transferable to sub-regions and regions,
results are non-ambiguous and allow for comparison of GES at union level.
4. Feasibility: assessment effort is such that each Member State is able to implement
the methodology with own resources and capabilities.
The four assessment approaches included in Table 1 were analyzed against the
four Harmonization Criteria established for the purpose of harmonization. Emphasis
was placed on the applicability by each Member State at national level taking into
account the available capacities. Furthermore, emphasis was placed on the
unambiguity of the assessment results in light of the available input data. Minimum
Table 1 Comparison of different assessment methodologies
Main
aspects
A: Mixed approach
(Dekeling et al.
2020; Merchant et al.
2017)
B: Population-based
approach (Dekeling
et al. 2020; Heinis
et al. 2015)
C: Habitat-based
approach
(Dekeling et al.
2020; Müller
et al. 2020)
D: Habitat-
based
approach
(Dekeling
et al. 2020)
Baseline Disturbance Disturbance TTS/disturbance Disturbance
Source data Noise registry Noise registry Noise registry Noise
registry
Effect
ranges
Observations for
species (based on
speci?c adverse
effect
e.g. disturbance
related to a speci?c
activity)
Propagation model Empirical
propagation
model/
measurements
Propagation
algorithms/
prede?ned
buffers
Assessment
areal focus
MA, e.g., OSPAR II,
MPAs
MA MA (EEZ) and
MPA
MA and
PUHA
Adverse
effect
Population (density) Population (decline
in density)
Habitat affected
(quality loss)
Habitat
affected
(quality loss)
Assessment
metric/
parameter to
evaluate/
interpret
Exposure curve
(index)
Population dynamics
(model-based)
Adaptable
percentage of
area over time
(based on
sensitive periods)
Percentage of
area and time
exposed
Options for
threshold
for GES
Change in the form
of the exposure curve
(or change in index)
Change of
population based on
a model result,
perhaps x %
reduction in
population
Percentage of
area (x % EEZ or
MPA) exposed
over time
E.g., x % area
exposed
(MA and
MPA) and y
% time
exposed
MA management area, MPA marine protection areas, PUHA potentially usable habitat area
6 C. Juretzek et al.
