Baltic Sea Ecosystem Structure and Dynamics – Consequences of Physical and Anthropogenic Forcing.
Conveners: Eero Aro (Finland) and Christian Möllmann (Denmark) (Session L) (Timetable) (Abstract)

Contributions to the Session should address the following themes:

• Evaluation, validation, and calibration of circulation and/or ecological models used for the study of the early life stages of fish.
• New methodologies (e.g. biochemical indices, genetics), technologies (e.g. acoustics/video), analytical or modelling approaches (e.g. coupled biophysical models) that can be used to investigate or characterize prey-predator relationships, larval condition, or origin/fate.
• Provide case studies, particularly examples detailing experiments using a combination of theoretical, field, and laboratory-based methods.

The Life History, Dynamics and Exploitation of Living Marine Resources: Advances in Knowledge and Methodology
(Session K)

• The life history of the principal groups of living marine resources.
• The status and trends in their size or age structure, growth, condition, maturity, and fecundity.
• The interactions of these characteristics with population density and environmental change.
• How these characteristics determine population trends.
• Changes or advances in the methods used to investigate these aspects.

An ecosystem approach is based on the application of appropriate scientific methodologies focused on levels of biological organisation, which encompass the essential structure, processes, functions and interactions among organisms and their environment. The need for an ecosystem approach to management of marine ecosystems and their resources has been clearly identified.

Until recently, there has been a tendency to treat fisheries management and ecosystem issues separately. However, an ecosystem approach redefines the boundaries that have traditionally guided our management strategies. Ecosystem-based management strategies seek to develop a more holistic and integrated approach and emphasize a systemic approach, recognizing that ecosystems function as whole entities.

The Baltic Sea is a comparatively simple ecosystem and the degree of trophic coupling is high. Although the trophic structure of the system is very well documented, relatively little is known about the spatial and temporal ecosystem functioning in relation to environmental forcing and human impact. This is especially true for lower trophic levels.

The physical environment in the Baltic Sea is highly variable due to its semi-enclosed nature and changes in atmospheric forcing. The recent two decades have been characterized by a low frequency of major inflows of North Sea water into the Baltic Sea, which resulted in stagnation of deep water masses. Further, the unusual high NAO period of the 1990s has resulted in a generally warmer and more humid climate in the southern Baltic and a more dry and warm climate in the northern areas. The resulting changes in the hydrography have affected plankton community composition and growth and recruitment of fish stocks. In parallel to this, the Baltic brackish water ecosystem suffers from human impact, i.e. eutrophication and overfishing, which has modulated the ecosystem in many ways. Thus the Baltic Sea is vulnerable to rapid changes and it is sensitive to physical and anthropogenic forcing.

A number of international and multidisciplinary research programs have been conducted in the Baltic Sea during last two decades (e.g., BOOSEX, BASYS, CORE, STORE, BACOMA, IBSSP I and II), and recently new large-scale projects have been initiated (e.g., MARE, BIREME, BSRP, BECAUSE, EFIMAS, GLOBEC-GERMANY). Results of these activities, covering investigations on all trophic levels using both extensive field and laboratory studies as well as modelling exercises, are now available and have the potential to increase the knowledge of the functioning of the Baltic Sea ecosystem, especially with respect to environmental forcing and human impact.

The goal of this Session is to synthesize the existing knowledge to provide a more holistic and integrated view of the functioning of the Baltic Sea ecosystem. Contributions covering studies on phytoplankton and zooplankton up to fish as well as their interactions, with special emphasis on environmental forcing and human impact are welcome.

• Are there any consistent patterns in the North Atlantic cases across trophic levels?
• Is there spatial and/or temporal coherence across geographic areas and ecosystems as is proposed for the North Pacific?
• Are there agreed methods of analysis? In particular, is Principal Components Analysis the most appropriate way to integrate heterogeneous data?
• Is there a generally acceptable explanation? Especially, are the patterns explicable in relatively passive terms as, for example, a low-pass filtering of physical variability? Or do we need basic ecological processes such as switching between different stable equilibria; top-down as well as bottom-up.

Answers to these questions are central to our attempts to introduce ‘ecosystem-based’ management of marine resources. The expected outcome of this Session would be some synthesis of observations and clarifications of concepts for the North Atlantic region.

• The role of the eastern North Atlantic slope current in providing a source of heat and salt and in forming a meridional link between different populations of marine species.
• The influence of the Mediterranean outflow on the properties of the eastern North Atlantic slope current.
• The role of filaments arising from slope current processes in transporting water from the continental shelf into the ocean basins.
• A description of slope processes in the Northwest Atlantic related to the Labrador Current, Gulf Stream eddies, exchanges with the continental shelf at trenches, and the deep western boundary current.
• Analyses of how the energy transported laterally by internal waves and internal tides, generated and reflected at the continental slopes, becomes available for boundary-intensified turbulent diapycnal mixing.
• The role of the slope currents of the North Atlantic in the global thermohaline circulation.
• The influence of climate variability on slope currents.
• The impact of slope current variability on processes in adjacent marginal seas.
• An evaluation of processes on continental slope dynamics arising from modelling and observational studies.
• General processes on continental slopes.

This Session is central to both plankton ecology and fish larval/recruitment work and is essential to attempts to consider larval fish in an ecosystem context for fish stock management purposes.

Contributions addressing any of the following issues will be welcome:

• Hydrobiological questions of temporal and spatial scales of population and metapopulation structures and the action and interaction between larval predators and their plankton prey.
• Plankton invertebrate predator fields and how, as competitors and predators, these may interact with fish population dynamics.
• Behaviours in plankton communities such as feeding in relation to, e.g., turbulence, diel migrations, patchiness, etc.
• Climate change scenarios and match/mismatch between the adaptive physiological ranges of fish larvae and key zooplankton prey, examining growth and production at local to basin scales.
• Questions of how to estimate and index plankton species diversity or productivity in ways meaningful to problems of fish larval/0-group growth, recruitment, and fish stock management.
• Biochemical approaches in studies of food chains, individual growth and survival, diet selection, and the relative trophic efficiencies of predators and prey.
• Post larvae and 0-group stages, which feed in the plankton.
• Consider diet switch in settlement phases to the consumption of the settled elements of epibenthic species production, for demersal species.
• New technologies (acoustics/video) for investigating the relationships between fish larvae and zooplankton, both prey species and competitors or predators such as chaetognaths or jellies.

Ecosystems of marginal and shelf seas are characterized by pronounced gradients and high spatio-temporal variability of both physical-chemical (temperature, salinity, nutrients, oxygen, turbulence) and biotic (e.g. food-web structure, productivity, taxonomic composition) characteristics. In addition, the structure and extent of human impact (eutrophication, pollution, fisheries, bio-invasions) differs between and within the seas. Better understanding of the physical-biological interactions which control the dynamics of the systems and the responses of the systems to natural and anthropogenic forcing is essential for proper management of natural resources, ranging from environmental quality to commercial fish stocks.

Contributions covering the range from detailed studies of the interaction between an organism or community and its environment to 3D ecosystem models are welcome.

The Iberian Atlantic coast extends from Gibraltar to the French border and constitutes a significant proportion of the European continental margin. Traditional uses of the sea and their living resources demand a permanent scientific/technical assessment and surveillance of the marine ecosystem. In fact, oceanographic research in Spain and Portugal has a long tradition with the first marine laboratory founded in Santander (Spain) in 1886.

During recent years marine research in the Iberian peninsula has experienced an important development based on: i) the mobilization and coordination of human resources and capabilities, ii) the implementation of new technologies, and iii) the participation in large integrated research projects mainly funded by the EC (e.g. SARP, SEFOS, SEAMAR, SARDYN, PELASES, JUVESUS, CANIGO, FERRYBOX).

Important collections of data and results are now available and this Session offers an extraordinary opportunity to present new results, discuss progress, and establish the basis for future advances in marine research in this region.

This Session invites contributions on:

• New results from large cooperative research projects conducted in the Iberian Peninsula waters and adjacent shelf seas.
• Critical review and limitations of research projects in this region.
Strategies for a better integration and representation of Iberian oceanographic science in the EU research and assessment bodies.

One of the key requirements for an acoustic survey is the allocation of detected echoes to fish species. This is currently based on ground-truth trawl data and the experience of the scientists. Modern scientific echo sounders are capable of operating at a number of frequencies between 12 and 200 kHz. Different fish species tend to have frequency-specific acoustic properties which may be used to identify fish aggregations to species. The second aim of this Theme Session is to invite papers on the methods for collection, analysis, and use of multi-frequency acoustic survey data specifically for the purpose of species identification.

In particular contributions are invited on:

• Protocols and procedures for the conduct of combined acoustic and bottom trawl surveys.
• Analysis procedures for the combination of acoustic and trawl data, including:
• relationships between acoustic observations and fish captured;
• relationships between acoustic observation on the trawl station and that between stations;
• The use of acoustic survey data for the interpolation of trawl data beyond the point of observation – this would extend to the production on combination indices;
• The use of combined acoustic and trawl indices in the stock assessment process.
• Improvements in bottom trawl survey design to optimise the collection of both types of data.
• The effect of spatio-temporal distribution patterns on the sampling strategy of these surveys.
• Improved algorithms for the detection of the seabed and accounting for the dead zone.
• Methods for collecting, analysing, and combining multi-frequency data, e.g., virtual echograms, etc.
• Descriptions of multifrequency algorithms for the identification of fish species.
• Algorithms for the removal of noise and plankton.
• Verification methods for multifrequency acoustic species identification.
• Case studies for the use of multifrequency data and comparisons of results with the traditional species ID approach.

Contributions to the Session should preferably focus on the inland habitat and as such address:

• The magnitude of non-exploitation anthropogenic impacts in contrast to exploitation.
• The effect of mitigating measures.
• The development of new concepts that embed non-exploitation-related anthropogenic impacts in a precautionary approach to stock management.

The aim of this Session is to bring together researchers who have used acoustic systems to classify and map the seabed for applications in fisheries and ecosystem studies. The philosophy of the Session will focus on how acoustic systems are used in combination with other sampling devices to characterise the seabed at a variety of scales. There are now a number of remote acoustic monitoring systems available for the classification of the seabed. These include commercial systems ranging from low-cost single-beam normal incident echosounders to high-cost multi-beam swath mappers, as well as more complex approaches under development. All these systems allow us to begin to map the seabed in a quasi-synoptic and continuous fashion. Previous mapping and classification has generally been geologically based, using point sampling with grabs and corers. There is now a growing interest in developing marine habitat classifications that are biologically relevant (e.g. marine bioregionalisation, assessing essential fisheries habitat, marine protected areas, and environmental monitoring). The degree to which the hydro-acoustics remote sensing survey approach can be applied to these needs is under constant review.

Contributions which address the following topics are particularly welcome:
• Case studies of marine habitat mapping and classification.
• Incorporation of ground-truthing data and integration with other technologies, e.g., video, towed and stationary physical samplers.
• Analytical and statistical approaches to developing classifications and mapping these.
• Problems of spatial and temporal scale: mapping deepwater seascape at a 100-km scale or mapping a small shallow reef at a 1- to 10-m scale?
• Limitations of the acoustic remote sensed tool for biological surrogacy (e.g. biodiversity).

Will Climate Change alter the Growth of Phytoplankton in the Ocean?
(Session U) CANCELLED

One of the key questions in climate change research is how the biological processes of the ocean will respond to chemical and physical changes in the atmosphere. Over the last decade the consequences of increased CO2 concentrations were studied within JGOFS. Other effects of climate change could encompass increased storms that increase mixing in the upper ocean. Will phytoplankton become more or less productive in such an environment? Windblown dust from soils and desert sands are rich in iron that, when it settles into the ocean, serves as “fertilizer” for the phytoplankton. Will this dust input increase as a result of climate change? Will this increase the efficiency of the biological pump and thereby increase the removal of CO2 from the atmosphere by the ocean?
There is some evidence that larger amounts of iron may be deposited in the ocean in the future as global warming causes increases in wind-blown continental dust. Theoretically, if iron-containing aerosols fall in large regions of the ocean that are limited by iron and rich in other nutrients, then this would act like “fertilizer” to promote burgeoning phytoplankton populations, thus slowing the rate of CO2 increase in the atmosphere and partially offsetting the anticipated warming.

While we know that short-term events dramatically affect phytoplankton concentrations, scientists aren’t sure how changes in ocean circulation and atmospheric forcing over the long term will affect the ocean’s productivity. Does a higher primary production as observed in iron fertilisation experiments also lead to an increased production of heterotrophs and to an enhanced conversion to higher trophic levels? In some areas, the whole marine food chain may be disrupted. Larger fish and mammals might either starve or move to where phytoplankton is more abundant. Linking these intense events with changes in climate variability is one of the most pressing issues in climate research. Yet, long-term trends are difficult to detect when natural variability is so high. A comprehensive programme of observations and modelling is necessary to improve our ability to make predictions on the future course of the Earth system.

In particular contributions are invited on:

• Observations in and comparisons between areas characterized by different limitation regimes.
• Relations between primary and secondary production.
• Food web relations in areas of different nutrient regimes.
• Effects of climatic changes on different hydrographic and hydrodynamic conditions in the ocean surface layers.

The future of aquaculture is dependent on several factors such as environment, water quality, feed resources, and especially development of new feeds based on plant resources, disease treatment methods, a sound generic policy including relationship between wild and farmed animals, development of various technologies for culture and water treatment, and product quality with a similar composition as for wild species. This suggests that many factors are involved in sustainable aquaculture development. This Session will focus particularly on feed resources and water treatment.

In general, the control of the freshwater environment is easier than the coastal zone. The latter environment is going to be more and more important for aquaculture production. It is also more vulnerable in the sense that many activities take place in this area. Water quality is, therefore, the basis for future aquaculture in that zone as well as in freshwater, where the water source is affected by discharged nutrients and pesticides from various activities such as agriculture and forestry as well as various human and industrial wastes. Development of new techniques for farming fish is essential. Shallow raceway systems on land may be one solution of establishing profitable techniques for grow-out.

It is obvious that feed resources of animal origin will be fully exploited in the near future if the present development of carnivorous fish species will increase in aquaculture. At present, more than 35% of the fishmeal and more than 50% of the fish oil resources in the world are used for production of fabricated feed for salmon, eel, and other carnivorous fish species. A sustained aquaculture development is dependent on development of feed based on plant material. Already, a small fraction of fish meal is replaced by soyameal and also fish oils are to some extent replaced by vegetable oil. The latter issue seems to be more problematic if the valuable fatty acid pattern were to remain in the product.

The issue of waste-water treatment includes nutrition factors. The development of fabricated feeds with less protein and higher fat content is an ongoing process, to diminish the nutrient waste from aquaculture systems. However, the process has raised some questions. The product quality of salmonids might be influenced by present trends in fish feed formulations. Further development of treatment units for land-based aquaculture is needed, especially for the large amounts of water used for cleaning the mechanical filters.
Product quality is mostly dependent on the feed used. The development of new fabricated feeds with lesser amounts of substances from animal origin for carnivorous animals is a challenge for the feed industry. The development of technique for using more plant material as raw material for feed is probably one of the most important issues in aquaculture technology for the future.

The Session should be of interest to commercial aquaculturists, managers, and scientists.

Contributions are invited which address:

• Feed resources for culturing various fish and shellfish species.
• Water treatment of the farm’s effluents.
• The technical challenges of the development of offshore or land-based farms.

The development of intensive methods for the culture of marine fishes requires in most cases pre-treatment of the water entering the fish tanks. In many places open systems for intensive cultures are still commonly used, although closed, recirculated systems have received increasing attention over the past years.

Traditional methods for water treatment in open systems have more or less been restricted to filtration of particles, maybe in combination with UV-treatment. These systems have been shown to be vulnerable for pathogens entering the system through the general water supply. An example of this is the VER-disease in larval halibut cultures caused by a NODA-virus. To improve this situation new techniques, including protein skimming and ozone, have been employed with good results. In most cases open systems demand temperature adjustment, which opens the possibility for gas supersaturation. Although recognized, very little is known about the physiological impact low tension gas supersaturation exercises on the organism.

Closed systems have the advantage of high controllability and stability. However, build-up of metabolic wastes like nitrate-compounds, and unfavourable bacterial communities may still be problematic. Ammonium and nitrite may represent severe hazards to the fish, and need to be controlled. Biofilters represent an additional culture that may cause problems, both in sustainability and in efficiency. The use of ozone in combination with protein skimmers has been shown to be very efficient in the removal of suspended particles. Oxidized residuals (e.g., bromate) are suspected to have a long-term negative impact on the fish, due to high redox potentials.

Paper and Poster contributions are particularly welcome on the following topics:

• Examination of methods for water treatment in both open and closed systems for intensive fish culture.
• Physiologic response of fish to environmental factors resulting from the culture conditions.

In recent years there has been increasing interest in marine protected areas (MPAs) to conserve biodiversity and as a fisheries management tool. Experience is accumulating on the effectiveness of MPAs, marine reserves, fishing reserves, and ecological reserves. However many questions remain as to their proper siting, design, and evaluation.

Contributions are particularly welcome on:

• Trade-offs between conserving biodiversity and sustaining fisheries.
• Siting and sizing an MPA in the ICES region from a fisheries science perspective.
• Siting and sizing an MPA in the ICES region from a conservation biology perspective.
• Evaluation of MPA design and experiences from existing MPAs, including biological, economic and social perspectives (e.g. meta-analyses).
• New approaches for the design of MPAs and indices to measure their effectiveness (e.g. modelling studies).
• Regulatory systems for implementing and maintaining the integrity of MPAs.
• What do MPAs offer that could not be achieved by TAC, effort control, and the traditional technical measures of fisheries management?
An anticipated outcome of this Session is an increased awareness of the value of MPAs to fisheries managers in the ICES area and an incorporation of MPA thinking into current practices.

There is an increasing use of biological effects methods to assess human impact on marine ecosystems. There are some cases in which the results from biological effects monitoring have been used to regulate inputs or the use of chemicals. One such example is the ban on TBT as an antifouling agent following monitoring of gastropod masculinisation along European coasts. Another case is the use of benthic community monitoring to regulate the inputs of drilling muds in the Norwegian offshore industry. Although management objectives commonly relate to ecological quality, there is still only limited use of methods to assess biological responses. The proposed session aims to address the question of how suitable the range of available techniques are for management purposes and how they can be implemented in, e.g., marine risk management.

Knowledge about the distribution, ecology and threats to deep-water corals and other habitats on deep shelves, continental slopes, seamounts and mid-ocean ridges has increased considerably on a global scale within the past 10 years. Octocoral forests, Lophelia reefs and giant carbonate mounds are among the highlights of the new discoveries. Many of these discoveries have come from recent multinational surveys (ACES, ECOMOUND). Many of these habitats are structure forming and have many associated species. Synchronous with this increase in knowledge and new discovery has been the realisation that these habitats are under immediate threat, predominantly from fishing activities.

Papers are invited on:

• Mapping, distribution and environmental correlates of cold-water corals and other deep-water habitats.
• Ecological importance of these corals and habitats.
• Evidence of damage to, and resilience of, these corals and habitats.
• Advantages and disadvantages of various protection mechanisms in deep water areas.

The present proposal relates to the availability of much unpublished information on cephalopod biology and fisheries arising from various EC-funded R&D projects. The Theme Session will facilitate the wider dissemination and publication of some of these results, with the long-term aim of providing information on future management decisions for the major fished stocks of cephalopods in European waters. European research programmes related to cephalopod biology and fisheries should also consider knowledge acquired on cephalopod populations outside the NE Atlantic. The Theme Session therefore also invites scientists working on cephalopod stocks outside the NE Atlantic to bring their expertise into the ICES community.

Papers presented should focus on one or more of the following topics:

• The current state of knowledge on exploited cephalopods (biology, fisheries, environmental relationships, stock identity) in European waters.
• Current fishery data collection, stock assessment, and management practices for cephalopod capture fisheries world-wide.
• The current status of cephalopod culture and the prospects for commercial aquaculture.
• Socio-economic issues related to cephalopod fisheries.
• Current knowledge of aspects of cephalopod biology and ecology related to their suitability as resource species for capture and culture fisheries, including life-history and ecological data and assessment of environmental factors which affect the immuno-competence and physiology of cephalopods.
• Assessment and management options for currently unregulated cephalopod fisheries.

The Theme Session is intended to encourage the exchange of ideas and collaboration among scientists in different areas of marine research that have interests in the survivability and recruitment of fish eggs/larvae. For example, “BASECOEX” (http://www.nfh.uit.no/projects/basecoex) is a multidisciplinary research programme (2001-2004), which integrates physical oceanography and field and experimental marine biology on a confined area and time-scale. Rooted in new theories, technologies, and models, the main aim of the programme is to establish new insights to the apparent lack of coexistence between capelin and herring in the Barents Sea ecosystem since the inter-annual abundance for the two species fluctuates inversely. Hence, we seek to investigate the linkage between capelin and herring and the role of herring and other potential predators on capelin larvae through meso-scale field investigations and laboratory studies.

Papers are invited on similar case studies from the North Atlantic, North Pacific, and adjacent shelves and seas. Papers should, in particular, address:

• The interplay between meso-scale physical forcing and the spatio-temporal distribution and behaviour of zooplankton, pelagic fish eggs/larvae, and predatory macro-zooplankton and fishes.
• Causes of mortality among pelagic fish eggs/larvae, e.g. predation, environmental stress, and brood fish-offspring linkages with respect to first-feeding failure.
• New field-based techniques and methodologies that are likely to yield useful information to ecosystem research.

Stock identification is an interdisciplinary field that involves the recognition of self-sustaining components within natural populations. Stock identification remains a central theme in fisheries science and management. Indeed, the reliability of stock assessments and therefore the effectiveness of fishery management are severely limited for many principal fishery resources, because stock structure and delineation are uncertain. Despite its importance, stock identification remains one of the most confusing subjects in fisheries science for non-specialists.

The ICES Stock Identification Methods Working Group was established to review methodologies of stock identification and develop a protocol for the application of stock identification results. The Group was organized in an open format to invite a wide participation of experts on stock identification to summarize the various approaches. Over the last decade, the Group has compiled a volume of contributions aimed at synthesizing the many disciplines involved in stock identification and focusing on the application of results to fishery science and management. Contributors to the publication and other researchers or managers with expertise in stock identification approaches are invited to present case studies or reviews relevant to stock identification.

Fishery managers are increasingly being required to take into account ecological considerations. Many of the high-profile issues which impact upon fisheries management stem from multispecies or ecosystem concerns. For example, discarding of non-target species and the extent of marine mammal bycatch, or the indirect impact of fishing and hence reduced stocks on predators and/or competing species. There remains little consensus concerning the conceptual and analytical tools that should be used to study marine ecosystems. Modelling remains one of the few tools available to address this new agenda. The past two decades have seen an explosive growth in the number and type of multispecies models directed at fisheries questions. It would thus seem timely that ICES dedicate a Theme Session within its Annual Science Conference to this important and growing field of research.

It is becoming very apparent that individual stocks cannot be managed in isolation. Technical measures aimed at protecting cod, for example, will also have impacts on haddock and whiting catches. Conversely, quotas for one species (e.g. haddock) are increasingly being reduced in order to protect stocks of a second species (e.g. cod) accidentally caught as bycatch in mixed fisheries. Recent developments in modelling technologies and in computer power mean that technical and biological interactions can now be taken into account in fisheries assessments, although the value of actually doing so remains somewhat equivocal.

Contributions are invited on:

• Assessment models which incorporate biological interactions (predator-prey relationships).
• Assessment models which incorporate technical interactions (including discarding and accidental bycatch).
• Contributions which assess the benefits of adding complexity to models and the issue of ‘minimum realistic models’.
• Other ecosystem/multispecies modelling approaches (e.g. size-based approaches).
• Models useful for evaluating marine mammal-fishery or seabird-fishery interactions.
• Multispecies models which consider the overlap in the geographic distribution of predators and their prey.