In fish, the parasite affects the cartilage near the spine, leading to skeletal deformities of the spine or skull. This causes the fish to abnormally whirl in a tail-chasing behaviour and/or display a blackened tail. Photo: S.Hallett

Whirling Disease detected in B.C. for the first time causing the closure of lakes in Yoho & Kootenay National Parks.

Whirling disease is a microscopic parasite that causes skeletal deformities , causing fish to whirl in a tail-chasing behaviour. It can potentially kill up to 90% of juveniles of trout, salmon, whitefish. On September 20, 2023 Park Officials reported a suspected case of the disease in Yoho National Park’s Emerald Lake. Further sampling and testing took place on the Kicking Horse and Kootenay rivers. Preliminary results found suspected cases of whirling disease in the Kicking Horse River, Wapta Lake, Finn Creek, Monarch Creek and the confluence of Emerald River and the Kicking Horse River. In order to prevent the spread Parks Canada has closed all waterbodies in Yoho and Kootenay National Parks until the end of March next year.

How can you help?

  • Never move fish or fish parts from one waterbody to another.
  • Use fish-cleaning stations where available or put fish parts in the local solid waste system. Do not dispose of fish, or any fish parts, in a kitchen garburator
  • Before moving a boat or any equipment (e.g. hip waders, life jackets, kayaks, etc.) between water bodies, be sure to follow Clean, Drain Dry protocol. Use hot water (at least 90° C) & pressure washer.

What should I do if I find a fish that is exhibiting signs of whirling disease?

  • Call the RAPP line 1-877-952-7277