Hydrilla closes in on the Great Lakes

The first collection of Hydrilla verticillata from
Tonawanda Creek. Credit: USFWS

You don’t necessarily need to be looking for an aquatic invasive species to find it. Sometimes it appears when you least expect it.

That’s exactly what happened in early September, when Lower Great Lakes Fish and Wildlife Conservation Office staff discovered Hydrilla verticillata, a highly invasive aquatic plant, in the New York State Canal System in Tonawanda, N.Y. The location was literally at the base of a boat ramp, a highly visible area that should lend itself to early discovery.

Nonetheless, it apparently went unnoticed for some time, hiding within the abundant native plants, particularly Canadian/common waterweed, a native aquatic plant similar in appearance. The distinction between the two is important, as hydrilla crowds out waterweeds and other essential plants. It slows water flow and can clog lakes and rivers enough to even eliminate swimming or boating.

Hydrilla has become a major nuisance in states including Florida and Virginia, where significant resources have been spent on its control. Just last year, the pest was discovered in the Cayuga Inlet of New York’s Finger Lakes region. Since then, local and state groups have launched a monumental effort to eradicate and contain it.

These jumps of hydrilla to separate and distinct locations are unfortunately becoming common in the Northeast, which raise the risk that our waters and wildlife may be impacted by the invasive plant. Hydrilla is now confirmed within one mile of the Niagara River (and thus the Great Lakes). The extent of its possible impacts to the Great Lakes remains unknown, but monitoring elsewhere suggests the plant can become quite a nuisance in waters up to 25 or 30 feet deep.

Biological science technician Kelly McDonald recording GPS coordinates of hydrilla,
which can be seen just below the boom arm of the electrofisher. Credit: USFWS

The Service’s Lower Great Lakes office is leading a rapid assessment team of state and federal agencies to determine the actual reach of the plant in the Tonawanda Creek and Niagara River corridor. Crews are combing the shorelines to find additional plants through visual observation or by rake toss; rake toss truly is throwing a rake into the water (at a specific interval) and crossing the bottom as you pull it back in. Once the extent of hydrilla is better determined, we can consider potential response options.

In the meantime, residents and visitors are asked to help avoid the spread of hydrilla by cleaning their boats, trailers and gear. They are also encouraged to report potential sightings to the National Invasive Species Hotline (1-877-STOP-ANS). Calls are recorded and sent to Service biologists who can quickly respond, usually within 48 hours.

The combined efforts from residents, crews and others can help not only assess the spread of hydrilla, but also keep it from taking over the Erie Canal and our other waters. 

Learn about the impacts of invasive plants and animals -- and what you can do to help.

More:
(From the New York State Department of Environmental Conservation)

• DEC begins emergency rule-making for hydrilla infestation treatment (May 2012)
• Hydrilla discovered in Erie Canal in North Tonawanda (September 2012)

Submitted by Mike Goehle, aquatic invasive species coordinator for the Service’s Northeast Region.