It says farms are required to monitor sea lice and seals are discouraged by acoustic deterrents and nets.

BBC: How can Scotland cope with China's salmon demands?

The strong tides in those northern waters wash through the farms, reducing the problem of sea lice and other ailments.

ECONOMIST: Pressure is mounting to do something about salmon farms

It follows four years of research and development aimed at finding a natural method of tackling the problem of sea lice.

BBC: Western Isles salmon farm in wrasse 'first'

It is hoped they will help minimise the impact of sea lice - a naturally-occurring parasite that attaches itself to both farmed and wild salmon.

BBC: Western Isles salmon farm in wrasse 'first'

Critics are concerned about the levels of sea lice at farms which can be passed on to passing wild fish and are particularly harmful to juvenile fish.

BBC: How can Scotland cope with China's salmon demands?