Eurasian Watermilfoil

Eurasian Watermilfoil (EWM) can form thick underwater strands of tangled stems & vast mats of vegetation that readily fill lake surfaces and even stop boat traffic.  It can crowd out native plants & become so thick that the larger fish cannot swim through the tangled mats.

EWM was first observed in Lake Wawasee in 1996 and was “established” (reproducing and recurring after spring thaw) in 2006.  The species cannot be completely eradicated once established, but it can be reduced to manageable levels.

EWM has been in the lake for decades & may currently be growing in most if not all areas of suitable habitat. Its total acreage would not be expected to increase dramatically although its overall percentage of the plant community could become greater.

The spring visual vegetation survey was performed on Lake Wawasee on June 13, 2017. Some 28.9 acres were identified in a high use area of the lake.  On June 16, 2017, this area was chemically treated.  The treatment acreage of this area was reduced from 32.5 acres in 2016 to 28.9 acres in 2017 because a portion of this historically dense bed was devoid in 2017.

Unlike our other “problem” invasive, Starry Stonewort, EWM is largely under control due to the attention and treatment of it by WACF and its partner LARE.

Much more detail on the EWM problem and possible solutions may be found in this very comprehensive PDF file 


Additional Invasive Species…
2016 – Aquatic Vegetation Flyer for Wawasee and Syracuse Lakes
2018 – Aquatic Vegetation Update March 2018