July 16, 2007
NEEDED: Hydrilla Hunters to Search for a Most Unwanted Species
It’s summertime and hunting season for the invasive plant Hydrilla verticillata. Michigan Sea Grant is looking for volunteers to check the state’s Great Lakes bays, inland lakes and other waterways for the ‘perfect weed.’
This aquatic plant forms large, dense mats on the water’s surface, creating havoc with the ecosystem and interfering with recreation, according to Michigan State University Extension’s inland lake specialist Howard Wandell. It has clogged waterways in many southern states and has been found as far north as Maine, Massachusetts and as close as a northern Indiana lake.
In recent years, Hydrilla hunters have reported searching dozens of lakes in more than half of the state’s counties, according to Sea Grant reports. So far, no one has found the invasive aquatic plant in Michigan.
Wandell says it’s very difficult and expensive to eradicate. “We have very limited effective options for controlling this invader, so it’s important to keep it out of the state if we possibly can and control it quickly—before it spreads—if it does appear.”
Michigan Sea Grant spokesperson Carol Swinehart says one key reason to take a preventive approach is that the plant can reproduce rapidly in at least four ways—from stem fragments, from its flowers, through a bud-shaped growth called a turion, and through underground tubers and runners that can overwinter.”
“If someone thinks they've found it, we ask that they compare the plant with the image on our web site or the Hydrilla Hunt card. The card provides instructions on how to collect a plant sample, how to distinguish it from the native aquatic plant elodea, and where to send it for confirmation of identification. If it has all the characteristics described there, send us a sample so that we can make sure,” Swinehart says.
See: Hydrilla Hunt cards and other information about the species
Citizens can also obtain Hydrilla identification cards and a fact sheet from Institute of Water Research and Michigan Sea Grant Extension offices at Michigan State University, Sea Grant Extension offices in Grand Haven, Traverse City, Tawas City, Mt. Clemens, Detroit and Marquette, as well as from MSU Extension offices in Antrim, Berrien, Benzie, Calhoun, Cass, Charlevoix, Emmet, Genesee, Grand Traverse, Kalamazoo, Leelanau, Manistee, Montcalm, Muskegon, and Oakland counties, the Kellogg Biological Station in Hickory Corners and Michigan Natural Features Inventory in Lansing.
The card also requests basic contact and location information. Swinehart asks people to report where they’re searching by sending an e-mail to cys@msu.edu. Put Hydrilla Hunt in the subject line and the name of the lake, pond, or river and the county in the text of the message.
Suggested searching strategies include the following:
- Conduct the search early in the morning on a calm, sunny day.
- Start with the public boating access, if available.
- Go slowly around the shoreline wearing polarized sunglasses to reduce glare.
- Look in water up to 20 feet deep.
- Pay special attention to any unusual plant growth.
- Check the lake’s outlet and any flow-restricting structures such as dams and spillways.
- Check for plants near stream inlets and in shallow bays.
It is illegal in Michigan to possess hydrilla, except to send it for expert identification. It is also illegal to take hydrilla across state lines, so Michigan residents and visitors can help by following good prevention practices when moving watercraft or other water recreation gear from one body of water to another. More information on prevention practices is available at www.protectyourwaters.net
Michigan Sea Grant is a collaborative program of Michigan State University and the University of Michigan, conducting Great Lakes research, education and outreach. It is one of 30 Sea Grant programs supported by the National Sea Grant College Program of the National Oceanic and Atmospheric Administration (NOAA). To learn more visit www.miseagrant.umich.edu
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