Dumped goldfish are overrunning Okotoks ponds
Fish released into wild by residents pose threat to native aquatic species
Normally found cruising in glass bowls, unwanted aquarium fish dumped into two Okotoks storm ponds have grown to almost a foot long.
At least 200 hardy goldfish, between 15 and 25 cm in length, are living in ponds in Drake Landing and Crystal Ridge, apparently dumped there by local residents.
While a pretty addition, they’re not at all welcome and the town and province are planning to eradicate them.
In the next few weeks, Alberta Environment and Parks will be treating the ponds with a plantbased chemical called rotenone.
The dead fish will removed afterward and taken to the Foothills Regional Landfill.
The town became aware of the rogue fish in spring 2015 and had considered reducing the ponds’ water level in the winter and freezing them.
But the fish survived, and even thrived through the winter. They can’t remain because the ponds are connected to the Sheep River and the goldfish can harm other fish and plants in that waterway.
“The problem is they are not native here and they can create a lot of problems. They breed — they are quite a prolific population,” said Tanya Rushcall, aquatics invasive species technician with Alberta Environment and Parks.
She said goldfish, which can live as long as 10 years, eat native fish eggs and plants and also may carry bacteria and disease.
“Basically, they out-eat and outlive the native species.”
Rushcall said Okotoks isn’t the only municipality dealing with itinerant goldfish. There are reports of them in urban storm water ponds from Fort McMurray to Medicine Hat and Lethbridge.
“They’re a very hardy series. They can survive in different water temperatures and fluctuating oxygen levels. And they can grow quite large once they’re removed from their fish bowls. Some have been the size of a dinner plate.”
To deal with the increasing problem, the province initiated an awareness campaign this spring called “Don’t let it loose” to warn about the dangers of releasing pet fish into storm ponds or even flushing
Landingweek downand pond duringthe will toilet.the be week treatedThe of Drakenext Aug. 25 or 29.
The Crystal Ridge pond will be treated the weeks of Sept. 5 and Sept. 19. The ponds will be fenced off before, during and for a few days after treatment.