Invaders to our waterways; what to watch for this spring

Red Swamp Crayfish have plagued Michigan since 2017
Flint Water
Posted at 5:23 AM, Apr 21, 2022
and last updated 2022-04-21 17:00:07-04

NOVI, Mich. (WXYZ-TV) — As we continue our deep dive into the health of metro Detroit's waterways, we're talking about invasive species.

There are hundreds, when you combine both plants and animals in our region. Many invasive species get little attention and even less funding to eradicate.

One invader to our waterways has been here since at least 2017. It's bright red, has raised spots, and looks like a mini-lobster; the Red Swamp Crayfish.

It may be a welcome addition to a southern fish boil, but here in Michigan these critters have been causing the Michigan Department of Natural Resources some serious problems.

“Since 2017 I think they’ve captured 34,000 crayfish," said Lt. Michael Feagan with the Michigan DNR, standing near a small pond in Novi off Haggerty Road.

Statewide, he said they've captured 150,000.

“So obviously trapping is very effective, we’re getting a lot. But it’s not effective in eradicating them," he said.

The DNR has tried chemical and CO 2 treatments to coax Red Swamp Crayfish from our water, but so far nothing has done the trick.

To many people's surprise, these not-so-welcome southern guests have actually survived our winters!

Photo Credit: Michigan State University

In addition to being more aggressive than our native species of crayfish, Red Swamp Crayfish compete with native species and further bank erosion by burrowing deep, sometimes feet into the ground.

Just in the last few years, Lt. Feagan said they made their way into neighboring ponds in Novi, likely through underwater channels.

“You may go out someday to a riverbank that you like and see that it’s kind of caved in from the erosion or the water quality is not as good," he said, which is why this problem could one day have a larger impact.

When it comes to invasive plants, we spoke with Kirsten Lyons. She heads up the Lake St. Clair Cooperative Invasive Species Management Area (CISMA).

She and her team are out to track, find, and get rid of the beautiful but troublesome water lettuce and water hyacinth. They're popular in home water gardens but when people dump those gardens in local rivers or even ditches, it's a real problem, she said.

“We’d like folks to understand that when they make the purchase or before they make the purchase, to have a plan," she said.

"They harm the environment because they can cause thick mats to grow on the surface of the water and that can shade out, and deplete the oxygen.”

Oxygen native plants need to thrive.

This year she and her team were awarded $100,000 from the Michigan Invasive Species Grant Program (MISGP) to among other things, survey and treat invasive species.

These free-floating plant invaders are spotted by August and last well into the fall. So before that season starts, Lyons is trying to boost awareness.

“They would be in slow moving water, and you’re going to find that in those areas along the shoreline," she said, pointing at a scalloped area along the Clinton River Spillway.

Last year, they removed 3,000 pounds of water lettuce and water hyacinth from the Miller Drain alone.

Miller Drain before thousands of pounds of water lettuce and water hyacinth were removed.

So far, these plants have not over-wintered here.

“With the warming climate and the mild winters we’ve been having, we are concerned that they may be starting to over-winter," she said when asked about the warming climate's impact on her team's work.

"They can reproduce really quickly.  So it could be very problematic for our local habitats. Especially the Spillway, because it has a lot of place where water lettuce and water hyacinth could grow."

The Spillway, which was created to help relieve flooding in Mt. Clemens and is considered part of the Clinton River federally designated "Area of Concern" (AOC), is now home to a thriving habitat.

“Now it’s hosting all kinds of birds and fish," Lyons said. “Another reason that we’re very interested in surveying for water lettuce and water hyacinth here is because we want to protect that investment.”

To report invasive species near you, you can do so using the Midwest Invasive Species Information Network (MISIN). There's an interactive app available for free in the app store.