Calgary

This is why the province says there's been a recent crayfish invasion in Calgary

Crayfish have clawed their way into Calgary waters — thanks to people intentionally moving the invasive species from other water bodies, according to Alberta Environment and Parks.

Introducing an invasive species into new waters is illegal and harms ecosystems

Crayfish sit on rocks near the Elbow River and Glenmore Reservoir Dam in June. (Falice Chin/CBC)

Crayfish have clawed their way into Calgary waters — thanks to people intentionally moving the invasive species from other water bodies, according to Alberta Environment and Parks.

The invasive species has historically been found in the Beaver River Watershed, in waters near Wainwright, Alta., more than 400 kilometres northeast of Calgary. 

More recently, the province has found crayfish in the south end of the Beaver River Watershed, Red Deer River and the Glenmore Reservoir. 

"By finding them in the Calgary area, it appears that people have been moving them around intentionally, where we have specific prohibitions around bait and moving live fish," said Nicole Kimmel, an aquatic species specialist with Alberta Environment and Parks. 

The province started getting reports of crayfish sightings above the Glenmore Reservoir Dam this year. (Falice Chin/CBC)

She said the province started hearing reports about crayfish piling up above the dam in the reservoir in the southwest end of the city. 

It is illegal to move fish from one water body to another in Alberta and doing so can result in harm to a local ecosysytem. It's also "extremely expensive" to restore a water body after an illegal introduction, according to the province's invasive fish species website.

No major health concerns, province says

Calgarians eager to both use the creatures as bait and fish for crayfish closer to home are likely the cause, Kimmel said. 

"We have had reports of people eating them and that's totally acceptable. There is no health concerns and it is apparently quite tasty, but a small morsel is all you get from one crayfish," she said.

The province has yet to conduct any surveys to determine the crayfish population. Officials haven't seen any major impacts due to the species moving into Calgary. 

Crayfish have invaded the Calgary area in recent years. (Falice Chin)

"But with anything, we can never really fully measure an unintentional species being introduced so we always err on the side of caution that that should never happen because we might not be able to measure the full impact of what they're doing to the ecosystem," Kimmel said. 

Be cautious with crayfish

She said the province is also concerned the quickly reproducing species — a crayfish litter averages around 241 eggs — will dominate Calgary's waters and threaten small fish populations as they overwinter "quite well." 

Crayfish can also pinch dogs and grab on to sticks, fingers and clothing. 

Kimmel asks Calgarians who come across the species:

  • Do not move the invasive species.
  • Do not use them as bait.
  • Capture them only by hand or using a net.
  • Report crayfish sightings to the province through the aquatic invasive species hotline at 1-855-336-2628.

With files from Elizabeth Snaddon

now