Scientific understanding and knowledge of the marine environment and its state on the one hand, and data and models to translate this into meaningful and useful information to support sustainable development, and, if necessary, effective interventions on the other hand, are therefore both crucial for marine environmental policy. The MyOcean Ocean Forecasting Systems bring to European Governmental Agencies a revolution. With a coupled physical-bio-geochemical forecasting capacity, monitoring the ocean state and its trends is now feasible. Current state estimates can be provided in real-time as well as inter-annual statistics to measure variability and trends at various space and time-scales (required by the ecological processes) against a given “reference” state (or initial state). What-if scenarios can also be performed by these systems exploring the impact of specific conditions for the future. The use of operational oceanography products opens the way to objective and scientific analysis and quantification of climate change impacts on the targeted marine ecosystems at different time and spatial scales through model downscaling. A set of environmental indicators will be presented and taken from the halieutic domain. Still challenges are not resolved as model uncertainties are big when you come to “under-observed” variables such as bio-geochemical ones and to low frequency signal such as climate change (50 years).