Goldfish a looming environmental problem in Canada

Friday, April 8, 2016, 11:03 AM -

A trusty childhood pet has officials panning the waters looking for gold in St. Albert, Alberta. Goldfish, that is.

Edgewater Pond, in the northern part of the city, has been infested with the animals since last summer and as they thrive in their adopted home, concerns for the local environment increase.

The species was likely introduced to the pond by well-meaning people who were releasing unwanted pets. Speaking to CBC News, aquatic invasive species specialist Kate Wilson said, "People who have aquariums, and don't want them anymore, instead of killing their fish or giving them away, they're dumping them in these ponds."

Unfortunately, they're dumping their problem on the environment instead. "The crazy thing about goldfish is they're so hardy," Wilson said. "These species can actually pose a great risk to the environment because they're so hard to kill."

And the city has tried several tactics to do away with the unwanted invaders. Last October, city crews attempted to freeze the fish out by draining the pond so it would freeze to the bottom through the winter months. Environmental co-ordinator for the city, Sarah Cicchini, told the St. Albert Gazette that the attempt was foiled by the warm season. With average daytime highs in the area straddling the freezing mark from December to February, even the partially-emptied pond never froze completely.

They've also tried netting the fish, and even electrocuting the water, so far without much luck. City crews have discussed using a pesticide, but there are concerns the fish would just be reintroduced by others abandoning their pets.

Like any invasive species, the goldfish pose a risk for the ecosystem they're unleashed upon. Wilson cautions they can breed more quickly than native Albertan fish, can crowd out native species, hoard food sources, and introduce parasites.

Goldfish are an ongoing problem in Albertan waterways. Wilson tells CBC News, "They can live in any water body in Alberta. We've found them as far north as Fort McMurray, which is really cold."

St. Albert crews will investigate the extent of the infestation throughout the city in May, meanwhile a screen will be placed across Edgewater Pond's outflow to help keep the pesky pets out of the Sturgeon River.

In Ontario, Hamilton Harbour faces a similar fishy problem. Earlier this year, researchers at the Royal Botanical Gardens reported to CBC News they'd counted at least two million of the animals in the bay; as many as 2,500 large goldfish and two million young.

Tys Theysmeyer, a researcher with RBG, says it's a growing problem. "People used to actively release goldfish into the bay a lot," he told CBC News. "In the last five years, their numbers have been rising and rising." He blames a combination of rising water temperatures and poor water quality for the non-native fish's ability to thrive. Poor water quality in the bay has led to a decline in native species like northern pike and minnows, giving the goldfish more room to manoeuvre, and warmer waters mean they can survive now where they couldn't 50 years ago.

Sources: CBC News | St Albert Gazette | 

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