The Scottish Government

This item was published during the term of a previous administration that ended in April 2007

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Warning against importation of salmon parasite

02/02/2004

Anglers and river users were today reminded of the dangers of introducing the parasite Gyrodactylus salaris (GS) into Scotland.

The Scottish Executive Environment and Rural Affairs Department (SEERAD) today issued a leaflet on GS which can cause serious damage to some UK strains of Atlantic salmon.

Gyrodactylosis, caused by the parasite Gyrodactylus salaries, which is barely visible to the naked eye, is a serious fish disease which infects the skin, gills and fins of salmon, trout and some other species of freshwater fish. GS has no impact on human health.

Deputy Minister for Environment and Rural Development Allan Wilson said:

"If the GS parasite were to be introduced into our waters, entire river systems could quickly become infected, with serious consequences for valuable freshwater stocks of salmon, both in the wild and in aquaculture.

"It is possible that the parasite could be brought in on fishing equipment or clothing. Therefore, it is vital that anglers who have been fishing abroad are warned of the dangers of possibly introducing Gyrodactylus salaris and reminded of the precautions they should take to ensure that their fishing equipment is properly disinfected and not contaminated.

"We would strongly encourage all anglers and river users to study the leaflet and poster we have produced describing the parasite and the effects of the disease. Most important, the leaflet gives practical advice on the steps that individuals can take to prevent its introduction into the UK, including here in Scotland."

Copies of the leaflet and poster; Keep fish disease out - A guide to protecting freshwater fish stocks from Gyrodactylus salaris, are being sent to major ports, travel agents specializing in fishing holidays abroad, leading tackle shops and angling clubs. Copies of the leaflet are also being sent to proprietors of salmon fishings in Scotland.

A Code of Practice on measures designed to reduce the risk of introducing Gyrodactylus salaris into GB was published in 2002. It describes activities that could potentially result in the introduction of GS and steps that should be taken to ensure the risk is minimised.

The GS leaflet aims to raise awareness of the disease risks associated with the bringing in of, for example, contaminated fishing gear used in countries which are not designated as free of Gyrodactylus salaris (GS).

The GS parasite occurs naturally in Baltic rivers of Finland and Russia. The native fish of these rivers, including the Baltic strain of Atlantic salmon, are tolerant of the parasite and the infection normally causes them no harm. However, river stocks of Atlantic salmon in other areas have little or no tolerance to it. For example, GS has had serious effects in Norway, severely reducing salmon populations in a large number of rivers.

Symptoms of Gyrodactylosis reflect the irritation which the parasite causes to the skin of fish - increased mucus production and behavioural changes such as flashing (darting and twisting of fish and erratic swimming (which an observer sees as flashes of light reflected from the paler parts of the sides and abdomen - exposed as the fish twists). Other symptoms, found when fish are closer to death, include fin erosion and secondary fungal infections.

Gyrodactylosis has been a notifiable disease in Great Britain since 1988 and national control measures have been in operation since then. In 1996, the UK successfully applied to the European Commission for safeguard measures to prevent the introduction of Gyrodactylus salaris into the UK. These measures set stringent criteria for imports, and their practical effect is that the UK does not import (save in very limited circumstances) any live or uneviscerated salmon.

Copies of the leaflet are available from SEERAD, Fish Health and Welfare Branch, Room 414, Pentland House, 47 Robb's Loan, Edinburgh, EH14 1TY. Telephone 0131-244-6225. It will also available on the Fisheries Research Services website www.frs-scotland.gov.uk

The "Code of Practice to Avoid the introduction of Gyrodactylus salaris to GB" was published in April 2002. The Code is available to download from www.frs-scotland.gov.uk. For those who do not have access to the electronic version, hard copies can be obtained from The Marine Laboratory, PO Box 101, Victoria Road, Aberdeen AB11 9DB Tel: 01224 876544.