3 cheers for the RAS

Aquaculture is a relatively new industry and has thus seen many advancements over the past few decades.  Many of these tweak efficiencies to improve feed conversion ratio (FCR), pump water more efficiently or monitor some important facet of the living environment to increase profits.  The greatest of all of these technologies must surely be the recirculating aquaculture system (RAS), which allows the user to farm virtually any fish species at any location; I even had a client who farmed marine fish 450km from the ocean at an altitude of 1400m.
 
A RAS is basically a set of fish tanks that are placed inside an insulated environment and then heated or cooled to maintain optimal conditions for the species of fish being farmed, regardless of the climate.  Due to the high capital cost of these systems the fish are stocked at elevated densities to increase the production from the infrastructure, making the investment worth while.  These high fish densities result in a large amount of metabolic waste being produced, which is removed and controlled by filters to maintain excellent water quality for the fish that are being farmed.  The high fish densities utilise a lot of oxygen which is replenished by means of aeration, but in extreme cases pure oxygen may be used.
 
RAS offers many advantages over earth ponds or cages, including:

·       Ability to farm fish far outside of their required climate
·       Growth to market size can be optimal
·       Option to farm fish close to the market
·       Vastly reduced water requirement
·       Small footprint
·       Fewer staff are required
·       Marginal agricultural areas can be used
·       Handling is simplified
·       Monitoring is simplified
·       Purging prior to harvesting is streamlined
·       Predators are excluded
·       Diseases can be excluded
·       Production is highly predictable
·       Stock management is simplified
·       Access control is high so theft can be limited
·       Escapees can be reduced to 0%
·       Reduced pollution

Despite all these advantages there are also some disadvantages to RAS, including:
 
·       High capital cost
·       High operational cost
·       Dependency on electricity
·       Risk of equipment failure
·       Need to use excellent quality feed to maximise growth and reduce waste
·       Staff require higher skill level
 
Most of the components of a RAS are available locally wherever you find yourself, although some of the items are only supplied by specialised dealers.  Always use the best quality equipment you can access and afford for a RAS as the risk of equipment failure is ever present, and without properly protocols and redundancies, can result is massive stock loss.
 
In short, the RAS offers a solution where species need to be farmed outside of their climatic zone, where water is scarce, if there is an opportunity to market the crop directly to a local market or where land is very expensive.  Not withstanding the associated risks and disadvantages, a well managed RAS can produce massive quantities of fish from a small footprint, and the reduction in environmental impact and improvement in product quality are all reasons why we shout out a big `3 cheers for the RAS’.