Lake Pocotopaug, East Hampton - 2024

2024 Aquatic Plant Survey Map of Lake Pocotopaug
Transect Data | Water Data

Lake Pocotopaug is a large, 511-acre lake in East Hampton, CT. The lake is heavily developed with homes along the majority of the shoreline. There is no public access, but there is a boat ramp at the town park.

The 2024 aquatic plant survey is the second survey performed by OAIS on Lake Pocotopaug. In 2006, only two plants were found, native eelgrass (Vallisneria americana) and native slender naiad (Najas flexilis) in the coves and inlets of the southern shore. There was a large algal population in 2006 that limited light for the growth of more aquatic vegetation. CT DEEP recommends that vegetation occupies 20-40% of the littoral zone for a healthy lake.

In 2024, water clarity was still limited with a green color to the water, but there was more aquatic vegetation present. Unfortunately, this also included the presence of a new invasive aquatic plant to the state, northern hydrilla (Hydrilla verticillata subsp. lithuanica). This plant, first established in the Connecticut River, has spread to at least ten other waterbodies throughout the state, including Lake Pocotopaug. Northern hydrilla was found throughout the northern and southern shorelines with some sparse populations along the western and eastern shorelines. The local stakeholders are actively working to keep the population under control.

Twelve aquatic plant species were found in the 2024 survey – a dramatic increase from the two found in 2006. Three species are invasive – northern hydrilla, curlyleaf pondweed (Potamogeton crispus), and minor naiad (Najas minor). Curlyleaf pondweed and minor naiad are both annual plants, so their populations may vary from year to year.

The other nine species were all native and common throughout the shoreline and the islands. The most common native plants found were slender naiad, Berchtold’s pondweed (Potamogeton berchtoldii), and coontail (Ceratophyllum demersum). During the OAIS survey, none of the aquatic plants reached nuisance levels that would impede recreation; however, northern hydrilla has the potential to cover much of the littoral zone and should be monitored closely.

Other Lake Pocotopaug Surveys: 2006