This fusion of three Norwegian operations represents an ongoing consolidation of aquaculture operations in Scotland.
The Scottish Executive is "aware that Pan Fish plans to rationalise operations in Scotland". Executive figures show that at least 500 jobs have been lost in salmon farming since 2002, falling from 10,000 in 2002.
SFPG chairman Bruce Sandison said: "We estimate that 500 jobs have gone since 2004 and if the Pan Fish deal goes through, another 500 jobs could go. The support for Norwegian fish farmers from the Executive, both financial and moral, is disgraceful."
A spokeswoman for the Executive said: "Ministers are committed to supporting a fully sustainable aquaculture industry, both large and small businesses."