Chilean salmon farmers told to cull ISA infected fish

SERNAPESCA made the announcement early this week as part of an overall contingency plan aimed at preventing the spread of the disease. In addition to ordering the immediate slaughter or harvesting of infected fish, the government agency ordered farmers to disinfect their facilities and reiterated an earlier ban on transporting fish in and out of the infected zones.

Last week, laboratories in Chile and Canada confirmed the presence in Chiloé of ISA. Early reports suggested the disease was detected on just two fish farms – both operated by the Norwegian company Marine Harvest. SERNAPESCA, however, has since acknowledged the presence of ISA on two other Chiloé fish farms. That announcement was echoed by Marine Harvest CEO Alte Eide, who told the Norwegian publication Intrafish that the ISA problem is not limited solely to his company’s farms (PT, Aug. 6).

So far neither SERNAPESCA nor SalmonChile – the country’s private producers association – have revealed which companies own the second pair of infected fish farms. It’s also unclear at this point whether the ISA outbreak has since spread further still.

ISA, not dissimilar to influenza, is a deadly virus that spreads easily and quickly. Symptoms include a paling of the gills, swelling of the liver and spleen, and internal hemorrhaging. Transmission of the disease has also been associated with Caligus, also known as sea lice. Caligus, a major problem in Chile, are parasitic crustaceans that attach themselves to fish, creating lesions that render their hosts susceptible to various diseases, including ISA (PT, July 17).

According to Dr. Sandra Bravo, a marine biologist from the Chile’s Universidad Austral, the illness was first discovered in 1984 on fish farms in Norway, the world’s leading salmon producing country. In 1996 ISA was detected in Canada, where it devastated New Brunswick’s then-budding farmed salmon industry. Scotland, another important salmon producing country, has had problems with the disease as well.

“In 1999 the annual cost of Infectious Salmon Anemia was US$11 million in Norway and US$14 million in Canada. In Scotland, meanwhile, the total cost of the epidemic was US$32 million between 1998 and 1999,” Dr. Bravo explained in an e-mail to the Patagonia Times.

SalmonChile has been careful to downplay the severity of the current situation, suggesting in a press release that the Chilean strain of the disease is more benign than ISA elsewhere. The association, nevertheless, reacted favorably this week to SERNAPESCA’s new contingency plan, describing it as “an adequate form of prevention for this case or any other health issue of the type that continually affect other food producing sectors.”