Alberta recently confirmed the presence of an unwanted addition to the waters of Sylvan Lake, just east of Red Deer. Prussian carp—an invasive fish species native to Europe and Asia—has been suspected in the lake since 2023, but the province received confirmation last Monday following escalated reports and DNA testing.
DNA testing was required because Prussian carp have an almost identical appearance to goldfish, another invasive species found in Sylvan Lake and across Canada. “When goldfish are first released by pet owners, they have that bright orange coloration. But after multiple generations of reproduction, they usually lose it in the wild, and then they look exactly like Prussian carp,” explains Nicole Kimmel, an aquatic invasive species specialist with the Government of Alberta.
Kimmel says the province can’t know for sure how the invasive carp arrived in the lake, but that it’s possible they travelled through waterways connected to surrounding bodies of water where Prussian carp have been identified. Other potential vectors include people illegally releasing them, and even waterfowl that have ingested Prussian carp eggs from other water bodies releasing them through excrement in Sylvan Lake.
Cottage Q&A: Will we ever “solve” the problem of invasive species?
Prussian carp are extremely hardy and it doesn’t take much for their populations to explode, making them a formidable invasive species. “They can actually clone themselves. All you need is one female fish to be introduced, and they can use minnows to inseminate and start egg development,” says Kimmel. It only takes one to two years for a female to become sexually mature and begin that cloning process again, allowing populations to grow rapidly.
At the same time, they possess competitive advantages that allow them to beat out other fish species. Trout populations, for example, have been devastated by Prussian carp on other lakes, says Kimmel. “They can basically survive off of anything they can fit in their mouth. Even decaying plants can sustain them, it appears,” she says. “Really harsh conditions like low oxygen and turbid, sediment-loaded water bodies also don’t seem to bother them.”
7 poisonous plants to watch out for in Ontario
The province has yet to do a population assessment, but Kimmel says carp numbers are robust and that the population is building quickly. “Due to their cloning abilities and having multiple spawning events every summer season, populations can explode quite exponentially,” she says.
While there is no way to eradicate Prussian carp from Sylvan Lake and surrounding bodies of water without harming other fish species, the government has focused on prevention efforts in order to keep populations down. This includes building awareness of the species’ presence in the lake and encouraging anglers to kill Prussian carp when they catch them, instead of releasing them. “We recognize that this probably won’t eradicate the population,” says Kimmel. “But it does offer some measure of removal, where none is really being offered otherwise.”
Related Story Here’s everything cottagers need to know about ticks this summer
Related Story We asked an expert how to deal with algae (the right way)
Related Story Ew! This is why some plants stink when they bloom