CAYUGA LAKE, N.Y. — After removing a two-acre lump of an invasive water chestnut species from Cayuga Lake in late August, the Seneca County Water and Soil Conservation District and local conservationists are remaining alert and seeking the public’s help in preventing future spread of the plant.

Cayuga Lake Watershed Executive Director Hilary Lambert said that the plant grows quickly and can significantly damage the native ecosystem of the lake. She emphasized the invasive species found in the northern section of Cayuga Lake is different from the edible water chestnuts used in Asian cuisine.

The invasive water chestnut in Cayuga Lake was first discovered on Aug. 15 by Lisa Cleckner, executive director of Finger Lakes Institute at Hobart and William Smith Colleges, while she was conducting research on the fish population in the lake.

Cleckner then reported the sighting to Seneca County Water and Soil Conservation District Manager James Malyj, who confirmed that the plant was indeed the invasive water chestnut.

The water chestnut plants closely resemble lily pads and can create a peaceful scene on the lake. However, Malyj said that despite their visual appeal, they pose harm to the environment.

“It’s a pretty plant but...it’s very aggressive so it shades out other plants, especially native plants,” he said.

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The three-member crew of the Seneca County Water and Soil Conservation District began a three-day clean-up of the infested area on Aug. 26 and cleared an area of two acres using aquatic harvesting machines. Approximately half an acre of the zone was heavily concentrated with water chestnuts, according to Malyj.

Lambert of the Cayuga Lake Watershed Network said that while many rivers and lakes in Upstate New York are affected by water chestnuts, Cayuga Lake has never had any serious instances. She suggested that the plant came to Cayuga Lake unintentionally via a boat that had been in water chestnut infested areas. The roots were likely tangled in the propellor and got loose when the boat came into Cayuga Lake.

She said that conditions at northern Cayuga Lake are ideal for water chestnuts because the water is shallow, free of insect predators and rarely disturbed by swimmers or boats.

Lambert said after just one year, water chestnut plants can get so dense that they can seriously affect the ecosystem of the lake.

“It crowds out native plants and it makes it difficult for fish and turtles and so on,” she said. “After the first year it gets so dense that they can’t move through it.”

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She also said that the plant can affect people who use the lake recreationally.

“You can’t swim. You can’t boat. You drive your boat through it and your propellor gets locked up,” she said.

Further, Malyj noted that the seeds the plant produces are very hard and have four sharp points that can be dangerous to lake-goers.

“ are almost like a carved piece of wood, and if they wash ashore, they will puncture your foot and may even puncture your tires as well,” he said.

In addition to the water chestnut plant’s fast growth rate, Lambert said it is also very resilient because its seeds can survive cold weather. The seeds detach from the stem once they are matured and can burrow into the soil until blooming in the spring.

Since the removal of the plant in late August, neither Malyj nor Lambert have received any reports of water chestnut sightings. However, their teams are remaining alert.

Malyj said that although he believes the removal operation was highly successful, he is “fairly certain” that not all of the plants were removed.

“The lake is just too large to find every plant that may be there. There may also be seeds in the lake from last year or possibly ones that have been imported from waterbodies that will germinate next year. This situation will have to be watched very closely in the coming years,” he noted.

As a result, Malyj said it is important to take precautions to prevent the spread of the plant.

“Always check the boat. If you drove your boat through an infested area and caught on your hoist or trailer, clean it off,” he said. “If you see this plant, report it to us and yank it out. If you want it identified contact me or Hilary but don’t leave it there.”

If you think you’ve spotted water chestnut at Cayuga Lake, you can contact the New York State Soil and Water Conservation Committee here.