This deliverable defines a comprehensive suite of indicators designed to assess and communicate sustainability in the aquafood sector, specifically focusing on capture fisheries, aquaculture, and nutrition. These indicators address critical dimensions of sustainability, environmental, and nutritional impacts, providing a measurable and evidence-based foundation for evaluating sustainability. Fisheries indicators: A suite of 21 indicators has been identified to measure sustainability in capture fisheries. These indicators include stock status metrics such as BMSY (biomass at maximum sustainable yield) and FMSY (fishing mortality at maximum sustainable yield), which assess whether fish populations are harvested within ecological limits. Indicators for ecosystem impacts evaluate habitat disruption, trophic effects, and bycatch rates, with a particular focus on vulnerable or endangered species. Climate-related indicators, such as CO2 emissions per kilogram of landed catch, highlight the carbon footprint of fishing activities and the environmental impact of gear types. Additional metrics address governance, such as compliance with fisheries management plans and efforts to prevent illegal, unreported, and unregulated fishing. These indicators are critical for monitoring the health of fish stocks, minimising ecological harm, and ensuring long-term viability of marine resources. Aquaculture indicators span a range of environmental, economic, and operational aspects, reflecting the complexity of this sector, as well as provide insights into the sustainability of aquaculture practices. Key metrics include feed efficiency, such as the food conversion ratio, and the use of wild-caught marine ingredients in feeds, which have implications for marine food webs. Indicators for waste and pollution, such as nutrient emissions and plastic reuse or recycling, assess the environmental footprint of aquaculture facilities. Habitat impact metrics evaluate site selection and potential alterations to surrounding ecosystems.Biosecurity measures, including antimicrobial use and disease management practices, reflect efforts to mitigate risks to animal health and productivity. Nutrition indicators focus on the composition and health benefits of aquafoods. These include high-quality protein content, which is essential for muscle maintenance and overall health, and the presence of omega-3 fatty acids such as EPA and DHA, which support heart and brain health. Micronutrient indicators vitamins andminerals, such as vitamin D, selenium, and iodine, which are vital for immune function, bone health, and metabolic processes. The indicators also consider energy content, sodium, and the ratio of saturated to unsaturated fats, reflecting the overall nutritional profile of aquafood. These metrics align with public health objectives, promoting aquafood as a nutrient-dense, potentially climate-friendly protein source. The indicators provide a basis for a rigorous framework for evaluating sustainability across fisheries, aquaculture, and nutrition. They are grounded in scientifically validated methodologies and reflect key priorities such as biodiversity conservation, resource efficiency, and public health. By enabling the measurement and communication of sustainability in the aquafood sector, these indicators can support informed decision-making and foster a more sustainable future for this vital sector in Europe.