The amount of salmon killed by diseases and other problems at fish farms has reached record levels, with death rates quadrupling over the last 18 years, according to an analysis of official figures.
More than 25,770 tonnes of caged salmon died prematurely in 2019, higher than in any previous year. That equates to over ten million fish.
The analysis also reveals that the mortality rate at fish farms has risen faster than salmon production over the years. In 2019, 13.5 per cent of the annual harvest died prematurely compared to 3.1 per cent in 2002.
Campaigners have condemned the deaths as “biblical in scale” and a “stain on the reputation” of Scotland’s food and drink industry. The salmon farming industry said it was investing to manage the “challenges to fish health”.
Salmon farming firm under fire over fish welfare after 700,000 deaths
Salmon deaths are reported by fish farming companies and published online by the Scottish Environment Protection Agency. The main causes of deaths are said to have been viral, bacterial and fungal infections, along with algal blooms, and “treatment losses” from mistakes with chemicals or de-licing machines.
Most dead fish have been transported south to be burnt in an incinerator in Widnes in Cheshire. Some have been incinerated in Shetland, or buried in pits.
The latest figures were analysed by Corin Smith, a campaigner who runs the Inside Scottish Salmon Feedlots website. They show that caged salmon deaths have risen from 4,421 tonnes in 2002 to 25,772 tonnes in 2019, more than the previous record high of 25,460 tonnes in 2017.
Estimates of the numbers of fish that died stopped being routinely published in 2013 after the industry complained the information was commercially damaging. But based on previous years, 25,772 tonnes could represent between 10 and 20 million fish deaths, depending on their size.
Smith compared the mortality tonnages to the annual harvest of farmed salmon, which has risen from 141,000 tonnes in 2002 to an estimated 190,499 tonnes in 2019. He found that mortalities as a percentage of the annual harvest had risen fourfold to 13.5 per cent over the period.
The rising death rates of farmed salmon in Scotland
| Year | Mortalities (tonnes) | Annual Harvest (tonnes) | Mortalities as a proportion of harvest |
|---|---|---|---|
| 2002 | 4,421 | 141,000 | 3.1% |
| 2003 | 6,287 | 167,000 | 3.8% |
| 2004 | 6,737 | 158,000 | 4.3% |
| 2005 | 5,007 | 135,000 | 3.7% |
| 2006 | 8,053 | 135,500 | 5.9% |
| 2007 | 11,377 | 135,000 | 8.4% |
| 2008 | 9,066 | 134,500 | 6.7% |
| 2009 | 7,818 | 141,000 | 5.5% |
| 2010 | 7,511 | 157,000 | 4.8% |
| 2011 | 9,494 | 159,000 | 6.0% |
| 2012 | 12,945 | 160,000 | 8.1% |
| 2013 | 10,329 | 160,500 | 6.4% |
| 2014 | 16,046 | 179,000 | 9.0% |
| 2015 | 18,302 | 170,000 | 10.8% |
| 2016 | 22,245 | 163,000 | 13.6% |
| 2017 | 25,460 | 189,707 | 13.4% |
| 2018 | 16,573 | 156,025 | 10.6% |
| 2019 | 25,772 | 190,499 | 13.5% |
Sources: aquaculture.scotland.gov.uk, Scottish Government and issf.org.uk.
According to Smith, the death rate on 19 fish farms was over 30 per cent. “The volume of salmon dying prematurely on salmon farms in Scotland is now biblical in scale,” he said.
“The suffering and waste that has become normalised on salmon farms is a stain on the reputation of the food and drink industry in Scotland.”
Smith claimed that the official figures could underestimate mortalities at salmon farms. “The true scale of death and suffering on salmon farms is often disguised by early harvesting,” he alleged.
“Despite decades of government sponsored research and financial support, life for farmed salmon is dramatically worse than it was fifteen years ago. Disease is rife and virtually out of control.”
The wild fish campaign group, Salmon and Trout Conservation Scotland, warned that lice spreading from fish farms were “decimating” wild stocks. “Mortalities on this scale, which would not be permitted if they occurred in terrestrial farms, are symptomatic of unsustainable practice and of poor levels of fish husbandry,” said the group’s director, Andrew Graham-Stewart.
“The Scottish parliamentary inquiry into salmon farming concluded in 2018. Both of the committees involved were adamant that regulation of the industry was inadequate and not fit for purpose, yet, two years on, the status quo of lax regulation continues.”
Millions of salmon ‘suffering and dying’
The animal welfare charity, OneKind, described the new figures as “troubling”. They meant that “millions of individual sentient beings were suffering and dying,” it said.
The group’s policy officer, Kirsty Jenkins, added: “If, as these figures suggest, mortality levels are increasing at a faster rate than production levels, the causes of that increase must be urgently scrutinised.
“People would be rightly outraged by such high disease and mortality levels in terrestrial farmed animals, but the inherent inaccessibility of salmon farms mean that the conditions in which salmon live and die are out of sight.”
The Coastal Communities Network, which brings together 15 groups concerned about their marine environments, argued that salmon farming should be better. “The diseases and parasites responsible for some of this shocking increase in mortality will also impact wild salmon and sea trout,” said the network’s John Aitchison.
“Many farmed fish also die during cruel physical treatments for sea lice. Adopting closed-containment methods on farms would eliminate sea lice but the industry prefers to use open nets that dump their waste in the sea for free.”
Don Staniford from Scottish Salmon Watch estimated that the number of farmed salmon dying each year was between 15 and 20 million. “Mass mortalities are a function of intensive production with salmon farms across Scotland suffering from infectious diseases, lice infestation and welfare abuse,” he said.
“A public register of all mortalities should be routinely published even if it is commercially damaging for salmon farmers. The public surely have a right to know the true scale of death and disease lurking in Scotland’s salmon farms.”
Mass deaths: nine million fish killed by diseases at Scottish salmon farms
The Scottish Salmon Producers Organisation (SSPO), which represents fish farming companies, accepted that in 2019 “environmental impacts necessitated preventative large-scale culling at a small number of farms in order to prevent potential suffering.”
It pointed out that wild salmon which make it to sea have a 95 per cent mortality rate. This showed how successful salmon farmers were in caring for and rearing their fish, it argued.
“The Scottish salmon farming sector continues to invest and innovate in the management of challenges to fish health,” said SSPO’s director of strategic engagement, Hamish Macdonell.
“Fish health and welfare will always be our members’ top priority. There are a number of initiatives underway to increase the number of health management tools available to Scotland’s fish farmers.
He added: “These are being complemented by focused research into understanding the impacts of recent environmental challenges, the Scottish 10-year farmed fish health framework and increased sector-wide information sharing.”
Photo of dead salmon dump in North Uist thanks to Corin Smith.
