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a photo of a crayfish on the sand under water
TheRockies.Life Staff

Have You Seen This Aquatic Menace?

The northern crayfish is spreading rapidly in Alberta, causing significant impacts where it does not belong

Last summer, a northern crayfish was spotted in a stream flowing into Bow Lake in Banff National Park. Usually, you’d spot these crustaceans on a plate at The Captain’s Boil in Calgary, but not this time.

Northern crayfish are identified by their rust-red shell and large claws, which are often blue. These little guys are mostly found east of Alberta. In Alberta, northern crayfish are only considered native to the Beaver River watershed south of Edmonton.

A photo of a captured northern crayfish on a ruler showing its size
The crayfish captured by Parks Canada last summer | Parks Canada, CBC News

But outside of the Beaver River watershed they are considered an invasive species and they are totally unexpected in the Bow River system. The northern crayfish has been spreading throughout the province way faster than expected for natural range expansion.

They certainly didn’t hike or book a plane ticket, so how did they get here in the first place? According to the province, humans are to blame.

Crayfish could have been introduced by anglers from other areas using crayfish as bait. Or they may have been put in lakes or rivers by people who kept them as pets. 

Alberta Parks employee holding northern crayfish | My Wild Alberta, Facebook

The invasive northern crayfish can impact the food web, which consists of all the food chains in an environment. A new species can change the amount and variety of food available to other species. 

The northern crayfish discovered last summer was the first found in the Bow River system. It was also a female of reproductive age, measuring about eight centimetres. 

Parks Canada quickly acted, monitoring the Bow River for more crayfish throughout the summer. Thankfully, the agency did not find any other northern crayfish. 

“Usually, when we find something like this, there are more. So, while we can hope this is the only one, I would suspect there are more,” Megan Goudie, a Parks Canada biologist, told CBC News.

In Banff National Park, non-motorized boats must complete a self-certification permit that shows a user has cleaned, dried and drained their watercraft for at least 48 hours before hitting the waters.

While you can’t use crayfish as bait, you are more than welcome to catch as many of the aquatic critters as you’d like. Just make sure you kill them immediately before you transport them. Otherwise, you could be slapped with a hefty fine which will cost you much more than a deluxe lobster meal at The Captain’s Boil! 

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