Farmed salmon 'infect wild fish'

Scottish Executive scientists found large numbers of sea lice near the mouth of the River Shieldaig in the Western Highlands, where young trout emerge into the sea.

And their research indicates the devastating parasites came from nearby salmon cages.

But farmers say the sharp decline in wild salmon and sea trout along the Scottish coastline began long before they were there, and they are developing better techniques to control disease.

Conservation groups say wild salmon have declined by two thirds in the past 30 years, and are increasingly susceptible to impacts from industry.

And, they claim, the rapid growth of salmon farming is one of the main threats to the wild fish.

'Working together'

The research suggested that every second year, when farms are at an early stage of breeding, numbers of sea lice fell.

Samples taken offshore also showed sea lice moving from cages to the shore - not the other way around.

But John Russell, from trade body Scottish Quality Salmon, said: "This report may be new but the information it contains is old.

"Fish farmers have learnt a lot. Under area management agreements we have worked with the government and anglers to tackle these issues.

"An extremely effective treatment for sea lice as well as improved farming techniques have made a dramatic difference."

Mr Russell added: "Our aim is to minimalise the burden of sea lice on farm salmon and wild fish, and we have to work positively together to do that.

"We are doing that in this area."

Salmon farmers around the North Atlantic produced 4,783 tonnes in 1980, and 658,735 tonnes in 2000.

Sale ban

The Atlantic Salmon Federation, Greenpeace and the global environment campaign, WWF, are calling for "fish-farming free zones" to protect rivers and bays.

They also want commercial wild salmon fisheries on migratory feeding grounds in the Faroes and West Greenland to close.

Meanwhile, the Scottish Executive has banned the sale of salmon and sea trout caught by rod and line in an attempt to conserve wild fish stocks.

Deputy rural development minister Allan Wilson said the ban had "overwhelming" support from the individuals and organisations consulted.

"In many of our rivers, anglers are being encouraged to release salmon and sea trout they have caught.

"And increasing numbers of them are doing this.

"It is unacceptable that sport fishermen try to catch as many as possible so they can sell them."

A Scottish Executive spokesman said the research provided "further useful information about sea lice interactions which we will be considering".

It reinforces the need for an "area management" based approach and close co-operation between farmed and wild fishery interests, he added.