An infectious disease which can devastate farmed Atlantic salmon stocks has been detected on Shetland, the Scottish government has confirmed.
Infectious Salmon Anaemia (ISA) was discovered at one salmon farm site, which has been empty of fish since 21 December, in the Burra area.
The disease is also suspected at a further two sites in Burra, one of which was emptied six weeks ago.
ISA does not affect humans, but can seriously damage farmed salmon stocks.
The Scottish government said it had immediately set up a National Disease Control Centre and was taking action to control the spread of the disease.
As part of the measures, statutory movement restrictions have been placed on all sites in the control zone and wider surveillance zone.
The Fisheries Research Service is sending a team of fish health inspectors to Shetland to investigate the affected sites and to advise the industry.
Investigations into the potential source and spread of the disease will also be carried out.
Environment Minister Mike Russell said lessons had been learned from an outbreak of ISA on Shetland, the Western Isles and Orkney in 1998 and 1999 which was estimated to have cost the industry £100m and led to the loss of 200 jobs.
He added: “We will be applying those lessons vigorously with the clear aim of containing and then eradicating the disease from the current affected site, which in fact is now laying fallow.
“To prevent the spread of any disease present, the harvesting of fish from neighbouring sites will be conducted under biosecure conditions and supervised by the Fisheries Research Services.”
Mr Russell said ministers were being kept fully briefed by those working to control the disease, and links with the local authority had already been established.
Scottish Liberal Democrat leader Tavish Scott, who is the local MSP, said he was “dismayed” by the outbreak.
Mr Scott added: “I vividly recall the difficulties for the Shetland salmon industry 10 years ago when ISA caused enormous financial problems for fish farmers.
“But the industry today in Shetland is very different. The lessons of the previous outbreak have been learnt and I hope that quick and decisive action by the farms concerned working with the regulatory authorities can deal with this incident effectively.”