The Scottish Government defied concerted pleas by salmon farming multinationals to keep photos of diseased and damaged fish secret, according to internal emails.
Nearly 200 fish farms are allowed to use a carcinogenic chemical called formaldehyde which is used to embalm corpses.
Caged salmon farms are being investigated by the Scottish Government’s green watchdog for allegedly breaching regulations designed to protect the environment.
At least nine million fish have been killed by diseases, botched treatments, poor handling and other problems at salmon farms around Scotland since 2016.
The £2 billion salmon farming industry marketed around the world as Scottish is virtually all owned by investors in Norway, Switzerland, Cyprus, Canada and other countries.