EURASIAN WATER MILFOIL (EWM) INFESTATION
BY 55 PERCENT IN 2008
TLA Announces Strategies for Long Term Success
WDNR Grants $149,701 to Continue Controlling Aquatic Invaders
MINOCQUA, WI (June 19, 2009) – The Tomahawk Lake Association (TLA) reported that the total acreage of Eurasian Water Milfoil (EWM) was reduced by 55 percent, or eighteen net acres, in the Tomahawk Lake system in 2008.
Eurasian Water Milfoil is an aquatic plant native to Europe and Asia that reproduces rapidly and has the potential to choke much of the shallow areas of a lake and adversely affect wildlife. It was first discovered on Tomahawk Lake in the fall of 2004 and, at the beginning of 2008, covered nearly 34 acres within the lake.
“We are encouraged by the successful reduction of eighteen acres of EWM in
2008,” said Todd Kavemeier, President, TLA, Inc. “The Tomahawk Lake Association has a clear strategy to not only continue the fight against EWM, but also maintain and increase the health and beauty of Tomahawk Lake long term. We are aggressively executing that strategy with conviction and innovation.”
Comprehensive Lake Management Plan Implementation
In 2008, the TLA developed a Comprehensive Lake Management Plan to address many facets of Tomahawk Lake’s ecology and ensure the lake’s long term health. The plan includes a goal to incrementally reduce the total acreage of currently established EWM by 80 percent over five years, from 2008 to 2012.
“We are focused on four main strategies to control EWM: chemical treatment, manual removal, boater and shore land owner education, and securing ongoing funding,” Kavemeier said.
Controlling EWM
EWM in Tomahawk Lake has been chemically treated with Wisconsin DNR financial assistance and oversight, as well as manually removed by divers using a Hydraulic Conveyor System. Based on a system utilized on Seven Island Lake and re-engineered by TLA volunteers, the Hydraulic Conveyor System is a suction-based, diver-directed system for lifting EWM manually from the lakebed to a transport watercraft on the surface.
“EWM primarily reproduces by plant fragmentation,” said Kavemeier. “Effective removal requires harvesting the entire plant – which grows in towers reaching up to 18 feet and 40 inches in width – along with its root ball. Because of its reproduction characteristics, manual removal also requires getting it to the water’s surface for disposal without any part of the plant breaking loose.”
To accomplish this, members of the TLA designed and built a submersible suction apparatus comprised of a water pump, siphon head and hose, and a collection bin installed on a 28 foot pontoon boat. The Hydraulic Conveyor System enables chemical-free plant removal. Because plants are selected and removed by a diver and transported by the hydraulic conveyor, the system allows selective targeting of EWM while leaving native aquatic plants and the bottom of the lake largely undisturbed.
Another key to controlling EWM is to quickly and accurately identify new out crops. A TLA volunteer group, the Tomahawk Lake Sentinels, surveys the lake system twice each summer to keep watch for alien plant growth and provide accurate location data for immediate manual removal or chemical treatment at the beginning of the next growing season.
Educating Boaters and Shore Land Property Owners
To prevent the spread of EWM and other invasive species, TLA volunteers have organized a “Clean Boats/Clean Waters” project to monitor boats entering or leaving three public boat landings on Tomahawk Lake.
“An important part of our effort is prevention,” said Kavemeier. “Our volunteers educate boaters and property owners on a variety of invasive plant species and how to prevent their spread.”
In a trial project in 2008, Tomahawk CBCS volunteers inspected 814 watercraft and spoke with more than 2,000 boaters.
Secure Funding
Fundamental to the success of the TLA’s Comprehensive Lake Management Plan is securing funding to execute the plan. The WDNR, local governments and private donors have been instrumental in providing the TLA with funding to initiate the plan. Their continuing support will be critical to achieving long term success.
Recently, Kevin Gauthier, WDNR Lakes Manager, Rhinelander, announced the award of a two year Aquatic Invasive Species Control Grant in the amount of $149,701 to the TLA. The grant will help implement the first two years of the Comprehensive Lake Management Plan.
“We are pleased and privileged to be a recipient of this DNR Aquatic Invasive Species Control Grant,” Kavemeier said. “This grant is testimony to the importance of our lake system and the success of our efforts to date.”
The grant funds provided by the WDNR will be matched with private cash donations from members of the TLA, by funding from the towns of Minocqua, Lake Tomahawk, Woodruff and Hazelhurst, and by the cash value of volunteer hours spent on TLA projects.
Boaters Prevent the Spread of Invasive Species
Boaters are encouraged to do their part to prevent the spread of aquatic species.
“Simply removing and properly disposing of all weeds from water craft, trailers, and fishing gear and dumping bilge, bait, and live well water before leaving a landing can go a long way to stopping the spread of aquatic invasives,” Kavemeier said.
The DNR recommends allowing the boat, trailer, and equipment to dry for five days before launching in another body of water. If a boater is headed to another lake in less than five days, a bleach wash of all wetted surfaces is suggested to remove the microscopic eggs, viruses and tiny segments of invasive plants that can revive when re-immersed in water.
