HALIFAX - Nova Scotia's fisheries minister is facing sharp criticism for suggesting Thursday that a recent viral outbreak at a large fish farm is just a routine part of the aquaculture business.

Asked about the outbreak of infectious salmon anemia at a Cooke Aquaculture operation in Shelburne Harbour, N.S., Sterling Belliveau said: "It's a normal business day, and these particular incidents are being managed in an appropriate fashion."

Rob Johnson, aquaculture co-ordinator for the Halifax-based Ecology Action Centre, said Belliveau's comments show he's ill-informed and irresponsible.

"That's reprehensible," Johnson said in an interview. "We've seen this virus break out in New Brunswick, it's wiped out the industry in Chile and it's a tremendous threat to the marine ecosystem."

Johnson said the virus could be spread to wild Atlantic salmon, which are already an endangered species.

"This is yet another one that we should be extra vigilant against it," he said. "If (Belliveau) is making light of it by suggesting this is normal business activity, he's ill-informed."

Johnson also said industrial fish farms pose a threat to the lobster fishery because they attract parasitic sea lice.

Infectious salmon anemia first appeared at fish farms in Norway almost two decades ago, then in New Brunswick and later Scotland.

In the late 1990s, New Brunswick salmon farmers slaughtered more than a million fish amid an outbreak. The federal government paid out tens of millions of dollars to settle compensation claims.

The virus was discovered in farmed Nova Scotia salmon as early as 1999, but in much smaller numbers.

Belliveau stressed the virus poses no threat to human health, and he insisted that the early detection and monitoring of the latest case will help stop the spread of the chronic disease.

The virus can kill up to 90 per cent of the salmon it infects, depending on the strain. It attacks the kidneys of salmon and causes discolouration.

"There's no effect on the traditional fishing industry," Belliveau said after a cabinet meeting in Halifax. "I can reassure you, based on the scientific information, that there's no effect on the lobster industry. Human health is not in question.

"This is part of life."

Cooke Aquaculture, based in Blacks Harbour, N.B., said last Friday it had destroyed all the salmon in two underwater cages in Shelburne Harbour after routine testing found suspected cases of infectious salmon anemia on Feb. 10.

Spokeswoman Nell Halse said salmon in a third cage tested positive this week and they, too, will be killed and shipped to a secure compost facility. She would not say how many fish are in each cage, but she said the facility has about 20 cages.

All three cages will remain empty until all of the salmon at the farm are harvested, she said.

"We are doing a very good surveillance, both the company and the government, and we caught this early," she said in an interview from Saint John, N.B.

Halse said the outbreak was "just a part of farming."

She also challenged Johnson's assertions, saying there's no evidence the virus poses a threat to wild salmon. As proof, she said New Brunswick's many battles with the disease did not have an impact on wild fish stocks.

As well, Halse said Cooke Aquaculture has never had to deal with sea lice in Nova Scotia, and there's no evidence that the parasites have affected lobster near the company's facilities in New Brunswick.

Halse said the company plans to move ahead with major plans for expansion.

Roland Cusack, Nova Scotia's fish health veterinarian, said there are no large populations of wild Atlantic salmon in the area because the rivers that empty into Shelburne Harbour are very acidic.

"We've heightened our surveillance across the province," he said, adding that seven of the province's 13 fish farms have been tested for the virus. The seven farms are spread along Nova Scotia's coast, from St. Margarets Bay in the east to St. Marys Bay in the west.

"I'm confident that a lot of good management is in place to prevent the spread," he said.

The Canadian Food Inspection Agency was unavailable for comment.

The Atlantic Salmon Federation has said early detection is the key to containing the disease.