Recirculating aquaculture systems (RAS) significantly reduce water usage in fish farming — using up to 95% less water than traditional open-net methods — while preventing effluent discharge into natural waterways and eliminating the operational need for antibiotics or synthetic chemicals. These land-based, closed-loop systems create controlled production environments that can reduce carbon emissions per kilogram of fish compared to conventional farming approaches.
Understanding land-based aquaculture and its measurable environmental characteristics
Land-based fish farming using RAS technology represents a distinct approach to aquaculture that uses closed-loop water systems, preventing waste discharge into natural water bodies whilst meeting growing global demand for seafood. Unlike traditional open-net farming, these closed systems are designed to retain water and waste within the production facility.
The core operational principles of RAS-based aquaculture include water recirculation, mechanical and biological waste processing, and controlled energy use. These systems eliminate the risk of farmed fish escaping into wild populations and reduce the transmission routes for diseases that can affect natural ecosystems. By controlling the production environment, these farms can operate without antibiotics or synthetic chemicals.
We at Finnforel have built our operations around these principles through land-based trout farming in Finland. Our closed-loop approach demonstrates how RAS technology can change the operational profile of aquaculture. Learn more about our farming practices and discover how our technology choices shape our production model.
What makes Finnforel’s trout farming distinct from conventional methods?
Our operational model is built on recirculating aquaculture systems (RAS), a category of closed-loop fish farming technology. These land-based facilities recycle water continuously whilst maintaining controlled conditions for trout growth, and they do not discharge liquid waste into surrounding waterways.
The Varkaus facility exemplifies this approach, producing three million kilograms of trout annually whilst using 95% less water than traditional open-net farming methods. The facility’s closed-loop technology captures and processes all waste products, converting them into byproducts such as organic fertiliser.
Our RAS technology maintains precise control over water temperature, oxygen levels, and waste processing. This design eliminates several environmental risks associated with open-water farming, including nutrient discharge, habitat disruption, and genetic mixing with wild fish populations. The system’s water efficiency also reduces the energy required per kilogram of fish produced compared to flow-through systems.
How do recirculating aquaculture systems reduce water pollution?
RAS technology prevents effluent discharge through multi-stage filtration and water recycling processes that capture waste before it can enter natural water systems. The technology employs multiple treatment stages, including mechanical filtration, biological treatment, and UV sterilisation.
The system continuously removes solid waste through drum filters and settling tanks, whilst beneficial bacteria convert harmful ammonia into less toxic compounds. This biological filtration process operates in a controlled environment that prevents discharge into surrounding waters.
Traditional open-net farming can discharge significant quantities of nitrogen and phosphorus into marine environments, contributing to algal blooms and oxygen depletion. Our closed-system design eliminates liquid waste discharge, using less than 5% of the water required by conventional open-net methods.
Why does local production matter for carbon emissions and supply chain efficiency?
Local production reduces transportation-related emissions by positioning farms close to consumer markets. Our land-based facilities can be located near urban centres, reducing the distances involved in seafood distribution compared to internationally sourced product.
Our same-day delivery model — from production to retail — reduces the energy required for extended cold storage and can reduce packaging needs. This shortened supply chain is associated with carbon emission reductions of up to 80% compared to imported seafood, based on the reduction in transport distance and cold-chain energy use.
Proximity to consumers also reduces food waste throughout the supply chain. Products with shorter distribution routes reach consumers fresher, extending shelf life, and local distribution networks can respond more quickly to demand fluctuations, reducing overproduction and waste.
What are the documented environmental characteristics of land-based fish farming?
Land-based fish farming using RAS reduces pressure on wild fish stocks by providing a production route that does not involve ocean extraction or open-water net pens. This approach supports wild stock levels by offering an alternative protein source that does not depend on depleting ocean ecosystems or disrupting marine food chains.
The carbon footprint per kilogram of fish produced in a closed RAS facility is lower than that of several other animal protein sources, including beef and pork, when measured at the farm gate. When distribution distances are also considered, locally produced RAS fish compares favourably to imported seafood across multiple emission categories.
Our expansion plans, including potential international projects, aim to replicate these operational characteristics in other regions. By deploying RAS technology in additional markets, we contribute to a broader shift in how seafood is produced, offering a model that other regions can adapt to their specific production and environmental conditions.
Land-based aquaculture: measurable environmental characteristics
Land-based fish farming using closed-loop RAS technology addresses several environmental challenges through its design: water recirculation reduces freshwater consumption, contained waste processing prevents effluent discharge, and local siting reduces transport-related emissions. Together, these operational features give RAS-based production a distinct environmental profile compared to open-net or flow-through systems.
Our contribution to reducing aquaculture’s water use and effluent output demonstrates that commercially viable fish production can be achieved within a closed-loop model that does not discharge waste into natural waterways. The technology and methods we employ show that measurable environmental outcomes and commercial objectives can be pursued together in modern food production.
Choosing fish produced in land-based RAS facilities supports a production model with documented reductions in water use, effluent discharge, and transport emissions. Contact us to learn how our production approach aligns with your procurement or environmental criteria, or explore our operational commitments to land-based aquaculture production.
