Citizens are being reminded not to dump their pet fish into water after a large school of goldfish were spotted in a stormwater pond in Port Perry, not far from Lake Scugog, earlier this month.
Word of the sighting was posted to Facebook on May 2 by the Scugog Lake Stewards, who warned about the potential impact the invaders can have on wild ecosystems, such as introducing harmful bacteria or viruses.
Pet fish dumping or flushing isn’t becoming more prevalent, but is certainly a long-standing problem, according to an invasive species expert with the Ontario Federation of Anglers and Hunters (OFAH).
“It is, more often than not, committed by people who do not want to euthanize an unwanted pet,” OFAH Aquatic Program Specialist Brook Schryer said.
In fact, goldfish – traded as an ornamental fish for centuries – are believed to be the original invasive species to North America, he said.
Schryer educates the public on the risks associated with aquatic invasive species, such as Asian carps, zebra mussels, and Eurasian watermilfoil via presentations, resource development, and the Invading Species Hotline.
The impacts of goldfish are not well known, but they do not thrive in open water environments like Lake Scugog mostly because of predation by fish such as largemouth bass, muskellunge, and yellow perch.
Goldfish cousins of carp
However, since they are a bottom-feeder like their common carp cousins, they will compete with native fish for food and space, Schryer said, noting the threat of transferring fish diseases to native species.
An outbreak of koi herpesvirus (KHV) killed thousands of carp in south-central Ontario, including Lake Scugog, in 2007 and 2008.
The key message here is not to dump your pets, Schryer said. “If they have unwanted pets, they should return them to the store where they were purchased or donate them to a school group.”
You can report sightings of goldfish to the Invading Species Hotline at 1-800-563-7711 or report them online here.