The Canadian Food Inspection Agency (CFIA), and the Alberta government have announced the spread of whirling disease from Johnson Lake in Banff National Park, into the Bow River system.

CFIA has confirmed whirling disease is in the headwaters of the Bow River in Banff National Park, Alberta Environment and Parks are now determining how far the disease has spread downstream.

Whirling disease is a parasitic disease of fish, and is not harmful to human health. The disease causes fish to swim in a whirling pattern and die prematurely.

Alberta Environment and Parks Southern Region Executive Director Roger Ram Charita, says in some cases it kills up to 90% of an entire fish population.

"It affects primarily salmon and trout," he says. "So we're very concerned of course for our trout fishery in the Bow River, it's a world class fishery. It includes a couple of endangered species, so we're working all steps possible to ensure that the trout in the Bow River are sustainable."

Alberta Environment and Parks has been collecting hundreds of fish samples from the Bow River, and will have a better understanding of how far the disease has spread once lab results come back in October.

The government has begun an emergency response plan to deal with the disease, involving three steps: determining the extent of the disease, mitigation, and education.

It has quarantined all commercial fish culture operations through Ministerial Order until each facility has tested negative for whirling disease, and has ceased provincial fish stocking until each of the five facilities has tested negative for the disease.

The government is also focusing on public engagement, as Albertans play a critical role in preventing the spread of whirling disease.

"It's important for people to clean fishing gear, boats, anything that comes in contact with infected waters needs to be properly cleaned and dried before you move it somewhere else."

The government has also created a Whirling Disease Management Committee who are working with stakeholders on preventing the spread of the disease.

Detection sampling has been completed in the main stem of the Bow River. Work is underway to collect samples from basins immediately adjacent to the Bow River, Oldman River and upper Red Deer River watersheds.

For more information on whirling disease click here.