What is aquaculture: types, advantages and species that reach your table

What is aquaculture?

Aquaculture is the controlled cultivation of aquatic organisms —fish, mollusks, crustaceans, and algae—in freshwater, brackish, or saltwater environments. Unlike traditional fishing, which captures wild animals from their natural habitat, aquaculture involves raising and managing these organisms throughout their life cycle in specially designed facilities: floating cages, rafts, ponds, land-based tanks, or coastal nurseries.

Simply put: if fishing is "hunting" at sea, aquaculture is "farming" in the water. It is to the ocean what livestock farming and agriculture are to the land.

And the figures speak for themselves: global aquaculture production reached 130,9 million tons in 2022, already representing 51% of all aquatic animals produced on the planet.

Types of aquaculture

Aquaculture is not a single system, but encompasses different cultivation methods that vary according to the environment, intensity, and technology used.

Marine aquaculture (mariculture)

It takes place in the ocean or in coastal facilities with saltwater. It is the most common type of fishing in Spain thanks to our 8.000 km of coastline. It includes:

• Floating cages in the open sea: for species such as gilthead seabream, European seabass and bluefin tuna.
• Bateas: floating platforms for mussel farming, typical of the Galician estuaries.
• Coastal nurseries: land-based tanks fed with seawater, such as those used for turbot in Galicia.

Continental (freshwater) aquaculture

It is carried out in ponds, fish farms, lakes, or terrestrial tanks with freshwater. In Spain, the star species is the rainbow trout , farmed in the interior of the peninsula using mountain rivers and streams.

According to the intensity of production

Each system has its advantages. Extensive farming is more environmentally friendly but produces less volume. Intensive farming allows for higher production per square meter, but requires more technology and monitoring.

Innovative systems

Beyond the three classic levels, modern aquaculture is advancing with technologies that combine efficiency and sustainability:

• Recirculating Air Systems (RAS): They operate in a closed circuit, reusing water. Ideal for areas with water scarcity or for growing crops near consumer markets.
• Integrated Multitrophic Aquaculture (IMTA): It combines different species in the same system: fish waste serves as a nutrient for algae, and the algae filter the water. A balanced ecosystem.
• Offshore aquaculture: Submersible cages in deep waters, far from the coast, with less visual and environmental impact.

Main species cultivated in Spain

Spain is the leading aquaculture producer in the European Union , accounting for 23% of the total EU volume. In 2024, production reached 268.564 tons , valued at €856,5 million . The main species are:

Main aquaculture species in Spain: gilthead seabream, European seabass, mussel, trout and turbot

Mussel: the undisputed king

With 184.593 tons per year, Spain produces 7 out of every 10 tons of mussels cultivated in the EU. They are grown on rafts in the Galician estuaries using extensive aquaculture: the mussels feed solely by filtering water, without the need for feed. It is one of the most sustainable farming methods available.

Lubin

The second most produced species by volume ( 27.376 tons ). It is farmed in sea cages in the Mediterranean, primarily in the Region of Murcia, the Valencian Community, and Andalusia. It is a versatile fish with mild, white flesh, ideal for both grilling and baking.

Golden

An emblematic species of Mediterranean aquaculture ( 10.765 tons ). The Valencian Community accounts for 63% of national production. Prized for its flavor and texture, it is a favorite in Spanish cuisine.

Rainbow trout

Main species of continental aquaculture ( 16.693 tons ). It is farmed in inland fish farms taking advantage of the cold, oxygenated waters of mountain rivers.

Turbot

Spain is the world's largest producer of farmed turbot ( 10.058 tons ), and 100% of it is farmed in Galicia, in land-based tanks using seawater. It is a product of high gastronomic value.

Bluefin tuna

With 10.312 tons and a value of €184,4 million , bluefin tuna farmed in sea cages (mainly in Murcia) is the species with the highest economic value per ton. Salmon (https://www.delfinultracongelados.es/salmon/), although not farmed in Spain, is another of the most consumed aquaculture species in our country, sourced from other markets such as Norway and Scotland.

Advantages of aquaculture

Why does aquaculture continue to grow? Because it offers advantages that neither traditional fishing nor other forms of animal production can match.

Environmental sustainability

The data is conclusive:

• 15 times less CO₂ than cattle farming. Producing 1 kg of farmed sea bass generates 2,4 kg of CO₂, compared to 36 kg for beef.
• 20 to 100 times less land use than terrestrial livestock farming.
• Superior food efficiency: Only 1,78 kg of feed is needed to produce 1 kg of fish, compared to 5 kg for pigs and 10 kg for cattle.
• Farmed mussels and algae act as carbon sinks, absorbing CO₂ from the water.
• It reduces pressure on the wild populations overexploited, allowing them to recover.

Food safety and traceability

• High quality protein, rich in omega-3, vitamins and essential minerals.
• Complete traceability From the farm to your table. 99% of Spanish aquaculture production has quality certifications.
• Planned and predictable production, which does not depend on variable catches or weather conditions.
• Permanent veterinary control and biosecurity plans in 100% of production centers.

Economic engine

• 856,5 millones de euros of value at first sale (Spain, 2024).
• More than 11.500 direct jobs In Spain: 1 in 4 aquaculture jobs in the EU.
• Key economic engine for regions such as Galicia, Murcia, Valencian Community and Andalusia.

Availability all year round

Unlike fishing, which is subject to closed seasons, quotas, and fishing bans, aquaculture allows for fresh fish to be available 365 days a year . This is especially important when combined with deep freezing (https://www.delfinultracongelados.es/ultracongelados-y-congelados/), which allows the fish to be preserved at its peak freshness for months.

Aquaculture and ultra-freezing: the perfect combination

Aquaculture and deep freezing complement each other like few other things in the food industry. Together, they solve one of the industry's biggest challenges: bringing top-quality fish to any home, at any time of year.

Why do they work so well together?

• Maximum freshness at the time of freezing. Farmed fish can be processed and flash-frozen practically at the time of harvest, minimizing the time between extraction and freezing.
• Product homogeneity. Farmed fish have more uniform sizes, which makes processing easier and ensures consistent portions.
• Stable supply chain. Planned production allows companies like Delfín Ultracongelados to offer constant product availability, without depending on variable catches.
• Property preservation. Ultra-freezing at -40°C (compared to -18°C in a domestic freezer) creates microcrystals of ice that do not damage the fish cells. The result: the flavor, texture, proteins, and omega-3 fatty acids remain virtually intact.

Paradoxically, frozen fish can retain more nutrients than supposedly "fresh" fish that has spent several days in the distribution chain. If you'd like to learn more about the differences, we recommend our article on wild vs. farmed salmon.

Myths and realities about farmed fish

Farmed fish suffers from some prejudices that don't correspond to reality. Let's debunk the most common ones.

“It has fewer nutritional properties than the wild variety.”

False. Farmed fish provides high-quality protein, omega-3 fatty acids, and essential minerals. The WHO and EFSA recommend consuming fish 2-3 times per week, without distinguishing between wild and farmed fish. Both are highly nutritious foods.

“It’s full of antibiotics and hormones”

False. The use of growth hormones is prohibited in EU aquaculture (Royal Decree 2178/2004). Antibiotics are only used occasionally to treat specific diseases, always under veterinary prescription and with a mandatory withdrawal period before marketing. 51% of veterinary medicines authorized for aquaculture in Europe are preventative vaccines.

“It tastes worse than wild fish”

It depends. Taste differences exist, but they vary depending on the species and farming method. Farmed fish offers a more consistent and predictable flavor. In blind taste tests, many consumers can't tell the difference, especially in cooked products.

“Aquaculture destroys the environment”

Not well-managed aquaculture. As we've seen, it generates 15 times less CO₂ than cattle farming, uses between 20 and 100 times less land, and farmed mussels act as carbon sinks. Furthermore, it reduces pressure on overexploited wild populations.

FAQ

What is the difference between fishing and aquaculture?

Wild-caught fishing captures wild organisms from their natural environment (rivers, seas, oceans). Aquaculture raises and cultivates these organisms in a controlled manner in specific facilities (cages, ponds, rafts). It's the same difference as between hunting and livestock farming.

Is farmed fish safe?

Yes. In Spain, 99% of production has quality certifications, all facilities implement biosecurity plans, and the product undergoes continuous veterinary controls. EU standards are among the strictest in the world.

Which aquaculture species are most consumed in Spain?

Mussels are the most cultivated species by volume (184.593 tons), followed by sea bass, rainbow trout, gilthead seabream, turbot, and bluefin tuna. Among imported species, salmon, primarily from Norway and Scotland, stands out.

Is aquaculture sustainable?

Yes, especially compared to other forms of animal production. It generates significantly fewer CO₂ emissions, uses less land and water, and has a much higher feed conversion efficiency. Furthermore, it allows wild fish populations to recover by reducing fishing pressure.

Why is frozen farmed fish a good option?

Because it combines the advantages of both worlds: the controlled quality of aquaculture (traceability, consistency, availability) with the optimal preservation of deep freezing (maintaining flavor, texture, and nutritional properties for months). It's the most efficient way to enjoy quality fish anytime.