RAS technology
Goldrush
with a catch
RAS veteran Ivar Warrer-Hansen shares his insights with Fish Farmer
I
var Warrer-Hansen knows fish – and he knows water. He was a co-founder of the Aquaculture Department of Denmark’s Water Quality Ins�tute in the late 1970s, and then ran his own trout farming business in Ireland between 1982 and 1992, growing it from a small opera�on to become the country’s biggest trout farm a�er which he entered into salmon smolt and salmon grow-out farming. For nearly two decades he has been a manager in and senior adviser to the recircula�ng aquaculture systems (RAS) industry, working with businesses like Inter Aqua Advance, Trouw Aquaculture/Skre�ng and most recently Nordic Aquafarms, where he was involved with the design of that company’s $450m project in Maine, USA. Now he has his own consultancy business, RASLogic, based in his na�ve Denmark. Fish Farmer caught up with him to hear his views on the current boom in RAS projects around the world – and whether this “gold rush” might have a downside. Fish Farmer (FF): Does the future of aquaculture lie in land-based farming now? Ivar Warrer-Hansen (IWH): It’s a new industry, which has been developing at a steady pace but then within a couple of years it has exploded. I think there’s room for both kinds of developments, the RAS and the conven�onal, cage farming and land-based. It is, though, no�ceable that not one of the large exis�ng salmon farming companies have invested in land-based grow-out so far. They have invested in smolt RAS facili�es but not grow-out; but suddenly landbased farming is mushrooming. All the new, large-scale RAS projects are for salmon, and projec�ons are that we will double the output of farmed salmon in 10 years, worldwide. We will be able to locate produc�on close to markets – such as the USA, China or Japan – and it will not be limited to the geographical areas where we could raise salmon previously. That is a very sound development. But salmon is a type of gold rush.
Back in 1992 in the conven�onal salmon industry there was also a gold rush, much of it by big interna�onal companies. It was seen as diversifica�on but it happened too quickly, and in 1992 we had a crash. There were four or five difficult years a�erwards. Having said that, the salmon market has developed, and there is greater demand for it, globally, but we could s�ll see slumps. The conven�onal salmon farming industry would be be�er placed to go through hard �mes thanks to its lower capital costs. For a RAS project, capital costs and deprecia�on could account for $2 per kilogram of fish produced. FF: How far advanced is RAS technology now? IWH: There will be some RAS concepts, even those already being built, which do not have the technology to stand the test. There is different thinking regarding parts of the process. For example, if you take biological filters, which are at the heart of the system, there are mistakes being made. In Norway, there has been a problem with post-smolt systems, and there have been more than 80 incidents of fish mortali�es due to hydrogen sulphide for example. For those RAS suppliers who have been used to supplying mostly fresh water systems, there’s a different way of thinking and a different set of risks with salt water. There are some designs that are good and some that are not good. But there are examples of good growth too and there are a couple of RAS systems opera�ng well now, where they have not had any problems. FF: How well do we understand the biology and how fish interact with a RAS system? IWH: We get wiser, of course. For example, it was always believed that fine par�culate ma�er in the water was more of a problem for smolts and smaller fish, but surprisingly, it appears to be more of a problem for larger fish. With biological filters there are some concepts that begin to create problems – - shi�s in bacterial flora – so that it can be difficult to keep them stable. Some people may be surprised that a year or two later, they see a drop in performance and are not ge�ng what they originally planned. The biological filter can “backfire”, essen�ally.
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Interview RASLogic.indd 38
Left: Ivar Warrer-Hansen Opposite: A RAS design
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07/06/2021 16:09:02
