Mull salmon farm to trial system

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Scottish Sea Farms is to trial a new system to protect salmon from plankton in what is being hailed as a first for the sector in Scotland.

It involves six pens at its Loch Spelve farm on Mull being connected to a new Canadian-built ‘Flowpressor’ system, with the other six served by a standard compressor.

Plankton can cause damage to the gills and deprive fish of oxygen so aeration of the water is one of several protective measures salmon farms take when rising plankton levels are detected.

Currently, salmon farmers use generic aeration compressors to aerate the water by pumping air into pens to boost water movement and water quality, but the current system can have mixed results.

If air flows are not evenly distributed, the pens closest to the compressor tend to receive the biggest boost of air.

The trial will seek to demonstrate the difference between the Flowpressor and traditional kit.

The Flowpressor system has been custom-designed for the aquaculture sector by Canadian-based Poseidon Ocean Systems.

Gill health is more of a challenge in Canada than in Scottish waters and the Flowpressor system is already in operation along Canada’s west coast where farmers have reported a 50 to 60 per cent reduction in algae inside pens.

It has also improved fish survival and improved growth due to fewer lost feeding days, the company said.

Innes Weir, regional production manager at Scottish Sea Farms, said: ‘Flowpressor effectively draws ‘clean’ water from the 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.’

He added: ‘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.

‘Crucially, we also want to gauge what protection the system can deliver during a plankton event or periods of low oxygen.’

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 per cent 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.’