This review aims to be a representative overview over the available types of trophic models in order to investigate, if their output can be used to quantify existing food-web indicators for the EU Marine Strategy Framework Directive (MSFD) . The goal is to obtain a comprehensive picture of the applicability of various model approaches to contribute to achieving MSFD objectives. The work will feed into XWEBS Task 3.3 on ’ Evaluation of the model application potential’. In total we have identified 27 food-web related models with different application areas in the Baltic Sea. We highlight the specific purpose for which each model was designed and the key assumptions underlying each model.

The assessment of model applicability here is focused on strengths and gaps of the models to realistically depict size and dynamics of functional groups in the Baltic Sea food web. Based on the latter, we illustrate existing gaps in the models, and assess the extent to which the models can be applied to represent status and dynamics of the Baltic Sea food webs. For the future, we recommend to use an ensemble approach where possible to determine guild biomasses as indicators for food web status. Spatial heterogeneity should be accounted for. This issue should be initiated by collecting all relevant processes in the Baltic Sea, such as source-sinks or coastal-offshore connectivity. The spatial and temporal scale of ecosystem models and potential food web indicators should be aligned as far as possible, and following functional criteria, such as topographic differences and known separated community structures. This way, one can avoid erroneous conclusions that are based on limited data projected over the whole Baltic.