A virus that has killed millions of salmon in Chile and ravaged the fish farming industry there was probably brought ...
A virus that has killed millions of salmon in Chile and ravaged the fish farming industry there was probably brought over from Norway, a major salmon producer has acknowledged.
Cermaq, a state-controlled Norwegian aquaculture company that has become one of the principal exporters of salmon from Chile, has endorsed a scientific study concluding that salmon eggs shipped from Norway to Chile are the _likely reason_ for the outbreak of the virus in 2007, according to Lise Bergan, a company spokeswoman.
But, she argued, _the report didn_t pinpoint any company_ as the culprit.
The virus, infectious salmon anaemia, or I.S.A., was first reported at a Chilean salmon farm owned by Marine Harvest, another Norwegian company. It quickly spread through southern Chile, wracking a fishing business that had become one of the country_s biggest exporters during the past 15 years. The Chilean industry, whose major clients include the United States and Brazil, suffered more than $2 billion in losses, saw its production of Atlantic salmon fall by half and had to lay off 26,000 workers.
The outbreak in Chile also revealed structural problems within the industry, including overcrowding in pens that environmentalists say probably helped speed the spread of the virus. Since then, the industry and the Chilean government have instituted a wide range of reforms to try to contain outbreaks, but despite extensive efforts to rein it in the virus continues to spread.
Last week, Chilean authorities said 23 production centers were suspected of having the virus, but of the nonvirulent type. There have been no reported outbreaks of virulent I.S.A. this year, officials said.
As the disease has spread, the industry has continued to push farther south, shifting cultivation away from the virus-afflicted areas. While the virus is not harmful to humans, some buyers, like the supermarket giant Safeway, restricted imports from Chile because of it.
Since 1984, when it was first diagnosed in Norway, the I.S.A. virus had an outbreak in every major salmon-farming region in the world except British Columbia, said Don Staniford, the global coordinator for the Global Alliance Against Industrial Aquaculture, a nongovernmental organization.
_Once it is discovered, it is impossible to get rid of,_ he said.
The scientific study at the University of Bergen linking the virus to eggs was commissioned by Cermaq and first published in 2008 in the Archives of Virology. But in early 2009, shortly after publication, a Norwegian company that breeds fish eggs, Aqua Gen _ which is partly owned by both Cermaq and Marine Harvest _ filed a formal complaint about the study with Norway_s National Commission for the Investigation of Scientific Misconduct, arguing that the science was flawed.
Patrick Dempster, general manager of Aqua Gen in Chile, said that Aqua Gen complained about the study because in 2006 they became the principal exporter of salmon eggs to Chile and were worried about losing business over concern about any vertical transmission connection with Norway.
The commission ruled on April 6 that there had been no scientific misconduct, clearing the three authors from the University of Bergen. Mr. Dempster said Aqua Gen stood by a study from the University of Prince Edward Island that concluded that the virus most likely entered Chile in 1996, when Aqua Gen was not exporting fish eggs to Chile. He noted that between 1996 and 2007 _a multitude_ of Chilean and Norwegian companies sent eggs from Norway to Chile.
_We initiated that research because we wanted to understand how I.S.A. was transmitted,_ Ms. Bergan said. _Before that, the scientific consensus_ was that the virus _could not be transmitted by eggs._
But while Cermaq has accepted the study_s findings, Chile_s own National Fishing Service, Sernapesca, said it did not necessarily support them. Instead, Sernapesca referred to the conclusion of the World Organization for Animal Health, which has said that there is insufficient evidence that the I.S.A. virus can be transmitted through eggs.
_Since the start of the I.S.A. outbreak, Sernapesca incorporated regulations both for the importing of eggs and for the production of eggs_ in Chile, the agency said in response to e-mailed questions.
The University of Prince Edward Island study, by Frederick Kibeng, an I.S.A. expert, was commissioned by Marine Harvest. It showed that some I.S.A. virus strains in Chile diverged from Norwegian strains around 1996. The study _does not confirm_ vertical transmission, but _it cannot be ruled out as a possible route of transmission,_ said Jorgen Christiansen, a spokesman for Marine Harvest.
Cermaq, which described itself as the leading exporter of salmon from Chile in the first quarter of this year, has also developed methods for screening the I.S.A. virus, invested in new facilities and moved its production of young Atlantic salmon to facilities on land, Ms. Bergan said.
Norway and Chile have become intertwined by their farmed-fish industries. Norway has the largest aquaculture industry in the world, but Chile is often viewed as the salmon market of the future, with room for rapid expansion. The governments have a cooperation treaty to exchange scientific and technical knowledge in aquaculture.