Has salmon farming outgrown itself?

This is embarrassing for Scotland where in the 1970's it was identified as the successor in remote regions to North Sea oil, and steadily subsidised by Government.

The first global study on the environmental effects of salmon aquaculture shows that the 1m tonne industry has serious side-effects on captive salmon's cousins in the wild.

Parasitic sea-lice, multiplying in millions around cage salmon, are shown to decimate wild runs across the study's range stretching from British Columbia on the Pacific to Nova Scotia and Newfoundland on the Atlantic and across to Ireland and Scotland.

The only country not studied was Norway because no areas were sufficiently free of salmon farming to act as comparisons.

Nova Scotia researchers the late Ransom Myers and Jennifer Ford found that wild runs near salmon farms suffered population losses of at least 50 per cent each year. Sea-trout, or anadromous brown trout, were particularly vulnerable.

The authors claim this scale of loss is unsustainable and say that diseases from aquaculture operations spread into the wild and that interbreeding with wild fish weakens the ability of future generations to survive.

The effect of this research on Scotland cannot be taken in isolation. Negative publicity for salmon farming has been unremitting. Last August John Fredriksen, the major shareholder in salmon producer giant Marine Harvest said whilst on an angling holiday that salmon farms should be in places without wild fish, in other words that the bulk of the industry was wrongly-sited.

In the last month or so farm salmon products have been recalled by supermarkets following news that they had been tainted with diesel during processing. Panicky supermarkets even waived the need for shoppers to produce receipts on order to get refunds.