STOCKMED Deliverable 15. Implementation of the GIS_MCDA framework scoring and comparing criteria and decision factors with the preparation of a synopsis of the stock units and the corresponding stock boundaries

Within the STOCKMED project, a methodological framework has been developed for identifying stock units and related boundaries of fishery resources according to a multidisciplinary approach. The present document describes the application of the developed framework to 19 fish and shellfish species of fishery interest in the Mediterranean. In Mediterranean, very few studies about the identification of populations exist and the knowledge of stock structure is still very fragmentary, related to few species, and limited in terms of spatial scale. In this context, this study represents the first attempt to face up with the issue of stock units identification at a Mediterranean scale using a formal multidisciplinary approach. It intends to be a simple and transparent approach which arises from an original conjugation of methods of spatial analysis, multi-criteria analysis and Geographic Information Systems. The results of the application of the STOCKMED methodological framework to 19 fish and shellfish species of fishery interest in the Mediterranean have been presented. The most plausible Hypotheses of stock structure have been identified. In some cases, there is agreement between the ranking based on the mean Cohen's Kappa and the acceptability analysis, suggesting that a single hypothesis is highly favoured. In other cases, the discrimination of the alternatives provided by both mean Cohen's Kappa and acceptability analysis is too weak to express a single preference. It must be pointed out that despite the framework has been conceived to be applicable even in poor-data situations, the reliability of results is strongly dependent from adequate data availability within the appropriate spatial scale.