Anglers: Prevent the spread of Gyrodactylus salaris in the Eden Valley, Cumbria

Gyrodactylus salaris is an extremely dangerous parasite and anglers must take careful steps to ensure it does not enter the River Eden and its tributaries. If it does it would wipe out the population of salmon in the Eden.

What are the risks?

G. salaris has been shown to survive away from a live fish host for five to seven days at ambient river temperatures and for 78 hours and 42 hours at salinities of 10 ppt (parts per thousand) and 20 ppt, respectively.

Risk is associated with movement of materials (animate and inanimate) that can carry low salinity water, have recently been in contact with infected fish, and which have been kept in cool conditions sufficient to permit the temporary survival of the parasite away from live fish. Equipment or products that have been kept cool and damp and are transferred rapidly (within one week) may present high levels of risk.

This parasite has destroyed the salmon stocks of over 20 rivers in Norway. It was introduced to the Atlantic coast of Norway on Baltic Sea Salmon taken to fish farms there. Baltic Salmon are immune to it, Atlantic Salmon are not – and tests have shown that Scottish Atlantic Salmon are destroyed by it just as easily as Norwegian.

It is also indigenous to, or has been spread to, Russia, Finland, Sweden, Germany, France, Spain and Portugal, largely through fish-farm movements of Rainbow Trout.

It is a minute, external parasite, less than half a millimetre long and can live away from fish, in the gravel, for a considerable time, making it extremely difficult to eradicate from any river. Desperate methods being used in Norway involve poisoning all of the life in the river with rotonate and leaving it fallow for several months to try and break the cycle. This would not be an option in the UK so the Atlantic salmon population would be wiped out and we would be unable to reintroduce it.

What you can do:

If you have fished outside the United Kingdom in the past three months please treat your equipment in one of the following ways before fishing the River Eden or its tributaries; 

• Dry to a minimum of 20 degrees for at least 2 days.
• Heat to above 60 degrees for at least one hour.
• Deep freeze for at least one day.
• Immerse equipment, for a minimum of 10 minutes, in a solution of; - Virkon 1% - Wescodyne 1% - Sodium chloride (common salt) 3% - Sodium hydroxide 0.2% All chemicals should be available from agricultural chemical suppliers, please follow the instruction on the pack.

Thank you for helping to protect the Eden Valley's Atlantic salmon stocks.

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