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ICES Working Group Report 2006 | 1
Working Group Name: ICES/BSRP/HELCOM Workshop on Developing a
Framework for Integrated Assessment for the Baltic Sea [WKIAB]
Executive summary
An ICES/BSRP/HELCOM Workshop on Developing a Framework for Integrated Assessment
for the Baltic Sea [WKIAB] has been held in Tvärminne, Finland, from 1-4 March 2006. 18
scientists from 7 countries, well representing the participating organisations/projects, attended
the meeting.
The main objectives of the workshop, as reflected in the terms of references, were to (i)
discuss different integrated assessment (IA) strategies/types and potential mutual benefits of a
future cooperation between ICES and HELCOM, (ii) conduct trial IAs for sub-regions of the
Baltic Sea, (iii) discuss monitoring strategies needed for a conducting IAs in the future, and
(iv) discuss IA needs from ICES (science groups) and the consequences for the ICES Baltic
committee expert group structure.
Different views on IAs were discussed and close future cooperation between ICES and
HELCOM in planning and conducting IAs was agreed. As a vehicle for this process a
common Working Group on Integrated Assessments of the Baltic Sea (WGIAB) is envisaged
to be established at the next ICES ASC. The group is supposed to communicate and
coordinate activities within and between ICES and HELCOM, update ecosystem overview
assessments on a regular basis for different subareas, conduct/contribute to HELCOM
thematic assessments (e.g. pollution, eutrophication, impact of fisheries) and use ecosystem
modelling in the assessment work.
For the present workshop it was agreed to follow the approach for ecosystem overview
assessments outlined by REGNS. Trial ecosystem overview IAs have been conducted for the
Gulf of Riga (GOR) and Central Baltic Sea (CBS), the latter covering the Bornholm Basin, the
Gdansk Deep and the Gotland Basin. Based on length of the covered period and consistency,
time-series were identified to be used in an integrated analysis applying Principal Component
Analyses (PCA). 39 (GOR) and 90 (CBS) time-series on biological, physical and chemical
variables, covering in maximum the period 1973 (1974 for CBS) to 2004, were used in the
analyses. For the GOR separate analyses of the ecosystem state and development were
conducted fo Spring and Summer. For both seasons a regime shift in ecosystem state was
observed after 1988. After a transition period lasting until 1991 or 1993 in spring and summer,
respectively, a new regime was reached lasting until 2004. The new regime is characterized by
high values for the Baltic Sea Index, air- and water temperatures leading in spring to large
Acartia spp. and Eurytemora affinis populations as well as high herring (Clupea harengus)
recruitment and biomass. In summer biological dynamics seemed to be unrelated to the
change in the physical environment. Similar regime shifts as in the GOR were also observed
in the CBS, displaying 3 regimes, i.e. 1974-87, 1988-93 and 1994-2004. The intermediate
regime is characterized by low salinities and high temperatures, separates the high salinity and
low temperature regime of the 1970s and 1980s from the high temperature and intermediate
salinity regime since the mid 1990s. Biologically the CBS system changed from cod (Gadus
morhua), herring and Pseudocalanus acuspes dominated to large populations sizes of sprat
(Sprattus sprattus) and Acartia spp.
The trial IAs proved the methodology to be capable of providing an integrated view on
ecosystem state and development. Based on the time-series collected and the analysis
conducted, short Ecosystem Status Reports have been produced to provide WGBFAS with
2 | ICES Working Group Report 2006
environmental information relevant to commercial fish stocks HELCOM with information on
the effects of fishing on the Baltic Sea ecosystem.
The results of the workshop indicated the need for revised monitoring strategies, covering key
biological, chemical and physical variables. In addition a proposal for a revised structure for
the ICES Baltic Committee expert groups was made, which has the goal to facilitate IAs in the
future and to better implement the ecosystem approach for the Baltic Sea.
ICES Working Group Report 2006 | 3
1 Opening of the meeting and adoption of the agenda
An ICES/BSRP/HELCOM Workshop on Developing a Framework for Integrated
Assessment for the Baltic Sea [WKIAB] (C. Möllmann, Denmark, B. Müller-Karulis, Latvia;
A. Andrushaitis, BSRP, and Juha Flinkman, HELCOM) will held in Tvärminne, Finland, from
1-4 March 2006 to:
a) develop a framework for an IA of the Baltic Sea, focusing on the role of the
environment for fish and fisheries as well as the impact of fishing on the
ecosystem, and considering the requirements of the HELCOM Monitoring and
Assessment Strategy, the HELCOM Baltic Sea Action Plan, the European Marine
Strategy and the UNEP Global Assessment of the State of the Marine
Environment;
b) review existing Integrated Assessments (IA) in the world‟s oceans and the
suitability of their conceptual and methodological application for the Baltic Sea;
c) review the information needs and data availability for IAs, with a view to
establishing a metadatabase for key data series and creating a common network
of expertise involving relevant ICES, HELCOM and BSRP groups;
d) propose a future structure for the ICES Baltic Committee study/working groups
and identify ToRs these groups should address to implement the ecosystem
approach based on the information needs identified in ToR c);
e) conduct trial IAs for selected sub-regions of the Baltic Sea as a basis for
contributions to the Theme Session on “Integrated assessments in support of
regional seas ecosystem advice - beyond quality status reporting” at the ICES
ASC 2006;
f) develop a monitoring strategy for future IAs taking into account existing
monitoring programmes and involving relevant ICES, HELCOM and BSRP
groups taking into account other international requirements (such as EU
Directives), e.g. enhancing present fish surveys to ecosystem surveys, developing
cost-effective methods of monitoring, and improving compatibility and
integration of physical, chemical, biological and fisheries data sources;
g) provide WGBFAS with environmental information relevant to commercial fish
stocks;
h) provide HELCOM with information on the effects of fishing on the Baltic Sea
ecosystem.
On behalf of the co-chairs, Christian Möllmann welcomed the participants (Annex 1) and
introduced the agenda (Annex 2) for the workshop. The following 4 major objectives for the
meeting were identified:
(i) discuss different assessment strategies/types and potential mutual benefits
between ICES and HELCOM for future cooperation;
(ii) conduct trial Integrated Assessments (IA) for sub-regions of the Baltic Sea;
(iii) discuss future monitoring strategies accomplishing the data needs of IAs and
the ecosystem approach to fisheries;
(iv) discuss IA needs from ICES (science groups) and the consequences for the
ICES Baltic committee group structure.
The first day of the workshop was devoted to presentations introducing the various IA
activities of ICES, BSRP, HELCOM and BALTEX with a plenary discussion of these (section
2). Further statistical methodology useful for IAs was introduced and the data availability for
the planned trial IAs was started. The work of the second day contained mainly data screening
and first analysis of the data, with short interruptions for presentations on specific related
topics. On the third day trial IAs were finished (section 3) and future monitoring strategies
(section 5) as well as the future ICES Baltic committee expert group structure (section 4) were
4 | ICES Working Group Report 2006
discussed. The last day was devoted to reviewing the results of the trial IAs, discussing the
future of WKIAB, drafting recommendations and new TORs.
2 Reviewing assessments (TORs a, b)
The “Reviewing Assessments” session included presentations of the assessment strategies and
work of ICES, HELCOM, BSRP and BALTEX, followed by discussions.
Christian Möllmann introduced the integrated assessment work conducted in the North Sea.
He emphasized that ecosystem-based fisheries management and/or ecosystem based
management is increasingly important and that setting goals or objectives, establishing
management protocols, and determining how close to the goals and objectives a system is
requires that we know the STATUS OF LARGE MARINE ECOSYSTEMS, i.e. an Integrated
Ecoystem Assessment (IEA). He pointed out that IEA can be seen as a process of actions
which support „adaptive management and the ecosystem approach´, but also the combined
numerical assessment of data and information from various sources (including monitoring and
R&D programmes). The latter was the intention for initiating WKIAB. He then introduced the
work and initial results of REGNS (Regional Ecosystem Study Group for the North Sea)
within ICES., as well as the history of the approach in North America.
He further showed the main trends in the Central Baltic ecosystem (from fish to
phytoplankton) displaying the effects of fishing and climate and a resulting Regime Shift over
all trophic levels in the late 1980s. Further there exists clear evidence for links between
physics, zooplankton and fish growth and recruitment, but it remains unclear whether there is
a strong link between eutrophication and commercial fish stocks. A conclusion from this was
that although single trends and processess leading to the observed ecosystem dynamics are
well known, an integrative analysis (over all trophic levels) of the functioning of the Baltic
ecosystem and the influence of various natural and anthropogenic pressures has not been done
yet. The major goal of WKIAB would thus be to start this process. If WKIAB would be
successful, the process should be continued and a common ICES and HELCOM
Study/Working Group should be establised which (i) communicates within and between ICES
and HELCOM, (ii) updates integrated ecosystem assessments annually, (iii)
conducts/contributes to thematic assessments (e.g. pollution, eutrophication, impact of
fisheries), and (iv) uses ecosystem modelling in the future work.
Juha-Markku Leppänen introduced the HELCOM strategy for Integrated Assessments. He
pointed out that (i) assessment for HELCOM is a framework that should address objectives
and targets set for the protection and conservation of the marine environment in a comparable
way, (ii) different assessments which cover (parts) of a region and should be consistent for
that region, (iii) assessments should be scientifically sound and aimed at the broadest level of
acceptability possible, and (iv) assessment should be usable by several organisations. The
objectives of HELCOM assessment activities are (i) to reveal how visions, goals and
objectives are met, (ii) link the quality of environment to management and (iii) use
performance indicators to assess how the objectives have been reached. The HELCOM
assessment system is further based on Indicator Fact Sheets and discerns between Thematic
Assessments (e.g. eutrophication, hazardous substances, maritime transport) and Holistic
Assessments. A HELCOM concept for the latter are the planned Biodiversity Assessments,
which are a concept for an IEA. These will integrate all ecosystem components (biotic and
abiotic) and human pressures and will be the basis for management advice to reach sustainable
use of the ecosystem goods and functions.
Hans-Jörg Isemer introduced the BALTEX (Baltic Sea Experiment) project and its goals. He
indicated that BALTEX shifts now from Phase 1 to Phase 2. Phase 1 had the goals
ICES Working Group Report 2006 | 5
to explore and model the varios mechanisms determining the space and time
variability of energy and water budgets of the BALTEX area and its interactions
with surrounding regions,
to relate these mechanisms to the large-scale circulation systems in the atmosphere
and oceans over the globe,
to develop transportable methodologies in order to contribute to basic needs of
climate-, climate impact-, and environmental- research in other regions of the
world.
In Phase 2 BALTEX has now enlarged its focus with the following objectives:
Better understanding of the energy and water cycles over the Baltic Sea basin;
Analysis of climate variability and change since 1800, and provision of regional
climate projections over the Baltic Sea basin for the 21st century;
Provision of improved tools for water management, with an emphasis on more
accurate forecasts of extreme events and long-term changes;
Gradual extension of BALTEX methodologies to air and water quality studies;
Strengthened interaction with decision-makers, with emphasis on global change
impact assessments;
Education and outreach at the international level.
Hans-Jörg Isemer additionally presented the BACC-project (BALTEX Assessment of Climate
Change for the Baltic Sea basin), which will assemble, integrate and assess available
knowledge of past, current, and expected future climate change and its impacts on ecosystems
in the Baltic Sea basin. The overall objective of BACC is to publish an assessment book by
the year 2006. The unique feature of BACC is the integrated assessment of climate change and
related both marine and terrestrial ecosystem changes. The material will be structured in
chapters dealing with
I. detection of past and ongoing climate change,
II. projections of future climate change, and
III. the impact of climate change on the regional environment, in particular both marine
and terrestrial ecosystems.
The overall project format is similar to the IPCC (Intergovernmental Panel on Climate
Change), with author groups for the individual chapters, an overall summary for policy
makers, and an external review process.
BACC/BALTEX has also established a joint venture with HELCOM (The Baltic Marine
Environment Protection Commission) in the sense, that the BACC material will be used for a
two-volume HELCOM Thematic Assessment Report, to be published in 2006 and 2007.
Finally Andris Andrushaitis reported news on the state and future for the BSRP. Presently the
2nd phase of the project is in planning although the funding is not assured yet. He further
reported on the achievements of the project and on the assessment work which is tightly
connected to the work of HELCOM.
The discussions during this session clearly demonstrated the different approaches of especially
ICES and HELCOM. Whereas the ICES IA-work is presently mainly focusing on evaluation
of development and state of an ecosystem, HELCOM considers IA as a full management
framework. Consensus was derived that a full management framework will be the future goal
of both parties and that the approach of WKIAB, to conduct trial IAs using multivariate
statistical methodology, is an important starting point. It was agreed that future activities in
this direction should be better coordinated and that a common working group would be the
forum of choice to do so. Further the work of BALTEX was considered as an important
contributor to future Baltic IAs and a further cooperation was agreed.
ICES Working Group Report 2006 | 6
3 Trial integrated assessments
Summary here – results as Ecosystem Overview Document in Annex
4 Future structure of Baltic committee expert groups
On the workshop the potential future structure for the ICES Baltic Committee study/working
groups was discussed (TOR d). Background of this TOR are discussions on a joint meeting of
SGMAB and SGBFFI in Riga, June 2005 which resulted in a Non-Paper discussed on the
ICES ASC in Aberdeen, September 2006 (see Annex 5). In summary, these discussions
indicated the need to re-organise the Baltic Sea research within ICES. Some of the main
arguments for re-organising the expert group structure were:
the need for advancing towards an Integrated Assessment (IA) of the Baltic Sea
ecosystem similar as initiated for the North Sea (i.e. REGNS), as a basis for
implementing the Ecosystem Approach to Fisheries Management (EAF);
the need for an improvement of co-ordination of the WG/SG-work with other
environmental organisations (e.g. HELCOM, EU Marine Strategy);
WKIAB thus became the duty to come up with a suggestion for a new structure which is
outlined in Fig. 4.1. The center of this structure is the established of a “Working Group on
Integrated Assessments of the Baltic Sea” [WGIAB], which will be the counterpart to the
present fisheries assessment groups [FAWGs, i.e. WGBFAS and WGBAST]. Both groups
should be supported by observational data from an “Ecosystem Survey Working Group”
[ESWG]. This group will be central in implementing the IA and the EAF as it should develop
in cooperation with HELCOM the present trawl and hydroacoustic surveys into ecosystem
surveys which provide both “tuning” and “ecosystem” data (see section 5). The work of the
assessment groups should be scientifically supported by 3 SGs, the SG for Baltic Fish Ecology
(SGBFE), the SG on Baltic Productivity (SGPROD), and the SG on Baltic Ecosystem Health
(SGEH).
WKs
SGBFE SGPROD SGEH
FA WG(s) WGIAB
ES WG
Fig. 4.1 Suggestion of a new structure for the ICES Baltic Sea assessment and scientific activities.
[SGBFE-Study Group on Baltic Fish Ecology, SGPROD – Study Group on Baltic Productivity, SGEH –
Study Group on Ecosystem Health, FAWGs-Fish stock Assessment Working Groups (WGBFAS and
WGBAST), WGIAB-Working Group on Integrated Assessments of the Baltic Sea, ESWG - Ecosystem
Survey Working Group, WK – Workshops].
ICES Working Group Report 2006 | 7
SGBFE will be the result of merging the present groups SGMAB, SGBFFI and SGABC.
SGBFE should deal with all issues related to commercially important Baltic fish species, but
especially (i) conduct bi-annual multispecies assessments providing natural mortality rates of
cod, herring and sprat for WGBFAS, and (ii) coordinate issues related to age-reading
problems of cod and sprat. It was proposed to shift the work on local, coastal fish stocks
conducted within SGBFFI, to the respective HELCOM group, to not double the work.
SGPROD and SGEH should continue their successful work on ecosystem issues conducted in
the frame of BSRP, independent of the future of the project. SGPROD should focus on lower
trophic level dynamics related to the physical and chemical environment, and linking these to
fish population dynamics. SGEH should e.g. continue its work of the DPSIR framework of
indicators, the development of various biological indices and on biological effects of harmful
substances. The work of these groups is of special importance for implementing the ecosystem
approach. A major task of these groups will be further to facilitate the communication to
scientific activities outside ICES, e.g. to EU-funded projects and to HELCOM and BALTEX.
Ecosystem modelling issues, as presently dealt with in SGBEM, were also considered to be
crucial for implementing the ecosystem approach. However, a group working separate from
groups dealing with the biological and ecological questions was considered as sub-optimal.
Therefore ecosystem model issues should be a crucial task in all the SGs to be formed. Cross-
group modelling efforts should be conducted using targeted workshops. The latter are
generally considered as an underrepresented tool in the present system. Therefore the more
frequent use of workshops dealing with up-to-date problems or “hot-topics” is encouraged.
Targeted workshops are considered of being more effective as e.g. establishing new SGs for
special questions, which will increase the number of permanent groups and the work load of
many scientists.
The most important change in the structure will be the implementation of a WGIAB. This will
(i) assure the conservation, further development and the integration of the work done within
BSRP in the broader scientific community, (ii) fullfill the request for an IA, which (iii)
enables ICES to react on the new requirements in terms of advice which is due to the change
in the management system of the Baltic and European waters. A special task for all SGs
should be therefore to support and react to the work of WGIAB. This is first of all to provide
quality checked indicator time-series for future IAs, but also the support in terms of
methodological and scientic expertise.
ICES Working Group Report 2006 | 8
5 Future monitoring strategy
The Baltic Sea is a well monitored marine ecosystem. However, data are collected under a
variety of programmes for specific purposes. There is often little data exchange between
different monitoring programmes and institutions involved, but integrated assessment (IA)
demands collection of data on all ecosystem components and their driving factors. In the
following, we suggest a strategy for IA that makes use of data collected in existing Baltic Sea
monitoring programmes and identify gaps that require additional monitoring efforts. We also
describe the requirements for data exchange to enable IAs timely.
Existing Baltic Sea monitoring programmes
Currently, in the open sea Baltic monitoring programmes are focused on the effects of
eutrophication and hazardous substances (HELCOM COMBINE) as well as on fishery
management (European Council regulation 1543/2000). Major Baltic Sea status assessments
are the annual fish stock assessments conducted by ICES working groups, and the HELCOM
assessments of eutrophication and biodiversity, the later covering longer time periods and are
planned to be updated in 2009 and 2010, respectively. Additional monitoring requirements are
created by the EU Habitats and Birds directives and in the future also by the upcoming EU
Marine Strategy. Further, in coastal and transitional waters, the EU Water Framework
Directive (WFD) demands extensive data collection on biological and chemical parameters
and regular assessment of ecological status. The WFD includes fish only in transitional area,
but HELCOM COMBINE also contains a coastal fish monitoring programme. Monitoring
programmes and the requirements of the individual assessments are briefly described in annex
6.
Data requirements for integrated assessment
While the HELCOM monitoring programme describes the lower trophic level of the
ecosystem (hydrography, nutrients, phytoplankton, zoobenthos), the upper trophic level (fish,
fishery) is mainly described by the EU fisheries data collection programme. Additional
monitoring for integrated assessments should focus on parameters and processes not covered
well in these programmes. These are primarily mesozooplankton, macrozooplankton, fish
stomach content, and to a lesser degree macrozoobenthos.
Mesozooplankton links fish to the lower parts of the foodweb, both as the food source for
planktivorous fish (herring, sprat), but also as the food supply of larvae for other fish species.
Therefore mesozooplankton information at the time of nauplii hatching could improve
recruitment predictions. Spawning and nauplii hatching time varies between species and Baltic
Sea regions. Zooplankton biomass in May would provide information relevant for the
recruitment success of many species. For planktivorous fish, zooplankton information is also
useful at the time of intensive feeding (August – October).
Zooplankton monitoring could be a combined effort between eutrophication and fishery
monitoring programmes, but the primary demand is as a food source for fish larvae and
planktivorous fish and therefore zooplankton data should be intensified by fisheries groups.
Currently, long-term data in the open Baltic exist primarily from the Latvian Fish Resources
Agency, while within HELCOM COMBINE, mesozooplankton is only a voluntary parameter.
Data is not compatible between different sources, as different gears (WP2, Juday net) and
mesh sizes are used. On the other hand, existing long-term data series should be continued
without change of gear. Technically, zooplankton data collection can be included into fisheries
surveys, when sufficient winch capacity exists. Considering the timing of spawning and
feeding of the major fish species, we suggest that zooplankton data collection should be
included into fishery surveys conducted in April/May and during summer surveys (August –
October).
ICES Working Group Report 2006 | 9
In coastal areas zooplankton monitoring is not included into the WFD monitoring
requirements. On the other hand, coastal areas are important fish nursery areas. Monitoring
efforts for coastal fish and WFD/Habitat directive requirements should be coordinated
nationally, ensuring that areas overlap and where relevant, zooplankton data should be
included into monitoring in coastal areas. It was also noted that current coastal fish monitoring
does not provide information suitable for biodiversity assessment, since not all coastal fish are
sampled by the current method. At the same time, continued funding has to be assured for the
programme, potentially by including the coastal fish monitoring into the EU funded fisheries
survey programme.
Macrozooplankton is an important food source for e.g. Baltic herring. Data on this food web
component is scarce, since it is not included into routine monitoring programmes. No
harmonized sampling methods exist. For both meso- and macrozooplankton, hydroacoustic
methods for abundance determination are currently under development. The use of these
methods during routine fishery surveys should investigated.
Macrozoobenthos is the chief food source of flatfish species (e. g. flounder), but is also
consumed by demersal species (e. g. cod) and coastal fish. In addition, it is a food source for
birds in coastal areas. The links between macrozoobenthos consumers and their prey and the
type of information needed to integrate the status of macrozoobenthic prey into fisheries
management could not be addressed at the workshop yet. However, there was agreement that
macrozoobenthos sampling cannot be integrated into routine fisheries surveys as the sampling
is time consuming and would require additional shiptime.
To increase the knowledge of predator-prey relations in the Baltic, stomach sampling and
analysis of stomach content should be included into routine fisheries surveys. Sample
collection does not require additional shiptime and samples can be preserved and analyzed in
the laboratory. However, funding and technical capacity for sample analysis has to be ensured.
CTD casts should be routinely included into fisheries surveys, including also dissolved
oxygen and chlorophyll a measurments. Temperature, salinity and oxygen influence fish
feeding and reproduction and affect their spatial distribution. It is technically feasible to
include a CTD casts at each haul station during trawl and hydroacoustic surveys. The high
spatial density of sampling greatly increases the precision of spatially averaged indicators as
for example the spawning volume of cod.
Phytoplankton information is currently sparse in the Baltic Sea. Including chlorophyll a
sensors into CTDs used on fishery surveys would increase the density of observations
available in the Baltic Sea at very little additional cost. Other promising phytoplankton
indicators are produced by ships of opportunities, since their temporal and spatial resolution is
sufficient to monitor key phytoplankton processes like the spring bloom (see appendix xxx).
Also nutrient analysis can technically be included into fishery surveys. If a rosette sampler is
available, the additional ship time requirement for water sample collection is small. However,
nutrient analyses have to be conducted on board immediately after sampling. They require
therefore additional personnel (1 – 2 persons) and laboratory space. Because nutrient fields are
monitored extensively under HELCOM COMBINE, we do not suggest to add nutrient
sampling to fisheries surveys, but rather to strengthen the data exchange between the different
Baltic Sea monitoring programmes.
Also HELCOM COMBINE surveys can technically be expanded to include fish monitoring,
when free capacity on research vessels is available. Information on planned cruises should be
exchanged between HELCOM and fishery monitoring communities to ensure that vessel
capacity is used most efficiently.
ICES Working Group Report 2006 | 10
Data exchange and timely data delivery
IA should provide an ecosystem status description to be used e.g. by fisheries assessment
working groups. This implies that IAs will have to be conducted annually, based on the data of
the previous year, during early spring (February, March), which presently creates timing
problems in the dataflow of many parameters. Analysis of biological parameters like
phytoplankton and zooplankton biomass/species composition, for which samples can be
preserved, might not be completed yet. Reporting of data – nutrients, hydrography, biota – to
databases has to be accelerated. Finally, data policies have to be harmonized and permission to
use monitoring data collected in different programmes have to be obtained.
IA should be based on time-series that characterize key ecosystem processes. Aggregating of
raw data into indicators and time series should be handled by experts in the relevant fields
who should be involved in the entire IA processes. Expert involvement is crucial to data
quality control, indicator selection, and to reducing data variability by spatial/temporal
averaging, as well as to interpreting IA results.
Raw data used in IAs should be stored in a database system that ensures their operational
availability. The database should also include information on data quality.
ICES Working Group Report 2006 | 11
Annex 1: List of participants
NAME ADDRESS PHONE EMAIL
Christian Möllmann Danish Institute for +45 3396 3458 cmo@dfu.min.dk
(Co-chair) Fisheries Research,
Charlottenlund Castle,
DK-2920
Charlottenlund
Bärbel-Müller Karulis Institute of Aquatic ????????????? baerbel@latnet.lv
(Co-chair) Ecology, Daugavgrivas
8, LV-1048 Riga
Andris Andrushaitis Institute of Aquatic + 371 7610851 andris@hydro.edu.lv
(Co-chair) Ecology, Daugavgrivas
8, LV-1048 Riga
Juha Flinkman (Co- Finnish Institute of +358 40 7503911 Juha.flinkman@fimr.fi
chair) Marine Research, P.O.
Box 2, FIN-00561
Helsinki
Johan Modin Swedish Board of +46 17346463 Johan.modin@fiskeriverket.se
Fisheries, SE-74071
Öregrund
Gedas Vaitkus Institute of Ecology, +370 699 99940 gedas@ekoi.lt
Akademijos 2, LT-
08412 Vilnius
Eugeniusz Sea Fisheries Institute, +48 587356146 eugene@mir.gdynia.pl
Andrulewicz Kollataja 1, PO-81-332
Gdynia
Elsbieta Lysiak- Institute of Ecology +48 58 62 88 252 Elsbieta.Lysiak-
Pastuszak and Water Pastuszak@imgw.pl
Management, ul.
Waszyngtowa 42, PO-
81-342 Gdynia
Hartmut Heinrich Bundesamt für +49 40-3190 3510 Hartmut.heinrich@bsh.de
Seeschifffahrt und
Hydrografie, Bernhard-
Nocht-Str. 78, D-
20359 Hamburg
Rabea Diekmann Institute for +49 40 42838 6621 Rabea.diekmann@uni-
Hydrobiology and hamburg.de
Fisheries Science,
Olbersweg 24, D-
22767 Hamburg
Yvonne Walther Swedish Board of +46 455 362852 Yvonne.walther@fiskeriverket.se
Fisheries, Utövägen 5,
SE-37137 Karlskrona
Maris Plikshs Latvian Fish Resources +371 7610 766 Maris.plikss@latzra.lv
Agency, Daugavgrivas
8, LV-1048 Riga
Heikki Peltonen* Finnish Environment
+358-9-40300236 heikki.peltonen@ymparisto.fi
Institute, P. O. Box
140, FIN-00251
HELSINKI,
Pirjo Kuuppo * P.O. Box 140; +358-400-232342 Pirjo.kuuppo@ymparisto.fi
Mechelininkatu 34A;
FIN-00251 Helsinki
Juha-Markku Katajanokanlaitura 6B, +358-207-421 627 Juha-
Leppänen* FIN-00160nHelsinki markku.leppanen@helcom.fi
Hermanni Backer* Katajanokanlaitura 6B, +358-207-421 627 Hermanni.Backer@helcom.fi
FIN-00160nHelsinki
12 | ICES Working Group Report 2006
Hans-Jörg Isemer* GKSS +49 4152 87 1661 isemer@gkss.de
Forschungszentrum
Geesthacht GmbH,
International Projects
Department SEP,
International BALTEX
Secretariat, Max-
Planck-Str. 1, D-21521
Geesthacht
Seppo Kaitala* Finnish Institute of +358-9-61394417 Seppo.Kaitala@fimr.fi
Marine Research
Erik Palménin aukio 1
(P.O. Box 2), FIN-
00561 Helsinki
* part-time
ICES Working Group Report 2006 | 13
Annex 2: Agenda
Wednesday 1 March
0900 – 0930 Welcome, practical information, introduction to the workshop
0930 – 1600 Session on REVIEWING ASSESSMENTS
Presentations:
1. Integrated assessments within a fisheries management context – lessons for the
Baltic Sea (Christian Möllmann)
2. The HELCOM assessment strategy for integrated assessment (Juha-Markku
Leppänen)
3. Assessment of Climate Change for the Baltic Sea basin - The BACC Project
(Hans-Jörg Isemer)
4. The Baltic Sea Regional Project and Ecosystem assessments (Andris Andrushaitis)
1615 - 1800 Session on DATA AVAILABILITY
1. Presentation on statistical methodology for integrated assessments (Rabea
Diekmann)
2. The use of indicators for evaluation of trends in the Balticb (Seppo Kaitala) – see
Annex 7
Thursday 2 March
0900 – 1030 Session on DATA AVAILABILITY
3. Regional Databases on the Baltic GIS Portal - Baltic Sea Regional Project GIS
CC (Gedas Vaitkus)
4. An integrated ichthyological-chemical-biochemical approach to assess the impact
of the environmental quality status of selected marine sites on ichthyofauna
health (Eugeniusz Andrulewicz)
5. Effects of Eutrophicationon Baltic Fish and Fisheries (Eugeniusz Andrulewicz)
1045 – 1800 Session on TRIAL INTEGRATED ASSESSMENTS
Friday 3 March
0900 – 1030 Review session on the TRIAL INTEGRATED
ASSESSMENTS
1045 - 1200 Review session on the TRIAL INTEGRATED
ASSESSMENTS cont. and session on STRUCTRE
1400 - 1600 Review session on the TRIAL INTEGRATED
ASSESSMENTS cont. and session on MONITORING
1615 - 1800 PLENARY SESSION summarizing the results
Saturday 4 March
0900 - 1030 REPORTING group work
1045 – 1200 Summary and closing of the workshop
ICES Working Group Report 2006 | 14
Annex 3: Me tadata- Table of time -series available for Trial
Integrated Assessments
Annex-Table 3.1. Time-series used in the Trial Integrated Assessment of
the Central Baltic Sea.
Variable Abbreviation Unit Area Season Source
Central
Sprat landings SPRland tonnes Annual ICES
Baltic *
Herring Central
HERland tonnes Annual ICES
landings Baltic *
Flounder Central
FLOland tonnes Annual ICES
landings Baltic *
Central
Cod landings CODland tonnes Annual ICES
Baltic *
Sprat No age 1 Central
SPRR1 Annual ICES
recruitment (10³) Baltic
Herring No age 1 Central
HERR1 Annual ICES
recruitment (10³) Baltic
Flounder No age 3 Central
FLOR3 Annual ICES
recruitment (10³) Baltic
Cod No age 2 Central
CODR2 Annual ICES
recruitment (10³) Baltic
Central
Sprat SSB SPRSSB tonnes Annual ICES
Baltic
Central
Herring SSB HERSSB tonnes Annual ICES
Baltic
Central
Flounder SSB FLOSSB tonnes Annual ICES
Baltic
Central
Cod SSB CODSSB tonnes Annual ICES
Baltic
Sprat fishing Central
SPR_F3-5 age 3-5 Annual ICES
mortality Baltic
Herring
Central
fishing HER_F3-6 age 3-6 Annual ICES
Baltic
mortality
Founder
Central
fishing FLOF4-6 age 4-6 Annual ICES
Baltic
mortality
Cod fishing Central
CODR4-7 age 4-7 Annual ICES
mortality Baltic
Central
Sprat weight SPRWC3 kg (age 3) Annual ICES
Baltic
Central
Herring weight HERWC3 kg (age 3) Annual LATFRA
Baltic
Flounder Central
FLOWC3 kg (age 3) Annual LATFRA
weight Baltic
Central
Cod weight CODWC3 kg (age 3) Annual LATFRA
Baltic
Salmon Central
SALCAT tonnes Annual LATFRA
landings Baltic
Central
Salmon weight SALW3 kg (age 3) Annual LATFRA
Baltic
Swedish
Perch cpue PERCPUE No/net/night Annual LATFRA
coast
White bream Swedish
WBRCPUE No/net/night Annual SBFÖ
cpue coast
ICES Working Group Report 2006 | 15
Variable Abbreviation Unit Area Season Source
Swedish
Roach cpue ROACPUE No/net/night Annual SBFÖ
coast
Swedish
Ruffe cpue RUFCPUE No/net/night Annual SBFÖ
coast
Coastal fish
No of Swedish
species Coast1Rich Annual SBFÖ
species coast
richness
Shannon-
Coastal fish Swedish
Coast1ShWi Wiener Annual SBFÖ
diversity coast
Index
Cod
Central
reproductive REPVOL Km3 Annual IFM
Baltic
volume
Acartia spp. Central
Acartia_Spr mg*m-3 Spring LATFRA
biomass Baltic Ø
Acartia spp. Central
Acartia_Sum mg*m-3 Summer LATFRA
biomass Baltic
Temora
Central
longicornis Temora_Spr mg*m-3 Spring LATFRA
Baltic
biomass
Temora
Central
longicornis Temora_Sum mg*m-3 Summer LATFRA
Baltic
biomass
Pseudocalanus
Central
acuspes Pseudo_Spr mg*m-3 Spring LATFRA
Baltic
biomass
Pseudocalanus
Central
acuspes Pseudo_Sum mg*m-3 Summer LATFRA
Baltic
biomass
Bosmina
Central
longispina Bosmina_Sum mg*m-3 Summer LATFRA
Baltic
biomass
Synchaeta sp. Central
Sync_Spr mg*m-3 Spring LATFRA
biomass Baltic
Synchaeta sp. Central
Sync_Sum mg*m-3 Summer LATFRA
biomass Baltic
Central
Secchi depth SB_Secchi M Summer ICES
Baltic
Bornholm
Bottom PO4 PO4_BBWinBot µmol*l-1 Winter ICES
Basin
Bornholm
Bottom NO3 NO3_BBWinBot µmol*l-1 Winter ICES
Basin
Bornholm
Bottom NH4 NH4_BBWinBot µmol*l-1 Winter ICES
Basin
Bornholm
Bottom O2 O2_BBWinBot µmol*l-1 Winter ICES
Basin
Bornholm
Surface PO4 PO4_BBWinSur µmol*l-1 Winter ICES
Basin
Bornholm
Surface NO3 NO3_BBWinSur µmol*l-1 Winter ICES
Basin
Gotland
Chlorophyll a Chla_GBSpr mg*m-3 Spring ICES
Basin
Gotland
Chlorophyll a Chla_GBSum mg*m-3 Summer ICES
Basin
Bornholm
Chlorophyll a Chla_BBSpr mg*m-3 Spring ICES
Basin
Bornholm
Chlorophyll a Chla_BBSum mg*m-3 Summer ICES
Basin
16 | ICES Working Group Report 2006
Variable Abbreviation Unit Area Season Source
Inflow Central
inflow Km3 Annual IOW
strength Baltic
Bornholm
Diatoms Bac_BBSpr mg*m-3 Spring ICES
Basin
Bornholm
Dinoflagellates Dino_BBSpr mg*m-3 Spring ICES
Basin
Bluegreen Bornholm
Cyano_BBSpr mg*m-3 Spring ICES
algae Basin
Bornholm
Diatoms Bac_BBSum mg*m-3 Summer ICES
Basin
Bornholm
Dinoflagellates Dino_BBSum mg*m-3 Summer ICES
Basin
Bluegreen Bornholm
Cyano_BBSum mg*m-3 Summer ICES
algae Basin
Gotland
Diatoms Bac_GBSpr mg*m-3 Spring ICES
Basin
Gotland
Dinoflagellates Dino_GBSpr mg*m-3 Spring ICES
Basin
Bluegreen Gotland
Cyano_GBSpr mg*m-3 Spring ICES
algae Basin
Gotland
Diatoms Bac_GBSum mg*m-3 Summer ICES
Basin
Gotland
Dinoflagellates Dino_GBSum mg*m-3 Summer ICES
Basin
Bluegreen Gotland
Cyano_GBSum mg*m-3 Summer ICES
algae Basin
Central
Runoff RunOff m3*s-1 Annual SMHI
Baltic
Gotland
Surface PO4 PO4_GBWin_0-10 µmol*l-1 Winter ICES
Basin
Gotland
Surface NO3 NO3_GBWin_0-10 µmol*l-1 Winter ICES
Basin
PO4_GBWin_100- Gotland
Midwater PO4 µmol*l-1 Winter ICES
120 Basin
NO3_GBWin_100- Gotland
Midwater NO3 µmol*l-1 Winter ICES
120 Basin
NH4_GBWin_100- Gotland
Midwater NH4 µmol*l-1 Winter ICES
120 Basin
PO4_GBWin_200- Gotland
Bottom PO4 µmol*l-1 Winter ICES
220 Basin
NH4_GBWin_200- Gotland
Bottom NH4 µmol*l-1 Winter ICES
220 Basin
Gdansk
Surface PO4 PO4_GDWin µmol*l-1 Winter ICES
Deep
Gdansk
Surface NO3 NO3_GDWin µmol*l-1 Winter ICES
Deep
Depth of 11 Gotland
11psu_GBAnn m Annual LATFRA
psu isoline Basin
Gotland
SST + T_GBSpr_0-10 °C May ICES
Basin
Midwater Gotland
T_GBSpr_40-60 °C May ICES
temperature Basin
Gotland
SST S_GBSpr_0-10 psu May ICES
Basin
Deepwater Gotland
S_GBSpr_80-100 psu May ICES
temperatre Basin
Gotland
SST T_GBSum_0-10 °C August ICES
Basin
ICES Working Group Report 2006 | 17
Variable Abbreviation Unit Area Season Source
Midwater Gotland
T_GBSum_40-60 °C August ICES
temperature Basin
Gotland
SSS + S_GBSum_0-10 psu August ICES
Basin
Deepwater Gotland
S_GBSum_80-100 psu August ICES
salinity Basin
Maximum ice Central
MaxIce Km² Annual ICES
cover Baltic
Bornholm
SSS S_BBSpr_0-10 psu Spring ICES
Basin
Deepwater Bornholm
S_BBSpr_70-90 psu Spring ICES
salinity Basin
Bornholm
SST T_BBSpr_0-10 °C Spring ICES
Basin
Bornholm
SST T_BBSum_0-10 °C Summer ICES
Basin
Midwater Bornholm
T_BBSpr_40-60 °C Spring ICES
temperature Basin
Swedish
SST T_CoastSum_Sur °C August ICES
Coast
Baltic Sea Central
BSI Winter IFM
Index Baltic
Breeding
Central
success White- breedsucc % Annual SMNH
Baltic
tailed eagle
* fish data from the following ICES assessment units: Sprat Subdivisions 22 to 32,
Subdivisions 25 to 29 and 32 excl. Gulf of Riga, Flounder Subdivisions 24 & 25, Cod
Subdivisions 25 to 32.
+
SST – Sea Surface Temperature, SSS – Sea Surface Salinity
ø
Zooplankton data are from the Gdansk Deep and Gotland Basin
ICES Working Group Report 2006 | 18
Annex-Table 3.2. Time-series used in the Trial Integrated Assessment of
the Gulf of Riga.
Variable Abbreviation Unit Season Source
Acartia spp.
Acartia mg*m-3 Annual LATFRA
biomass
Eurytemora
Eurytemora mg*m-3 Annual IAE
affinis biomass
Limnocalanus
grimaldii Limnocalanus mg*m-3 Annual IAE
biomass
Cladoceran
CLADOCERA mg*m-3 Annual IAE
biomass
Synchaeta sp.
Synchaeta mg*m-3 Annual IAE
biomass
Rotatorian
ROTATORIA mg*m-3 Annual IAE
biomass
Cercopagis
Cercopagis mg*m-3 Annual IAE
pengoi biomass
Secchi depth Secchi m Spring IAE
Secchi depth SSecchi m Summer IAE
Chlorophyll a Chla mg*m-3 Spring IAE
Chlorophyll a SChla mg*m-3 Summer IAE
Herring
RecCur No age 1 Annual ICES
recrruitment
Herring biomass Herring tonnes Annual ICES
Herring
Catch tonnes Annual ICES
landings
Herring weight HerWeight kg Annual ICES
Herring fishing
F (3-7) age 3-7 Annual ICES
mortality
Cod landings Codcatch tonnes Annual ICES
Airtemperatire AirTemp °C February LATFRA
Winter
Tfeb °C Febuary LATFRA
temperature
Spring
TMay20 °C May LATFRA
temperature
Summer
TAug20 °C August LATFRA
temperature
Spring salinity SalMay20 psu May LATFRA
Summer salinity SalAug50 psu August LATFRA
PO4 PO4 µmol*l-1 Annual IAE
NO4 NO23 µmol*l-1 Annual IAE
Runoff RunoffJanAug m3*s-1 January-August IAE
DIN load DIN load
µmol*l-1 previous year IAE
previous year previous
DIN load µmol*l-1 January-August IAE
Baltic Sea Index BSI Winter IFM
Abbreviations: ICES – from ICES data centre; LATFRA – Latvia Fish Resources Agency,
SBFÖ – Swedish Board for Fisheries Öregrund; IFM – Leibniz Institute for Marine Science
Kiel, IOW – Leibnitz Institute for Baltic Sea Research; SMHI – Swedish Meterological and
Hydrological Institute, SMNH – Swedish Museum for Natural History; IAE – Institute for
Aquatic Ecology Riga.
ICES Working Group Report 2006 | 19
Annex 4: State of the Baltic ecosyste m
Introduction
This document summarizes the state and development of two Baltic Sea subsystems, i.e. the
Central Baltic Sea (CBS; incl. the Bornholm Basin, the Gdansk Deep, and the Gotland Deep –
ICES Subdivisions 25, 26, 27 and 28) and the Gulf of Riga (GOR), during 1974 to 2004. It is
an output of the ICES “ICES/BSRP/HELCOM Workshop on Developing a Framework for
Integrated Assessment for the Baltic Sea [WKIAB]” and meant to provide background
environmental information for the ICES assessment work (e.g. WGBFAS, WGBAST), but
also information on the effects of fishing on the Baltic ecosystem for HELCOM.
This status report comprises information on the development of (i) the climate over the Baltic
Sea area with resulting changes in the hydrography, (ii) the nutrient loads, (iii) the phyto- and
zooplankton populations, and (iv) the major fish stocks and their fisheries, and (v) a bird
population. Finally multivariate analyses of all time-series are presented, providing an
integrated view on changes of the ecosystem structure and functioning.
Of the time-series which were available to the workshop, only those with a sufficient temporal
coverage were used in this status report as well as in multivariate analyses (see below).
Although consequently potentially important components of the ecosystem are not represented
(e.g. macrozooplankton, benthos), the report is believed to give a sufficiently broad overview
of the ecosystems. In the future, lacking ecosystem components will be included, if data are
made available. A description of the time-series used and their sources is given in Annex 3.
Multivariate analyses (Integrated analysis)
To provide an integrated view on the state and development of the CBS and the GOR,
multivariate analyses were conducted on the available time-series. All data-series available
had a frequency or were compiled to one assessment per year and covered in maximum the
period 1973 to 2004.
In total 90 variables were considered in an “annual” analysis of the CBS. The GOR datasets
were separated into spring and summer measurements. In total 22 variables were used in a
“spring” analysis and 23 variables in a “summer” analysis.
Time series were analysed by Principal Component Analysis (PCA). To improve linearity
between variables and reduce the relationship between the mean and the variance some of the
variables were ln(x+1) transformed. Subsequently a standardized PCA based on the
correlation matrix was performed on the transformed values. Variable vectors and scores
(years) were displayed on the first factorial plane and the years were connected in
chronological order. Year scores along PC1 and PC2 were additionally plotted against time to
detect possible regime shifts.
Finally the raw values of each variable were categorised into quintiles and each quintile was
given a specific colour, following the traffic light framework used in stock assessments (Link
et al. 2002). The variables were sorted according to their loadings along the first PC to detect
systematic patterns in the time series.
ICES Working Group Report 2006 | 20
Central Baltic Sea (CBS)
Climate and hydrography
The development of the climate over the Baltic Sea area in the last 3 decades is displayed by
the Baltic Sea Index (BSI), which is well correlated with the Index of the North Atlantic
Oscillation (NAO) (Lehmann et al. 2002). While during the 1970s and 1980s the index was
mainly in a negative state, it was mainly positive afterwards (Fig. CBS-1). This change in sign
of the index was associated with more frequent westerly winds, warmer winter and eventually
a warmer climate over the area. This is very well demonstrated by the convincing correlation
fo the BSI with the maximum ice extend in the Baltic (r=0.84). Time-series of water
temperatures in the Bornholm (BB) and Gotland Basin (GB) in spring and summer reflect this
warming during the 1990s.
0.4 300
Ice
BSI 200
Maximum Ice Extend
0.2
100
(km2)
BSI
0.0 0
-100
-0.2
-200
-0.4 -300
8
GB_surface Spring
6 GB_midwater
BB_surface
4 BB_midwater
2
0
Temperature anomaly
-2
-4
(deg C)
4
2
0
-2
-4
Summer
1975 1980 1985 1990 1995 2000 2005
Fig. CBS-1. Time-series on the Baltic Sea Index (BSI), maximum ice extend, and temperatures in
the Bornholm Basin (BB) and the Gotland Basin (GB).
Beside the influence on the thermal conditions, climate also influences the salinity in the
Central Baltic Sea (Fig. CBS-2). During the high BSI-period since the late 1980s only 2 major
Baltic inflows were recorded. The absence of major inflow events to the Baltic since the
1980s, although unpredictable to date, has been hypothesized to be related to the high NAO
period (Hänninen et al. 2000). Increasing runoff leading to sea level variations may have
hindered major inflow events (Matthäus and Schinke 1999). However, no increase in runoff
has been recorded during the last 30 years (Fig. CBS-2). Deep water salinity has clearly
decreased during the low inflow frequency until 1993, demonstrated by the depth of the 11psu
isoline in the GB and the bottom salinity in the both BB and GB. During the last decade deep
ICES Working Group Report 2006 | 21
water salinity was on a higher level again, especially after the 2003 inflow. Surface salinity in
both basins continuously declined due to increased precipitation (Hänninen et al. 2000).
inflow
runoff
depth of 11 psu in GB
BSI
40 0.4 0 40
30 0.2 50 20
Runoff (km3)
Depth (m)
Inflow
100
BSI
20 0.0 0
150
10 -0.2 -20
200
0 -0.4 -40
3
2
Salinity (psu)
1
0
-1
GB_bottom
-2 GB_surface
BB_bottom
BB_surface
-3
1975 1980 1985 1990 1995 2000 2005
Fig. CBS-2. Time-series on the Baltic Sea Index (BSI), runoff, depth of the 11psu isoline in the
Gotland Basin (GB), and salinity in the Bornholm Basin (BB) and the Gotland Basin.
Nutrients
Surface winter PO4 showed a similar trend in both the Bornholm and the Gotland Basin (Fig.
CBS-3). Decreasing trends at the end of the 1970s were followed by high PO 4 levels during
1980s and early 1990s. After a pronounced drop in PO 4 surface concentrations, values were on
an intermediate level recently.
Winter PO4 bottom concentrations were mainly higher in the Gotland Basin. Values were
increasing in the Gotland Basin until the early 1990s before dropping sharply. In recent years
the concentrations decreased in the Bornholm Basin, but increased in the Gotland Basin.
Deep water winter NH4 concentrations were insignificant in the Bornholm Basin, but
increased in the Gotland Basin until the early 1990s. Afterwards values dropped sharply,
increasing in the early 2000s.
Some words with references on mechanisms?!
22 | ICES Working Group Report 2006
0.9
BB_surface
0.8 GB_surface
0.7
PO4
0.6
0.5
0.4
0.3
10
BB_bottom
8 GB_bottom
6
PO4
4
2
0
50
BB_bottom
40 GB_bottom
30
NH4
20
10
0
1975 1980 1985 1990 1995 2000 2005
Fig. CBS-3. Time-series on nutrient concentrations (µmol*l-1) in the Bornholm Basin (BB) and
Gotland Basin (GB).
Phytoplankton
The development of the spring phytoplankton community was characterized by a strong
increase in dinoflagellates compared to diatoms in the 1990s (Fig. CBS-4). This trend,
observed in both the Bornholm and Gotland Basin was discussed to be a result of decreased
silicate availability for diatoms after warm winters, which were prevailing in the 1990s
(Wasmund et al. 1998). Chlorophyll a time-series do not show a pronounced increase during
the 1990s, rather single outstanding peaks have been observed. An increase in summer
dinoflagellate biomass during the 1990s is only observed in the Gotland Basin. Generally
combined diatom and dinoflagellate biomass decreased until the late 1980s, increasing
afterwards. Chorophyll a trends in both basins support a decrease in phytoplankton stocks in
the 1980s, fluctuating on a higher level during the 1990s.
ICES Working Group Report 2006 | 23
1800 10
1600
BB_spring
1400 8
dinoflagellates
1200 diatoms
chlorophyll a 6
1000
800
4
600
400 2
200
0 0
18
3000 GB_spring 16
14
2500
12
Dinoflagellate and diatom biomass (mg*m-3)
2000
10
1500 8
Chlorophyll a (mg*m-3)
6
1000
4
500
2
0 0
1800 4.0
1600 BB_summer
3.5
1400
1200 3.0
1000
2.5
800
600 2.0
400
1.5
200
0 1.0
4.0
1600 GB_summer
1400 3.5
1200
3.0
1000
800 2.5
600 2.0
400
1.5
200
0 1.0
1975 1980 1985 1990 1995 2000 2005
Fig. CBS-4. Dinoflagellate and diatom biomass, as well chlorophyll a in the Bornholm Basin (BB)
and Gotland Basin (GB).
Zooplankton
The dominating zooplankton species in the CBS are the copepods Acartia spp., Temora
longicornis and Pseudocalanus acuspes (Fig. CBS-5a, b). During spring a clear shift has
occurred from a dominance of P. acuspes until the end of the 1980s to Acartia spp. and T.
longicornis afterwards. This shift has been explained by decreased salinity and high sprat
predation pressure (P. acuspes) and increased temperature (Acartia spp., T. longicornis)
(Möllmann and Köster 2002, Möllmann et al. 2003). During summer this shift is still visible,
despite a higher variability.
24 | ICES Working Group Report 2006
25 1000
a) P. acuspes Synchaeta b)
T. longicornis
20 800
Acartia spp.
15 600
10 400
Biomass (mg*m )
-3
5 200
0 0
40 1000
c) B. longispina maritima d)
800
30
600
20
400
10
200
0 0
1975 1980 1985 1990 1995 2000 20051975 1980 1985 1990 1995 2000 2005
Fig. CBS-5. Time-series on biomass of dominating zooplankton species in the Central Baltic Sea in
spring (a) and summer (b, c, d).
In summer, the zooplankton biomass is dominated by the rotifer Synchaeta sp. and the
cladoceran Bosmina longispina marittima (Fig. CBS-5c). While the time-series of the latter
shows two outstanding peaks, in the early 1980s and 1990s, the former diplayed only one in
the early 1990s.
Fish and fisheries
Landings of the commercially important fish species in the Baltic Sea are dominated by cod
(Gadus morhua), sprat (Sprattus sprattus) and herring (Clupea harengus) (Fig. CBS-6). While
during the 1980s cod and sprat constituted the largest part of the commercial catches, since
then sprat is the commercially most important species.
600
herring
500 sprat
cod
Landings (1000 t)
400
300
200
100
0
1975 1980 1985 1990 1995 2000 2005
Fig. CBS-6. Landings of cod, sprat and herring in the Baltic Sea.
ICES Working Group Report 2006 | 25
The decrease in landings of cod and herring since the late 1980s was mainly due to a decline
of the stock biomasses of these species (Fig. CBS-7). The cod stock collapsed due to climate-
induced recruitment failure and a continuously high fishing pressure (Köster et al. 2005),
while herring decreased mainly due to reduced growth (Möllmann et al. 2005), but also lower
recruitment. In contrast the sprat stock increased to record levels during the 1990s being a
result of climate-induced recruitment success and lower predation pressure by cod (Köster et
al. 2003, MacKenzie and Köster 2004). The only locally important stock of flounder
(Plathychtis flesus) displayed an undulating development with peak SSB in the early 1980s,
1990s as well in the present decade. These peaks are clearly associated with improved
reproductive success.
SSB (t) R (n*10 )
-6 WECA (kg)
800 1000 2.4
600 800 2.2
COD
600 2.0
400
400
1.8
200 200
1.6
0 0
2000 3e+5 0.018
3e+5 0.016
1500
SPRAT
2e+5
0.014
1000 2e+5
0.012
1e+5
500 0.010
5e+4
0 0 0.008
2000 40000
0.07
HERRING
1500 30000 0.06
1000 20000 0.05
0.04
500 10000
0.03
0 0 0.02
35 60 0.55
FLOUNDER
30 50 0.50
0.45
25 40
0.40
20 30 0.35
15 20 0.30
1975 1980 1985 1990 1995 2000 2005 1975 1980 1985 1990 1995 2000 2005
Fig. CBS-7. Spawning stock biomass (SSB), recruitment R and weight in the catch (WECA) of
Baltic fish species.
Cod and sprat exhibited clear density-dependent responses in individual weight (Fig. CBS-7).
Since the 1990s individual cod weight was high in parallel to low stock size and vice versa for
sprat. In contrast individual herring weight declined with stock size stabilizing since the mid
1990s, which is partly a result of the varying proportion of local populations with variable
growth patterns (ACFM 2005). Further a real growth reduction since late 1980s was observed
and discussed to be a result of competition with the large sprat stock (Casini et al. 2006,
Möllmann et al. 2005). Further, for both pelagic fish species, but especially for herring, the
decreased population size of the copepod Pseudocalanus acuspes, their main food source in
spring, is an important factor for reduced individual growth (Möllmann et al. 2003, 2005,
Rönkkonen et al. 2004). Individual weight of flounder increased since the late 1990s
irrespective of stock size, which might be a result of reduced competition with cod for
invertebrate food.
26 | ICES Working Group Report 2006
Integrated analysis
An empirical overview of the temporal change of all CBS time-series is presented in Fig.
CBS-8. Generally there is a trend from variables placed at the top of the plot having high
values during the 1970s and early 1980s, to variables at the bottom displaying high values in
the recent 15 years. The first group consists e.g. of variables related to cod, herring,
Pseudocalanus acuspes, salinity and maximum ice extend, while the second group consists
e.g. of temperature, sprat, flounder, Acartia spp. and Temora longicornis. An intermediate
group is further visible with relativ high values in the 1970s/1980s, high values between 1988
and 1993, and again low values afterwards. This group consists mainly of indicator time-series
related to nutrients and phytoplankton.
The relative influence of the various time-series on the observed changes can be derived from
the factor loadings (Fig. CBS-9) of the first 2 principal components PC1 and PC2 derived by
PCA (Fig. CBS-10). These first two composite variables explain 22.8 and 12 % of the total
variance. PC1 reflects mainly a temperature increase due to climatic processes (Alheit et al.
2005), while PC2 reflects changes in deep water salinity, bottom water nutrient and oxygen
conditions. The common result of both trends is a regime shift, best visible in fish and
zooplankton populations. High cod stocks in the late 1970s/early 1980s are replaced by a
period of sprat dominance since the 1990s. The decrease in the cod stock is mainly caused by
recruitment failue due to low salinity and oxygen conditions (Köster et al. 2005), while the
higher water temperatures during the 1990s favoured sprat recruitment (MacKenzie and
Köster 2004). Similarly the shift in the zooplankton from P. acuspes to Acartia spp. is caused
by opposite hydrographic preferences (Möllmann et al. 2003). PC1 loadings additionally
suggest that fishing mortality contributed to the dynamics of the cod stock, while this was less
important for sprat.
PC2 summarizes trends in the dynamics of the deep water in the Baltic basins, i.e. salinity,
nutrient and oxygen conditions. The cumulative effects of the long lasting stagnation period
since the late 1980s, with major inflows only in 1993 and 2003, lead to a gradual increase of
NH4 and PO4 concentrations in the bottom water. High loading on PC2 for winter surface PO 4
in both the Bornholm and Gotland Basin indicates, that the bottom water nutrient
concentrations have a pronounced effect on the surface layer PO 4 pool The loading for runoff
is opposite, suggesting that the contribution from bottom water to surface nutrient pools is
much larger than the river runoff nutrient loading.
Relationships between phytoplankton related parameters – Secchi depth, chlorophyll a,
biomass of phytoplankton groups – and the first two principal components are weak. Only
spring dinoflagellate biomass in the Gotland Basin has a high loading on PC1. This could be a
reflection of temperature induced species shifts in spring phytoplankton (Wasmund et al.
1998). Summer chlorophyll a as well as spring diatom and dinoflagellate biomass are reflected
by PC2, but have opposite dynamics than the winter phosphate pool. The low correlation
between phytoplankton and other parameters could also be caused by the shortness of the
phytoplankton related time-series, which reflect only conditions during the 1980s and 1990s,
and by the low temporal stability of phytoplankton indicators. While most other variables have
a turnover time of weeks to years, phytoplankton turnover is on the order of days and
therefore much more susceptible to fluctuations in e.g. weather conditions during sampling.
ICES Working Group Report 2006 | 27
PC1 PC2 Variable
1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
-5.1 0.3 CODSSB
-5 -0.3 HERWC3
-4.9 0.3 S_GBSpr_0-10
-4.9 1.3 CODR2
-4.8 -0.1 CODland
-4.7 -0.2 HERSSB
-4.5 -0.9 HERland
-4.4 0 S_BBSpr_0-10
-4.2 -1.6 Sync_Sum
-4.1 -2.8 SPRWC3
-4 -0.4 S_GBSum_0-10
-4 0 HERR1
-3.7 1 Pseudo_Sum
-2.8 -0 Pseudo_Spr
-2.7 3 S_GBSpr_80-100
-2.5
-2.4
2.4 MaxIce
4 S_GBSum_80-100
Fig. CBS-8. Traffic-light plot of the development
-2.2
-1.7
-0.6 PO4_GDWin
-3.5 PO4_BBWinSur
of the CBS ecosystem. Time-series are
-1.7
-1.5
0.6
0.9
inflow
SB_Secchi
transformed to quintiles and sorted according to
-1.5 1.5 Chla_BBSum PC1. For abbrevations see Annex3.
-1.4 -1.7 Bosmina_Sum
-1.2 NH4_GBWin_100-120
-2.2
-1.1 1.3 Cyano_BBSum
-0.9 -3.4PO4_GBWin_0-10
-0.9 0.6 O2_BBWinBot
-0.9 PO4_GBWin_200-220
-4.2
-0.8 -2.5NO3_GBWin_0-10
-0.7 -0.7 Temora_Sum
-0.7 -1.8 NO3_BBWinSur
-0.6 2.3 Bac_GBSpr
-0.6 2.4 RunOff
-0.5 NO3_GBWin_100-120
-1.1
-0.5 -4 SALcat
-0.4 2.4 Dino_BBSum
-0.4 2.3 REPVOL
-0.4 -1.1 NO3_GDWin
-0 2.8 FLOSSB
0.1 1.3 Coast1ShWi
0.1 -0.5 Bac_BBSum
0.1 NH4_GBWin_200-220
-4.4
0.1 1.4 NO3_BBWinBot
0.4 0.7 Cyano_GBSum
0.6 -2.1 NH4_BBWinBot
0.7 PO4_GBWin_100-120
-2.1
0.7 -1.6 Cyano_BBSpr
1 1.3 Chla_GBSpr
1.1 1.5 Chla_GBSum
1.1 -1.6 PO4_BBWinBot
1.3 2.4 Dino_GBSum
1.3 3.8 WBRCPUE
1.3 0 T_BBSum_0-10
1.4 -0 Coast1Rich
1.4 1 Bac_GBSum
1.5 4.3 SPR_F3-5
1.5 -2 T_BBSpr_0-10
1.7 0.3 CODWC3
1.7 -3.3 BSI
1.8 -0.9 Bac_BBSpr
1.8 2.4 S_BBSpr_70-90
1.9 2.6T_CoastSum_Sur
1.9 0.2 Chla_BBSpr
2.1 -0.9 ROACPUE
2.1 -4.1 11psu_GBAnn
2.2 0.3 Acartia_Sum
2.3 -2.3 Sync_Spr
2.4 -0.1 Cyano_GBSpr
2.5 -2.2 T_GBSpr_40-60
2.5 -2.4 CODF4-7
2.5 -1.9 T_GBSpr_0-10
2.6 -1.1 T_GBSum_0-10
2.7 -1 Temora_Spr
2.7 1.8 Dino_GBSpr
2.7 -1.7 T_BBSpr_40-60
2.9 0.1 FLOF4-6
3 0.8 SPRR1
3.1 2 FLOWC3
3.1 -1.4 RUFCPUE
3.2 -1.8T_GBSum_40-60
3.3 1.7 PERCPUE
3.5 -0.6 HER_F3-6
3.7 0.9 FLOR3
3.8 2.7 FLOland
3.8 0 Dino_BBSpr
4 -0.3 Acartia_Spr
4.2 -1.6 SALw3
4.7 2.3 SPRland
4.8 0.8 SPRSSB
ICES Working Group Report 2006 | 28
0.4
0.2
PC-scores
0.0
-0.2
-0.4
1975 1980 1985 1990 1995 2000 2005
Year
Fig. CBS- 9. Scores of principal components 1 (black circles) and 2 (white circles).
The time-trajectories of PC1 and PC2 nicely summarize and demonstrate the change in states
after 1987 and 1993, with transitional periods when both PCs are close together (Fig. CBS-9).
The shifts are even more visible when plotting the time-scores of PC1 and 2 against each other
(Fig. CBS-10). Clearly, 3 regimes are detectable and can be classified according to the mean
hydrographic conditions in spring, e.g. in the Gotland Basin. The first regime (1974-87) was
characterized by the lowest SST (5.0±0.5 ºC) and the highest deepwater salinity (10.2±0.5
psu). The intermediate period (1988-93) displayed the reverse conditions with on average the
highest temperature (7.5±3.1 ºC) and lowest salinity (8.9±0.7 ºC). The last years of the
investigated period exhibited intermediate values (6.9±2.0 ºC; 9.3.0±0.7 ºC).
0.4
1979 1977 2004
1980 1997
1978
1996
1995
0.2 1998
1974
2003
PC2 (12.0%)
1994
1976
1981 1975
1985 2002 1999
1987 2000
0.0 1982 2001
1983
1984
1986
1988
-0.2 1993
1991
1992
1989
-0.4 1990
-0.4 -0.2 0.0 0.2 0.4
PC1 (22.8%)
Fig. CBS-10. Time scores of pricipal components 1 and 2 (PC1 and PC2); variance explained by
PCs in brackets..
ICES Working Group Report 2006 | 29
In summary, the integrated analysis revealed major regime shifts in the ecosystem as has been
reported for other areas, e.g. the Canadian Eastern Scotian Shelf (Choi et al. 2005), the U.S.
continental shelf ecosystem (Link et al. 2002) and the North Sea (Beaugrand 2004). The major
reasons for these regime shifts are changes in the temperature due to climate variability and
change. For the CBS climate-driven physical conditions seem to be the major driver for
ecosystem dynamics as well. In contrast to truly marine areas, the CBS experienced not only a
regime shift during the late 1980s, but another one after 1993. The reason behind this is the
additional importance of deep water salinity and oxygen conditions for the brackish Baltic
Sea. The change in inflow frequency and related salinity and oxygen variability is thus a
second factor affecting the structure and functioning of this ecosystem, in contrast to truly
marine areas.
ICES Working Group Report 2006 | 30
Gulf of Riga (GOR)
Climate and temperature
The development of the climate over the Baltic Sea area in the last 3 decades is displayed by
the Baltic Sea Index, which well correlated with the Index of the North Atlantic Oscillation
(NAO) (Lehmann et al. 2002). While during the 1970s and 1980s the index was mainly in a
negative state, it was mainly positive afterwards (Fig. GOR-1). This change in sign of the
index was associated with more frequent westerly winds, warmer winter and eventually a
warmer climate over the area. This very well demonstrated by the convincing correlation fo
the BSI with the air temperature (r=0.81). All time-series of water temperatures in the GOR
reflect this warming during the 1990s.
February (whole water column)
May (0-20m)
August (0-20m)
0.4 4 20
Air temperature (degC)
0.3 18
Water temperature (degC)
2
0.2 16
0.1 0 14
BSI
0.0 -2 6
-0.1 4
-4 2
-0.2
0
-0.3 -6 -2
1975 1980 1985 1990 1995 2000 1975 1980 1985 1990 1995 2000
Fig. GOR-1. Times-series of the Baltic Sea Index (BSI), as well as air and water temperatures.
Nutrients
Recordings of NO23 and PO4 were only available for the 1970s and since the late 1980s (Fig.
GOR-2). Clearly both time-series show higher nutrient levels in the recent period compared to
the ealier one. An intermediate minimum in nutrient concentrations was observed during the
mid -1990s.
25 1.2
1.1
20
1.0
PO4 (µmol*l-1)
NO23 (µmol*l-1)
15 0.9
10 0.8
0.7
5 NO23
PO4 0.6
0 0.5
1975 1980 1985 1990 1995 2000
Fig. GOR-2. Time-series on nutrient concentrations (µmol*l-1).
ICES Working Group Report 2006 | 31
Phytoplankton
Chlorophyll a concentration as an index for phytoplankton biomass displayed in spring an
increase until the mid-1980s, dropping drastically afterwards (Fig. GOR-3). In the early 1990s
there was a continuous increase despite pronounced fluctuations. The generally low summer
chlorophyll a concentration increased steadily throughout the whole investigation period.
30
Spring
25 Summer
Chlorophyll a (mg*m-3)
20
15
10
5
0
1975 1980 1985 1990 1995 2000
Fig. GOR-3. Time-series on spring and summer chlorophyll a concentrations.
Zooplankton
The development of the main zooplankton populations in spring (Fig. GOR-4) is characterized
by a shift from a dominance of Limnocalanus grimaldii to Acartia spp. and Eurytemora
affinis, which started in the late 1980s. In summer, cladocerans are dominating the
zooplankton biomass, with however very low biomasses since the end of the 1990s. A decline
in the summer biomass from the early 1980s to the early 1990s was also observed for E.
affinis and L. grimaldii, while Acartia spp. biomass was rather stable.
Spring Summer
350 350
Cladocerans
300 Acartia spp. 300
E. affinis
250
Biomass (mg*m-3)
250
Biomass (mg*m-3)
L. grimaldii
200 200
150 150
100 100
50 50
0 0
1975 1980 1985 1990 1995 2000 1975 1980 1985 1990 1995 2000
Fig. GOR-4. Time-series on biomass of dominating zooplankton species in the GOR in spring and
summer.
Fish and fisheries
Cod (Gadus morhua) was only caught in the GOR when the Eastern Baltic stock was large
during the early 1980s (Fig. GOR-5). In contrast, herring (Clupea harengus) is the most
32 | ICES Working Group Report 2006
important commercial fish species in the GOR. Catches were stable until the early 1990s,
drastically increasing afterwards.
50000
Herring
40000 Cod
Landings (tonnes)
30000
20000
10000
0
1980 1985 1990 1995 2000
Fig. GOR-5. Cod and herring catches in the GOR.
Fig. GOR-6 demonstrates the increase in herring catches to be due to an increase in stock
biomass as a result of the high recruitment level during the 1990s. Mean individual weight of
herring decreased in parallel to the stock biomass displaying a density-dependent process.
However, in recent years individual weight increased despite the high stock levels, which
might be a result of a changed food supply. Fishing mortality of this stock is relatively low
and seems not to be the driving force for herring stock dynamics.
200 8000
180 7000
Biomass (1000tonnes)
Recruitment (millions)
160 6000
140 5000
120 4000
100 3000
80 2000
60 1000
40 0
0.030 0.8
0.028
0.7
0.026
Mean weight (kg)
0.6
0.024
F ages 3-7
0.022 0.5
0.020
0.4
0.018
0.3
0.016
0.014 0.2
1975 1980 1985 1990 1995 2000 1975 1980 1985 1990 1995 2000
Fig. GOR-6. Time-series on herring biomass, recruitment (age 1), mean individual weight and
fishing mortality (F).
ICES Working Group Report 2006 | 33
SPRING
PC1 PC2 Variable 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
-4.505 -2.3 TempMay20
-4.407 3.0 Herring
-4.299 -0.6 Eurytemora
-4.062 -0.8 Acartia
-3.835 -2.7 AirTemp
-3.835 -0.4 Cladocera
-3.808 -2.8 TempFeb50
-3.718 -2.7 BSI
-3.45 -2.6 Synchaeta
-3.373 2.8 RecCur
-3.12 1.7 PO4
-2.884 3.7 Catch
-2.174 -2.2 Runoff
-1.827 -2.5 NO23
-0.743 -3.4 DIN load previous
1.11 0.0 Chla
2.214 -0.2 Secchi
3.23 -1.3 Limnocalanus
3.539 0.0 F(3-7)
3.638 -2.8 HerWeight
4.27 -0.8 SalMay20
4.662 -2.7 Codcatch
SUMMER
PC1 PC2 Variable 1973 1974 1975 1976 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
-4.855 -1.2 Herring
-4.195 -2.7 Catch
-3.902 -1.3 RecCur
-3.775 -0.3 PO4
-3.71 0.76 SChla
-3.606 -2.2 Cercopagis
-3.333 3.06 TMay20
-3.212 1.87 TAug20
-2.437 3.66 Tfeb
-2.427 3.78 BSI
-1.683 2.79 RunoffJanAug
-0.682 3.64 DINloadJanAug
-0.497 3.31 NO23
1.011 -2.5 Limnocalanus
1.477 2.36 Acartia
2.115 -1.5 SSecchi
2.858 3.3 Cladocera
3.099 -1.3 F(3-7)
3.997 0.63 Eurytemora
4.004 0.82 HerWeight
4.407 0.99 Rotatoria
4.47 -0.3 SalAug50
5.058 0.56 Codcatch
1st 2nd 3rd 4th 5th quintile
Fig. GOR-7. Traffic-light plot of the development of the GOR ecosystem in spring and summer. Time-series are transformed to quintiles and sorted according to PC1. For
abbrevations see Annex3.
ICES Working Group Report 2006 | 34
Integrated analysis
An empirical overview of the temporal change of all spring and summer GOR time-series is
presented in Fig. GOR-7. Generally, there is a trend from variables placed at the top of the
plot having low values until the late 1980s and high values afterwards, to variables at the
bottom with the opposite trend. The first group consists in spring of hydroclimatic variables,
the BSI and temperatures, as well as nutrient, zooplankton and herring time-series. The group
of time-series with the opposite trend in spring consists of e.g. the copepod Limnocalanus
grimaldii, cod catch and herring weight. In summer, a similar pattern was observed, although
most of the zooplankton species (i.e. Acartia spp., Eurytemora affinis, cladocerans) were now
found in the second group.
The relative influence of the various time-series on the observed changes can be derived from
the factor loadings (Fig. GOR-8) of the first 2 principal components PC1 and PC2 derived by
PCA (Fig. GOR-9). PC1 explains most of the variance (37.6 and 36.0% in spring and summer,
respectively) and reflects mainly a temperature increase due to climatic processes (Alheit et al.
2005) and the resulting positive effect on thermophilic species (e.g. herring and zooplankton).
PC2 represents the opposite trend due to various biological mechanisms. An example is the
opposite trend of the zooplankton species Acartia spp., Eurytemora affinis, cladocerans, which
increase in spring, but decrease in summer. This shows that climatic processes act on the
ecosystem mainly in spring (Dippner et al. 2000, Möllmann et al. 2003), but indicates also an
increased predation pressure by the enlarged herring stock in summer (Kornilovs et al. 2004).
Another internal mechanism is the decrease in herring weight, which may be due to density-
dependent competition in the large herring stock. Runoff and nutrients are further related to
the change in climatic conditions and increased since the late 1980s, while chlorophyll a as an
index for the phytoplankton did not. This may be due to the quality of the sampling.
The common result of both trends is a regime shift in the ecosystem caused by changed
atmospheric forcing as seen in the CBS and other areas of the world ocean (see above). The
time-trajectories of PC1 and PC2 summarize and demonstrate the change in states, which
occurred in the GOR in contrast to the CBS between 1988 and 1989 (Fig. GOR-8).
0.6
Spring Summer
0.4
0.2
PC-scores
0.0
-0.2
-0.4
1975 1980 1985 1990 1995 2000 2005 1975 1980 1985 1990 1995 2000 2005
Fig.GOR- 8. Scores of principal components 1 (black circles) and 2 (white circles) for the spring
and summer analyses.
The shifts are even more visible when plotting the time-scores of PC1 and 2 against each other
(Fig. GOR-9). Clearly, the shift in regime is detectable with a transitional period until 1991 in
spring and 1993 in summer.
ICES Working Group Report 2006 | 35
1996
Spring 2003 Summer 1990
0.4 0.4 1989
1983
1993 1991
1975
1997
0.2 0.2 1981
1995 2000 1992
2001 1994 1999 1976 1977 1986
PC2 (15.4%)
2004
PC2 (16.4%)
1987
1998 1985
1988 1982
2002 1992 2002 1998
1993 1974 1979
0.0 1984 0.0 2000
1994
1995
1973 1978
1991 1988 1982 1980 1980
1984
1973 1978 2004
1999 1985
1987
1981 1979
1986 2001
1975 1974
1976
1997
-0.2 -0.2
1996
1989 2003
1990
1983
-0.4 -0.4
-0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 -0.4 -0.2 0.0 0.2 0.4
PC1 (37.6%) PC1 (36.0%)
Fig. GOR-10. Time scores of principal components 1 and 2 (PC1 and PC2) for the spring and
summer analyses; variance explained by PCs in brackets.
References
ACFM 2005. Report of the Baltic Fisheries Assessment Working Group (WGBFAS). ICES
CM 2005/ACFM:19.
Alheit, J., Möllmann, C., Dutz, J., Kornilovs, G., Löwe, P., Mohrholz, V. and Wasmund, N.
2005. Synchronous ecological regime shifts in the North and Central Baltic Sea in 1987-
88. ICES Journal of Marine Science 62: 1205-1215.
Beaugrand, G. 2004. The North Sea regime shift: evidence, causes, mechanisms and
consequences. Progress in Oceanography, 60: 245–262.
Casini, M., Cardinale, M., and Hjelm, J. 2006. Inter-annual variation in herring, Clupea
harengus, and sprat, Sprattus sprattus, condition in the central Baltic Sea: what gives the
tune? Oikos 112: 638-650.
Choi, J. S., Frank, K. T., Petrie, B. D., and Leggett, W. C. 2005. Integrated ecosystem assess-
ment of a large marine ecosystem: a case study of the devolution of the Eastern Scotian
Shelf, Canada. Oceanography and Marine Biology: an Annual Review, 43: 47–67.
Dippner, J.W., Kornilovs, G., and Sidrevics, L. 2000. Long-term variability of
mesozooplankton in the Central Baltic Sea. Journal of Marine Systems 25: 23-32.
Hänninen, J., Vuorinen, I., and Hjelt, P. 2000. Climatic factors in the Atlantic control the
oceanographic and ecological changes in the Baltic Sea. Limnology and Oceanography,
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Köster, F.W., Möllmann, C., Neuenfeldt, S., Vinther, M., St. John, M.A., Tomkiewicz, J.,
Voss, R., Hinrichsen, H.H., Kraus, G., and Schnack, D. 2003. Fish stock development in
the Central Baltic Sea (1976-2000) in relation to variability in the physical environment.
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Köster, F.W., Möllmann, C., Hinrichsen, H.-H., Tomkiewicz, J., Wieland, K., Kraus, G.,
Voss, R., MacKenzie, B.R., Schnack, D., Makarchouk, A., Plikshs, M. and Beyer J.E.
2005. Baltic cod recruitment – the impact of climate and species interaction. ICES Journal
of Marine Science 62: 1408-1425.
Kornilovs, G., Möllmann, C., Sidrevics, L. and Berzins, V. 2004. Fish predation modified
climate-induced long-term trends of mesozooplankton in a semi-enclosed coastal gulf.
ICES C.M. 2004/L:13.
Link, J.S., Brodziak, J.K.T., Edwards, S.F., Overholtz, W.J., Mountain, D., Jossi, J.W., Smith,
T.D., and Fogarty, M.J. 2002. Marine ecosystem assessment in a fisheries management
context. Canadian Journal of Fisheries and Aquatic Sciences 59: 1429–1440.
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Lehmann, A., Krauss, W., and Hinrichsen, H.-H. 2002. Effects of remote and local
atmospheric forcing on circulation and upwelling in the Baltic Sea. Tellus 54A: 299-316.
MacKenzie, B.R., and Köster, F.W. 2004. Fish production and climate: sprat in the Baltic Sea.
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Matthäus, W., and Schinke, H. 1999. The influence of river runoff on deep water conditions of
the Baltic Sea. Hydrobiologia 393: 1-10.
Möllmann, C., and Köster, F.W. 2002. Population dynamics of calanoid copepods and the
implications of their predation by clupeid fish in the Central Baltic Sea. Journal of
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Möllmann, C., Köster, F.W., Kornilovs, G., and Sidrevics, L. 2003. Interannual variability in
population dynamics of calanoid copepods in the Central Baltic Sea. ICES Marine
Science Symposia 219: 220-230.
Möllmann, C., Kornilovs, G., Fetter, M. and Köster, F. W. 2005. Climate, zooplankton and
pelagic fish growth in the Central Baltic Sea. ICES Journal of Marine Science 62: 1270-
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Wasmund, N., Nausch, G., and Matthäus, W. 1998. Phytoplankton spring blooms in the
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ICES Working Group Report 2006 | 37
Annex 5: Non- Paper
Regional integrated assessment and the research organisation in the
Baltic Sea within and outside ICES
This document is a result of the joint meeting of SGMAB and SGBFFI in Riga, June 2005.
While reviewing TORs f) – i) of SGMAB, dealing mainly with the future of the SG, the
coordination with other SGs (especially those related to the BSRP) and contributions to the
2006 Theme Session on Regional Integrated Assessments, the need to re-organise the Baltic
Sea research within ICES was discussed. The main arguments for re-organising the WG/SG-
structure were:
I. the need for advancing towards an Integrated Assessment (IA) of the Baltic Sea
ecosystem similar as initiated for the North Sea (i.e. REGNS), as a basis for
implementing the Ecosystem Approach to Fisheries Management (EAF);
II. the need to react on the changing advisory requests after the replacement of IBFSC
by bilateral negotiations between the EU and Russia.
III. the need for an improvement of co-ordination of the WG/SG-work with other
environmental organisations (e.g. HELCOM, EU Marine Strategy);
IV. the need for an improvement of co-ordination of the WG/SG-work with the
multitude of activities/research projects outside ICES (e.g. EU-funded projects
BECAUSE, PROTECT)
Presently the research in the Baltic Sea is conducted within a variety of fora ranging from
ICES WGs and SGs, EU-funded research projects and WGs, to HELCOM WGs and projects.
Between these different working frames, tasks and duties are either partly overlapping,
although often conducted by the same institutions and/or scientists (ICES vs. STECF), or a
tight connection is yet to be established (ICES vs. HELCOM). Even within the ICES Baltic
community, activities are diversified in several sub-groups either overlapping in themes or
being widely seperated, thus hampering an integrated view on the ecosystem.
ICES presently faces the challenge to implement an EAF for which an IA of the ecosystem is
needed as a basis. Consequently a regional ecosystem SG has been implemented North Sea
(REGNS). In the Baltic Sea community a step towards this goal was made by implementing
the GEF Baltic Sea Regional Project (BSRP). The project and its affiliated ICES SGs
(SGBFFI, SGPROD, SGBEH and SGBEM) made considerable improvements in widening the
perspective within the ICES Baltic community from rather “fish and physical environment -
focused” to a more integrated view including lower trophic levels, ecosystem health issues and
alternative approaches to ecosystem modelling. The project further initiated the development
of indicator sets for assessing the state of the ecosystem and initiated progressive initiatives
which should be templates for the future work, e.g. a combined ecosystem hydroacoustic
open-sea survey. BSRP has further strengthened the communication and cooperation with
HELCOM.
Despite of these successes, the present approach of implementing an IA using BSRP as a
vehicle, has several shortcomings: (i) the participation of non-funded “western” countries is
low and decreasing which has the risk of separating communities, (ii) the different “discipline
groups” work still largely seperated hampering an IA, and (iii) as the future funding of BSRP
is unclear there is a risk to loose the first steps towards an IA when not implemented in the
broader community.
The above discussed challenges the present organisation of the work within the ICES Baltic
science community. A new structure should consequently be developed providing the
following:
I. a platform for conducting an IA;
38 | ICES Working Group Report 2006
II. a concentration of the work in a reduced number of WGs/SGs;
III. a better “outside communication/cooperation” with the EU-commission (i.e. STECF,
JRC and EU-funded projects), as well as HELCOM and other international
initiatives (e.g. BALTEX, BOOS, GLOBEC);
IV. flexible tools to react on “hot topics” or “short-notice tasks”.
In Fig. 1 a basic suggestion for a new ICES working group structure in the Baltic is sketched.
This structure is suggested as a basic discussion frame which needs involvement of the
different WG/SGs, the Baltic committee as well as the three ICES advisory committees.
The structure is centered around two assessment groups, one for fish stocks and fisheries (FA
WG) and one for the IA (IAWG). Both groups will be supported by observational data from
an “Ecosystem Survey Group” (ESWG). This group will be central in implementing the IA
and the EAF as it should develop in cooperation with HELCOM the present trawl and
hydroacoustic surveys into ecosystem surveys which provide both “tuning” and “ecosystem”
data.
SG SG SG SG
WK WK
FA WG(s) IA WG
WK WK
WK WK
ES WG
Fig. 5.1. Suggestion of a new structure for the ICES Baltic Sea assessment and scientific activities.
[SG-Study Group, WK-Workshop, FA-Fish stock assessment, IA-Integrated assessment, ES-
Ecosystem survey]
Both assessment groups will be supported by a limited number of SGs providing them with
additional knowledge and information. On the “fish-side” this should include assessments and
related issues, like multispecies modelling and age-determination. For the “ecosystem-side”
this should include physical, chemical, lower trophic level (phyto- and zooplankton) and
ecosystem modelling expertise, thus integrating the present BSRP-groups. A major task of
these groups will be to facilitate the communication to scientific activities outside ICES, e.g.
to EU-funded projects (from the “fish-side”) and to HELCOM (from the “ecosystem-side”).
An important part of this suggested structure should be the increased use of workshops (WK).
These should be vehicles to tackle “hot topics” or “short-notice tasks” coming up in various
groups and should be solved in common, avoiding diversification and doubled work.
ICES Working Group Report 2006 | 39
The most important change in this structure is the implementation of an IAWG. This will (i)
assure the conservation, further development and the integration of the work done within
BSRP in the broader scientific community, (ii) fullfill the request for an IA, which (iii)
enables ICES to react on the new requirements in terms of advice which is due to the change
in the management system of the Baltic and European waters.
A second important issue will be the development of a common monitoring programme
combining all available resources to effectively survey the whole ecosytem as a basis for an
IA.
ICES Working Group Report 2006 | 40
Annex 6: Existing Baltic Sea monitoring programmes
HELCOM COMBINE
The HELCOM COMBINE monitoring programme is targeted to assessing the effects of
eutrophication on the Baltic ecosystem. It covers a list of mandatory core and voluntary main
parameters, addressing hydrography, nutrients, and biota (Table 6.1).
Table 6.1: Parameters included in the HELCOM COMBINE monitoring programme
Hydrography Nutrients Biota
phosphate, total
temperature, salinity, phosphorus, nitrate chlorophyll a, phytoplankton
oxygen, hydrogen + nitrite, (species composition, abundances,
core
sulphide, ammonium, total biomass), macrozoobenthos (species
transparency nitrogen, composition, abundances, biomass)
silicate
zooplankton (species composition,
abundances, biomass), primary
production, phytobenthos
current speed and
main (composition and abundances),
direction
sinking rate of particulate matter,
fluorescence profiles, fish (coastal
areas)
The station network used for COMBINE monitoring is dense, but monitoring intensity
typically decreases from hydrographic parameters to nutrients and biota. Representative for
stations with intensive sampling programme, Fig. 6.1 shows the distribution and sampling
frequency of chlorophyll a under HELCOM COMBINE. It also has to be noted that the
transect Helsinki – Travemünde monitored by Finland at by-weekly intervals is carried out by
ships-of-opportunity measurements and covers only surface data.
The HELCOM COMBINE monitoring programme is currently under revision in the
HELCOM MON-PRO project. MON-PRO suggested structuring HELCOM COMBINE into
trend and surveillance monitoring, operational monitoring and investigative monitoring. Trend
and surveillance monitoring would be conducted annually in areas with acceptable
eutrophication status, whereas operational monitoring would survey areas exceeding
acceptable eutrophication status. Investigative monitoring is planned to improve the
understand of eutrophication effects. The planned operational monitoring scheme includes 1 –
2 representative stations in each Baltic Sea sub-basin, where hydrographic parameters and
nutrients as well as chlorophyll a/phytoplankton during the growth season would be measured
at monthly intervals. The network of representative station will be supplemented by mapping
surveys covering key ecosystem processes (winter nutrient concentrations, late summer
oxygen minimum, spring and summer phytoplankton communities) together with annual
(summer) surveys of phytobenthos and macrozoobenthos. Zooplankton is included into this
proposed scheme as an optional parameter at representative stations and during a summer
mapping survey (HELCOM MONAS 8/2005, Document 6.1/2).
HELCOM COMBINE monitoring results are published in indicator fact sheets that are
updated annually. Additionally, thematic and holistic assessments are produced at regular time
intervals.
ICES Working Group Report 2006 | 41
Figure 6.1. COMBINE stations with intensive sampling programme (HELCOM MON-PRO 3,
Document 2.1.)
ICES Working Group Report 2006 | 42
EU Water Framework Directive
The EU Water Framework Directive requires regular assessment of the ecological status of
coastal and transitional waters. Coastal waters are defined as marine waters within one
nautical mile from the simplified coastline configuration, from which the breadth of territorial
waters are measured. This definition includes many bays and inlets completely as coastal
waters, even though their central areas might be further away from the coast then one nautical
mile. Transitional waters are areas influenced by fresh water adjacent to river mouths.
Classification of ecological status is based on mandatory biological quality elements, which
are in turn supported by physico-chemical elements. Good ecological quality is reached, when
both biological as well as physical-chemical elements reach the normative definitions for good
quality. The water framework does not explicitly state a suite of parameters required for
monitoring, but rather gives a list of quality elements, and a normative definition for the status
classes (Table 6.2). Choice of indicators and monitoring parameters is left to national
authorities.
Each water body should be monitored at least once in the live time of a water management
plan, covering the seasonality of all quality elements (surveillance monitoring), or, in the case
of water bodies already at good status and under low pressure, the quality elements most
sensitive to pressure (operational monitoring). Monitoring frequency most be chosen to
minimize the effect of seasonality on assessment results and the WFD explicitly sets minimum
monitoring frequency requirements. Further, the EU WFD demands to quantify confidence
(power) and precision (relative confidence interval) of monitoring results, and to specify their
target levels in the river basin management plans. To achieve reasonable confidence and
precision of monitoring programs, in most cases the sampling frequency will have to be higher
than the minimum frequency given in the WFD (CIS 2003).
EU WFD monitoring networks have to be established in 2006 and reported to the EU
Commission 22 March 2007 (http://europa.eu.int/comm/environment/water/water-
framework/transposition.html). Assessment and consequently also monitoring under the WFD
proceeds in 6 year cycles formalized in River Basin Management Plans. Water quality will be
compared to the good water quality target in the years 2015, 2021, and 2027. For the first
time, draft river basin management plans have to be prepared in 2008, and their final reporting
deadline, including programs of measures to achieve good water quality, is 22 March 2010.
ICES Working Group Report 2006 | 43
Table 6.2. Quality elements, normative definition of good ecological status and minimum monitoring frequency for coastal and transitional waters in the WFD.
Minimum monitoring
Quality element Quality element definition Normative definition of good status
frequency
Biological
slight changes in composition and abundance compared to reference
Phytoplankton composition, abundance and biomass conditions, no accelerated growth and no undesirable effects on biota, water 6 months
and sediment, only slight increase and intensity of type-specific blooms
slight changes in composition and abundance compared to reference
composition and abundance of
Other aquatic flora conditions, no accelerated growth and no undesirable effects to biota and 3 years
macrophytes and angiosperms
water
composition and abundance of slight changes in composition and abundance compared to reference
Benthic macro invertebrates 3 years
benthic invertebrate fauna conditions, most type-specific sensitive taxa present
abundance of disturbance-sensitive species slightly distorted due to
Fish (only transitional composition and abundance of fish
anthropogenic impacts on physico-chemical or hydromorphological quality 3 years
waters) fauna
elements
Hydromorphylogical
depth variation, structure and
Morphological conditions substrate of the coastal bed, structure 6 years
conditions consistent with the achievement of criteria for good status
of the intertidal zone
specified for biological quality elements
direction of dominant currents, wave
Tidal regime exposure, in transitional waters 6 years
freshwater flow
Physico-chemical
Transparency 3 months
Thermal conditions 3 months
do not reach levels outside the range of ecosystem functioning and the
Oxygenation 3 months
achievement of good status specified for biological quality elements
Salinity (only transitional) 3 months
Nutrient status 3 months
Pollution by all priority substances
being discharged and all other priority substances 1
Specific pollutants not in excess of standards
substances discharged in significant month, others 3 months
quantities
ICES Working Group Report 2006 | 44
EU commercial fish stock monitoring, fish stock assessment
European Council regulation 1543/2000 sets the data collection requirements for the EU
Common Fisheries Policy. For the Baltic Sea, the program requires monitoring of catches,
including length and age composition, for the main commercial fish species (glass eel, yellow
eel, silver eel, herring, cod, hake, blue whiting, Norway lobster, flounder, plaice, salmon, sea
trout, sole, sprat), as well as collection of fishing effort and fishing capacity information.
Priority fish surveys supplement the monitoring programme.
Out of the species listed in the council regulation for Baltic Sea fish monitoring, only herring,
cod, flounder, salmon, sea trout, and sprat are relevant for the Baltic Proper because of the low
salinity. For these species the sampling program also requires collection of weight at
age/length, maturity, and sex ratio data. The monitoring data further feed into fish stock
assessment, which is based on age-structured modeling to reconstruct stock numbers in each
age-class. While catch data drives the assessment models, scientific survey data are used for
tuning. The EU sampling program identifies priority surveys for cod and sprat in the Baltic
Proper, as well as for herring in Baltic Proper, Gulf of Riga, Gulf of Bothnia and Gulf of
Finland (Table 6.3). The ICES Baltic International Fish Survey Working Group (WKBIFS)
coordinates the surveys among the Baltic Sea countries.
Table 6.3. Priority fisheries surveys in the Baltic Proper and Gulfs (herring surveys)
Survey Survey type Target species Season
First and fourth
Cod and other
BITS Trawl survey quarters (usually
demersal species
March and November)
Third and fourth
Herring acoustic Acoustic with
Herring, sprat quarters (usually May
survey control trawls
and October)
Acoustic with Second quarter
Sprat acoustic survey Sprat
control trawls (usually october)
Fish stock assessment is organized with ICES working groups. The ICES Baltic Fisheries
Assessment Working Group (WGBFAS) meets annually in April to assess the state of Baltic
Sea fish stocks (cod, flounder, herring, sprat) and propose reference points and management
measures. Salmon and sea trout assessment is produced by the ICES Baltic Salmon and Trout
Assessment Working Group (WGBAST), which also meets annually in April.
HELCOM coastal fish monitoring
HELCOM coastal fish monitoring is presently carried out in 15 areas of the Baltic Sea, using
multi-mesh gillnets and gillnet series (Fig. 6.2). The program is targeted to describe the long-
term trends in coastal fish populations and to link them to natural and anthropogenic pressures.
Monitoring is carried out in August and is mainly directed towards demersal and
benthopelagic fish living in coastal areas during the warm season. Pelagic species (herring,
smelt, sprat) are caught in significant numbers but with high random variability. The
abundance of small-bodied fish (gobies, pipefishes, sand laces, sticklebacks) cannot be
evaluated with the present monitoring methods. Coastal fish monitoring also includes
measurements of temperature, salinity, wind speed and direction and transparency (HELCOM
2006).
ICES Working Group Report 2006 | 45
Figure 6.2 HELCOM coastal fish monitoring stations (HELCOM 2006).
Habitats and Birds directive, Baltic Sea Protected Areas
Habitats and Birds directive require designation of protected areas (special areas of
conservation - SAC, special protection areas – SPA, respectively) to establish favorable
conservation status for species or habitats. Annexes of both directives prioritize species and
habitats in need for protection. SAC and SPA form the network of Natura 2000 sites. A
similar managed site network is formed by the Baltic Sea Protected Areas created according to
a joint HELCOM/OSRPAR ministerial declaration (Bremen 2003).
For Habitats and Birds directives, management plans and monitoring programs have to be
established to ensure reaching or maintaining favorable conservation status of the species or
habitat for which the site was designed. Potential links between the monitoring needs of
habitats and birds directives and Baltic Sea integrated assessment are the food requirements of
target species in SAC and SPA (macrozoobenthos, fish), disturbance of SAC and SPA species
by fishing (bycatch of birds and mammals, removal of prey species), and the consequences of
increasing target species stocks for their prey (e.g. conflicts between increasing seal stocks and
fisheries in the Baltic).
The Habitats Directive proposes a similar 6 year reporting cycle as the Water Framework
Directive, with national reports to be submitted in 2007 and 2013.
ICES Working Group Report 2006 | 46
Baltic Sea monitoring and reporting deadlines
Table 6.4 lists presently known Baltic Sea monitoring, reporting and assessment deadlines.
While EU fisheries data collection, fish stock assessment and also HELCOM indicator reports
are produced on an annual basis, EU WFD and Habitats directive monitoring as well as
HELCOM thematic and holistic assessments follow longer reporting cycles.
Table 6.4. Important Baltic Sea monitoring, reporting and assessment deadlines
Annual activities:
EU fish
monitoring & fish EU WFD and Habitats HELCOM thematic and
Year
stock assessment Directive holistic assessments
HELCOM
indicator reports
HELCOM Thematic
Assessments on
eutrophication, biodiversity
2006 x
and nature protection,
hazardous substances,
climate change
Habitats Directive (reporting
2007 x
on conservation status)
2008 x
Water Framework Directive HELCOM EUTRO-PRO
2009 x (river basin management (eutrophication assessment
plans, due March 22 2010) based on target levels
HELCOM biodiversity
2010 x
assessment (planned)
2011 x
2012 x
Habitats Directive (reporting
2013 x
on conservation status)
2014 x
Water Framework Directive
2015 x (river basin management
plans)
References
HELCOM, 2006. Assessment of Coastal Fish in the Baltic Sea. Balt. Sea Environ. Proc. No.
103 A
CIS 2003. Common Implementation Strategy for the Water Framework Directive
(2000/60/EC). Guidance Document No 7, Monitoring under the Water Framework
Directive.
ICES Working Group Report 2006 | 47
Annex 7: Extended Abstract
The use of indicators for evaluation of trends in the Baltic
Seppo Kaitala
Dept. of Biological OceanographyFinnish Institute of Marine Research, Erik Palménin
aukio 1 (P.O. Box 2), FIN-00561 Helsinki, Finlandtel. +358-9-61394417 fax +358-9-
323 2970E-mail:Seppo.Kaitala@fimr.fi
Indices are a useful tool in integrated ecosystem analysis. Two examples (spring bloom index
and cyanobacteria bloom index) are shown to develop ideas for the integrated assessment of
the Baltic Sea.
Phytoplankton spring bloom indexChlorophyll a concentration is a relative measure of
phytoplankton biomass in the water. Since high nutrient concentrations increase
phytoplankton growth and subsequently the intensity and frequency of blooms, chlorophyll a
can be used as an indicator of the eutrophication in a sea basin.
The intensity of the spring bloom reflects the scale of the nutrient reserves. The spring bloom
species of diatoms and dinoflagellates consume most of the phosphorus and nitrogen nutrients
that were built up in the water mass
during the previous winter.
The seven-day running average
chlorophyll a curve in 2005 in the
Western Gulf of Finland (green).
Pink „area‟ illustrates the intensity
index of the spring bloom, the
spring bloom threshold is shown
with a broken line. Also the peak
and length of bloom are presented.
ICES Working Group Report 2006 | 48
The spring bloom estimates for Arkona Basin (AB), the Northern Baltic Proper (NB) and the
Western Gulf of Finland (GOF) from 1992 to 2005. Estimates: spring bloom intensity index,
mean chl a during bloom, length of bloom, highest peak of the bloom and the starting day of
the bloom. Years in which data have not covered the beginning of the bloom are marked with
an asterisk.
ICES Working Group Report 2006 | 49
Cyanobacteria bloom index
Automated flow-through sampling system on merchant ships, sampling depth ca. 5 m.
Samples for microscopical analyses of cyanobacteria are collected at eight of the 24 sampling
points on the route across the Baltic Sea from Travemünde to Helsinki during the period from
February/March to October/November. The indices are calculated by integrating the area
under the local regression curve representing the occurrence of cyanobacteria (A. flos-aquae
and N. spumigena) or toxic N. spumigena alone between days 100 and 300 of the particular
year . Over the years the means of the indices are used as a reference point.
Occurrence of A. flos-aquae (green) and N.
spumigena (red) in year 2004, the rank
abundance refers to the semiquantitative
ranks obtained with the microscopy method
of Algaline. The original samples are from
automated ship of opportunity sampling
between Helsinki and Travemünde (see the
section metadata) and the curve was fitted
with non-linear smoothing. On the x-axis is
the running day (Julian day) of the year. The
indices were obtained by integrating the area
under the fitted curve from Julian day 100 to
300. For the cyanobacteria bloom index the
area values for the two species were summed
up.
Cyanobacteria bloom index (the total bars
consist of the two main nitrogen fixing
bloom formers Aphanizomenon flos-aquae
indicated with green color and Nodularia
spumigena in red) and the mean (upper black
broken line) of values, and the toxic
Nodularia spumigena index with the mean
(lower line) for the years 1997-2004.
References
Vivi Fleming, Seppo Kaitala 2005: Phytoplankton spring bloom biomass in the Gulf of
Finland, Northern Baltic Proper and Arkona Basin in 2005. HELCOM Indicator fact sheet
2005. http://www.helcom.fi/environment2/ifs/ifs2005/en_GB/estimates/
Vivi Fleming, Seppo Kaitala 2005: Phytoplankton Spring Bloom Intensity Index for the Baltic
Sea Estimated for the years 1992 to 2004 . Hydrobiologia. 554: 57 – 65.
Seppo Kaitala, Maria Laamanen, Seija Hällfors and Heidi Hällfors 2005:
Cyanobacteria bloom index. HELCOM Indicator fact sheet 2005.
http://www.helcom.fi/environment2/ifs/ifs2005/en_GB/bloom_index/
ICES Working Group Report 2006 | 50
Annex 8: Abstract for I CES ASC Session P
ICES CM 2006/Session P
An integrated ecosystem assessment of the Central Baltic Sea and the
Gulf of Riga
Christian Möllmann, B. Müller-Karulis, R. Diekmann, J. Flinkman, G.
Kornilovs, E. Lysiak-Pastuszak, J. Modin, M. Plikshs, Y. Walther, and N.
Wasmund
An integrated ecosystem assessment of two sub-systems of the Baltic Sea was
conducted in the frame of the ICES “Workshop on Developing a Framework
for an Integrated Assessment for the Baltic Sea [WKIAB]”. We present initial
results of meta-analyses of oceanographic, nutrient, phyto- and zooplankton as
well as fisheries data for the Central Baltic Sea (CBS) and the Gulf of Riga
(GOR), the former comprising the highly stratified deep basins of the Baltic
while the latter represents a shallow low saline coastal bay. Considering the
period 1974 to 2004, 88 and 20 variables for the CBS and the GOR,
respectively, were used in a Principal Component Analysis. Our integrated
analyses demonstrate different regimes within the considered period, which
were confirmed by chronological clustering. Major changes in ecosystem
structure (regime shifts) were detected at the end of the 1980s, consistent with
other areas of the world ocean. Our results further contribute to the
understanding of the functioning of the ecosystems under anthropogenic and
climatic pressure.
Keywords: Central Baltic Sea, Chronological Clustering, Gulf of Riga,
Integrated Ecosystem Assessment, Meta-analysis, Principal Component
Analysis
Contact author:
Christian Möllmann: Danish Institute for Fisheries Research, Dept. of Marine
Fisheries, Charlottenlund Castle, DK-2920 Charlottenlund, Denmark[tel: +45
3396 3458, fax: +45 3396 3333, e-mail:, cmo@dfu.min.dk]
ICES Working Group Report 2006 | 51
Annex 9: Re commendations
RECOMMENDATION ACTION
1. To establish WGIAB (see below)
2. database at ICES DC
3.on sturcture of the Baltic committee expert groups
4.on developing a future monitoring strategy
5.
6.
ICES Working Group Report 2006 | 52
Annex 10:
The ICES/HELCOM Working Group on Integrated Assessments of the Baltic Sea
[WGIAB] (Co-Chairs: Christian Möllmann, Denmark, Bärbel Müller-Karulis, Latvia. and
Juha Flinkman, Finland, will meet in Malta from 10–14 March 2007 to:
a) updating and further developing the Integrated Assessments (IA) for the Central
Baltic Sea and the Gulf of Riga, and starting IAs for other subsystems of the
Baltic Sea, i.e. the Gulf of Finland;
b) cooperate with the HELCOM Biodiversity Assessments (BA), especially through
developing an adaptive management framework (DPSIR);
c) develop a common ICES and HELCOM indicator database and link the data to
the HELCOM indicator fact sheets;
d) prepare ecosystem overview and assessment documents as the basis for
ecosystem-based management;
e) provide an inventory on survey and monitoring activities by the different
countries in 2006 for a sound planning of future IAs;
f) review the various ecosystem modelling approaches available for the area and
their importance and utility towards future IAs.
WGIAB will report by DATE to the attention of the Baltic Committee.
Supporting Information
ICES Working Group Report 2006 | 53
PRIORITY: This Working Group is supposed to communicate and coordinate activities integrated
ecosystem activities within and between ICES and HELCOM, specifically to update
ecosystem overview assessments on a regular basis for different subareas, to
conduct/contribute to HELCOM biodiversity and thematic assessments (e.g. pollution,
eutrophication, impact of fisheries) and to use ecosystem modelling in the assessment
work. Implenting this working group is a step towards implementing the ecosystem
approach in the Baltic
SCIENTIFIC The Working Group contributes to Actions 1.2, 1.7, 1.5, 1.7, 1.11, 1.12(1.12.6), 2.2,
JUSTIFICATION AND 2.8, 2.9, 3.2, 3.3, 3.5, 3.6, 3.15, 4.2, 4.2, 4.11, 5.2, 5.3, 5.6, 7.3 of the ICES Action Plan.
RELATION TO
ACTION PLAN:
Key to the implementation of an ecosystem approach to the management of marine
resources and environmental quality is the development of an Integrated Assessment
(IA) of the ecosystem. An IA considers the physical, chemical and biological
environment – including all trophic levels and biological diversity - as well as socio-
economic factors and treats fish and fisheries as an integral part of the environment.
Contrary to e.g. the North Sea (REGNS) an IA for the Baltic ecosystem has not been
developed, although a unique amount of data and expertise is available for the area.
Individual components of a Baltic Sea ecosystem assessment have been prepared within
ICES and HELCOM. ICES is routinely producing advice on the Baltic Sea commercial
fish stocks. HELCOM assesses the effects of eutrophication on the Baltic ecosystem
since in 2005 conducted an assessment of Baltic Sea eutrophication within the
HELCOM EUTRO project. The Baltic Sea Regional Project provides a structure of
coordination centres designed to address fish & fisheries, productivity, ecosystem health
and socioeconomic modules of Baltic Sea management in accordance with the LME
concept.
The Workshop would start the process of establishing an IA for the Baltic Sea by
developing a framework adapted to the ecosystem characteristics, human pressures, as
well as the existing and emerging (e.g. EU Marine Strategy) assessment and
management systems of the area. The first session of the Workshop will set up the
scene: review existing approaches, methodologies, and legal framework(s), identify data
needs and availability, select the appropriate site(s) for trial IA, and, depending on the
identified information needs, initiate discussion on the optimisation of WG/SG/WK
structure under BCC parentship and propose ToRs for these bodies. Trial IAs for
selected sub-areas of the Baltic Sea will be performed to clarify the information needed
and the assessment framework suitable for creating a holistic assessment. The trial IAs
will provide supporting environmental information for fish stock assessment groups and
contributions to the 2006 ASC “Theme Session on Regional Integrated Assessments”.
A suite of biotic, abiotic and socio-economic metrics will be used with the goal to
describe the impact of human activities and natural forcing (climate change) on the
Baltic ecosystem and to derive potential reference points for ecosystem-based
management. This involves multivariate statistical analyses of multiple time- series. The
Workshop will build on the results and experiences of ICES EG related to the Baltic
Sea, e.g. WGBFAS, WGBIFS, SGMAB, SGFFI, SGRPOD, SGEH, SGBEM, WGGIB,
WGZE, WGPE, as well on the experience of relevant HELCOM projects (HELCOM
EUTRO, HELCOM MON-PRO) and subgroups (HELCOM MONAS, HELCOM
LAND). Building on the experiences gained from the trail IA, the Workshop will also
suggest a future structure of working and study groups in the ICES Baltic Committee
and will identify crucial terms of reference that have to be addressed within these
groups to implement the ecosystem approach to Baltic Sea management.
RESOURCE Assistance of the secretariat in maintaining and exchanging information and data to
REQUIREMENTS: potential participants.
PARTICIPANTS: The Working Groupp is expected to attract 25-30 participants, most of who would
contribute data. Although many will be drawn from the ICES scientific community,
success will be crucially dependent on the participation of scientists from outside ICES
(especially HELCOM).
SECRETARIAT None
FACILITIES:
FINANCIAL: None
LINKAGES TO Relevant to the work of the ACE, ACME, and ACFM.
ADVISORY
COMMITTEES:
LINKAGES TO BCC, WGBFAS, WGBAST, REGNS, all SG/WG related to Baltic Sea issues
OTHER COMMITTEES
OR GROUPS:
LINKAGES TO Baltic Sea Regional Project (BSRP), HELCOM, BALTEX
OTHER
ORGANIZATIONS:
SECRETARIAT 100%
MARGINAL COST
SHARE:
ICES Working Group Report 2006 | 54
We suggest that each Expert Group collate and list their recommendations (if any) in a
separate annex to the report. It has not always been clear to whom recommendations are
addressed. Most often, we have seen that recommendations are addressed to:
Another Expert Group under the Advisory or the Science Programme;
The ICES Data Centre;
Generally addressed to ICES;
One or more members of the Expert Group itself.
After submission of the report, the ICES Secretariat will follow up on the recommendations,
which will also include communication of proposed terms of reference to other ICES Expert
Group Chairs. The "Action" column is optional, but in some cases, it would be helpful for
ICES if you would specify to whom the recommendation is addressed.
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