I am interested in the application of genetic techniques to answer fisheries-related questions. I am currently doing a PhD in the Molecular Ecology and Fisheries Genetics Laboratory (MEFGL). The project aims to integrate genetic data into the general framework of stock assessment and management to assure more sustainable exploitation of marine fish species. Commercial marine fish species are assessed and managed throughout stocks. The stock is the unit of study in fisheries science. Genetic markers offer a significant contribution in defining stock units. The match between stock units used in assessment and management and the biological units, as identified perhaps by genetic methods, is essential to have reliable stock assessment and management. The first part of my project is to understand to what extent genetic data has been used in defining stock units of commercial marine fish species in the European Seas. I am focusing on fish species assessed and managed in the North-East Atlantic Ocean and the Mediterranean Sea. After reviewing available evidence on genetic population structure, the presence of mismatches between biological and current management units will be evaluated. Successively, the biological and economic impacts of these mismatches will be explored. In the second part of the project, I will contribute to developing a portable DNA based method to identify and quantify the species composition in mixed fisheries of mesopelagic fish.