The Scottish farmed salmon industry is using loopholes to cover up evidence of environmental harm, poor animal welfare and high levels of disease, an investigation has found.
Using open data, investigators from the charity WildFish allege salmon farms are avoiding mandatory reporting of sea lice prevalence in fish to cover up the scale of parasite infestations, which in some cases are more than 20 times those stipulated in the industry’s own code of good practice.
WildFish says the scale of disease in the waters is putting wild salmon and trout at risk, as well as exposing poor animal welfare standards in the industry.
“In allowing these diseases to proliferate in farmed salmon … salmon farming companies are risking the health of populations of wild Atlantic salmon and sea trout. Furthermore, they are potentially sending to market fish that have been raised in pens suffering from high mortalities, disease and sea lice infestations,” the report says. “This is the antithesis of responsible farming.”
The report says the mortality rates of farmed salmon in marine cages are unacceptably high; the most recent available data shows that on average 24.1% of the salmon stocked in Scottish marine farms died before harvest. The Scottish salmon industry produces about 200,000 tonnes of fish annually and production rates are expected to increase to 400,000 tonnes annually by 2030.
The report says some companies are using “harvesting” – slaughter for market – as a way of avoiding submitting mandatory sea lice counts each week to Marine Scotland. A loophole in the regulations means farms do not have to submit lice counts if they are about to harvest the fish – known as the withdrawal period prior to harvesting.
“There are clear and frequent instances of industry use of the reasoning ‘withdrawal period prior to harvesting’ for lack of supplying weekly average sea lice counts for prolonged periods of time, where the lice burden in the weeks preceding has been high,” the report says.
Scottish Sea Farms’ Hunda farm in Orkney gave no count for 25 weeks of the most recent single production cycle, instead stating “withdrawal period prior to harvesting”, according to data analysed for the report. “This translated into no weekly lice counts being given for almost the entire final six months of this farm’s 18-month marine production cycle,” the report says.
It also says farms are using extended periods of harvesting as a means of disease management in high-infestation areas. When deployed, rapid harvesting – or culling – can prevent ongoing suffering, disease spread and mortalities in farmed salmon populations, and reduce the risk of sea lice transfer to wild salmon populations. But slow harvests over months prolong livestock suffering and increase the environmental impact of open net salmon farming, the authors said.
“This report finds numerous examples of salmon being harvested out from diseased farms over a prolonged period of time, raising questions about the welfare of the fish, the subsequent environmental impact of diseased fish on the surrounding wild fish populations, and the motivation behind the decision-making process.”
Report investigator Dr Matt Palmer, farmed salmon campaign manager for WildFish, said: “Our report paints a shocking picture of what is happening on salmon farms in Scotland – with one in four fish dying prematurely, and sea lice parasites proliferating in huge numbers. This has a serious impact on the surrounding environment, and wild fish populations – not to mention it being at odds with the image presented publicly by the salmon farming industry.”
One of the companies named in the report for carrying out prolonged culls to control disease is Loch Duart, which provided salmon for the Cop26 climate conference in Glasgow last year and the Wimbledon tennis championships.
Loch Duart began reporting high weekly mortality rates at its Sound of Harris site in July last year, the report said. The report found that at one point there was a weekly sea lice value of 3.04. At the time the industry code of practice recommended treatment at sea lice values of over 1.
The site eventually reported a total marine production mortality rate of 50.3%, more than double the industry average. Loch Duart harvested the remaining salmon from the diseased pen over a period of five months.
Dr Palmer said: “Farmed salmon is being marked as a high-welfare, responsibly farmed source of omega-3 and protein. However, our report findings raise some serious questions about this industry’s transparency and commitment to the health and welfare of the salmon it farms – contributing to the eye-watering 11m fish deaths across the most recently reported production cycle.”
The report said the Scottish government promotes the Scottish Atlantic salmon farming industry as a sustainable and innovative livestock production model.
“However, as the industry expands, so too does criticism of its high environmental costs, the inherent unsustainability of its business model, and the unacceptable levels of animal suffering due to disease, parasites and poor husbandry,” the report said.
A spokesperson for Loch Duart said: “WildFish is an anti-salmon-farming activist group whose misinterpretation of this data spreads untruths. At Loch Duart we are passionate about caring for our fish and we will always choose to raise our salmon using small-scale, low-impact farming approaches. We always put welfare before profit.
“Loch Duart is the only salmon farm in Scotland that has welcomed a local wild fisheries trust onsite to independently audit our sea lice counts and fish health checks, a further commitment from Loch Duart highlighting the importance of transparency and accurate sea lice reporting.”
Scottish Sea Farms referred questions to Salmon Scotland. Tavish Scott, chief executive of Salmon Scotland, said: “WildFish have again made it clear they have little understanding of our business, despite our members remaining open to engaging directly with them. Respectfully, the organisation, its membership, and wild fish would be better served by them attending to the pressures of fishing for sport and other human-induced impacts affecting critical freshwater habitats.”
