Lake Biology Environmental Fact Sheet
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BB-4	1999

Weed Watchers
An Association to Halt the Spread of Exotic Aquatic Plants

Milfoil (Myriophyllum heterophyllum, Myriophyllum spicatum) and fanwort (Cabomba caroliniana) are exotic aquatic plants that have become economic and recreational nuisances in some of New Hampshire's lakes and ponds. Dense stands of these plants inhabit shoreline areas frequented by water based recreationalists. Exotic plants can create the following problems:

Displacement of beneficial wildlife.
Reduction of aesthetic quality of lakes.
Devaluation of waterfront property.
Littering of beaches with plant fragments.
Makes swimming difficult and dangerous.
Snags fish lines and stunts fish life.
Becomes tangled in outboard motor propellers.
Chokes boat traffic lanes.
Requires substantial funds for managing.

The spread of these plants to other uninfected waterbodies by transient boat traffic has increased over the last few years. If accidentally introduced into a lake, they grow at explosive rates. Many times new infestations are not discovered by state biologists until the weeds become a nuisance requiring expensive control methods. Once fully established, they are virtually impossible to eradicate. Therefore, education, vigilance, and early detection are key components in keeping these non-native nuisance weeds in check.

"Weed Watchers", a volunteer association dedicated to monitoring the lakes and ponds for the presence of exotic weeds, was formed by the NH Department of Environmental Services in 1988. Volunteers are given a special "Weed Watchers Kit" which contains the following:

Photographs of exotic plants.
Detailed drawings of the plants.
An information bulletin on exotics.
A list of lakes known to have exotic plants, including a map.
Recommendations on how to conduct a plant survey.
A complete set of fact sheets and pamphlets on exotics in NH.

The Weed Watchers Kit can be sent to you at no expense. Any individual wishing to participate in the "Weed Watchers" program should contact the Exotic Species Coordinator at:

Department of Environmental Services
Biology Bureau
29 Hazen Drive
PO Box 95
Concord, New Hampshire 03302-0095
(603)271-3503

What does a Weed Watcher provide?

All that weed watching involves is a small amount of time during the summer months. Volunteers survey their waterbody once a month from June through August. To survey, volunteers slowly boat around the perimeter of that waterbody and any islands it may contain. Using the materials provides in the Weed Watchers Kit, volunteers will then look for any species that are of suspicion and send them to DES. After a trip or two around the waterbody, volunteers will have a good knowledge of its plant community and will immediately notice even the most subtle changes.

What happens if a Weed Watcher finds an exotic plant in a waterbody?

In most cases, volunteers will be instructed to send a plant specimen through the mail or deliver the specimen in person. Please try to collect a portion of the suspect plant when it is in flower. This may be the only way to precisely identify the plant. If the plant is an exotic, a biologist will visit the site to determine the extent of the problem and to formulate a plan of action to control the nuisance infestation.