A spokesperson from Mainstream Canada told TheFishSite that as they caught the disease early through routine diagnostic testing the mortalities are still low, but it is too early to tell what the cull is likely to be.
The company is following strict protocols to limit the spread of the virus.
"As part of our fish health management plan, Mainstream has strict bio-security protocols that are already in place with additional quarantine protocols in the event of a fish health incident. This includes limiting boat movement in and around the site and restricting visitors and contractors."
However, following a breach of the quarantine zone by an anti-salmon farming activist, salmon and jobs at other farms in the area have now been put at risk.
Scottish Environment Minister Stewart Stevenson has welcomed confirmation that movement restrictions for Infectious Salmon Anaemia (ISA) on fish farms in the south west Shetland mainland area are to be revoked.
Mr Stevenson said: "This is clearly good news for the reputation of the Scottish aquaculture industry and is a healthy reflection of close cooperation between the Scottish salmon aquaculture industry and Marine Scotland following the outbreak of ISA in 2009.
“Scotland is now recognised as being free of ISA. This makes a significant contribution to the sustainability of the Scottish salmon aquaculture industry and helps maintain the high health status of Scotland's farmed fish."
In Norway, a new outbreak of ISA has been reported to the OIE. Affecting a salt water farm in Romsdal, the outbreak has resulted in the death of 50 salmon with morbidity and mortality rates standing at one on a scale of zero to five.
