Carver County recently removed as many as 50,000 goldfish from an inlet connected to Big Woods Lake in Chaska.
The household pet is also an invasive species in Minnesota and can cause problems for native plants and animals. The fish uproot plants and compete with native species for food and shelter.
Goldfish, similar to the carp, can also easily reproduce and survive with low levels of oxygen during the winter in Minnesota.
The Carver County Water Management Organization initially noticed large numbers of goldfish around Big Woods Lake in April of 2019. The goldfish likely made their way to the area thanks to one of more people illegally dumping their pets into the water, according to the county's goldfish removal project website.
To study the movements of the goldfish and remove them, staff began capturing and tagging the fish last spring. Staff tagged goldfish in Big Woods Lake and Lake Hazeltine, as well as the creek connecting the two lakes.
Then, on Oct. 26, Carver County staff observed large numbers of goldfish in the inlet and mobilized to remove them.
Using a box net, staff removed between 30,000 and 50,000 goldfish. The county will continue using data collected over the spring to inform further management efforts.