The world's biggest salmon farming company is one of a number of firms under investigation for possible misreporting of chemical use. The BBC can reveal Mowi, formerly known as Marine Harvest, is among those being investigated by Scottish regulators.
Fish farming is big business - the industry now produces about 100 million tons a year, and with salmon prices soaring, producers are turning to lasers, automation and artificial intelligence to boost production and cut costs. How do you know if farmed salmon have had enough to eat?