Survey Reveals Curly-Leaf Resurgence

Above: 2016 Survey Map: Red dots show Curly-leaf Pondweed sites. 
Blue line is the survey track.

The Lake Waramaug Task Force's annual shoreline survey to evaluate the presence of invasive plants has revealed an alarming increase in the number, size and density of sites with Curly-leaf Pondweed.

The survey, conducted in late May and early June by Northeast Aquatic Research, discovered 104 sites with the non-native plant, more than double the number from the 2015 study. Of these, 32 contained only a single plant and 17 had five or fewer. However, 19 contained moderate plant growth defined as patches up to 50 square feet in area, and 18 sites had severe infestation with dense mats of up to 9,000 square feet.

Curly-leaf Pondweed (Potamogeton crispus) is an aquatic plant native to Eurasia that is considered an invasive in North America. It can spread rapidly; replacing native vegetation, clogging waterways and limiting recreational use. Ten years ago, CLP was the first invasive plant to be discovered in Lake Waramaug.

During this decade, the Task Force has been combating CLP though the use of hand-pulling by divers whose efforts are aided by the use of suction-harvesting equipment. However, the LWTF's plant scientist has identified 7 sites where CLP has been especially resistant and he has concluded that "hand removal in these areas is not working," raising questions concerning the efficacy of using these techniques alone.

Consequently, the Task Force is beginning to study the feasibility of alternative methods that have had long term success in other lakes, including testing the limited and targeted application of chemicals on large, dense patches of CLP. In addition, LWTF is considering additional surveys to monitor the threat more closely.

Alternative methods of controlling CLP will be thoroughly studied and the lake community will be informed of these findings.

The 2016 shoreline survey did provide some positive news: no other invasive plants, such as water chestnut and water clover, were discovered.