Attack of the clones: Sperm-stealing Prussian carp threaten to overwhelm Alberta waterways


Middle schools of Prussian carp — a sperm-stealing fish capable of cloning itself — are invading Alberta waterways, divulges an Edmonton researcher. 

The discovery of wild goldfish the size of dinner panels in a St. Albert storm pond is just the latest appearance of invasive fish in rivers and lakes across the tract.

A genetic cousin to the invasive Asian goldfish, Prussian carp accept been fished out of waterways from the Red Deer River to the Bow River.

Deep-bodied and unhesitatingly, Prussian carp are similar to common goldfish and often mistaken for them. But the Prussian  species has an foremost distinction from other freshwater fish.

‘They’re all clones’

“This strength be a little shocking, but males are not actually needed for reproduction for this species. This is a bit bizarre in the fish world,” said Mark Poesch, a researcher and assistant professor with the University of Alberta’s potential of agricultural, life and environmental sciences.

“The females can reproduce clonally. They can clone themselves on and over and over again.”


For the past three years, St. Albert has been tough to eradicate an invasive goldfish species from local storm branch water ponds. (Zoe Todd/CBC)

The carp can reproduce through a process called gynogenesis, indulging each individual fish a carbon copy.  This process forces “stolen” sperm found floating around in rivers and lakes, alleged Poesch.

“The females lay the eggs and actually take sperm from another species, so another species when one pleases fertilize the eggs but they won’t actually contribute any genetic material,” he influenced.

“This allows them to reproduce in huge numbers. It also indicates that all the individuals, and we’ve done some preliminary genetic work, they’re all clones. They’re all same to one another.”

The silvery fish have been captured in the Bow, Red Deer, and South Saskatchewan river basins in the previous decade.

Government officials have made a concerted effort to spur on recreational fishing of Prussian carp, but populations continue to proliferate.

‘Reproductive hindrance’

The fish are voracious plant eaters and their presence can deplete resources, bring oning native species to fight for food and space.

There is also disquiets around “reproductive interference” with native species, said Poesch.

“They’re winsome the sperm from another species, and so that sperm is not going to fructify their own eggs, so they’re really taking advantage of this together reproductive system,” he said.

“They’re here, they’re having refusing impacts, and they could actually overwhelm the system.”

The hardy instances spawn in huge numbers and can live up to 10 years.

How the fish, inherent to eastern Europe and parts of Asia, came to Alberta remains a enigma, but Poesch believes the fish may have been released by unwitting pet holders from backyard ponds.

Currently, there are no established eradication applications in place for Prussian carp in Alberta other than recreational fishing and apprehend, and many conservationists fear this won’t be enough to eradicate them.

“Goldfish are organize throughout the province and people do release them. And we think that’s how this scanty guy got in here and now they’re really starting to take over,” said Poesch.

“We dream up they first came here in 2000 and the reason it took the so dream of to find them is that people misidentified them as goldfish.

“They word go arrived in Medicine Hat and since then, we find them all the way up to the city of Red Deer, and they are in fact everywhere.”

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