The Scottish salmon farming industry is facing major problems from sea lice, which have led to a cut in output, fast rising costs and a big rise in prices.
The problem is not new, but it has burgeoned during this decade. Chemicals have been extensively used, but lice are becoming increasingly resistant.
Bathing the salmon in warm water is an expensive treatment, but it led to the accidental slaughter of 95,000 fish in one incident last year.
The industry has admitted it has a serious problem, and is spending at least £30m a year on measures to respond to it.
That is in addition to reduced profits and lower production, down worldwide by an estimated 7% last year.