Why should we opt for a flowing water aquaculture system?

Traditional aquaculture faces dual challenges from resources and the environment: producing one tonne of fish consumes 15,000 tonnes of freshwater, while accumulated uneaten feed triggers water eutrophication. Stagnant water and high-density farming lead to frequent disease outbreaks. Seeking high-quality, sustainable development within limited resources is crucial for future progress.

I. What is a Flow-Through Aquaculture System?

A flow-through aquaculture system is a technical model enabling high-density, intensive fish farming through artificial control of water flow direction, velocity, and circulation patterns. Its core function involves removing fish excreta and replenishing oxygen via water movement, while maintaining water quality stability through physical filtration, biological purification (e.g., microbial decomposition), and chemical treatment (e.g., ozone sterilisation).

Open-flow systems: Rely on continuous inflow from natural sources (e.g., rivers, mountain springs) with direct outflow of used water; suitable for mountainous terraced farming.

Technical Highlights:

Intelligent Monitoring: Real-time tracking of dissolved oxygen, pH, ammonia nitrogen, etc., with automatic alerts and water quality adjustments.

Segregated Waste Removal: Bottom drains collect solid waste while surface overflow pipes remove oil contamination, reducing post-treatment burdens.

Low-carbon design: Features such as air-lift aerators replace conventional motors, achieving over 30% energy savings.

II. Why is a flowing water aquaculture system necessary?

Its emergence addresses four major pain points in traditional farming:

Resource pressure: Conventional pond farming consumes up to 15,000 tonnes of water per tonne of fish produced, whereas recirculating systems reduce this to under 100 tonnes.

Environmental pollution: Uneaten feed and excrement cause water eutrophication.

Frequent Disease Outbreaks: High-density static water farming is prone to epidemic outbreaks; flowing systems mitigate risks through UV and ozone disinfection.

Land Constraints: Urbanisation reduces farming space; vertical flowing troughs (e.g., high-rise farming workshops) increase yield per unit area tenfold.

III. Global Market Share and Regional Characteristics

Based on aquaculture market size data (2022 global total: CNY 1.4148 trillion) and technology application analysis:

Asia (dominant market, 65% share): China serves as the core driver, with flow-through aquaculture accounting for 44% of total aquatic production (2024). Hainan Free Trade Port develops deep-sea wave-resistant cages; Zhejiang promotes the ‘runway fish’ model (IPRS), reducing grass carp farming cycles by 30%¹².

Americas (20% share): Mississippi dominates catfish farming with large-scale IPRS systems, converting waste into fertiliser via automated suction devices⁵.

Europe (12% share): Subject to stringent ecological standards, Dutch smart greenhouse shrimp farms employ closed RAS systems integrated with photovoltaic power generation, reducing energy dependency by 30%.

Africa/Middle East (3% share): At an early stage yet highly innovative, Saudi Arabia combines desalination with solar-powered recirculation systems, while Israel achieves factory-scale sturgeon farming in arid regions.

IV. Analysis of Four Core Advantages:

1. Ecological Sustainability:

Water savings exceeding 90%, with effluent meeting discharge standards or reused for agricultural irrigation.

Reduced antibiotic usage, achieving ‘zero drug residue’ in red-spotted seabass farming in Sanya, Hainan.

2. Significant Economic Benefits:

Increased yield per unit: Factory-farmed sea bass in Xinjiang produces 5 tonnes annually per tank (80m³), an eightfold increase over traditional ponds.

Cost optimisation: Automated feeding and waste extraction systems reduce labour costs by 30%.

3. Enhanced Quality and Safety:

Constant water flow promotes fish exercise, yielding firm flesh (e.g., Xiuning mountain spring grass carp commands a 50% premium per jin).

Fully controlled environments prevent heavy metal contamination.

4. Intelligent and intensive operations:

IoT management: 120 systems in Ningde, Fujian transmit 8 million data points annually with <0.4% failure rate.

‘Multi-storey aquaculture’ model: High-rise shrimp farming at Fengjiawan Industrial Park in Wenchang boosts land use efficiency by 300%.

V. Future Trends and Key Development Directions Technological Evolution Pathways:

Deep-sea expansion: Wanning, Hainan, develops storm-resistant cages for deep-sea breeding of high-body yellowtail amberjack fry;

Breeding chip breakthroughs: Molecular breeding cultivates disease-resistant strains, such as genetically tagged Litopenaeus vannamei shrimp;

Tertiary Industry Integration Innovation: Xiuning County, Anhui's ‘ancient fishpond tourism + dining experience’ model boosts farmer incomes by 30%.

Flow-fed aquaculture systems represent an imminent industrial revolution for traditional fish farming. This technologically-empowered approach transforms fisheries from weather-dependent to hydrology-informed operations, embodying the exquisite fusion of hydrodynamics and ecological engineering. From mountain streams to deep seas, from tradition to innovation, this approach enables farmers to achieve more efficient and sustainable aquaculture with economic returns, while providing consumers with high-quality, safe fish products.

The flowing water speaks not, yet the future is already here. Flow-through aquaculture systems have become the mainstream model in farming. With continuous development, they will undoubtedly become the most advantageous support for fish farmers!