These two goldfish were pulled out of a pond in Duluth. They started out as small, aquarium goldfish, but when introduced into the wild, they can grow up to more than a foot in length. (Photo by Chris Julin)
You can hear frogs croaking and chirping in the middle of a city these days. You can see cattails and water lilies out your window even if you live nowhere near a lake. Water gardens are all the rage. But some scientists are warning that we have to be careful with our gardens. If plants or animals get out of a backyard pond, they can endanger native species. As part of an ongoing series called “Your Choice; Your Planet,” the Great Lakes Radio Consortium’s Chris Julin reports:
Transcript
You can hear frogs croaking and chirping in the middle of a city these days. You can see cattails and water lilies out your window even if you live nowhere near a lake. Water gardens are all the rage. But some scientists are warning that we have to be careful with our gardens. If plants or animals get out of a backyard pond, they can endanger native species. As part of an ongoing series called “Your Choice; Your Planet,” the Great Lakes Radio
Consortium’s Chris Julin reports:
For a while this spring, this pond was empty. Workers pumped out the water so they could catch fish. There were a few puddles, here and there on the pond bottom, and Tyler Winter got the job of scooping fish out of the puddles. He’s a college biology student. His five-gallon plastic bucket was half-full of fish — each one about the size of his hand.
“We got domestic goldfish, of various sizes and colors. This is the same kind of a thing that you would find at a pet store, but when introduced into the wild and they have more room to grow and they don’t die quickly, they can grow up to 10 or 16 inches.”
It appears that somebody — lots of somebodies — took the goldfish from their aquariums and water gardens and tossed them into this pond. They probably thought it was better than flushing the fish down the toilet.
The problem is, the pond flows into a designated trout stream. Trout need clean water, but goldfish stir up muck from the bottom when they feed. That could make the stream uninhabitable for trout.
People release lots of animals and plants, even though it’s often illegal. In the Great Lakes region alone, 38 species of aquatic animals and plants have reached the “infestation” level after being released into the wild. These plants and animals are crowding out native species.
(sound of gurgling pond)
Debbie Braeu’s back yard is thick with trees and shade-loving plants.
“There’s a pump in the pond that recirculates and the water comes down the stream, goes back up. As you can see, this is real close to our house, so we can sit and have coffee and we can watch the goldfish.”
The Braue’s run a nursery and landscaping business, and they’ve helped a lot of other people start water gardens. They’re big fans of native plants — irises and water lilies that naturally grow here. They sell some exotic pond plants, too, but not the ones that can escape, and live through a Great Lakes winter, and spread.
That’s what Barb Liukkonen likes to hear. She’s a hydrologist with Minnesota Sea Grant, and she’s trying to slow down the spread of non-native water plants. She wants gardeners to use more native plants.
“There are a lot of invasive aquatic plants — some that nobody would import intentionally. Things like Eurasian watermilfoil, or curly-leaf pondweed, things that cause a real problem in our lakes. But there are a whole range of plants that are being used for water gardens and to restore shorelines that may also be very invasive. They’re really pretty. Things like yellow iris, floating yellow heart — plants that look good, but they can be very invasive.”
Barb Liukkonen says gardeners sometimes put exotic plants in a lake intentionally — even though it’s against the law. And beyond that, gardeners sometimes spread exotic plants by accident. Liukkonen says the State of Minnesota recently paid for research into aquatic-plant-buying on the Internet.
“Ninety-two percent of time, the plants that are ordered had hitchhikers – that is, unintended plants or animals or seeds. And those can be introduced when you plant those plants along your shoreline or into your water garden.”
She says the researchers found something else disturbing.
“When they ordered plants that were prohibited, that is illegal to own or to plant or to sell in Minnesota, they still received them 13 our of 14 times. So even though they’re against the law here, people can still order those plants.”
Barb Liukkonen says local greenhouses are more likely to know what plants are banned in their areas. She and colleagues across the country are putting together a public education campaign. They’re designing stickers and fliers that businesses can attach to plants and aquariums. Their message is simple: Don’t release exotic plants and animals into the wild. Keep your goldfish and your garden plants at home.
For the Great Lakes Radio Consortium, this is Chris Julin in Duluth.