Invasive fish species, capable of cloning itself, puts Saskatchewan fish at risk

This Prussian carp was caught on Stockwell Lake, about 70 kilometers southeast of Rosetown. (Courtesy: Saskatchewan Sportfish Research Group)

Prussian carp, fish that can clone themselves, are putting Saskatchewan-native fish at risk, according to a Regina researcher.

“It’s one of the worst invasive fish species in the world,” Christopher Somers, a professor at the University of Regina and Canada’s research chair in genes and the environment, said.

Somers said he fears the invasive species will out-populate Saskatchewan fish.

“They can reproduce really rapidly and spread very quickly. They're just better at using resources than the fish that they're competing with,” Somers told CTV News by the South Saskatchewan River, where the fish have been spotted.

The invasive species are believed to originate from Asia or Europe. Prussian carp can be pets, and scientists suggest the fish got into Canada after someone released their pet in Alberta.

The first Prussian carp was spotted in Lake Diefenbaker about six years ago. Since, the fish has been spotted sporadically throughout the Saskatchewan River system. About two weeks ago, several fish were found in the Anerley Lakes, which concerns Somers.

"This was the first time that we've ever seen them in large numbers in this province. We are potentially going to see an explosion in those Prussian carp in our southern waters here, at the expense of our native fish that we would like to keep as part of our healthy fisheries,” Somers said.

The invasive species are predominantly female. The fish are able to clone themselves by stealing other species’ sperm.

“It’s extremely strange. It’s not something that’s common, certainly not in freshwater fish,” Matt Tyree, the Ministry of Environment’s manager of the fisheries unit, told CTV News.

The ministry is monitoring where the fish are spotted in the province.

“Prussian carp, like all invasive species, are a concern to the province. We’re interested in preventing future spread of the species,” Tyree said.

If someone catches a Prussian carp, Tyree suggests people notify the Ministry of Environment about where the fish was caught and then discard the fish.