Physical address
Warehouse #3, 11 Stott Road, Selby, Johannesburg, 2001

Postal address
P.O. Box 55599, Northlands, Johannesburg, 2116

William Kelly
T: +27 82 886 7114
E: william.kelly@rydawi.co.za

Hugo Höll
T: +33 60 703 3391
E: hugo.holl@rydawi.co.za

Ross Matthews
T: +27 83 307 3073
E: ross.matthews@rydawi.co.za

RAS

RAS or Recirculated Aquaculture Systems

It became apparent early on that large scale aquaculture project development for business operations require RAS in order to be successful. This is primarily due to climatic constraints in that aquaculture production, as a general rule, is reliant on optimum temperatures (differing according to species) within tight tolerances of a degree or two Celsius.

Temperature is just one such parameter however. Other constraints on production rates are typically oxygen levels, carbon dioxide levels, feed rates and many more. A great deal of these influence each other – by way of example oxygen levels reach saturation at lower levels when the water temperature is higher. What this means is that warmer water, such as may be required by tilapia or barramundi, have less oxygen dissolved in it meaning fewer fish can be stocked in an equivalent body of water of lower temperature (at which they don’t grow as fast).

Simple production forecasts can be done to verify how important optimum conditions are. A slight deviation of what may look insignificant on paper can result in declined growth rates that can wipe 30% off production for as little as a four degree variation in temperature.

Consider the knock on impact of this across the rest of your value chain. Harvesting will be affected. Processing. Cold storage. Assets capable of handling a production volume will effectively be dealing with 30% less and the financial impact is likely to be severe.

RAS systems are complex and expensive to implement. However because they give you quantifiable control over production, the complexity and expense is justified in a business model that becomes predictable. Equally it is critical that a RAS system design is on point, proven and bankable. The engineering behind it is sophisticated and similar to a mine’s ore processing plant, the consequences of it not performing to specification are onerous.

RAS is rapidly becoming the aquaculture technology of choice globally. RAS offers a more environmentally friendly foot print with near zero waste emissions, water usage levels that dwarf alternate production techniques, continually lowering overall net cost of production and freedom from the tyranny of location.