Salmon stocks in Norway are under threat from a deadly parasite which may be being spread by record numbers of salmon-trout hybrids, says a report in New Scientist.
The parasite, Gyrodactylus salaris, is a type of skin fluke and can be carried by the hybrid fish while they remain seemingly healthy.
In a very extreme measure, Janne Sollie, Director for Nature Management in Norway, called for efforts to sterilise the nation's rivers to be stepped up. They propose treating the waters with rotenone - a poison that is deadly to Gyrodactylus, as well as most other living organisms... They propose to restock later with farmed fish.
In the UK, The Scottish Executive Environment and Rural Affairs Department (SEERAD)has issued a leaflet on Gyrodactylus salaris (dubbed GS in the fish-farming community).
Allan Wilson told FishUpdate.com: "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."
A UK code of practice to reduce the danger of GS becoming a problem in the UK was published in 2002.