Norway may be culprit of Chile's salmon disease problems

The deadly infectious salmon anemia (ISA), which has decimated fish farms in Chile and damaged the salmon industry there, may have been introduced from Norway back in 1996, according to researchers.

The disease may have been circulating undetected for more than 10 years before changing into a deadly outbreak two years ago.

The spread of ISA in Chile's salmon industry may have started around 2005 after the virus mutated, based on genetic analysis, said research team leader Fred Kibenge, professor of virology at Canada's University of Prince Edward Island.

Chile first reported an outbreak of the disease in 2007. Marine Harvest ASA, the world's largest salmon producer, said this month it would take a US$115 million charge for its Chilean unit after the disease forced the company to harvest smaller fish. Marine Harvest had been forced to shut down more than 10 production centres in Chile due to ISA.

A study published in Archives of Virology in November 2008 already linked the virus in Chile with Norway, suggesting that the virus may have been transmitted via Norwegian exports of salmon embryos to Chile.

Marine Harvest expects its Chilean salmon production to slump to less than 30,000 tonnes this year from more than 90,000 tons in 2008.

Chile, the world's second largest salmon producer after Norway, may post a 25-percent drop in production this year, with further declines in 2010 because of the ISA outbreak, according to AquaChile SA.