THE Scottish fish farming industry has admitted that it threw away up to ten million salmon last year – nearly a quarter of its stock – because of diseases, parasites and other problems.

Official figures reveal the tonnages of dead fish that had to be disposed of has more than doubled from 10,599 in 2013 to a record high of 22,479 in 2016. Most are transported south to be burnt at an incinerator in Widnes near Warrington in northwest England.

Campaign groups warn that the industry is facing an “environment catastrophe”, is “haemorrhaging cash” and “shames Scotland”. Companies accept that they have been plagued by disease and sea lice, and that their businesses have suffered.

Unwanted mortalities at salmon farms have long been a problem, but in the last three years they have risen to record levels. There have been successive, significant increases in 2014, 2015 and 2016.

Latest figures for the months up to June 2017 show another another 7,700 tonnes of dead salmon discarded, suggesting that the problem is not going away. There are also thought to have been significant mortalities in the Western Isles since then.

The company that suffered the biggest losses was Marine Harvest, headquartered in Norway, whose mortalities leapt threefold to 7,609 tonnes between 2013 and 2016. Over the same period, the Scottish Salmon Company, which is registered in the Channel Islands, saw its dead fish more than double to 5,873 tonnes.

Critics estimate the total number of dead, discarded salmon last year to have been between 10m and 20m. But the industry says it sustained losses of “between 6 and 10 million fish, depending on their size”.

Scottish Government figures show that in 2016 the total number of smolts – young salmon - put into fish farm production in Scotland was just under 43 million. Total salmon production was 162,817 tonnes.

The Scottish Salmon Think-Tank, a new group of fish farm critics, accused the industry of failing to address “appalling” collateral damage. “Self-regulation is simply not working,” said the group’s Lynn Schweisfurth.

“The whole salmon farming business model is broken and far from sustainable as it claims to be. These worrying figures are the hallmarks of an industry in crisis and it's our rural communities that will suffer as the problems continue.”

She urged next year’s parliamentary inquiry into fish farming to tackle the industry’s “systemic” problems. “Until they do, lorry loads of dead fish and the broader environmental and welfare issues that beset the industry will continue to shame Scotland.”

Dr Richard Luxmoore, senior nature conservation adviser for the National Trust for Scotland, described the disposal of huge amounts of rotting fish as “stomach churning” and a waste of good food. “It is the sign of an environmental catastrophe,” he said.

“The salmon farming industry has lost the ability to control fish diseases and this results in escalating quantities of toxic chemicals being poured into the sea in an increasingly fruitless attempt to control them. It also inevitably leads to the release of an infectious soup of disease organisms into our coastal waters.”

He called for the industry to shift to a “closed containment system” that would protect the fish and the marine environment. The same demand was made by the wild fish campaign group, Salmon and Trout Conservation Scotland.

“Disease and mortalities on Scottish salmon farms continue at shocking levels,” said the group’s Guy Linley-Adams. “What concerns us is that the Scottish Government has almost no idea what the effects are on wild salmon and wild sea trout in Scottish sea lochs.”

Don Staniford from the Global Alliance Against Industrial Aquaculture warned that plans to double the salmon farming business by 2030 were “environmental lunacy”. “Infectious diseases and lice infestation are crippling the Scottish salmon farming industry which is haemorrhaging cash,” he claimed.

The Scottish Salmon Producers Organisation (SSPO), which represents the industry, accepted that there had “unfortunately” been losses. “Last year saw some problems which resulted in the loss of between 6 and 10 million fish, depending on their size,” said SSPO chief executive, Scott Landsburgh.

“This is something which the industry takes very seriously and is working hard to minimise. Disposal of mortalities is managed in line with the government’s approved methods and legislation.”

Marine Harvest insisted it had been “very transparent” about the issues it had been facing with sea lice and amoebic gill disease (AGD). “We would clearly prefer if we had not had this level of mortalities,” said the company’s business support manager, Steve Bracken.

“But what is more positive is that the picture is changing. We are making strong progress in reducing the sea lice levels and tackling the challenge of AGD.”

The Scottish Salmon Company agreed it had faced “biological challenges and unprecedented mortalities” in 2016. “We have taken decisive action to tackle these challenges,” said a company spokesperson.

The Scottish Government pointed out that fish and shellfish farming contributes £620m to the Scottish economy every year, supporting more than 12,000 jobs. “We have a duty to protect Scotland’s marine environment and the health and welfare of farmed fish is of utmost importance,” said a spokesperson.

“The Scottish Government is committed to working with the aquaculture sector to develop a strategic health framework that ensures we make progress in tackling major problems, including emerging disease and sea lice.”

Who is throwing away the dead salmon

fish farm company / tonnes in 2013 / tonnes in 2016

Marine Harvest / 2,224 / 7,609

Scottish Salmon Company / 2,436 / 5,873

Wester Ross / 86 / 3,142

Kames / 51 / 2,854

Scottish Sea Farms / 1,897 / 1,678

Grieg / 0 / 611

Dawnfresh / 122 / 200

Loch Duart / 581 / 33

Others / 3,202 / 479

Totals / 10,599 / 22,479

Salmon farming 2016 in numbers

162,817 tonnes production

3,903 tonnes organic production

43m young salmon

10m mortalities

311,496 fish escaped

253 fish farm sites

10 companies

1,486 staff

£1.8bn business

£3.6bn target business for 2030