Current scientific management objectives for ICES roundfish stocks are to ensure conservation of the biological resource and do not explicitly consider economic or social objectives. For example, there are currently no objectives to maximize the sustainable yield or to reduce variability in total allowable catches (TACs). This is despite the fact that the current system can result in wide annual fluctuations in TAC, limiting the ability of the fishing industry to plan for the future. Therefore, this study evaluated management strategies that stabilized catches by setting bounds on the interannual variability in TACs. An integrated modelling framework was used, which simulated both the real and observed systems and the interactions between system components. This allowed the evaluation of candidate management strategies with respect to the intrinsic properties of the systems, as well as our ability to observe, monitor, assess, and control them. Strategies were evaluated in terms of risk (measured as the probability of spawning-stock biomass falling below a biomass threshold for the stock) and cumulative yield. In general, bounds on interannual TAC change of 10% and 20% affected the ability to achieve management targets, although the outcome of applying TAC bounds could not have been pre-judged because results were highly dependent on the specific biology of the stock, current status, and the interaction with assessment and management. For example, for North Sea haddock, management became less responsive to fluctuations resulting from large recruitment events. Simulated target fishing mortality levels were rarely achieved, regardless of the TAC bound applied, and actual fishing mortality rates oscillated around the target. In the longer term, more restrictive bounds resulted in oscillations of greater amplitude and wavelength in yield and SSB. Bounds had less effect when a stock was close to the biomass corresponding to the target F. Risk for stocks that are declining or currently at low abundance may be greater, because if bounds restrict the extent to which TACs can be reduced each year, they could lead to collapse of the stock and the loss of all future revenue. However, for a recovered stock or one at high abundance, the loss of yield as a result of bounds would be smaller than that caused by the total collapse of the fishery. At low stock size or if the stock was declining, catches should be changed more rapidly than when the stock was increasing or at a high level, especially high stock sizes acting as an insurance against uncertainty. Therefore, rebuilding strategies, and strategies aimed at maintaining the stock above prescribed limits, should be considered separately.

This paper describes a simulation study that evaluated the performance of the scientific advisory process used by ICES to recommend total allowable catches (TACs) for roundfish stocks. A “management strategy evaluation” approach is used, involving development of an operating model to represent the underlying reality, and an observation model to generate pseudo data that are then used within a management procedure. The management procedure comprises an assessment that uses data to estimate parameters of interest and a decision rule to derive TAC recommendations for the following year. There are two important results: including realistic sources and levels of uncertainty can result in far from optimal management outcomes based on the current procedures; and current ICES biomass and fishing mortality reference points are not always consistent, and several are clearly inappropriate. This is because the types of projection used by ICES do not incorporate important lags between assessing stock status and implementing management measures, and they also ignore important sources of uncertainty about the actual dynamics, as well as our ability to collect data and implement management regulations (i.e. model, measurement, and implementation error, respectively). The simulation approach also showed that better management is not necessarily going to be achieved by improving the assessment, because even with a perfect assessment (where the simulated working group knew stock status perfectly), stocks may crash at fishing levels that standard stochastic projections would suggest were safe. It is proposed that, in future, operating models that represent the best available understanding of the actual system dynamics be used to evaluate models and rules considered for application. These operating models should capture the plausible range of characteristics of the underlying dynamics, but not necessarily model their full complexity. In general, they will be more complex than those used by assessment working groups, so developing management procedures that are robust to a broad range of uncertainty. However, the models and rules used as part of the management procedure should be simpler than those used at present.

Dankel, D. J., Aps, R., Padda, G., Röckmann, C., van der Sluijs, J. P., Wilson, D. C., and Degnbol, P. 2012. Advice under uncertainty in the marine system. – ICES Journal of Marine Science, 69: 3–7. There is some uncertainty in the fisheries science–policy interface. Although progress has been made towards more transparency and participation in fisheries science in ICES Areas, routine use of state-of-the-art quantitative and qualitative tools to address uncertainty systematically is still lacking. Fisheries science that gives advice to policy-making is plagued by uncertainties; the stakes of the policies are high and value-laden and need therefore to be treated as an example of “post-normal science” (PNS). To achieve robust governance, understanding of the characteristics and implications of the scientific uncertainties for management strategies need to come to the centre of the table. This can be achieved using state-of-the-art tools such as pedigree matrices and uncertainty matrices, as developed by PNS scholars and used in similar science–policy arenas on other complex issues. An explicit extension of the peer community within maritime systems will be required to put these new tools in place. These new competences become even more important as many countries within the ICES Area are now embarking on new policies.

The aim of this paper is to assess the potential oil spill related ecological risk for the southern Gulf of Finland coastal waters using the Bayesian Belief Network (BBN) methodology. The BBN prior probabilities were obtained from knowledge on spatial variability in the sensitivity of coastal ecosystem of the southern Gulf of Finland. The sensitivity data represented the three different ecosystem elements: the EU Habitat Directive Annex 1 habitats and associated habitat forming species, the EU Birds Directive Annex 1 birds and seals. Information on bird, seal and habitat layers were integrated into a single measure of ecosystem sensitivity. For this purpose the maximum value of different layers was calculated in each raster cell. The scenario modelling results showed that the western Gulf of Finland could be considered as an area of the highest ecological risk for the all seasons.

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Aps, R., and Lassen, H. 2010. Recovery of depleted Baltic Sea fish stocks: a review. – ICES Journal of Marine Science, 67: 1856–1860. Attempts to recover some depleted Baltic fish stocks between 1995 and 2008 are reviewed. Management measures aimed at recovery were adopted by competent authorities (until 2005 the International Baltic Fisheries Commission, IBSFC), including the Baltic Salmon Action Plan (1997), Long-Term Management Strategy for Cod Stocks in the Baltic Sea (1999), Long-Term Management Strategy for the Sprat Stock in the Baltic Sea (2000), Recovery Plan for Baltic Cod (2001), and the Long-Term Objectives and Strategies for the Management of Baltic Sea Herring (2000–2002). For all stocks, TACs have been set systematically more than the scientific advice based on sustainable exploitation. We interpret this as “decision overfishing”. There is also evidence of extensive underreporting of catches, which is interpreted as “implementation overfishing”. This means that a management body is knowingly maintaining a situation of overfishing. Nevertheless, measures have also been taken to combat the situation. Our analysis suggests that decision overfishing is related strongly to overcapacity of the fleets. The combination of decision overfishing and implementation overfishing, and not the management measures per se, could be the reason for the failure of depleted stocks to recover.

Methods and technology have been developed to solve a wide range of problems in the dynamics of sea currents and to assess their "impact" on objects in the marine environment. Technology can be used for monitoring and forecasting sea currents, for solving the problems of minimizing risks and analyzing marine disasters associated with the choice of the optimal course of the ship, and assessing the pollution of coastal zones, etc. The technology includes a numerical model of marine circulation with improved resolution of coastal zones, a method for solving the inverse problem of contamination of the sea with a passive impurity, and a variational algorithm for constructing the optimal trajectory of the vessel. The methods and technology are illustrated by solving problems of Baltic Sea dynamics. The model of sea dynamics is governed by primitive equations that are solved on a grid with an improved resolution of the selected coastal zone-in this case, the Gulf of Finland. The equations of the model are formulated in a bipolar orthogonal coordinate system with an arbitrary arrangement of poles and the sigma coordinate in the vertical direction. An increase in the horizontal resolution of the allocated zone is achieved due to the displacement of the north pole in the vicinity of the city of St. Petersburg. A class of dangerous technogenic situations and natural phenomena (sea accidents, which can be investigated with the help of the proposed methodology), includes tanker accidents in the case of a possible collision with a stationary object (with "dynamic danger") or a moving object (including another ship), accidents on oil-producing platforms and oil pipelines, and coastal pollution.

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