To halt the loss of biodiversity in accordance with the Convention on Biodiversity (CBD) and the Aichi objectives, France aims to classify 10% of its territory as a strong protection zone by 2030. These new conservation zones will have to fit into the puzzle of marine spatial planning and respond in space and time to ecological, economic, social and be resilient to climatic issues. Resilience in marine population is tightly linked to population connectivity. Population connectivity enables genetic mixing and accelerates the recovery of a population after a demographic accident. On land, this is achieved through the "green and blue network", by creating corridors of green spaces, removing dams on rivers, and building animal bridges over freeways to link natural areas together. At sea, we call it the "marine blue grid", but it's invisible to us humans. It cannot be developed, but follows the currents of the sea, a network of underwater routes that the vast majority of marine species must use. How can we imagine it? This seminar will present the current state of knowledge and research on the marine blue network in the Gulf of Lion (French Mediterranean coast) as a template methodology for the on-going work on Andaman islands.