Recirculating Aquaculture Systems (RAS)

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 requires 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 pollution. 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.