Recirculating Aquaculture Systems (RAS)

We are the global leaders in RAS

Today, Skretting is the market leader for feeds specifically designed for recirculating aquaculture systems.


Recirculating Aquaculture Systems are land-based aquaculture facilities that reuse water by cycling it through a filtration system so it can be used again. The highly sustainable nature of these operations reduces the amount of water and space needed for aquaculture. The population of RAS-based facilities has grown exponentially and more are being implemented worldwide, year after year. The increased use of RAS represents a paradigm shift for aquaculture as they are becoming the standard, not only for early stages in freshwater, but the entire life cycle for many species.

RAS farming can be a fully controlled system offering a number of advantages and opportunities. Firstly, it alleviates the need for aquaculture to be in an existing environmental ecosystem that complements the species. This allows the convenience of diversity with species and location. Secondly, the overall health and growth of the species can be improved as water quality is carefully monitored to ensure conditions remain optimal. Some of the parameters monitored regularly include oxygen, carbon dioxide, pH, temperature, nitrite, nitrate and ammonia. Finally, RAS also require very little water and space making it much more sustainable in comparison to traditional methods. 

RAS come with their own unique challenges, in particular maintaining consistent water quality. The filtration of organic matter (physical and dissolved waste) produced by the aquaculture species needs to be efficiently removed by the system in order to reduce the water. The system uses an array of filters including a live microbial filter (bio-filter) that is key in removing and reducing harmful dissolved waste. It is essential that all other filters remove excess waste and nutrients so that the microbial balance remains in this filter. It is imperative to only use optimal diets to decrease waste output and maximise filtration in order to maintain high quality water conditions thus improving growth, FCR, product availability and increased biomass. 

Skretting has invested many research resources into RAS because of their potential to enhance the sustainability of the aquaculture industry. We have three dedicated RAS-based research facilities across the world, each of which has a unique focus. Our central RAS team at the Skretting Aquaculture Research Centre (ARC) is comprised of many knowledgeable researchers,specialising in these systems.

Learn more about Skretting RAS research

The knowledge and expertise that Skretting continues to amass along with the R&D facilities that we have in place will prove invaluable as more and more of these systems come on stream
RecircReady graphic

Skretting’s dedicated concept for RAS, RecircReady, was introduced to the global aquaculture market back in 2009 - an industry first. The concept takes into account modelling capabilities, nutrient recycling solutions and health monitoring in addition to tailored feed solutions.

Learn more about RecircReady

Skretting feed

Feed the fish, feed the system

Skretting’s first feed for RAS was an industry milestone, designed to provide farmers with the best possible solution to optimise land-based production based on three key principles: improve faeces quality, make mechanical filtration more efficient, and reduce nutrient load for biofilters.

Consistency is important for RAS to successfully maintain the rearing environment. For this reason, we have meticulous procedures to ensure that the physical and nutritional quality is consistent from batch to batch. We also use turbidity testing to evaluate the impact water quality to validate the performance of the pellet in water.

See our feed solutions for RAS

RAS in the news

RAS equipment Skretting
Feednavigator on Skretting and RAS

Skretting, a pioneer in diets specifically designed for recirculating aquaculture systems (RAS), has upgraded its integrated feed concept for the closed containment farmed fish production method.

RAS equipment Skretting
Intrafish on Skretting and RAS

Skretting upgrades Norway research facilities with new RAS unit. The company added 12 independent recirculating aquaculture systems to its research center in Stavanger for land-based salmon, trout feed trials.


RAS facilities Skretting
The Fish Site on Skretting and RAS

Skretting, the world’s largest supplier of specialised recirculating aquaculture system (RAS) feeds, is ready to launch a new line of feeds called RecircReady.

RAS news from Skretting


Skretting North America at Aquaculture America tradeshow and Trout Farmers Social event, San Antonio, Texas

Aquaculture America, the industry’s biggest trade show in North America returned this year. The event was held in the beautiful city of San Antonio, Texas and brought the aquaculture industry together again and this time in person. Considering the current situation, there were specific measures in place related to COVID-19 safety protocols.

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Sustainability report banner

Accelerating the sustainable growth of aquaculture: concrete targets underpin Skretting’s sustainability strategy

Published today, Skretting’s Sustainability Report 2020 identifies some of the key initiatives undertaken to ensure that fish and shrimp producers can increasingly contribute to global food and nutritional security.

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Employee Highlight - Jeremiah Kerr, Quality Assurance Supervisor

Jeremiah Kerr, Quality Assurance Supervisor Skretting Canada East speaks to us about his experience working with Skretting, his love for running and more.

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In this section

RAS Research
RAS technical guidance