Lake Stibbs | Water Chestnut Removal Project

Why is water chestnut such a problem?

Water chestnut was first documented in Connecticut in 1999 when it was discovered in Keeney Cove, a freshwater tidal cove of the Connecticut River in Glastonbury. Infestations in the Hockanum River and Podunk River were first treated in 2000. Water chestnut (Trapa natans) is a highly invasive aquatic plant that forms dense, floating mats that clog the water in shallow areas and along shorelines. It also limits light and reduces oxygen levels for plants and animals that live in the water column. It can crowd out native plants that are food sources for native animals. This non-native, invasive plant competes with native vegetation, is of little value to wildlife, and impacts recreational activities such as boating, fishing and swimming. They congest streams, block boats, and kill fish. As water chestnut decomposes, it decreases dissolved oxygen that fish and other aquatic life need to survive.

One water chestnut seed can produce up to 15 rosettes and each rosette can produce just as many seeds, with the potential to generate 200 or more new seeds in a single year. Seeds can remain viable in the sediment for up to 12 years and, while most seeds germinate within the first two years, management efforts must be conducted for several years to ensure eradication. Water chestnut can spread to new locations naturally by water and birds, and accidentally by fishing gear.

Removal of the water chestnut plants before their seeds mature and drop is proving to be a very effective means of controlling this non-native invasive aquatic weed. Water chestnut is an annual that spreads only by seed dispersal. With your help, we can drastically reduce the amount of seeds dropped in Lake Stibbs this season.