Fresh thinking
Europe loves to import shrimp, but would we be better off growing our own? Robert Outram investigates.
The world’s favourite shrimp is without doubt Litopenaeus vannamei, a crustacean known variously as Pacific white leg shrimp, white tiger prawn or – for most British consumers – “king prawn”.
This is by far the most commonly farmed shrimp, and producer countries like Thailand, Vietnam, India and Ecuador export it to consumers all around the world.
The success of the sector has come with problems, however. Coastal shrimp farming is associated with pollution and over-use of antibiotics, as well as environmental damage, particularly in terms of the destruction of precious mangrove forests which remove more CO2 per m2 than any other ecosystem on Earth and provide coastal protection against storms and sea-level rise.
A number of recent reports have highlighted labour force abuses in several shrimp-producing countries. And, of course, there is the issue of freezing shrimp – which sometimes stays in storage for many months – before shipping it many hundreds or thousands of miles to customers in Europe and North America.
Bavarian shrimp
What if, however, shrimp could be produced as a domestic product in European countries?
The UK Sustainable King Prawn Project (https://sites.exeter.ac.uk/kingprawn) was set up to answer that question. As Professor Rod Wilson of the University of Exeter explains, it began with a study into crustaceans and what they need in order to moult and grow successfully.
He and his colleague, Rob Ellis, were visiting Thailand as part of that research, and saw at first hand the reality of coastal shrimp farming in some places.
Wilson explains: “We thought ‘there is a lot to be improved here’, but we could see how as biologists we could help the industry because there were some obvious easy wins if we could find the ideal conditions for growing shrimp indoors in RAS using renewable sources of heat for this tropical species.”
The initiative now has several strands or “work packages”. The first is a study of the environmental economics of prawn RAS production; and the second is a study of the biological factors, including water chemistry and diet, to find the optimal conditions for growing L. vannamei. A third involves a demonstrator shrimp farm near St Andrews (see page 48 for more on this).
The initiative has received funding from the BBSRC (Biotechnology and Biological Sciences Research Council) which is looking for ideas to help transform the UK’s food systems (ukfoodsystems.ukri.org/).
Prof Rod Wilson
The king prawn is already a well-liked product and there is a ready market for it.
Wilson says: “We could grow the freshest prawns you’ll ever have and, importantly, they can be completely sustainable.”
Linking the initiative to existing terrestrial farming, the team are looking at how farm waste (manure and crop sidestreams) in anaerobic digesters can be used to produce both methane and – as part of the process – heat. Currently the latter is mostly wasted because heat is hard to transfer over any distance. So why not put a tropical shrimp farm that needs warm water next to an anaerobic digester?
Farmers would be able to add to their revenue from either farming shrimp themselves or, more likely, letting the farm to specialist operators.
There is still a lot to learn, since this approach is very different from typical coastal pond farming. As Wilson stresses: “We are still in the early days of knowing what prawns need to grow optimally in an indoor recirculating system.”
Researchers are also looking at whether shrimp can flourish at lower levels of salinity – this would mean the effluent from the farm is less salty and easier to find uses for.
Wilson says: “We want to produce guidelines for water salinity, calcium, pH, alkalinity and so on, for which we ideally need real-time sensors to monitor and manage the water chemistry.”
Technology exists for some of those but not all – for example calcium sensors would need to be developed as shrimp actively remove so much calcium from the water to harden their new exoskeletons after each moult.
The researchers are also looking at how waste from the shrimp farms could be valorised – as fertilisers or soil enhancers, for example.
The initiative is two years into a three and a half year programme, with 11 academic researchers from Exeter and Reading universities and Rothamsted Research, as well as 11 industry partners involved.
The fourth work package addresses a potential limitation though. Currently, any UK farmer would need to import shrimp juveniles as there is no hatchery in the country. Wilson says: “We would need a hatchery in the UK to guarantee a biosecure supply. There isn’t one at present, but a lot of people are interested in the idea.”
The idea of a National Aquaculture Centre has been mooted which could involve not only a hatchery to supply farming operations for shrimp (and why not other aquaculture species too?), but also a centre to provide a trained workforce and a research and development capability, as well as engaging in outreach to get important messages to consumers.
The end result, if this initiative succeeds, would be a premium, fresh product with a greatly reduced environmental footprint, if not a completely circular and sustainable healthy seafood production concept. As Wilson stresses: “The UK might not compete on price with the cheapest overseas pond-based imports, but if the true environmental cost of producing shrimp was taken into account, we would blow the competition out of the water.”
Oceanloop farm facility
In the (Ocean) loop
Meanwhile in Germany, Oceanloop operates RAS shrimp farming facilities in Munich, Bavaria, and in Kiel, on the country’s north coast. The company, founded in 2016, has developed its own unique platform-technology for land-based farming of diverse seafood species and is currently also farming grouper, a premium grade tropical fish.
Dr Fabian Riedel, Founder and CEO of Oceanloop, estimates there are already around 20 shrimp farms in Europe, but so far all of them are fairly small. Oceanloop’s Munich facility produces 20 tonnes per annum and the Kiel plant produces five tonnes. The company has plans to scale up significantly, however.
First, the pilot plant at Kiel will be expanded to an annual capacity of 60 tonnes, while a project being developed in Spain is hoped to produce up to 2,500 tonnes annually.
Riedel stresses: “The only way to survive in this market is to scale up production. Our Spanish farm, at 2,000-2,500 tonnes, would bring our opex [operating expenditure] down to €5.80 per kilogramme (£4.88), which is competitive with imported shrimp.”
Oceanloop is already selling “Bavarian shrimp” through its distribution arm, Honest Catch, which also sells a range of externally sourced, sustainable seafood.
Riedel says: “We had first mover advantage, so the question was what price point do we go for?”
Oceanloop farm facility
The answer was to price the homegrown shrimp as a premium product. Fresh, sashimi-grade Bavarian shrimp is currently on sale at €99.96 per kilogramme (about £84) – but it is finding a market.
Probably the most important aspect of Oceanloop’s offering, however, is the RAS technology. As Riedel stresses: “Shrimp are very sensitive and mortality is quite high. There is also a high danger of disease, so shrimp farming needs a controlled environment.”
The most common system for shrimp farming in RAS is biofloc, where cultivated microorganisms are used to help detoxify the recycled water. This, Riedel argues, does not scale up very well and instead, Oceanloop operates a clearwater RAS system, with mechanical filtration. Also, it uses raceways with a constant flow rather than the typical round tanks seen in most RAS systems, keeping the water fresh.
Because shrimp tend to prefer staying close to surfaces, to make the best use of the volume in the raceways Oceanloop has developed “urban mangroves”: stacked shelf-type units that offer the shrimp some shelter. Riedel describes the set up as “Manhattan underwater”.
Dr Fabian Riedel
Another advantage of the raceway system is that it can accommodate a three-compartment layout with moveable walls, so the space for each cohort can be expanded as the crustaceans grow. This avoids the need to pump the shrimp into larger tanks as they grow, a process that can be highly stressful.
The company has also developed a computer vision modelling system to monitor the biomass and welfare levels of the shrimp in ways the human eye could not match.
Energy is a key issue for RAS farming, but the Kiel plant uses waste heat from a public water treatment system, while the Spanish farm will have access to solar and wind power.
Shrimp
Oceanloop has already invested €20m (£16.8m) and is looking to raise a further €120m (£101m), having already secured debt facilities of €35m (£29.5m).
With shrimp consumption in Europe alone estimated to reach $13bn (£9.9bn) by 2028 (source: Statista/Straits Research), even a small part of that market represents a huge opportunity.
