fish disease

Anglers warned of dangers of salmon parasite Gyrodactylosis, caused by the parasite Gyrodactylus salaris, is a serious fish disease which 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. GS has no impact on human health. Anglers and river users were today warned, by Countryside Minister Carwyn Jones, of the dangers of introducing the parasite, Gyrodactylus salaris (GS) into the UK. A UK-wide campaign was being launched today to raise awareness of the parasite and to encourage river users to be vigilant. Warning people of the dangers of GS Countryside Minister Carwyn Jones said: "If the GS parasite were to be introduced into UK waters it could have disastrous consequences. Entire river systems could quickly become infected, resulting in the decimation of valuable freshwater stocks of salmon, both in the wild and in aquaculture. "The parasite could be brought into the UK on fishing equipment or clothing. Therefore, it is vital that anglers who have been fishing abroad are aware of the dangers of introducing Gyrodactylus salaris into the UK and know the precautions they should take to ensure that their fishing equipment is properly disinfected and not contaminated. "To get the essential points across, a leaflet and poster on GS has been produced, which describes 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. I would encourage all anglers and river users to look at these leaflets and take on board the information given." 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, rod licence holders, and angling clubs. 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. Notes 1. 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). 2. 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. 3. 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. 4. 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. 5. A copy of the leaflet has already been sent to salmon rod licence holders in England and Wales, with the latest edition of the Environment Agency’s Salmon magazine. 6. Copies of the leaflet are available from Welsh Assembly Government, Fisheries Branch, 1st Floor, Cathays Park, Cardiff, CF10 3NQ Tel: 02920 823567. It will also be available to download from 7. The A Code of Practice on minimising the risk of introducing Gyrodactylus salaris to GB was published in April 2002. The Code is available to download from 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.