Large scale effort aims to keep Scotland's farmed fish healthy

Antimicrobial resistance (AMR) – where bacteria, viruses, fungi and parasites become resistant to a medicine, making infections harder to treat and increasing the risk of disease spreading – is considered by the World Health Organisation to be amongst the top 10 threats to global health.

Whilst this resistance can occur naturally, it’s thought that over-reliance on antibiotics in human and animal health could be adding to the problem.

Medical and veterinary professionals around the world have been tasked with reducing antibiotic usage wherever possible, so too have food producers. 

Scottish Sea Farms has been working proactively to reduce its use of antibiotics for several years now, with no antibiotics used on its marine farms around Scotland’s west coast, Orkney and Shetland Islands since 2012 and only minimal use at its freshwater facilities in recent years. 

In 2020 however, the salmon grower achieved its target of zero antibiotics across all its farming activities, representing an important first for Scottish Sea Farms. 

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.

“Salmon, wild-caught or farmed, can suffer from bacterial infections. Whilst these aren’t the same bacteria that infect humans, and the risk of cross-over of AMR from salmon to humans is therefore low, Scotland’s farmers are keen to play their part in the global response.

“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.”

The Scottish Salmon Producers Organisation, which represents 100% of Scotland’s salmon farmers, is a member of RUMA (the Responsible Use of Medicines in Agriculture alliance) an independent non-profit group that promotes and monitors best practice and the responsible use of animal medicine from “farm to fork”.

The alliance is uniquely important as it allows all UK animal farming sectors to support each other with the overall aim of improving animal welfare.

Working with RUMA, the Scottish salmon sector has committed itself to an ambitious and low antibiotic use target of 5mg of antibiotic active substance per kg of salmon produced.

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 attributes this sector-leading success to a combination of ongoing improvements in fish husbandry practices and investment in a new £58 million biosecure hatchery. 

“Our use of antibiotics in the freshwater phase of production has been because infections can occur before fish are big enough to be vaccinated,” explained Soutar. 

“However, new husbandry protocols and major investment in biosecure facilities are making such infections increasingly rare.

“Out on our marine farms, meanwhile, fish health strategies such as reducing handling and stress, reacting quickly when environmental conditions change, and the timely removal of any ailing fish, are all helping reduce the risk of sea-borne infections.”

This ‘prevention over cure’ approach to fish health and welfare is very much a holistic one, with the company’s vets involved at every stage of the farming cycle, from salmon egg through to humane harvesting. 
Not only has it helped drive down antibiotic use to zero in 2020 but it has also contributed to the salmon grower achieving an average fish survival rate of 92 per cent over the same 12 months. 

“But there is no room for complacency,” cautioned Soutar. “There is an element of luck because there is always a possibility, whether you’re farming plants or animals, of emerging diseases that appear and cause problems.

“We will consider antibiotic use if, in specific circumstances, veterinary advice is that it is essential for the protection of fish welfare. 

“The important thing is to keep applying the lessons learned from dealing with other bacterial diseases in the past to any new threats – that and developing more and better vaccines to further reduce the need for antibiotics.

“While there are a number of promising new developments in therapies other than antibiotics, the last year has really confirmed our long-held belief that vaccines are the answer.” 

Commenting on Scottish Sea Farms’ achievement, Dr Iain Berrill, Head of Technical at the Scottish Salmon Producers Organisation, said: ‘Raising fish in the natural environment can lead to challenging and unpredictable biological conditions, yet antibiotic use remains very low across the Scottish salmon sector. 

“This is in part thanks to the use of vaccines for all our fish combined with good husbandry techniques as outlined in the sector’s Code of Good Practice.

“Scotland is already world-leading when it comes to reporting of survival data and management of sea lice, which is something we can all be proud of. Our sector will continue to invest in fish health and welfare because it is at the heart of everything we do in the Scottish salmon sector.

“New techniques, technology and research continue to assist our experienced vets and fish health professionals in caring for our salmon responsibly.

“We congratulate Scottish Sea Farms on their progress and look forward to further fish health milestones being reached 
throughout the sector in the future.”

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Leading seafood firm shores up welfare standards with new £1m feeding centre

FARMED fish are living beings, so looking after them well is the right thing to do. However, protecting their health can bring substantial economic benefits too, as many companies in the sector will testify.

Among them is Grieg Seafood Shetland. With 16 salmon farms, a hatchery, a harvesting plant and more than 200 employees, it is one of the biggest businesses in the Northern Isles. 

Staff at Grieg Seafood Shetland’s feeding operations centre use the latest technology to ensure good health in fish stocks

The company’s commitment to high standards of fish welfare was demonstrated earlier this year when it opened a £1 million, state-of-the-art centralised feeding centre in Lerwick. 

This will improve monitoring of the fish and their nutrition as well as reducing feed waste.

“In essence, we are the same as any other farmer”, says Managing Director Grant Cumming. “We make money by selling a product and if the salmon don’t grow well and prosper, then we obviously don’t have a product to sell.

“However, we also have to consider the moral and ethical dimension. We have a duty of care over the salmon – to look after them and protect them. Then there’s the environmental aspect. 

“We don’t want to be wasting the finite resources of the planet.”
The salmon have to be carefully and properly fed, he says, but this is more complex than with onshore farmed livestock as they are underwater.

“We used to feed them from the surface and tried to judge if they had received enough, but their pens could be 30 metres down or even deeper, if you were lucky on a nice day you might see what’s happening in the top five metres. 

“That meant we were largely guessing, which wasn’t a good thing for fish health. If we didn’t feed them enough, they didn’t grow properly, but if we fed them too much, that would waste feed that could potentially cause pollution and would certainly cause us a loss of income.”

To solve this problem, the farm moved to using underwater cameras. “That meant we were feeding looking up, rather than down, and that helped a lot” says Cumming.  

However, the disadvantage of this was that the monitoring had to be done from a barge that could rock about at sea.
The next step was to move the monitoring to a number of portacabins spread across Shetland, but spreading the exercise across different locations wasn’t ideal either.

The new centralised base is in the main town of Lerwick, with connections to the farms made via fibre optic cable. “It’s a much nicer facility to be in”,  Cumming explains.

“It also allows the whole team to be together in one place.
“That means there’s a better exchange of ideas – the team can talk to and mentor each other, give advice and figure out the best methods of working.

“Instead of picking up a phone to talk to each other, people can literally just walk from desk to desk.”

Irene Walden is the Feeding Operations Manager at the new centre. “It makes it much easier for me to oversee things,” 
she says. 

“We can now feed the fish better and create greater efficiencies.

“It also gives us greater flexibility as it means we can feed through slacker tides when we need to – strong currents may not be good for feeding the fish.

“Some salmon also actually prefer being fed at different times to others and the technology we have now allows us to do that. Plus being together allows us to share best practice.”

Cumming says they are still in the early days of using the centre, but it is already paying dividends.

“The fish are feeding more and they have a better appetite than we would have expected. We expect to see a relatively quick return on investment – we’re very pleased.”

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ERADICATING ANTIBIOTICS

KEY elements of Scottish Sea Farms’ strategy to eliminate antibiotic use include:

• Biosecurity measures to avoid the introduction of bacterial pathogens
• Stock selected for resistance to disease and robustness from leading genetics providers
• Hygiene including daily removal of dead or ailing fish to minimise infection
• Vaccination against known bacterial threats wherever possible and appropriate
• Stress reduction to maximise fish welfare and avoid immune compromises
• Nutrition to boost fish robustness and ability to fight infection