Invasive goldfish taking over sensitive Kelowna ecosystem

Photo: Wendy Eiler Photography

An infestation of goldfish in Munson Pond on January 31, 2023

Kelowna’s Munson Pond, a unique and endangered ecosystem, is now at risk after being infested with goldfish.

Goldfish were first reported in Munson Pond in 2021, but since then have grown massively in both size and quantity, as illustrated by recent photos captured by photographer Wendy Eiler.

The only way the goldfish would have made it into the pond was being transported there by an aquarium owner, say experts.

“Goldfish are actually pretty durable fish, and they're not native, so they will out compete the native fish, takeover… food supply and habitat,” said Gail Wallin, executive director of the Invasive Species Council of B.C.

The carp are willing to eat nearly anything, which will be a problem in a sensitive ecosystem like Munson Pond. The Central Okanagan Land Trust says the pond is red-listed as an endangered plant community.

“Munson Pond is a tiny jewel in the region’s rapidly disappearing wetland inventory,” the land trust says online. “At one time, this black cottonwood/water birch ecological community covered much of the Okanagan lowlands but has been displaced by agriculture, urban development, and the channelization of streams and rivers.”

Elsewhere in B.C. goldfish infestations have taken over larger lakes. The provincial government is currently trying to manage an infestation in Yellow Lake, a popular fishing spot outside Penticton.

Dragon Lake just outside Quesnel is filled with goldfish weighing up to five pounds.

“They're absolutely monsters,” Wallin said. “I've actually transported barrels of goldfish (out of Dragon Lake) down to the research lab.”

She says goldfish are able to live with very little oxygen, meaning they can survive the winter kill associated with lake ice that impacts native species.

Once they get established, it is very difficult to remove them. The provincial government is experimenting with electrofishing at Dragon Lake, but Wallin says that is not always possible.

“There's a risk to other fish,” she said.

Wallin says they are focusing on education and letting the public know about the devastation the simple goldfish can cause in the wild.

“If you don't want your goldfish, talk to your friends, go back to your store, but don't release it,” she said. “I mean, we've got to stress that because these are so durable of a fish, we don't want more than out there.”

Photo: infini[Ty]center / YouTube

Munson Pond in 2021 when the goldfish were much smaller