New study on Chinese mystery snail could help manage spread in Alberta

A new study out of the University of Alberta in collaboration with the province could help manage the spread of Chinese mystery snails. 

The invasive species can be found in other parts of Canada, but so far in Alberta, it is believed to be contained to the north bay of McGregor Lake — and scientists want to keep it that way.

"It's really important that if we learn that this is here, that we jump on it right away and make sure that we're getting it and nipping it in the bud to understand what's going to impact our water bodies," said study co-author Megan Edgar, a master of science student studying conservation biology at the University of Alberta.

The Chinese mystery snail is native to eastern Asia but in 2019 scientists found it in McGregor Lake, a reservoir about 90 kilometres southeast of Calgary.

The snail concerns researchers because in other provinces it has outcompeted native snails and impacted the entire aquatic food web, Edgar explains. 

It's unknown how it got into the lake but it was likely human caused, she adds. 

Chinese mystery snails — also known as the trapdoor snails — are larger than the species that are native to the area. They have a dark brown and green hard shell.

The study Edgar worked on was able to confirm that the large snails spotted in McGregor Lake are indeed Chinese mystery snails, but it also confirmed they are free of parasites.

Researchers also studied the snail's characteristics to help inform future management decisions.

'Difficult to eradicate'

What was discovered is that their physical features make them tough to get rid of, says Nicole Kimmel, aquatic invasive species specialist with Alberta Environment and Parks, and a collaborator on the study. 

"They're quite tricky because they have this trapdoor that can seal up the snail shell completely for weeks at a time. So even if we tried to dry them out, or freeze them out, or use chemicals, they have this ability to seal themselves up and avoid those exposures, making them very difficult to eradicate," she said. 

Edgar echoed this, adding that their shell makes them good at camouflaging, and the way the shell seals up helps them evade most methods of chemical management.

"So, this makes them pretty tough against any kind of predation," said Edgar. 

The best strategy seems to be containment.

Kimmel said that's why there is a ministerial order at McGregor Lake for watercraft users to clean, drain and dry their gear to ensure they aren't accidentally transporting the snails.

The snails can live a long time, so if they are stuck on a boat, they could easily be transferred to another body of water.

"That would be pretty devastating, especially for Chinese mystery snails, because they can live out of water for up to nine weeks, which is incredible," said Edgar.

"The more that people know about it, the more it can stay contained and the more people will notice these things and be aware when they do see them and report them."

Sightings of the Chinese mystery snail can be reported to the province's Aquatic Invasive Species hotline at 1-855-336-2628.

"The impacts to the ecosystem seem quite high, so we don't want to jeopardize any of our native mollusks or fish habitat, so that's really the goal," said Kimmel.