The MedAID project (Mediterranean Aquaculture Integrated Development) aims to increase the competitiveness and sustainability of the Mediterranean marine fish aquaculture sector along its value chain, by improving its technical productivity and economic performance with a market- and consumer-oriented approach, as well as higher social and environmental acceptability and better governance (Aguilera et al. 2019). The development of aquaculture will necessarily involve an increase in the spaces devoted to this activity, due to the expansion of existing businesses and / or the creation of new ones. Conflicts with the use of marine space and the implementation of existing policies and legislation are two of the main factors hindering aquaculture growth (Galparsoro et al. 2020). There are needs to improve Marine Spatial Management to facilitate site selection processes, establish transparent procedures and licencing process and thus reduce the length and cost to develop new aquaculture activities. In addition, the increase of production will generate a proportional increase in the amounts of feed, which are often produced outside the countries concerned. If aquaculture is to double its production by 2030, the sector must improve its productivity, without compromising environmental performance (Lotze et al., 2019). Aquaculture can affect ecosystems (socially, economically, environmentally) positively or negatively, and aquaculture could be impacted by other human activities. Environmental impacts vary greatly depending on the type of farming (inland open flow, RAS, cages in protected areas or offshore) and husbandry practices (species, stocking density, feed composition, etc ...). As for marine fish, whereas fry production takes place in inland hatcheries, as well as many pre-ongrowing farms, most ongrowing production takes place in sea cages, where the carrying capacity of the surrounding environment (hydrodynamic circulation, sediment characteritics etc...) is a critical constraint. To ensure a sustainable development, ecological carrying capacity should be considered and environmental impacts of aquaculture should be minimized by either improving farm management, production system, site selection, etc... In addition, all other uses of water and natural resources must also contribute to ensuring sustainable ecosystem services. The objective of this report (D8.5) was to review inputs and recommendations from international organizations and recent EU projects on Environmental Impact assessment, Environmental monitoring procedures and discuss technical solutions to reduce environmental impacts of Mediterranean fish farming and promote environmental sustainable development. After a brief introduction on Mediterranean fish farming production based on Medaid results, the “Ecosystem Approach to Aquaculture” (EAA) framework and the general aquaculture constraints at different spatial scales (farm, waterbody and regional scales) are described. We then focused on the key steps of EAA: Marine Spatial Planning (MSP), Site Selection, Environmental Impact Assessment (EIA) and Environmental Monitoring Procedure (EMP) and explained how recent EU projects have developed tools an methods to facilitate these differents steps. We reviewed decision support tools and methods tested and developed to facilitate spatial planning ( AQUASPACE), site selection and licencing procedures (TAPAS). We then have listed key indicators selected by stakeholders for Environmental Impact Assessment (EIA) and Environmental Monitoring Procedure (EMP) during different projects (including Indam, PerformFish). Finally, the local (eutrophication) and global (fisheries ressources use, foot print) environmental impacts related to feed and fish faeces are discussed. The main strategies and recommendations to minimize impacts of feed are: improving feed utilization through improvement of FCR, feed composition or best management practices , develop innovative farming systems such as recirculating aquaculture system (RAS) and Integrated Multi-trophic Aquaculture (IMTA) to improve the treatment and valorization of waste. Finally, prevention of fish escapees are reviewed (Prevent-Escape project).