This project targets the urgent challenge to reduce nutrients to BSR waters, limit GHG emissions, and quickly enhance European self-supply with food, feed and energy. Together, aquaculture, agriculture, and the industry can provide solutions to the challenge by connecting in industrial symbioses based on full exploitation of local blue/green biomasses that are initially grown and/or harvested with the particular objective to produce positive ecosystem services. Thus, the very production of e.g. grass, mussels or seaweed to enter the industrial symbioses improves carbon storage, reduces nitrogen deposits to the atmosphere and the water. In "bio-industrial symbioses", each company produces bio-products and transfers residuals as resources to the next companies in the chain. Thus, one biomass leads to more consumer goods and to an improved local environment. Experiences have shown that local authorities play crucial roles in initiating industrial symbioses. While a number of industrial symbiosis toolkits are already available, practitioners in municipalities need a toolkit that addresses the enhanced complexity when the symbiosis is also including the landscape and primary production (agriculture, aquaculture). The Blue-Green Toolkit to be developed in this project targets those practitioners, and enable them to become identifiers of local resource streams, facilitators of company matchmaking and value-chain workshops, and mediators of conducive policy environments.