PRODUCTION should be cut at Scotland’s biggest salmon farms over the high number of fish lost to parasites and disease, it is claimed.

Industry figures published in October show up to 10 million salmon were disposed of by Scottish producers in 2016. The total tonnage – almost 22,480 – is a record high and more than double that of 2013.

Now the Global Alliance Against Industrial Aquaculture (GAAIA) is calling for restriction on the country’s largest producers in light of new data obtained under Freedom of Information law. Data released by the Scottish Environment Protection Agency (SEPA) shows almost 2.3m fish were lost by Marine Harvest alone in the first nine months of 2017.

The company is the largest producer of its kind in Scotland, in a sector which makes up a crucial part of the economy.

Exports amounted to £483million between January and September last year, the same period cited by GAAIA. Salmon is the UK’s biggest-selling seafood, with Scotland’s west coast home to around 250 separate farms dedicated to feeding that demand.

The Scottish Parliament’s environment, climate change and land reform committee is currently holding an enquiry into the sector’s impact, with findings set to feed into broader work on the industry by the rural economy and connectivity panel.

Key bodies including SEPA, Scottish Environment Link and the Scottish Salmon Producers Association will give evidence to the current investigation tomorrow.

Ahead of the session, GAAIA, which also obtained results from Scottish Sea Farms and The Scottish Salmon Company, says it is time to put restrictions in place to address the rate of loss at fish farms and improve animal welfare.

Conditions including gill disease were listed amongst the causes of deaths, as was anaemia and thermolicer treatment, which employs an increase in temperature to target parasitic sea lice.

GAAIA director Don Staniford said: “This shocking new data blows the industry’s claims that they are dealing with diseases out the water. Digesting the litany of infectious diseases reported at Marine Harvest, Scottish Sea Farms and The Scottish Salmon Company is enough to put even the most ardent supporter of salmon farming off their fish supper.

“The Scottish Parliament needs to take immediate action to reduce production on Scottish salmon farms which are ridden with diseases.”

John Robins of the charity Animal Concern said the mortality rate is more than 25 per cent, adding: “Scottish salmon is a welfare nightmare. The general public would be horrified if over a quarter of our cows, pigs, chickens or sheep were dying.”

The Scottish Salmon Company declined to comment and Marine Harvest – whose director Ben Hadfield co-chairs a new working group on improving fish health – did not respond. However, Scottish Sea Farms said: “The health and welfare of our salmon is our number one priority at all times – everything we do, every pound we invest, is driven by that. As with any farmer however, the natural environment continues to present new challenges, which is why we are constantly honing our practices. For example, our increased use of cleaner fish has significantly reduced the incidence of naturally occurring sea lice, while state-of-the-art phytoplankton monitoring is enabling us to better pre-empt other potentially damaging environmental challenges.

“In 2017 alone, advances such as these saw us invest over £100m in optimising fish health and welfare, in order that we meet increased demand for farmed Scottish salmon in the most responsible, sustainable way.”