A recirculating aquaculture system (RAS) is an advanced fish farming technology that continuously filters and reuses water in closed-loop tanks, enabling land-based fish production with reduced environmental discharge compared to flow-through systems. This innovative approach allows fish to be raised near consumers whilst maintaining optimal water quality through sophisticated filtration systems. Learn more about Finnforel’s fish farming practices and how this technology is reshaping the aquaculture industry.
What is a recirculating aquaculture system and how does it work?
A recirculating aquaculture system operates by continuously cycling water through specialised filtration components that remove waste, add oxygen, and maintain optimal conditions for fish growth. The system creates a controlled environment where water quality parameters such as temperature, oxygen levels, and pH remain stable throughout the production cycle.
The core components include mechanical filters that remove solid waste, biological filters containing beneficial bacteria that convert harmful ammonia into less toxic compounds, and oxygenation systems that ensure adequate dissolved oxygen levels. UV sterilisation units eliminate pathogens, whilst temperature control systems maintain ideal growing conditions year-round.
This closed-loop design enables fish farming in locations previously unsuitable for aquaculture, including urban areas and regions far from natural water bodies. The technology represents a significant advancement in modern aquaculture, offering precise control over environmental factors that directly impact fish health and growth rates.
How does Finnforel raise rainbow trout in its production facilities?
We operate comprehensive production facilities that manage the entire lifecycle from healthy roe to premium fillets using advanced RAS technology. Our Varkaus Gigafactory produces three million kilograms of rainbow trout annually, demonstrating the scalability of land-based, closed-loop fish farming.
Our production process begins at the Hollola breeding centre, which specialises in broodstock management and fry production specifically for recirculating systems. This integrated approach ensures genetic quality and optimal adaptation to RAS environments from the earliest life stages.
The complete control over our production chain enables processing and packaging on-site, delivering fresh fish to retailers on the same day. This vertical integration reduces handling stress on fish, maintains product quality, and significantly shortens the time from harvest to consumer, ensuring maximum freshness and nutritional value.
How does a recirculating system differ from traditional fish farming in terms of resource use?
Water efficiency represents a measurable operational advantage, as RAS technology uses up to 99% less water than conventional flow-through systems. The closed-loop design eliminates the continuous discharge of nutrient-rich wastewater into natural ecosystems, which in open systems can contribute to eutrophication and reduced local water quality.
Land-based production can reduce transportation distances by enabling fish farming near population centres. Shorter supply chains may lower carbon emissions associated with long-distance shipping and can reduce food waste through improved logistics coordination.
The controlled environment removes the need for antibiotics and chemicals that are commonly used in open-water farming, whilst the closed system prevents fish escapes that could affect wild fish populations. Solid waste from RAS facilities can be collected and processed for use as agricultural fertiliser, enabling material recovery within the production cycle.
What benefits does a recirculating system offer consumers?
Consumers receive exceptionally fresh fish through local production that eliminates lengthy transportation and storage periods typical of imported seafood. The controlled environment ensures consistent quality and taste profiles throughout the year, regardless of seasonal variations.
Food safety standards in RAS production benefit from the controlled environment and reduced exposure to environmental contaminants compared to open-water systems. Our LOHI brand offers fresh rainbow trout fillets in individual and family portions, plus alder-smoked varieties, whilst Saimaan Tuore focuses on domestic market requirements.
Year-round availability ensures stable pricing and supply, protecting consumers from market fluctuations common with wild-caught or seasonally dependent fish sources. The traceability inherent in RAS production provides complete transparency about fish origin, feed sources, and production methods.
How does Finnforel ensure fish welfare in recirculating systems?
Continuous water quality monitoring maintains optimal conditions through automated systems that track oxygen levels, temperature, pH, and waste concentrations in real-time. This precise control reduces the stress factors that fish may experience in less controlled farming environments.
Our feeding protocols utilise high-quality feed from Raisio’s Fenno Aqua production, specifically formulated for both traditional and recirculating aquaculture systems. This specialised nutrition supports optimal growth rates whilst maintaining fish health throughout the production cycle.
Stocking densities are carefully managed to provide adequate space for natural swimming behaviours whilst maintaining efficient production. Regular health monitoring and preventive care protocols ensure early detection and treatment of any potential issues, maintaining high welfare standards throughout the fish lifecycle.
What are the future opportunities for recirculating aquaculture systems?
Technological advancement continues to improve system efficiency and reduce operational costs, making RAS technology increasingly viable for global food production. Automation and artificial intelligence integration promise further optimisation of feeding, water quality management, and fish health monitoring.
The role of recirculating aquaculture in global food security becomes increasingly important as traditional fishing grounds face pressure and climate change impacts marine ecosystems. RAS technology offers a scalable solution for protein production that can be implemented worldwide, regardless of geographical or climatic constraints. Contact us to learn more about our aquaculture operations, or discover more about how Finnforel raises fish for your next meal.
