Scotland's river managers are warning that one careless angler could wipe out the country's wild salmon stocks and cripple rural communities.
It is feared an angler could accidentally introduce the parasite
They fear that a fisherman will accidentally import a deadly parasite which has already devastated stocks in 20 Norwegian rivers.
The salmon farming industry said it could be shut down within 18 months of an outbreak, costing hundreds of jobs.
The Scottish Executive is seeking new powers to reduce the risk.
Next week it will also be testing contingency plans.
The Gyrodactylus Salaris (GS) 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.
Fish in Scotland do not have any resistance to the disease
Scotland's river managers are planning to use Thursday's 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.
Dee river director Mark Bilsby told BBC Scotland: "If it comes to Scotland our fish do not have any resistance to this disease and would be killed.
"Hundreds of jobs rely on salmon in rural areas so our villages would be much quieter."