When done in a sustainable way, aquaculture can help to solve some of the most pressing issues we face today.

- Aquaculture delivers nutritious and diverse food to a growing world population.

- Aquaculture reduces the need to catch more wild fish to meet the increasing demand for fish and therefore contributes to preserving fish stocks.

- It can provide food that is fresh and local. Supplying food closer to the consumer allows reducing carbon emissions in transport.

- Aquaculture can produce food and feed with a lower climate and environmental impact than other types of farming (e.g. farming of bovine animals for milk or meat). By consuming more food from aquaculture, we can also reduce the pressure of farming on land.

- Aquaculture activities can be a source of income and development for remote coastal and rural communities where few alternatives are available. Certain types of aquacultures contribute to the preservation of ecosystems and biodiversity (e.g. mollusc farming, extensive aquaculture in ponds and wetlands, and the farming of algae and other invertebrates). These services include cleaning the water from excess nutrients and organic matter or the conservation and restoration of ecosystems and biodiversity.

- Before aquaculture farms can operate, future aquaculture producers must obtain an authorisation from the competent national authorities (sometimes regional authorities may be responsible for authorisations). In their assessment, the authorities check if the location proposed is suitable and carefully verify the potential impact of the farm on the environment.

- Aquaculture producers need authorisation before using seawater or fresh water for the farm. When they return it to the environment, the status of the water body must not deteriorate.

- In addition, aquaculture establishments must be registered or approved by sanitary authorities dealing with animal health, and both the farmer and these authorities have an obligation to carry out surveillance for possible diseases.

- Once all authoritations are obtained, aquaculture producers have to comply with several conditions to ensure that aquaculture activities are respectful of the environment, human and animal health and animal welfare.

- Authorised farms must continue to monitor their impact on the environment.

- To protect the environment, producers may only use authorised feed, cleaning products and medicines.

- With respect to animal health, farmers also have the obligation to keep several records, including those concerning how many animals enter and leave the farm and how many die. They must also record the measures they take to prevent and manage any risk of disease. To protect consumers’ health, aquaculture farmers must follow strict rules on food hygiene and animal health. They must only use authorised and controlled feed.

- The use of veterinary medicines requires a prescription from a veterinarian, and only authorised veterinary medicines are permitted, respecting prescribed withdrawal periods and residue limits. Farmers must record all the veterinary medicines they use and keep a copy of the prescriptions.

- In addition, farmers must ensure humane treatment of farmed animals throughout their production cycle and during slaughtering and transport.

To know if an aquaculture project can be carried out in an area, a viability study of the area (e.g. availability of quality water, non-interference with other uses, conditions for the establishment of aquaculture sites in the area) and of the possible species to be farmed must be carried out. There are many possible sites for aquaculture (e.g. on land, in coastal waters, offshore, estuarine, in ponds, next to rivers). To get a license, each site has different conditions and the studies to be carried out are different. The competent authorities sometimes identify previously studied areas where aquaculture activity is possible and prioritised, and this makes obtaining permits for a farm in the area quicker.

Although in theory all fish species could be used for aquaculture farming, only a few of them (around 10) are currently an important part of EU aquaculture production. In particular, those species whose biology is well-known and whose reproduction in captivity is possible are farmed. At the same time, there needs to be a market demand for these species and a market price that allows the production to be profitable.

There are very diverse production methods for EU aquaculture species, some of the main ones are the following (STECF Aquaculture economic data table, 2023):

- Enclosures, pens, recirculation systems and tanks for salmon;

- Tanks and raceways, recirculation systems and ponds for trout;

- Pens, tanks, ponds, recirculation systems for sea bass and sea bream;

- Rafts, polyculture, logline for mussels;

- Ponds, tanks, raceways, gages, polyculture for carp;

- On-bottom, longline, rafts and polyculture for oyster;

- Ponds, raceways, tanks for crustaceans;

- On bottom, tanks and raceways, pens, recirculation systems, polyculture, rafts, longline, tanks for seaweed;

- Open or closed-system bioreactors for microalgae.

In addition, during the early growth stages, most fish species and seaweeds need to be in a hatchery and a nursery. Seeds of molluscs are produced in hatcheries or collected from the wild.

Like any economic activity, aquaculture has an impact on the environment. This depends on the quality of management of the activity, the suitability of the location and the production system. When properly managed, aquaculture can also be a method of protein production with a lower carbon and environmental footprint than other types of farming. Furthermore, certain forms of aquaculture (e.g. mollusc farming, aquaculture in ponds and wetlands, and the farming of algae and other invertebrates), when appropriately managed, can offer many ecosystem services. These services include the absorption of excess nutrients and organic matter from the environment or the conservation and restoration of ecosystems and biodiversity.

EU environmental legislation and implementing national legislation have set the regulatory framework for EU aquaculture that ensures the mitigation of the impact that aquaculture activities may have on the environment (be it in terms of carbon footprint, effluents, waste or other impacts on marine and freshwater ecosystems), and that aquaculture activities do not significantly harm ecosystems or biodiversity.

The environmental performance of the EU aquaculture sector can nevertheless be further improved by: (i) ensuring that environmental legislation is fully applied and its objectives are met; (ii) further mitigating the impact of aquaculture; and (iii) promoting aquaculture with lower environmental impact and aquaculture that provides ecosystem services.

The ‘Strategic guidelines for a more sustainable and competitive EU aquaculture for the period 2021 to 2030’ aim to improve the environmental performance of the aquaculture sector by further limiting the impact of aquaculture, as well as promoting the types of aquaculture that are most beneficial for the environment and the climate such as low trophic aquaculture and organic aquaculture.