Mass mortality, sea lice infestations and disease are endemic in the Scottish salmon farming industry, according to a new investigation.

Scotland is the largest producer of farmed Atlantic salmon in the EU, and the third largest globally, after Norway and Chile. There are just over 250 Atlantic salmon farms in Scotland, which together produced 35 million salmon in 2016.

The new report, by animal campaign group OneKind, showed “extremely high” mass mortality rates – 10 million salmon died on seawater sites in 2016, rising to an estimated 11 million last year.

Escapes are also common, with 300,000 fish escaping from salmon farms in 2017; these fish are not adapted to living in the wild and will suffer, the campaigners said.

The report also reveals that sea lice infestations and disease are rife on salmon farms. For example, over 100,000 salmon died of amoebic gill disease over a period of 10 weeks in 2016, whilst 68,265 died from cardiomyopathy syndrome (which affects the heart muscle of fish) in 2016, and an estimated 27,000 salmon died from infectious salmon anaemia on one site alone in 2018.

The Scottish government has plans to double the value of the salmon industry to the economy by 2030. However, OneKind has called for a moratorium on the expansion until the welfare issues are addressed. The group also called for a stocking density limit of 22 kilos per cubic metre.

Compassion in World Farming is also calling on the government to put the brakes on its ambitious plans, citing increased consumer awareness of fish welfare.

A ComRes poll commissioned by CIWF and Eurogroup for Animals published in August showed that 76% of consumers feel the welfare of fish should be protected to the same extent as other livestock reared for human consumption. Three quarters (75%) said they’d like to see information about fish welfare on product labels.

Fish are incredibly misunderstood, said CIWF’s head of fish policy Krzysztof Wojtas. “They are sentient, able to feel pain, pleasure and other emotions. Despite this, fish receive very little legal protection and are either farmed in inhumane conditions or caught from the wild in cruel ways.”

Matt Mellen, the group’s fish campaign manager said: “Currently, many people do not realise the extent to which fish suffer in order to satisfy market demands. Fish farming does not have to be intensive, industrial, cruel and unsustainable.”