What is Aquaculture? UK Fish Farming, Water Quality Standards and Tank Storage Solutions

Aquaculture is the farming of aquatic organisms including fish, shellfish, seaweed, and other aquatic plants in controlled freshwater and marine environments. It is one of the fastest-growing food production systems in the world, already supplying more than half of all seafood consumed globally. Whether you have heard it called fish farming, mariculture, or simply aquafarming, this guide covers everything you need to know: the types of aquaculture, the UK fish farming landscape, the regulations every operation must meet, water quality standards, and the tank storage infrastructure that makes it all work.

What is Aquaculture? 

Aquaculture is the farming of aquatic organisms including fish, molluscs, crustaceans, aquatic plants, and algae in controlled or semi-controlled aquatic environments. It is the water-based equivalent of agriculture, applied to rivers, lakes, coastal waters, and enclosed land-based tank systems.

The key distinction between aquaculture and conventional fishing is one of control. Capture fisheries rely on harvesting wild aquatic organisms from open seas and rivers. Aquaculture involves deliberate cultivation: stocking, feeding, managing water quality, and harvesting under regulated conditions. The Food and Agriculture Organization (FAO) recognises aquaculture as the single most important source of growth in global food fish supply, with worldwide aquaculture production now exceeding capture fisheries in volume for the first time in recorded history.

Types of Aquaculture: What Are the Main Methods?

Aquaculture is not a single method but a broad category of farming practices. The main types of aquaculture vary by species, environment, and production system.

Fish Farming

Fish farming is the most common form of aquaculture, involving species such as salmon, trout, tilapia, and catfish raised in net pens, ponds, or enclosed tank systems. It takes place across both freshwater and marine environments. Freshwater aquaculture typically produces trout, tilapia, and catfish; marine aquaculture most commonly produces Atlantic salmon in coastal net pen systems. On-land fish farming operations rely on correctly specified tank infrastructure to maintain water quality throughout the production cycle. HDPE-lined corrugated steel tanks are the industry standard for holding, treatment, and recirculating systems, chosen for their non-toxic surface, ease of cleaning, and large capacity range.

Shellfish Aquaculture

Shellfish aquaculture covers the cultivation of oysters, mussels, clams, and scallops. Shellfish feed by filtering nutrients from the water column, requiring no supplementary feed, making shellfish aquaculture one of the most environmentally benign production methods available. In the UK, oyster and mussel farming is well established in Wales, Scotland, and Cornwall.

Seaweed Farming

Seaweed farming (algaculture) is the cultivation of marine algae and aquatic plants. It requires no land, freshwater, fertiliser, or feed, making it one of the lowest-impact food production methods available. Seaweed absorbs excess nitrogen and phosphorus from surrounding waters and sequesters carbon at impressive rates. UK waters offer excellent conditions for seaweed farming, and commercial-scale operations are growing rapidly.

Shrimp Farming

Shrimp farming is one of the most economically significant aquaculture sectors globally. Intensive shrimp farming production systems typically operate in coastal ponds or enclosed tank systems with careful management of water quality, salinity, and dissolved oxygen. The management practices required mean that robust water storage infrastructure is essential for any viable operation.

Recirculating Aquaculture Systems (RAS)

Recirculating aquaculture systems (RAS) represent the most technologically advanced production method in modern aquaculture. Rather than drawing continuously on natural water sources, RAS filter, treat, and recirculate water within a closed loop, dramatically reducing water consumption, effluent discharge, and disease risk. A recirculation aquaculture system typically incorporates mechanical filtration, biological filtration, UV sterilisation, and oxygenation. These systems require reliable, large-capacity tank infrastructure. Butek Tanks corrugated steel tanks, available from 2m3 to 5,000m3, are well suited to RAS installations due to their modular sectional design and compatibility with standard pipework fittings.

Why is Aquaculture Important?

The most pressing reason aquaculture matters is straightforward: the world's wild fish stocks can no longer meet global demand for seafood. According to the Food and Agriculture Organization, over 35% of the world's fisheries are now classified as overfished. Global aquaculture production has therefore become essential to food security, with aquaculture and fisheries together employing an estimated 600 million people worldwide.

Aquaculture also offers a compelling feed conversion advantage over land-based livestock. It takes approximately 6.8 pounds of feed to produce a pound of beef, but only around 1.1 pounds of feed to produce a pound of farmed fish, making fish production one of the most resource-efficient sources of animal protein available.

UK Fish Farming: The State of the Aquaculture Industry in Britain

The UK aquaculture industry is diverse and economically significant. Scotland dominates salmon aquaculture, producing around 200,000 tonnes of Atlantic salmon per year, making it the third-largest salmon-producing nation in the world. Salmon production faces growing regulatory pressure around sea lice, fish escapes, and water quality, driving operators towards more controlled land-based steel tank systems with closed-loop water treatment.

Freshwater aquaculture in the UK primarily involves rainbow trout farming, as well as smaller-scale production of carp, tilapia, and catfish in heated indoor facilities. Offshore aquaculture is an emerging frontier, with submersible cage systems being piloted in UK waters for salmon and sea bass production. The UK also has a well-established shellfish sector with oyster and mussel farming across Wales, Scotland, and South-West England, alongside a rapidly growing seaweed farming industry supported by government and conservation bodies.

UK Aquaculture Regulations and National Legislation

Anyone establishing or operating an aquaculture farm in the UK must navigate a clear regulatory framework. National aquaculture legislation exists to protect human health, wild fish populations, and the wider aquatic environment.

Key regulatory bodies include:

• DEFRA (Department for Environment, Food and Rural Affairs) is the primary body responsible for aquaculture policy in England.
• The Food Standards Agency (FSA) regulates food safety standards for farmed fish and shellfish destined for human consumption. Its standards broadly align with food and drug administration requirements for export markets.
• The Environment Agency governs water discharge consents and abstraction licences for aquaculture operations in England.
• The Marine Management Organisation (MMO) oversees marine licensing for offshore cage systems and coastal aquaculture infrastructure.

Core legislation includes the Aquatic Animal Health Regulations 2009, the Environmental Permitting Regulations 2016 (governing effluent discharge), and Water Framework Directive requirements retained in UK law post-Brexit. Standards from the national oceanic and atmospheric administration and Food and Agriculture Organization also inform UK policy development, particularly for aquaculture operations targeting export markets.

Water Quality in Aquaculture: Standards Every Fish Farm Must Meet

Water quality is the single most critical determinant of production success in aquaculture. Without consistently high-quality water, farmed fish and shellfish will suffer stress, disease, and mortality regardless of the quality of feed or management. The following parameters must be monitored continuously across all aquaculture systems. This is also where the choice of tank liner material becomes critically important, as the wrong liner can leach contaminants that disrupt these parameters.

• Dissolved Oxygen: Most farmed species require DO levels above 7 mg/L. Salmon and trout require 8 to 10 mg/L for optimal growth.
• Temperature: Atlantic salmon perform best at 8 to 14 degrees C; tilapia prefer 25 to 30 degrees C. Temperature management is especially critical in freshwater aquaculture and RAS facilities.
• Ammonia: Fish excrete ammonia as a metabolic waste product. Total ammonia nitrogen must be maintained below 0.02 mg/L unionised ammonia to avoid gill damage.
• Nitrate and Nitrite: Elevated nitrite is highly toxic. In RAS systems, nitrate accumulation must be managed through partial water exchange or denitrification.
• pH: Most marine and freshwater species tolerate pH 6.5 to 8.5. Extremes suppress immune function and increase susceptibility to pathogens.
• Turbidity: High turbidity impairs gill function and reduces feed efficiency. Mechanical filtration and settling systems manage suspended solids in enclosed aquaculture systems.

Clean, correctly lined storage tanks play a vital role in maintaining these standards. HDPE liner kits are the preferred choice in aquaculture because HDPE is non-toxic, non-leaching, and easy to disinfect, making it the global standard for fish farming tank liners. For operations storing liquid fertilisers or chemicals alongside water, Landflex ES liners offer excellent chemical resistance, while Butyl rubber liners are the premier choice for potable and clean water contact.

Aquaculture Facilities and Tank Storage Solutions

The physical infrastructure of an aquaculture facility is fundamental to operational performance. Tanks serve multiple roles: holding and treating source water, housing live stock, supporting recirculation and filtration, and containing effluent before discharge. Butek Tanks, a UK steel tank manufacturer operating since 1965, supplies corrugated steel water storage tanks used across the aquaculture sector, with volumes ranging from 2m3 to 5,000m3, the largest range available in the UK.

HDPE-lined tanks are the aquaculture industry standard. HDPE is chemically inert, has no leachable substances that could affect fish health, and is the easiest liner material to clean and disinfect between production cycles. Butek Tanks manufactures HDPE liner kits in-house, combining them with Magnelis coated corrugated steel shells that offer superior corrosion resistance in the humid conditions typical of fish farms.

Roof Kits for Aquaculture Tanks

Open-top tanks in fish farming environments are susceptible to algae growth, contamination from wildlife, and evaporative water loss. Butek Tanks roof kits include Anti-Algae Covers that block sunlight without restricting access, Aqua-Float covers that prevent up to 98% of evaporation, and heavy-duty Steel Roof Kits for outdoor tanks in exposed locations.

Accessories for Aquaculture Systems

A complete aquaculture tank system needs more than a shell and a liner. Butek Tanks accessories include inlets and outlets from 2 to 12 inches compatible with Camlock, BSP, and Bauer fittings; gate, ball, and butterfly valves for flow control between RAS stages; level indicators; vortex inhibitors to protect pump equipment; and lockable low-level man-ways for tank cleaning and maintenance. Rainwater harvesting kits are also available for operations looking to reduce mains water dependency.

Butek Tanks provides a full installation service using directly employed, fully accredited site teams, including a free site survey, RAMS documentation, and ongoing maintenance support.

The Environmental Impacts of Aquaculture

Aquaculture carries both positive and negative environmental implications. On the positive side, it reduces pressure on wild stocks from capture fisheries, enables local food production, and creates economic opportunity in coastal communities. Shellfish aquaculture actively improves water quality, and seaweed farming sequesters carbon while absorbing nutrient runoff. RAS systems eliminate effluent discharge to natural water bodies entirely.

Challenges include water pollution from poorly managed effluent, disease and sea lice spread from farmed to wild fish, and the historical use of wild-caught fish meal in aquafeed. The shift to land-based enclosed aquaculture operations with properly lined and covered tank systems directly addresses many of these issues in aquaculture. Closed tanks eliminate fish escape risk, allow effluent collection and treatment, and enable far more precise water quality management than open-water systems.

The Future of Aquaculture in the UK

The FAO projects that aquaculture will account for over 60% of global seafood production by 2030. In the UK, several trends are shaping the sector's next decade: large-scale land-based RAS projects for Atlantic salmon production are in planning across Scotland and England; seaweed farming is moving from niche to commercial scale; offshore aquaculture development is being piloted in open UK waters; and sustainable aquafeed innovation is reducing dependence on wild-caught fish meal. The consistent requirement across all of these developments is reliable, scalable, and correctly specified water storage infrastructure.

Frequently Asked Questions About Aquaculture

What is aquaculture in simple terms?

Aquaculture is the farming of aquatic organisms including fish, shellfish, seaweed, and other aquatic plants in controlled freshwater or marine environments. It is the water-based equivalent of agriculture.

What are the main types of aquaculture?

The main types of aquaculture are fish farming (salmon, trout, tilapia, catfish), shellfish aquaculture (oysters, mussels), seaweed farming, shrimp farming, and recirculating aquaculture systems (RAS).

What aquaculture species are farmed in the UK?

The main species farmed in the UK are Atlantic salmon, rainbow trout, oysters, mussels, and seaweed. Smaller-scale production of tilapia, catfish, and carp also exists in land-based indoor facilities.

What water quality standards must UK fish farms meet?

UK fish farms must comply with the Environmental Permitting Regulations (for water discharge), the Aquatic Animal Health Regulations, and Water Framework Directive requirements. Key parameters including dissolved oxygen, ammonia, temperature, and pH must be maintained within species-specific safe ranges.

What type of tank is best for aquaculture?

HDPE-lined corrugated steel tanks are the industry standard. HDPE is non-toxic, non-leaching, and easy to clean. Butek Tanks supplies HDPE-lined steel tanks in sizes from 2m3 to 5,000m3, fully customisable for freshwater, marine, and RAS applications.

Conclusion

Aquaculture is already essential to global food production and the UK sector is set to grow significantly across fish farming, shellfish, seaweed, and land-based RAS operations over the coming decade. None of this growth is possible without the right infrastructure. Whether you are establishing a new aquaculture farm or expanding an existing aquaculture facility, Butek Tanks has the products, expertise, and installation capability to support your project. Contact our team today for a free site survey on +44 (0)1277 653 281.