Farmed salmon and trout are the main species in farmer fish production.
Farmed salmon is by far the largest, accounting for around 40% by value of Scottish food exports and contributing £2bn annually to the UK economy.
The main challenge in farmed salmon has been Furunculosis, a bacterial fish disease that is also found in wild salmon. From fairly widescale use of antibiotics in the 80s to control the inevitable bacterial infection the fish would develop, the development of an effective vaccine has virtually eliminated the use of antibiotics to treat the disease. Controlling it in the farmed fish has also helped reduce the disease reservoir in wild fish.
Sales of antibiotics into the fish sector reduced from 1.7 tonnes of active ingredient in 2014, to less than one tonne in 2015.