Mussel aquaculture in Thermaikos Gulf is facing a great challenge to tackle both institutional and production planning aspects. Local stakeholders are concerned about the future design of an efficient and equitable legal planning framework for the aquaculture, as well as about the improvement of production planning in order to optimize the total economic outcome of mussel activity in the area. The present paper focuses on the assessment of alternative production planning decisions, under the assumption that an efficient and socially acceptable institutional framework is already established. To this end, a case-specific decision-making tool is designed aiming to combine simulation modelling and multicriteria analysis. The main interactions between the environmental and cultivation conditions and the socio-economic parameters of the local aquaculture are specified according to a previous modelling effort concerning the long-line mussel farms of the study area. These interactions are then incorporated into a multicriteria model, which is formulated to handle the decision-making problem of selecting the best alternative planning decisions. This is actually a problem of evaluating and choosing the most promising policy options in terms of local society preferences. An integrated approach is followed, by means of an analytic hierarchy process, aiming at analysing the preferences of local community by determining the weights for a specific set of (sustainability) criteria. The relative importance of these criteria is determined through a questionnaire survey among the local stakeholders. The results from this application show that future planning policies should focus on production techniques, which are likely to enhance the quality of mussel production and, at the same time, to minimize the economic risk associated with the local occurrence of Harmful Algal Bloom events.