8 minute read
Insights from Ivar Warrer-Hansen
Goldrush
with a catch
RAS veteran Ivar Warrer-Hansen shares his insights with Fish Farmer
Ivar Warrer-Hansen knows fi sh – 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 diversifi ca� on but it happened too quickly, and in 1992 we had a crash. There were four or fi ve diffi cult 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 fi sh 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 diff erent thinking regarding parts of the process. For example, if you take biological fi lters, 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 fi sh 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 diff erent way of thinking and a diff erent 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 fi sh interact with a RAS system?
IWH: We get wiser, of course. For example, it was always believed that fi ne par� culate ma� er in the water was more of a problem for smolts and smaller fi sh, but surprisingly, it appears to be more of a problem for larger fi sh.
With biological fi lters there are some concepts that begin to create problems – - shi� s in bacterial fl ora – so that it can be diffi cult 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 fi lter can “backfi re”, essen� ally.
Left: Ivar Warrer-Hansen Opposite: A RAS design
FF: What sort of thing can cause really major problems at a RAS site?
IWH: Salt water has a naturally high sulphate content. Under certain naturally occurring condi� ons, the sulphate can be reduced to hydrogen sulphide by bacteria. Sulphate in itself is completely harmless but hydrogen sulphide is toxic, and those processes, if you have not designed your system properly, can and do take place in a RAS.
For example, say you have emp� ed a tank and the system’s design means that it is impossible to completely empty out a pipe or other part that is not being used, then when you fi ll the tank again the water le� in from before could kill your fi sh.
A lot of RAS design looks good on paper but when you work with it, it does not always do “what it says on the � n”.
FF: So monitoring is very important?
IWH: Yes – and it is improving all the � me. There are some very good control systems, but for hydrogen sulphide, probes that can measure down to the levels required. have only just been developed in the last year or so.
Also, when we see systems not performing well, they may not kill the fi sh but just like hydrogen sulphide, sub-lethal levels of methane, say, may entail a limi� ng eff ect on fi sh growth. Fish have an amazing sense of smell and there are things that would stress them and aff ect their growth poten� al, including processes inherent in some types of biofi lters.
FF: How has fi sh feed had to adapt, for RAS farms?
IWH: Fish feed for RAS needs to be improved. We have subs� tuted fi shmeal and oils with vegetable protein and oils, and while that has had li� le impact on cage-grown fi sh, it has had some quite signifi cant consequences for RAS.
The issue is what comes out of the fi sh! I am impressed with what the feed manufacturers have been able to achieve as far as fi sh growth is concerned. But waste has changed and that makes it more diffi cult to treat the water.
FF: What other species might RAS be suitable for – apart from salmon?
IWH: There are many fi sh species already produced in RAS systems, like � lapia or ca� ish, but they are low value fi sh in terms of price. There is also poten� al with sea bass and sea bream, but even these are not the fi sh fetching the highest prices.
I’m very pleased to see what is happening with yellowtail kingfi sh because that is a super fi sh; it is marketable, it is a very good product and I’m happy that it has taken off but it is s� ll at a very small scale.
There are other very a� rac� ve fi sh that taste amazing – like grouper – that have never really hit the market globally.
I would say that turbot has a lot of poten� al. It has been tried in RAS farms and there were some systems which did not work so well, but we know the biology of it now, we know more about husbandry, and with today’s RAS concepts it would be a brilliant candidate. It fetches a high price and it is marketable worldwide. And it is [chef and TV presenter] Rick Stein’s favourite fi sh!
FF: What do you see as the prospects for large-scale RAS grow-out farms?
IWH: I have worked with and have had experience with – more or less – all the concepts in the market. If a system doesn’t stand the test it can have disastrous consequences. Out of the 15 or so major RAS suppliers, only around a third have the poten� al to build a good system for a large scale facility, that is producing 10,000 tonnes or more. Even well established companies don’t always get it right.
If we do go into � mes with poor market prices for prolonged periods, it might be the conven� onal fi sh farmers that have the last laugh. There will be systems that are not op� mal and I can envisage that we will see some failures, with unproven technology.
But there is of course an amazing drive to con� nue, and that is what saved fi sh farming back in the 1990s. Commitment and spirit kept the industry alive. Thank God we see that today too. FF
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