Deliverable D5.1 – “Blue Assessment VRE Specification” aims to provide a detailed description of the requirements, the specifications, the effort and the design of the Blue Assessment VREs within Work Package 5. The Blue Assessment Work Package develops and exploits two ‘generic’ VREs, each of which will be customizable to meet community needs for specific functionality: Stock Assessment VRE and the Global Record of Stocks and Fisheries. Those VREs have been set-up to offer environments where experts in the domain can identify the data sources to exploit, select the candidate models, identifies the software frameworks and applications to exploit, and perform validations of the chosen resources.