Scottish Sea Farms celebrates an antibiotic-free year

Scottish Sea Farms has reached an important milestone in its mission to reduce the use of antibiotic treatments, with zero usage recorded for the company’s marine farms and hatcheries.

The over-use of antibiotics in aquaculture, just as for land-based agriculture or human healthcare, can lead to antimicrobial resistance (AMR), with strains of pathogenic bacteria, viruses, fungi and parasites developing resistance to the antibiotics used to treat them.

Scottish Sea Farms says it has managed to avoid using antibiotics at its marine sites since 2012, but 2020 also saw zero use at the company’s freshwater hatcheries. The company attributes this success to a holistic, vet-led approach to fish welfare.

Ronnie Soutar, Head of Veterinary Services at Scottish Sea Farms, said: “We’re very proud to have reached this stage. It is important on a global scale that antibiotic use is minimised and only used when absolutely essential, in recognition of concerns over antimicrobial resistance. Scottish salmon farming generally has a very low use of antibiotics compared with other livestock sectors and Scottish Sea Farms has consistently had antibiotic usage well below the sector’s target.”

RUMA (Responsible Use of Medicines in Agriculture Alliance) set a goal in 2016 of 5mg antibiotic active substance per kg of salmon produced. This compares to a target of 25mg/kg for poultry meat (broilers) and 99mg/kg for pigs.

In the four years between 2015 and 2018 inclusive, Scottish Sea Farms averaged 3.6 mg/kg but in 2019 this dropped to 0.25 mg/kg (5% of the sector target), with no antibiotic usage at all in 2020.

Soutar said: “Our use in the freshwater phase of production has been because infections can occur before fish are big enough to be vaccinated. However, new husbandry protocols and major investment in biosecure facilities are making such infections increasingly rare.”

He added, however, that there is no room for complacency and the company would consider the use of antibiotics if the veterinary advice is that it is essential.

Meanwhile, Scottish Sea Farms is also trialling a new aeration system to protect its stock from harmful plankton. Concentrations of plankton can, under some circumstances, create dangerously low oxygen levels in seawater.

The Flowpressor system has been designed by Poseidon Ocean Systems in Canada specifically for use in aquaculture. Unlike a standard industrial compressor, it distributes aerated water evenly among several pens, and it draws water from lower levels, well away from the surface where plankton is concentrated.

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.

Innes Weir, Scottish Sea Farms Regional Production Manager for Mainland, said: “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.”

Innes Weir, Scottish Sea Farms