Work began last week to clear oversized goldfish from Okotoks storm-ponds as crew applied a chemical that is toxic to fish in two water bodies in the Drake Landing area.
The Town is using the chemical Rotenone to eliminate goldfish found in four storm-ponds in the Drake Landing and Crystal Ridge areas. The fish were pets that were released into the ponds and many have grown to be several inches in length.
Parks manager Christa Michailuck said goldfish are an invasive species that would be a significant problem if they made it into the Sheep River.
“All of our storm-ponds do eventually outlet into the Sheep River so it’s really important that we’re not releasing non-native species into the Sheep River,” she said.
The Drake Landing area ponds were treated on Aug. 18-19. Additional treatments are planned at the two ponds within the next week. The chemical will also be applied at two ponds area where goldfish have been found in the Crystal Ridge in September.
Michailuck said the second treatment needs to be done at least seven days after the first. It’s necessary to deal with any fish from eggs that hatch after the first treatment, she said.
Michailuck said a diluted amount of three parts per million is being applied to the ponds. At this level, she said the chemical is toxic to fish, but it is not harmful to humans, pets and other wildlife in the levels used to treat the Drake Landing ponds. However, crews still had to take safety precautions for anyone handling concentrated Rotenone product before applying it to the pond.
The Drake Landing ponds were fenced and Michailuck said anyone working inside the fence was required to wear protective gear.
“Once the Rotenone is diluted in the pond and the application is complete then [the protective equipment] is no longer required,” she said.
Water levels in the pond were reduced during the application and crews used a boat during the application. Crews removed fish from the pond that they could reach with nets and the dead fish will be disposed at the Foothills Regional Landfill.
The cost of the work is being covered, in part, by a $10,000 grant from the Alberta Conservation Association. Last week’s treatment application was led by someone from the Alberta Invasive Species Council. Town personnel will be certified to complete further treatments.
Michailuck said the Town would look at additional treatments if more goldfish are found in storm-ponds in town.
“We’re not aware of goldfish in any other Okotoks ponds that we’re aware of at this moment,” she said.
Michailuck reminded people not to release pets and domestic animals into the wild.
