International maritime policies aim to achieve environmental sustainability through effective regulation and management of sea-based activities, such as transport, offshore energy, tourism, coastal development, fisheries, and aquaculture. Ecosystem based management (EBM) is the accepted regulatory mechanism for managing the sustainable use of marine goods and services while maintaining good environmental status. The SYMBIOSES RTD (Research & Technology Development) initiative creates a new modeling system designed to support the practical application of EBM as an effective management approach. SYMBIOSES is expected to move forward from todays regulatory risk assessment procedures towards procedures that are more ecologically-relevant. The system connects individual models into a computational framework located on a supercomputer. It is designed to simulate marine ecosystem components in three dimensional space and time and predict impacts from selected combinations of sea based activities i.e. fisheries and petroleum operations. Model output will be visualised through a user-friendly graphical interface.