Involuntary invaders — goldfish, turtles, aquarium plants and even the occasional alligator — are crowding Minnesota lakes, dumped there by negligent owners.

Just last week, Rochester police got a panicked call from residents who thought they spotted a gator paddling around Cascade Lake. Last summer, authorities wrangled two small alligators out of the Brainerd Lakes Area and into wildlife sanctuaries.

The exotic pets returned to custody are the lucky ones. A young gator, found frozen into the ice on Lake Marion near Burnsville in 2013, shared the fate of many pets let loose into an ecosystem where they don’t belong.

Dumping exotic pets and plants into the Minnesota landscape is bad for the creatures, bad for the environment and it’s illegal. The Minnesota Department of Natural Resources, which devotes a considerable chunk of its own resources to the battle against invasive species — can slap offenders with fines ranging up to $500.

“It’s not humane treatment of animals [and] in most cases it’s illegal to release most nonnative species in the wild in Minnesota,” said DNR invasive species specialist Keegan Lund. “There’s always better options to find new homes for these animals and plants.”

It should go without saying that you shouldn’t release carnivorous reptiles into residential lakes. But even seemingly harmless species can wreak havoc.

Goldfish can thrive in cold lakes, bloating to monstrous proportions and squeezing out native species. Aquarium plants can take root beside them. A decade ago, Minneapolis deployed herbicides to wipe out a colony of Brazilian waterweed in Powderhorn Park — a common aquarium plant that has no business growing wild in this hemisphere. The Wood Lake Nature Center is using largemouth bass to try to wipe out the huge goldfish infesting the lake.

“We run into released goldfish all the time,” Lund said. Goldfish, like common carp, stir up pond sediment and disrupt the habitat of native species. .

There are options out there for people looking to safely rehome an exotic pet, Lund said. Groups like the Minnesota Aquarium Society and the Minnesota Sea Grant offer fish swaps and surrender programs as safe alternatives to the nearest pond.

“Rather than dumping in the environment, find a new home for these organisms,” Lund said.


Jennifer Brooks 612-673-4008