Animal Equality UK is calling on the government to make fish mortality reporting mandatory, after it submitted a Freedom of Information request, which discovered repeated incidences of serious infections across rainbow trout fish farms in England.
Following the FOI inquiry, the campaign group said it had been left alarmed by a ”critical data gap” in the number of fish that die from highly infectious diseases.
Investigations undertaken by the Fish Health Inspectorate between 2020 and 2025 revealed recurring diseases, including flavobacterium psychrophilum, bacterial gill disease, furunculosis and proliferative kidney disease, infectious pancreatic necrosis virus, enteric redmouth and aeromonas and pseudomonas bacterial infections, the NGO discovered.
These are known to cause skeletal deformities, boil-like lesions, haemorrhages, internal organ damage, kidney swelling, pancreatic necrosis and suffocation, resulting in high death rates among farmed fish, Animal Equality UK warned.
Altogether nine outbreaks were recorded during the five-year period, according to the Centre for Environment, Fisheries & Aquaculture Science (Cefas), the government regulatory body.
However, Animal Equality UK claimed Cefas was unable to provide records of the number of fish that died, as death data is said to be only collected for certain ‘listed diseases’ as per the EU’s Council Directive 2006/88/EC.
“Rainbow trout feel pain and distress, yet they are crammed into enclosed spaces where disease can spread rapidly,” said Abigail Penny, executive director at Animal Equality UK. “The absence of thorough record-keeping risks allowing the industry to go completely unchecked.”
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Penny called on the government to introduce species-specific slaughter legislation and mandatory mortality reporting.
“It’s the least these animals deserve,” she added. “To ignore their deaths is to ignore their lives and their suffering.”
A Defra spokesperson said: “We are proud to have some of the highest animal welfare standards in the world.
“Any allegations of fish welfare issues will be investigated by the Animal & Plant Health Agency, and where there is non-compliance with the strict regulations, appropriate action will be taken.”
At the start of the year, MSPs called for urgent action to improve Scottish salmon standards.
The plea followed an inquiry by the Scottish Parliament’s Rural Affairs & Islands Committee, which found “slow progress” had been made on the recommendations put forward by its predecessor committee in 2018, which had flagged significant environmental, fish mortality and welfare concerns within the sector.
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