Another salmon farm in British Columbia is dealing with an outbreak of IHN, a fatal virus that can devastate fish populations.

Greig Seafood says its farm on Culloden Point, in Jervis Inlet on the Sunshine Coast, north of Vancouver, has produced preliminary positive results for IHN, or infectious haematopoietic necrosis virus.

The Canadian Food Inspection Agency is doing more tests and final confirmation is expected over the weekend. In the meantime, the company has voluntarily quarantined the facility.

IHN was also detected on Monday at a Mainstream Canada facility north of Tofino, in Millar Channel. Mainstream has also isolated the site to try to limit the spread of the virus. It says there have been no mass fish die-offs at the farm since the discovery.

In May, the virus was detected at another Mainstream Canada farm in Tofino, this time at a fish farm in Dixon Bay. The company says that given the length of time between the cases, it doesn’t think the virus at Millar Channel came from the Dixon Bay farm.

“Migrating wild salmon, natural carriers of the virus, are a more likely source,” the company said in a news release.

IHN is a virus that causes fish bellies to swell and can quickly lead to death, especially in younger fish. The virus is considered endemic to the Pacific Coast and is transmitted in the water through infected fish feces, urine and external mucous.

It’s often fatal in farmed Atlantic salmon, because the fish are not native to the Pacific Ocean and do not have any natural resistance.

This is the first time the virus had been detected in farmed fish in the area in more than nine years. The last time, it led to a two-year-long outbreak in which 36 farms were infected. More than 12 million salmon either died or had to be culled.

Joe Foy, the national campaign director of the Wilderness Committee says salmon farms should simply be banned in British Columbia. He says with so many fish in one location, it's no wonder the virus is making a return.

"When you get the salmon farms bunching the disease together and getting these outbreaks, you can have unexpected disasters in the wild stock. And that's what we're very, very concerned with,” Foy says.

With a report from CTV British Columbia’s Nafeesa Karim