Bob Allen has run Allen's Trout Farm on the southwestern outskirts of Calgary for more than half a century but now a quarantine put in place on his business to try and prevent the spread of whirling disease has all but sunk his once buoyant business. 

The disease — which affects trout, salmon and whitefish — causes infected fish to swim in a whirling pattern and die prematurely, with mortality rates as high as 90 per cent in some jurisdictions, according to the province.

The Bow River watershed has been found to be infected with the disease, as well as the Oldman River basin and Red Deer River basin. 

'They ruined the whole frigging industry'

Allen was informed in September 2016 that he was no longer permitted to sell his fish to stock ponds and lakes. He was only allowed to sell the fish for consumption as the disease is not dangerous to humans.

He estimates that in a regular year prior to being subject to the quarantine, his business could make anywhere between $500,000 to a $1 million depending on the year. This year he doesn't expect to crack $100,000. 

"I got nice healthy fish there and they got a disease in the river. And they're trying to shut down — not just my fish farm but the one across the river — they shut three or four of them down. They ruined the whole frigging industry," Allen told CBC News. 

whirling disease

This rainbow trout displays the characteristic black tail and skeletal deformities indicative of whirling disease. (Stephen Atkinson/Oregon State University)

'Killing our fish isn't going to solve the problem'

Allen said he was offered a payout by the province to kill his fish, but he said it was too small an offering to consider at the time. 

"Fifty-six years in this business, I'm not going to step away for $75,000," he said. 

Allen said he knows of two other business owners in his shoes who have taken the deal and closed up shop. CBC News was unable to reach those owners for comment. 

Allen said he finds the prospect of having to agree to such a deal "sickening" because the disease had already spread down the river, so he doesn't understand what signing the government's deal, and killing his fish would accomplish. 

"Killing our fish isn't going to solve the problem." 

Alberta map whirling disease as of June 2017

This map shows the areas infected with whirling disease as of June 2017; reaching from Red Deer to Lethbridge. (Government of Alberta)

But the financial reality is hitting home for Allen all the same. Two weeks ago he put his acreage up for sale.

He'll wait to see what happens, but for now he's staying put. 

'This is a difficult situation,' says province

In a statement, a spokesperson for Alberta Environment and Parks said, "In the year since whirling disease was found in the Bow River, the province has worked with local stakeholders and the federal government to contain and prevent it from spreading."

"Because of potentially catastrophic effects on fish populations, fish farms that are unable to eradicate the disease can no longer stock ponds. However, they can sell the fish for consumption as it has no impact on human health.

"We recognize that this is a difficult situation for several businesses. That is why the province has offered relief to several uninsured businesses."

what is whirling disease?

This diagram shows what happens to fish infected with whirling disease. Mortality rates can reach up to 90 per cent. (Government of Alberta)

With files from Colleen Underwood