Goldfish posing invasive species problem in B.C. lakes

By Marina Wang

This year, our beloved childhood pet, the goldfish, has swarmed Pinecrest Lake near Squamish, and this isn’t the first time they’ve posed an invasive species problem in the province.

“People have been observing schools of 30 to 40 fish schooling together at a time. They vary in sizes, some small, some up to five inches [13 centimetres] big,” Clare Greenberg, executive director of the Sea to Sky Invasive Species Council, told the CBC.

The fish are thought to have been released by local pet owners in the early spring or summer. Now, they number in the hundreds and can grow up to the size of a football. Concerned residents contacted the council to investigate the environmental concern that the invasive species are causing.

“It seems that goldfish, once they establish in a lake, do really well and it’s very difficult to control them once they’re there,” said Greenberg. Goldfish are omnivorous bottom-dwellers that can outcompete native fish species for food and increase lake turbidity. In addition, they aren’t the preferred food source for natural predators, it would be difficult to eliminate them that way.

Options for dealing with the infestation include selectively removing the fish or applying a fish poison. The first method would involve a process called electrofishing, where a current is applied to the lake to attract and stun the fish. The goldfish could then be selectively removed. Otherwise, the natural poison Rotenone could be applied, killing all the fish.

The council is yet to meet with provincial experts to conduct a site-specific assessment and determine a course of action. Greenberg also warned against the dumping of unwanted pets in lakes.

Previous goldfish infestations have occurred in Dragon Lake near Quesnel, Millars Pond in Whistler, and White Lake in Salmon Arm.

One Response to Goldfish posing invasive species problem in B.C. lakes

  1. nonconfidencevote says:

    Well,no problem.
    Just let people know that powdered “goldfish” are a cure for male impotence and I’m sure within a decade the world will see them listed on an endangered species list next to Rhinos and elephants………

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