ICES WKGMSFD
Report by Jurgen Batsleer on behalf of NSAC.
ICES organised three workshops in response to a request from DGENV for a technical service
to review the MSFD 2010 Decision document (2010/477/EC) on descriptor 3 (status of
commercial fish and shellfish stocks), 4 (Food webs) and 6 (seafloor integrity). The 2010
Decision of the MSFD raised many challenges. Many of these are concerned with the scientific
interpretation of the ideas and concepts of the Decision. The workshops aimed to provide
scientist the opportunity to give input into the review process of the Marine Strategy Framework
Directive (MSFD) and focus on scientific challenges with a view to clarify the text and make
the Decision more understandable.
1.
Descriptor 4: Foodwebs (26-27 August 2014)
GES for descriptor 4 is defined as “All elements of the marine foodwebs, to the extent they are
known, occur at normal abundance and diversity and levels capable of ensuring the long-term
abundance of the species and the retention of their full reproductive capacity”.
1.1 Criteria for D4
The existing criteria were too prescriptive and implied a judgement that top-predators are the
most important elements in the foodweb to be assessed. Therefore, foodweb criteria were
revised and two new criteria 4.1 foodweb structure and 4.2 foodweb functioning, being natural
attributes of the foodweb, were proposed. These criteria are general terms and to avoid
Member States assessing only one ecosystem component, guidance should be given on the
minimum requirements to be covered under each criteria. Hence, the term trophic guilds was
introduced, capturing both trophic groups and functional groups which should be assessed.
The use of resilience as a third criteria was discussed. Resilience is an abstract concept and
the definition was unclear. Conclusion was that we do not understand resilience well enough.
In addition, it was argued that by assessing structure and functioning we assess resilience as
well, therefore, resilience was not included as a separate criteria.
1.2 Use of common indicators
During the meeting the pros and cons of using common indicators were discussed. It was
concluded that Member States should have some common indicators on a regional/subregional scale in order to perform joint assessments. However, there is no need to force
common indicators across a region, but rather have an open process were Member States can
develop indicators. Therefore, minimum requirement on what aspects need to be assessed in
combination with a common methodological standard which should be used in order to assess
progress towards GES.
1.3 Pressure state relationship of marine foodwebs
Relations between marine foodwebs and human pressures and/or natural variability are
complex and often indirect. Few indicators are expected to have a tight link with pressure and
respond to multiple, interacting drivers. Hence changes are difficult to interpret or do not
directly respond to management measures. The group argued that the proposed indicators for
D4 need to be considered as being surveillance indicators. Surveillance indicators monitor the
health of the ecosystem and provide information the impact of human pressures as well as
natural variations on the progress towards GES. Surveillance indicators should be used by
defining boundaries around a range of natural variability. If indicator falls outside the range,
research is needed to identify the cause (could be by looking at other descriptors) and set
further steps which actions should be taken.
2.
Descriptor 6: Seafloor integrity (02-03 September 2014)
GES for descriptor 6 is defined as “Sea-floor integrity is at a level that ensures that the
structure and functions of the ecosystems are safeguarded and benthic ecosystems, in
particular, are not adversely affected “.
2.1Reference levels for GES of Seafloor integrity
In assessing GES for D6 two factors need to be considered. Indicators need to be developed
reflecting recovery, i.e. rapid and secure changes from perturbations must be expected, while
indictors also need to demonstrate a not adversely impacted functionality of the benthic
ecosystem. Assessment of GES needs to capture both factors.
The group discussed the difficulties in defining fully recovery and concluded that the
assessment on recovery should focus on speed and security of movement in the desired
direction if pressures are managed effectively.
To assess the functionality of an ecosystem pressure indicators should be used in combination
with indicators closely linked to specific functions (abundance of species/functional groups).
Data or model-based rationale will be mainly used to conclude that some ecosystem functions
are being degraded. However, the group noted that monitoring will remain an important part of
assessing GES.
The approach to estimating benchmarks for change in a function in a GES assessment should
be follow a decision tree approach.
a) Where there is information on functionality and indicators of ecosystem status, analyses
should look for tipping points (non-linearities) in ecosystem state – function relationship.
b) In cases where there is not sufficient information to even look for non-linearities in the
relationship between function and indicators of ecosystem status it is noted that any loss
of functionality is a degrading of GES. Information from less perturbed areas should be
reviewed to see if they can provide information/estimates on levels of functions. Hence,
direction and scale of change can be identified.
c) Data from most benthic systems are derived from systems that have already been altered.
Therefore we cannot know what The more perturbed the system is known to be, the
greater the rationale to at least reduce pressures to see if the functionality will increase.
d) When experimental or opportunistic reduction in pressures is possible, and can be
accompanied by appropriate monitoring, then information can be gained on whether or
not GES may be higher than current status. Feedback form such designed or natural
experiments should be used to revise GES benchmarks for future assessments.
As for D4, resilience of the system is also discussed in relation to D6. It is argued that resilience
is fostered through habitat/environmental heterogeneity and regional connectivity. Connectivity
can promote higher local species richness and functional diversity. However, science to
include resilience directly in GES assessment is incomplete.
2.2Attributes
Seafloor integrity is an integrative property of the states of several attributes of integrity. 9
attributes were defined: substrate, bioengineers, oxygen, contaminants, species composition,
size composition, trophodynamics, life history traits and habitat/environmental heterogeneity.
The discussion on these attributes concluded that (a) no further attributes should be taken into
account for measurements of indicators on seafloor integrity, (b) some attributes can be
merged into a broader category and (c) some of these attributes are already being addressed
by other descriptors (caution is required, interpretation in assessing attributes can make them
different between descriptors).
An important issues raised is the need to create indicators which are easily understandable
and to focus on tangible indicators and minimum requirements that are achievable by all
member states.
2.3 DPSIR framework
Layers reflecting both system sensitivity (state) and cumulative pressures (pressures) should
be used to determine the distance to GES for seafloor integrity (impact). It is thus recommend
that GES for seafloor integrity has three steps.
a) Identify the ecological structures and functions of particular importance.
b) Identify the human pressures known or likely to reach levels that degrade environmental
status.
c) For the ecosystem components and pressures identified as being of greatest importance,
use a suite of appropriate attributes and indicators to assess status relative to preidentified standards for GES, along gradients reflecting meaningful scales of the seafloor
attributes and pressures. Assessments can start with specific attributes of the seafloor.
General criteria for screening indicators should be specific (i.e. respond to properties they are
intended to measure), sensitive to changes, responsive to effective management actions,
measurable (in practice and theory), cost-effective (monitoring resources are limited) and
concrete (directly observable and measurable).
3.
Descriptor 3: Status of commercial fish and shellfish (04-05 September 2014)
GES for descriptor 3 is defined as “Populations of all commercially exploited fish and shellfish
are within safe biological limits, exhibiting a population age and size distribution that is
indicative of a healthy stock“.
3.1 definition of the descriptor
The group had a discussion on the content of the terminology used in the definition.
a) “all commercially exploited fish and shellfish” - The description applies to all the
species/stocks covered by the DCF regulation. Therefore the species listed by region
in Annex VII of 2010/93/EU are the commercial fish and shellfish species that should
be considered under D3 at a minimum. In addition, Member States can include other
commercially exploited species or stocks not covered by CFP or DCF or stocks that
have social or economic importance.
b) “Safe biological limits” – Two attributes are currently used to assess stocks. First they
should be exploited sustainably consistent with high long-term yields (Fmsy) and
second, they should have full reproductive capacity (Bmsy or MSY Btrigger).
c) “Exhibiting a population age and size distribution that is indicative of a healthy stock”
– requirement to manage the demographics of the fish stocks. This is a concept that
states that a healthy population is characterised by a high proportion of old and large
individuals. This is a concept which is not part of the existing fisheries management
concepts and may be at odds with the recent CFP landing obligation (EU 1380/2013).
The definition is still unclear and may also differ between pelagic and demersal species.
3.2 Criteria for D3
Criterion 3.1 – Fishing pressure is assessed via a primary indicator that requires that all
species/stocks should be fished at F values that are equal or lower than Fmsy, the level
capable of producing MSY. Where stock production-based assessments are available, the
catch/biomass ratio yielding MSY can be taken as indicative reference (secondary indicator).
Alternatively to the catch/biomass ratio, secondary indicators may be developed on the basis
of any other appropriate proxy for fishing mortality, adequately justified.
Criterion 3.2 – Indicator for the reproductive capacity of the stock was discussed by the group.
The use of SSB being above MSY Btrigger or SSB being larger than Bmsy. If chosen to set
the indicator at Bmsy it is debatable whether all stocks can achieve this level and thus GES
can be achieved. The achievement of GES in regards to criterion 3.2 needs to take into account
and be able to differentiate between shifts that are due to fishing pressure and those that are
due to shifts in climatic/hydrological conditions. As secondary indicator for data-limited or datapoor stocks would be the use of biomass indices.
Criterion 3.3 – Monitoring the population age and size distribution is important given its linkage
with the selectivity pattern of the fishery/gear and the impact this might have on the MSY
reference levels. Simulation studies suggest that not all proposed indicators within the Decision
document provide suitable sensitivity in the time-scales required for management. The
indicators in 3.3 should be robust to natural variation in natural processes such as recruitment
variability, regional and seasonal variation in spatial distribution of juveniles, adults, small and
large species. Hence, the process to define and select appropriate indicators (both state and
pressure indicators) that respond to changes in the population subject to fishing requires
further work. The group opted to have an expert workshop to evaluate the proposed indicators.
3.3 Problems assessing GES for D3
The group discussed several issues to consider when assessing if GES for D3 is achieved.
Main issues involved the selection of stocks to be included (DCF stocks), the reference levels
applied (i.e. comparing current value of the indicators with the specified reference levels to
determine if each stock is in GES for each indicator), and the aggregation method(s) used. For
the latter no aggregation criteria are mentioned in the Decision document and the group was
not able to conclude on an appropriate method.