Lake Mahopac Park District Lake Mahopac Park District Lake Mahopac Park District
About Us
What's New
How can you help
Newsletters & Lake Reports
Fish Survey 2020
Winter deIcers
Points of Interest
Historic Lake Mahopac
Environmental Information
Construction on the Lake
Site Search
Photo Gallery
Related Associations
Eurasian Milfoil

Eurasian Milfoil

If you haven’t noticed – It’s Back!

We’ve had a good ride, for about 20 years since 1994, when triploid grass carp were introduced to Lake Mahopac, to consume an invasive aquatic plant species. Eurasian Milfoil is making a comeback, it was noticed as of late last summer. The Lake Mahopac Park District has been in contact with the New York State Dept. of Environmental Conservation (NYSDEC,) since last September concerning this issue. Triploid carp are vegetarians and do not eat fish also, they are sterile and cannot reproduce.

 There are three (3) ways to deal with milfoil; mechanical, chemical and biological.
  1. Mechanical, such as a weed harvester was tried for several years; it was expensive; for the machinery and personnel, noisy and ineffective for a 583.4 acre lake.
  2. Chemical is too expensive for a lake this size and Lake Mahopac is a domestic water supply for many residents; those two reasons are why we ruled it out.
  3. Biological, in the form of grass carp, was the preferred choice.

The NYSDEC has agreed to come out and survey the lake in mid July to assess the extent of the weed coverage and give a better estimate of how many triploid carp are needed to control the milfoil. Once we get this information we can be permitted to restock the carp. More on this later.