By Mark Breederland
In August, 2006, the invasive plant Hydrilla verticillata was confirmed in a lake less than an hour’s drive from Michigan southern border, nearby, but outside of the Great Lakes drainage basin. Michigan Sea Grant and MSU Extension educators had begun in 2004 leading a statewide effort, in conjunction with the Michigan Department of Environmental Quality, to encourage waterfront property owners, boaters, anglers and swimmers to search the state’s inland lakes to make sure the weed had not infested bodies of water in Michigan. Sea Grant also asked recreational users to take precautions against potentially transporting hydrilla and other aquatic invasive species on their boat trailers and other gear. The good news is that no hydrilla was ever confirmed in Michigan and, after costly, drastic multi-year measures in treating Lake Manitou (near Rochester, Indiana, just 55 miles south of the Michigan border near U.S. 131), Indiana officials announced in 2009 that the problem was under control; they however, kept strictly enforced boating rules in place before and after boating on this lake.
Now, almost a decade later, the battle against this damaging weed continues inside the Great Lakes basin in the Tonawanda, New York area, near Buffalo. The weed was discovered by the U.S. Fish and Wildlife Service growing in the Erie Canal in 2012. The “Tonawanda Creek section” is a 15 mile stretch of the canal which empties into the Niagara River, one of the connecting channels of the Great Lakes system, and the hydrilla beds are listed as patchy and limited to the shallow shoreline areas outside the main navigational channel. On May 27, 2015, the US Army Corps of Engineers announced a public meeting to describe the hydrilla plant, present results of the 2014 treatment, provide a schedule and identify treatment areas for the 2015 field season.
Why is hydrilla the perfect aquatic weed? It is called perfect because it has many adaptive qualities and many methods of reproducing itself. The adaptive qualities allow it to outcompete and greatly diminish populations of native species. It can grow in low-light areas. It absorbs carbon from the water more efficiently than other plants. It is very tolerant to both standing and flowing water and can also grow up to an inch per day. Finally, its reproductive abilities make it particularly threatening. The tubers that grow from the roots can persist, in a viable state, in the lake bottom for several years. It can also reproduce through flowers, fragments and turions (cone-shaped growths) on its stalks.
The efforts in New York are hugely important, as this is a connected system into the Great Lakes and then potentially into Michigan. The Corps of Engineers has been working with the New York State Canal Corporation, New York State Department of Environmental Conservation, U.S. Fish and Wildlife Service, Ecology and Environment, Inc., and others to address and manage the excessive growth of this invasive plant.
While the “Michigan Hydrilla Hunt” campaign officially ceased several years ago, these materials may well be updated and readied for future education and outreach in order to prevent this most serious economic and environmental weed from gaining a foothold within Michigan.
Background information and a specimen identification card are available through the Michigan Sea Grant website.
It is illegal to possess hydrilla in Michigan (except to send it for identification) or to take the plant across state lines. Michigan residents and visitors can help prevent the spread of hydrilla by properly cleaning watercraft or other water recreation gear.
More information on invasive species prevention practices is available at www.protectyourwaters.net.