Wed July 2, 2014
State Studies Inland Lake Invasive Species
Aquatic biologist Jennifer Johnson wades toward a motorboat on Klinger Lake in St. Joseph County. She’s holding a brown, palm-sized mussel, a native one.
“It looks like a fatmucket,” she says.
Several zebra mussels, small by comparison, have attached to it.
“Native mussels burrow from this end, so right about here is where they’re going to be in the sediment,” she says, indicating the part with no zebra mussels.
“The rest of this is exposed, so you can see the zebra mussels attaching to right where their siphons are so it makes it very hard to feed.”
Invasive plants and animals are unwelcome but well-established in many Michigan waterways. Some, like the fingernail-sized zebra mussel, can devastate an ecosystem under the right conditions.
The Department of Environmental Quality says right now, it only knows so much about how invasive species have affected the state’s inland lakes. But the DEQ and several other state agencies hope a new study will change that.
“The last few years we’ve greatly expanded our efforts in monitoring for aquatic invasive species,” Johnson says, referring to the DEQ and several other state agencies cooperating in the study.
“We started planning last fall about lake selection, the approach that we were going to take, how many lakes we should do.
"We actually got rained out the first three lakes, so this is the second lake that we’re doing.
“We’ll do the entire perimeter of the lake, the littoral zone, looking over the boat. And if we see something that we need to look at further we’ll do a rake toss, pull it in and ID some stuff.”
One of the species Johnson and Walters are watching out for is an invasive plant called Eurasian watermilfoil. In an area where long, stringy plants reach up from the lake bottom, Johnson gathers a few and puts them in a tray.
Johnson says the invasive milfoil tends to form “dense mats on the surface.”
“Whereas the native milfoil, kind of what I was seeing, it just kind of goes up in a straight line and doesn’t form those mats that can cause problems for boaters, it could get tied up in their motors.”
This milfoil might be a hybrid of the native and the invasive plants. Johnson saves a piece of it. She’ll have the DNA tested to find out.
But there’s at least one invasive species in the tray.
“You can tell like I was saying before, the zebra mussels will attach to anything,” she says, pointing out several attached to the plants.
“There’s two of them right there. Actually, three. The more you look the more you find."
“We usually start at the boat launches, and we do fifteen-minute snorkel searches and near-shore wading searches,” she adds, explaining their method for studying the lake.
Walters is captain of the motorboat today. Johnson watches the GPS as they look for a snorkel site.
“I have previously marked points here where we get out and survey,” she says, watching the GPS screen. “And then I’m just following – just in the general area, that’s where we’ll go.”
Johnson climbs out and Walters sets the stopwatch. While he waits, he explains the outreach and education work on invasive species he does for DEQ.
“We have some priority species that we think are of particular concern because their impacts are so bad that definitely don’t want them here or they’re species that if they were to come here we think we have a reasonable chance of eradicating them or stopping them,” he says.
That watch list includes Asian carp, northern snakehead, a plant called parrot feather.
“And we don’t necessarily know where all those species are now or if we have those. So this survey will add to that,” he says.
“Even if a lake has zebra mussel or has Eurasian watermilfoil if it’s at a low enough abundance there’s things you can do to control it. But once it’s widespread and everywhere in the lake and is starting to take over, there’s not a lot you can do or not a lot you can do that’s cost-effective and isn’t long-term, many many years of ongoing treatment.
“We have the mobile boat wash where we’ve been taking it around to kind of priority locations.
“It has kind of dual purpose. One is actually cleaning things off of boats and decontaminating boats with zebra mussel larvae and aquatic plant material and potential fish diseases.
"But the real point is education and outreach. And it gives us a chance to tell people, ‘hey, did you know that you’re required by law to drain the water out of your bilge and your live well when you leave a boating access site.
“Or ‘did you know you can’t launch a boat with aquatic plant material attached to your boat. Did you know you’re supposed to dump your bait in a garbage can, your leftover worms and minnows, they’re not supposed to go back in the lake. Because you can transfer diseases or transfer invasive species that way.’” So it give us a chance to give that message.
He checks the time. “All right, Jen!”
“Hopefully we can add on to what we’re currently doing when we’re monitoring lakes,” Johnson says.
“’Is this a great method for a biologist to incorporate?’ And so hopefully we can learn a lot – a lot of lessons – and just move forward each year.”
The DEQ plans to survey fifteen lakes this summer – the last ones in the Upper Peninsula in early August.