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Schools of invasive goldfish — some of which are the size of dinner plates — are plaguing Alberta.
The provincial government is sounding the alarm on the significant risks native ecosystems are facing due to the introduction of goldfish into bodies of water across Alberta.
“Goldfish belong in aquariums, not in Alberta’s waters. Don’t let it loose,” said provincial Environment Minister Grant Hunter in a Monday news release.
Goldfish have been detected in more than 100 locations throughout Alberta — and according to the province’s aquatic invasive species specialist Nicole Kimmel, new locations are added to that list every year.
“This isn’t because people are flushing them down the toilet and they’re making their way to the waterways,” she told CBC News. “People are actually intentionally dumping them into our waterways, and they are overwintering and thriving and finding ways to reproduce.”
The province’s “Don’t Let It Loose” campaign aims to curb the illegal releasing of species into waterways — a crime that can come with fines of up to $100,000 and/or a year in prison.
“Never release anything into the water that it didn’t come from,” Kimmel said.
“People might think that they’re just dumping goldfish, but actually they might be introducing snails, fish disease, plant fragments that can also take over a water body in Alberta.”
Goldfish can pose significant risks to native aquatic ecosystems.
“They’re so adaptable, and they can eat anything they can fit in their mouth,” Kimmel said.
In contrast, many native fish are pickier about what they eat, as well as where they reproduce.
Goldfish also have no problem surviving Alberta’s harsh winters, and a single goldfish can produce an estimated 40,000 offspring in just three years.
“Those competitive advantages give [goldfish] every opportunity to thrive,” Kimmel said.
Goldfish are ‘global invaders’
The invasive goldfish problem extends far beyond Alberta.
“They’re global invaders,” says University of Toronto biology professor and invasive species researcher Nicholas Mandrak.
“They can withstand extreme environments. I’ve caught them in Siberia, in lakes that get a metre of ice in the winter … hence, they are found broadly in Canada and globally.”
Mandrak says storm-water management ponds are prime locations for goldfish to spawn.
“Because these are adjacent to houses, they’re convenient places for people to release their goldfish,” he said.
“On top of that, they are highly suitable for goldfish, and they’re typically a little warmer than our lakes and rivers, and that means that goldfish reproduce at a higher rate and they grow faster.”
Mandrak’s work in Ontario includes studying ways to control the spread of goldfish from storm-water management ponds into the wild.
As Epcor chemically culls invasive goldfish in a stormwater pond in the Glastonbury neighbourhood, a group of Edmonton residents reflect on what is lost, as well as the wins of their months-long campaign to convince the utility company to use a greener approach.
The Alberta government keeps tabs on goldfish populations across the province.
There’s no specific way to deal with goldfish once they’ve established themselves, meaning when culling is necessary, the entire fish population has to be destroyed through chemical treatments or draining of that body of water.
“If we don’t stop the illegal introduction of goldfish in these ponds and their subsequent movement into the wild, this is going to be a nationwide problem — not just isolated to cities, but throughout the country — and having these negative impacts on those native species that we value,” Mandrak said.
The province says Albertans should report sightings of goldfish and other invasive fish to the Aquatic Invasive Species Hotline at 1-855-336-BOAT (2628) and provide a clear photo showing the fish’s entire body and fins for identification purposes if possible.
People who witness the suspected intentional release of an aquatic invasive species in Alberta are encouraged to call the 24/7 Report A Poacher hotline toll-free at 1-800-642-3800.
