GAIN aims to support the intensification of the aquaculture industry in the EU and European Economic Area while ensuring the sustainability and compliance of such intensification with EU regulations on food and environmental safety, therefore requiring the integration of scientific and technical innovations as well as social and economic policies to promote the implementation of the principles of circular economy. By developing and optimizing feeds without increasing the pressure on wild fish stocks and land ingredients, improving the utilization of by products, side-streams, and secondary materials to minimize environmental footprint and improve profit, and using sensor, biomarker and Big data, as well as predictive models to improve feed conversion and fish welfare, and reduce waste in aquaculture farms, GAIN will address integrated policies and assess which barriers are currently hindering the implementation of circular economy in the aquaculture production.