The July 28 "jail break" from Drummond Fish Farm on Loch Ern was not reported to wild fishing interests by the Scottish Executive until Thursday, The Scotsman reported.

Andrew Wallace, director of the Association of Salmon Fishery Boards, said the report should be “a source of acute embarrassment” to the fish-farming industry. He said freshwater fish farms should either move to land locations or to lakes with no significant wild fish populations.

"Rainbow trout farmers have a long-standing record of extremely poor containment, with repeated and significant escapes over many years in many of our most important wild fish systems,” Wallace said.

Otters made about 20 holes in nets several feet underwater, allowing an estimated 30,000 young trout to escape.