Invasive Species Alert

Whirling disease detected in Yoho National Park

Photo Taken By L. Scott
Alert Date:Posted on

A statement from Parks Canada indicates a suspected case of whirling disease in Emerald Lake, Yoho National Park. This is the first known occurrence of the disease in British Columbia. Sampling is ongoing to confirm the presence of whirling disease, but preliminary results have identified suspected cases in the Kicking Horse River, Wapta Lake, Finn Creek, Monarch Creek, and the confluence of Emerald River and the Kicking Horse River.  

Whirling disease is caused by the invasive parasite Myxobolus. It causes damage to the nervous system of fish and creates deformities in cartilage, causing the fish to swim in circular ‘whirling’ patterns. 

While it is harmless to humans, whirling disease can decimate populations of salmonid fish. If brought to the Okanagan, this could impact our rainbow trout and sockeye salmon populations.  

A previous outbreak of whirling disease in Johnson Lake, Banff led park officials to drain the lake and eliminate all the fish to reduce the risk of spread. This may not be an option for Emerald Lake due to its size. This puts other lakes in BC at risk, including here in the Okanagan. Here’s what you can do to help prevent the spread of whirling disease into our lakes: 

  • CLEAN, DRAIN, and DRY all watercraft and gear before entering any new body of water  
  • Read the Parks Canada statement and follow the described procedures within Yoho National Park  


To read the Parks Canada statement, click here.   

For more information on how to Clean, Drain, Dry, click here.