Warning over deadly fish parasite

Scotland's river managers are warning that one careless angler could wipe out the country's wild salmon stocks and ruin rural communities. They fear that a fisherman will accidentally import the deadly Gyrodactylus salaris parasite which has already devastated stocks in 20 Norwegian rivers. The salmon farming industry said it would be shut down within 18 months of a widespread outbreak.

The parasite, which is native to Baltic rivers, has destroyed salmon populations in countries where the native fish have no resistance. Whole river systems have been poisoned to eradicate the creature.

Scotland's river managers are planning to use the opening of the Dee season to warn that a single parasite in wet fishing gear could start an epidemic in this country. They said that would cost rural communities 3,000 jobs and more than £100m.

Gyrodactylosis, caused by the GS parasite, is a serious fish disease that infects the skin, gills and fins of salmon, trout and some other species of freshwater fish. Barely visible to the naked eye, the parasite can nonetheless cause serious damage to some UK strains of Atlantic salmon. However, it has no impact on human health.

If the GS parasite were to be introduced into UK waters, entire river systems could quickly become infected, resulting in the decimation of valuable freshwater stocks of salmon, both in the wild and in aquaculture.

Scotland is the third largest producer of Atlantic salmon in the world, employing an estimated 10,000 people and millions of pounds of compensation could be paid out to farms in the event of an outbreak.

The Aquaculture and Fisheries Scotland Bill, which is currently going though Holyrood, contains measures to prevent the parasite's march. The Scottish Executive will also be testing contingency plans.

Holyrood's environment committee has said the scale of escapes of Scottish farmed fish means that the parasite could devastate wild salmon, necessitating the chemical treatment of rivers. The chemical measures used to tackle the parasite, however, could have a huge effect on biodiversity and other water users, including the whisky, leisure and renewable energy industries.