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Scottish Sea Farms is to trial the potential of a new greener aeration system, Flowpressor, to protect its salmon from potentially harmful plankton, a major threat to the health and welfare of farmed fish worldwide.
Whilst many species and concentrations of plankton are vital to a healthy ecosystem, others can be harmful to humans and animals; in the case of farmed salmon, they can cause damage to the gills, depriving fish of oxygen.
Aeration – the process of pumping air into salmon pens to boost water movement and, in turn, water quality – is one of several protective measures taken by salmon farmers when rising levels of plankton are detected during daily water monitoring.
Standard aeration systems use generic industrial compressors to pump in this air but with mixed results; if air flows aren’t evenly distributed for example, then those pens closest to the compressor tend to receive the biggest boost of air.
The Flowpressor system, in contrast, has been custom designed for the aquaculture sector by Poseidon Ocean Systems in Canada where gill health challenges can be more intense with as much as 1.5-2 million cells per litre of algae compared to 50 to 1,000 in Scottish waters.
Combining a specially engineered compressor, main distribution line and tripod diffusers placed deep within every pen – each pen with its own eight-channel control panel – the revolutionary new system moves water with lower phytoplankton and higher ambient oxygen upwards, improving the environment within all pens.
Innes Weir, Scottish Sea Farms Regional Production Manager for Mainland, said: ‘Flowpressor effectively draws ‘clean’ water from depth of the pen – in other words, well away the planktonic surface layers – and distributes it upwards, improving water quality throughout the whole pen.
‘It also comes with the additional option of ‘bubble curtains’ which create a barrier to plankton and other biological challenges such as jellyfish infestations, significantly reducing the concentration of these potentially harmful organisms within open pen systems.’
The pilot, which will start this month, will see six of the trial farm’s 12 pens connected to the Flowpressor and the remaining six pens served by a standard compressor.
‘We will be looking to see what day-to-day difference the system makes to the feed rate, growth and survival of our salmon overall,’ said Weir.
‘Crucially, we also want to gauge what protection the system can deliver during a plankton event or periods of low oxygen.’
Flowpressor is already in operation along Canada’s west coast, with farmers reporting a 50-60% reduction in algae inside the pen, improved fish survival and improved growth due to fewer lost feeding days.
The system can be set to run 24/7 for routine water quality improvement then moved to protection mode as required, with energy efficiency integral to its design.
Matt Clarke, Co-founder of Poseidon Ocean Systems, said: ‘Not only is Flowpressor more effective at protecting farmed fish health than standard systems, it’s also 56% more fuel efficient, reducing CO2 emissions by as much as 700 tonnes for each unit installed. That’s the equivalent of taking 150 passenger vehicles off the road for one year.
‘Designed for longevity, the system also has an operating life estimated to be three times that of other options on the market, further reducing its carbon, water and waste footprints.’
Stewart Hawthorn, Director of Trimara Services, the exclusive UK distributor of Poseidon’s Flowpressor system, added: ‘It’s fantastic to see this novel technology being trialled in Scotland for the first time. Working closely with Scottish Sea Farms, we have designed a bespoke solution suited to the particular marine conditions of the trial site and look forward to verifying the fish performance gains through the data amassed.’