Winter kill of invasive goldfish in Vernon's Cools Pond

A kill-off of goldfish in a Vernon pond has the local naturalists club wondering where the invasive fish came from.

Social media was abuzz this week about dead gold fish in Cools Pond in the BX.

Some were concerned about what killed the fish, but Harold Sellers is more concerned the fish were there in the first place.

There are not supposed to be any fish in the pond, let alone goldfish, says the co-chair of the North Okanagan Naturalists Club.

Shallow bodies of water like Cools Pond can experience what is known as a winter kill, which is caused by low levels of oxygen.

Goldfish have become common in bodies of water not only only in the Okanagan, but throughout North America.

“It's a pretty widespread problem everywhere,” says Sellers. “When people get tired of their goldfish pets, they don't want to kill them, so they look for some place to dump them, and most of our ponds have goldfish in them.”

As goldfish are an introduced species, they can cause damage to the ecosystem.

“Without the restraint of an aquarium, they can grow quite large. I know there are goldfish in the McKay Reservoir which have grown very large – up to a foot long in some cases. They are related to carp, so they can do a lot of damage to vegetation by rooting in the soil, and they can eat the eggs of things like frogs and salamanders,” says Sellers.

They can also feast on the eggs of spadefoot toads, which are an endangered species in the area.

“We are not sure if the ones in (Cools Pond) all died off. There has been a pretty extensive winter kill everywhere in B.C. this winter. So we are going to monitor it to see if there are any more,” says Sellers.

Otter Lake in Spallumcheen also had a winter kill, with hundreds of carp dying.

Sellers encourages people not to dump goldfish into local waterways. There is an effort to have pet stores take back goldfish or any other fish they sell.

The only viable option to remove goldfish from places like Cools Pond would be to trap them or catch them with a scoop net.

“The one benefit of them is they do provide food for herons,” says Sellers.

The naturalists club is monitoring Cools Pond on behalf of RDNO. If anyone sees live fish, they are asked to post on the NONC Facebook page.