Quebec town faces off against goldfish that threaten local wildlife

It's not uncommon to see dead fish on the shores of Quebec waterways this time of year, but visitors strolling along one town's popular pond have been a bit surprised to see bright orange bodies floating belly up.

Goldfish are becoming a problem in Burbank Pond, located in Danville, Que., about 165 kilometres east of Montreal.

"There are more and more each year," said Brydon Rodd, a biologist and vice-president of the organization that oversees the pond's development, Corporation de dveloppement de l'tang Burbank.

Known as tang Burbank, the pond has more than three and a half kilometres of walking trails and three observation towers where visitors can view some 220 types of birds. The pond is a square kilometre, and has attractions like a playground, an indoor exhibit and even guided tours in the summer.

It's also becoming a goldfish hotspot.

The goldfish likely began as pets that were released into the waterway and then began multiplying, said Rodd. It's not uncommon to see fish dying this time of year, he explained, because the decomposition of aquatic plants, which is accelerating with the rise in temperature, reduces oxygen in the water.

The goldfish are invasiveand conflict with native fish eating their eggs, Rodd said. The goldfish also feed on fish larvae and insects, taking food resources away from native fish, he said.

"These are fish that get very big, so it's a big problem," said Rodd.

How big can they get? In 2021, more than two dozen goldfish were found around Keller Lake in Burnsville, Minn., and some were larger than a football, weighing up to 1.8 kilograms, prompting local officials to plead with residents not to release their pet goldfish into the wild.

Goldfish invasion sparks worry

Goldfish, native to East Asia, are considered an invasive species throughout North America.

It's becoming an issue in many regions of Canada, including the Great Lakes, where goldfish numbers have "really spiked since 2015," said Jennifer Bowman, an aquatic ecologist for the Royal Botanical Gardens based in Burlington, Ont.

"It's getting a lot worse. They are very successful when they get together; a couple of goldfish can get access to a pond and you have thousands the next year," she told CBC last year.

According to Ontario's Invading Species AwarenessProgram, goldfish are able to tolerate fluctuations in water temperature and water with low levels of dissolved oxygen.

"In healthy ecosystems, goldfish do not appear to compete well with some native fish. However, they are quite tolerant of poor water quality, as such, may threaten some native species in degraded ecosystems," the program says on its site.

Getting rid of goldfish in Burbank Pond

This threat is why Rodd's organization is looking for ways to safely eradicate the invasive fish from Burbank Pond.

Solutions include lowering the water level or using chemicals, but that could kill everything in the water and new, native species would need to be stocked with new, native fish, he explained.

Taking each goldfish out individually is also a possibility, he said, but "it would be a really big operation. It would take a lot of workers and it would be very expensive."

The Corporation de Dveloppement de l'tang Burbank will be taking a species inventory as it searches for the best way to curb the spread of goldfish.

Danville Mayor Martine Satre is well aware of the problem.

"We have very pretty photos of birds flying away with a big goldfish in their beaks," she said.

And while that might be amazing to see, she added, Danville's administration is ready to do what's needed to preserve the pond, which is very important to the municipality.