Tag Archives: Water Chestnut

Targeting a Watery Invader at Lake Taghkanic

Thanks to a “hands-on” kayak mission against invasive water chestnut this summer at Lake Taghkanic State Park, this popular lake ought to be clearer of these aquatic invaders for next paddling season.

And timing is critical in dealing with water chestnuts, floating plants which can rapidly spread to create dense patches that can clog a lake, damage the native ecosystem and make it hard for canoeists and kayakers to paddle.

Water chestnut (Trapa natans) is one of the several Aquatic Invasive Species (AIS) that are monitored in hopes of reducing abundances in state waterbodies. Widespread in the state, water chestnut is now found in 43 counties.

The aquatic invasive water chestnut can be found in 43 countries across the state. Counties shaded green are known to be infested. (Photo Credit – NYS Department of Environmental Conservation)

Invasive species, like water chestnuts, are organisms that are non-native to an area, typically causing harm to human health, the economy, and the environment. If left unchecked, AIS can spread quickly from one body of water to another, threatening biodiversity and potentially impeding recreational opportunities.

The key to battling the an infestation discovered this season at Lake Taghkanic in Columbia County was to remove hundreds of plants before going to seed. Water chestnuts are annuals, and thus must reseed themselves each year to propagate.

Anyone who has been out along a shoreline and came across a strong, spiny, star-shaped brown nut-like “fruit” or seed pods has found a water chestnut nut. Bearing four sharp spines or points, each nut contains a single seed that can produce 10 to 15 stems.

Anchored to the water bottom, the plants have submerged, feathery brownish leaves on stems that can grow up to 15 feet long. On the water’s surface, these stems come to an end with a floating rosette, or circular arrangement of leaves. The leaves are triangular shaped with toothed edges.

These clusters can float on the surface due to buoyancy bladders connected to the leaf stems, forming dense floating mats that can be nearly impenetrable. Each rosette produces about 20 of the hard nut-like fruits in the late summer and early fall which, after dropping from the plant to the water bottom, lay in sediment over the winter to sprout in the spring

You can imagine the concern when water chestnut showed up in Lake Taghkanic State Park, a park focused on boating, swimming, water sports and beach activities. Controlling water chestnut at the park was vital to support these recreational opportunities as well as the native fauna of the lake, including one rare species known there.

Due to the fast-growing nature of water chestnut, it is important to control newly introduced infestations as soon as possible, also known as “early detection, rapid response” (EDRR). If left unchecked, patches of water chestnuts can spread prolifically.

A map of Lake Taghkanic, showing the area of water chestnut infestation highlighted in green. (Photo Credit – NYS Parks)


Water chestnut is an invasive species of high concern for many waterbodies in New York State, having potential ecological, economic and health impacts. The plant can form dense mats on the water’s surface, greatly impacting the organisms below. These layered mats can block sun and oxygen from submerged plants, resulting in a die back of native species and fish populations. Recreation is also inhibited by dense patches of water chestnuts, making it difficult to swim, boat, kayak, or fish. The spiny nuts often drift to shore, creating an additional hazard for pets and people to step on.

Effective control of water chestnut depends largely on preventing seed formation. By manually removing the plants in mid-summer before mature seeds can drop, managers can halt such potential reproduction.

At Lake Taghkanic, staff from the Office of Parks, Recreation and Historical Preservation, state Department of Environmental Protection, and Capital Region Partnership for Regional Invasive Species Management (PRISM) worked to rapidly respond to the infestation. This team of ten individuals were well-versed in the control of invasive species, and several team members had prior experience manually removing water chestnut.

Held July 16, the pull was led by Matt Brincka (NYS Parks Invasive Biologist), with other participants including Falon Neske (NYS Parks), Lindsey DeLuna (NYS Parks), Lauren Gallagher (NYS Parks), Rebecca Ferry (NYS Parks), Kristopher Williams (Capital Region PRISM), Lauren Mercier (PRISM), Lauren Henderson (PRISM), Steven Pearson (DEC), and Catherine McGlynn (DEC).

The team navigated to the water chestnut infestation in kayaks, maintaining social distancing and wearing face coverings when necessary. When manually pulling water chestnut plants, it’s important to reach as far down the stem as possible to pull the root system from the bottom sediment.

At Lake Taghkanic, water chestnut was mixed in among lily pads, presenting a challenge to pulling by hand from kayaks. (Photo credit – NYS DEC)

Once pulled, the water chestnuts were collected in garbage bags, drained, and weighed. Within a day, more than 100 pounds, or from 300 to 400 plants were removed! The information was recorded for upload to iMapInvasives so that the infestation of water chestnuts can be tracked.

Afterward, the team also surveyed the 3.7 mile lakeshore to ensure there were no other visible water chestnuts. Parks staff developed a control plan that will include monitoring and hand-pulling at Lake Taghkanic annually in order to deplete the seed bank (seeds can remain viable for several years at the bottom) and keep the problem at bay.

Over the years, NY State Parks has organized and participated in several invasive species pulls, additionally having a seasonally staffed AIS Strike Team and Boat Steward program. Reader more about these programs in the posts below.

Selkirk Shores State Park has been one focus area for State Parks staff in efforts to control a water chestnut infestation. In 2015, about 240 bags of water chestnut were removed there, visibly reducing the biomass by 40 percent. During the 2016 season, another 12.5 tons were pulled out. This removal resulted in a decrease in abundance of water chestnut during from 2017 through this year, further maintaining the value of this State Park.

Prompt invasive species responses, such as water chestnut pulls, work towards ensuring recreational enjoyment and preserving natural ecosystems in our parks. Early detections of invasive species are often reported by patrons.

The next paddling season may be months away, but remember: If you believe you have found a new population of an invasive species at a State Park, tell a park staff member or reporting it in iMapInvasives will ensure that swift eradication action is taken.

Protecting Our Waterways

You may have seen them in a park near you, these super heroes and heroines in disguise. Since 2008, New York State Parks have deployed Invasive Species Strike Teams. These Strike Teams conduct invasive species surveys and manually remove non-native invasive plants in areas of significance. The goal is to protect native plant and animal … Continue reading Protecting Our Waterways

Cover shot: Members of the removal team spread out in kayaks on Lake Taghkanic.

Post by Lauren Gallagher, State Parks Water Quality Unit

New York State Invasive Species Awareness Week 2016

This week marks New York Invasive Species Awareness week!

July 10th – 16th, 2016 the State of New York is celebrating their third annual Invasive Species Awareness Week (ISAW). The purpose of this week is to bring awareness to the public regarding the harmful effects of invasive species around our state. Invasive species are non-native species that inhabit a new environment, causing harm to that new environment. Not all non-native species are considered invasive. In order to classify a species as invasive, it can cause ecological, social, human health, and or economic damage. Invasive species often spread unintentionally through human activity. The trade of goods around the world is one of the primary sources of invasive species transfer. Cargo ships for instance can carry aquatic invasive species in their ballast tanks or insects in their shipping containers. Once established in these new environments invasive species can spread quickly because these ecosystems often have no natural predators or control. The presence of these hitchhikers is one of the leading threats to our native species and ecosystems. By out-competing, preying upon native species or carrying disease, invasive species can be detrimental to native species and the biodiversity of natural habitats.

Invasive species come from near and far and affect all types of habitats found throughout New York State. Since many of our commercial, agricultural, and recreational activities are dependent on a healthy native ecosystem the presence of invasive species can impact all people and the natural world. Aquatic invasive species such as hydrilla (Hydrilla verticillata), water chestnut (Trapa natans) or zebra mussels (Dreissena polymorpha) have inhabited many of New York’s water ways. On land, species such as Japanese knotweed (Fallopia japonica), can overcrowd native environments.

Boat Stewards
Over the years, NYS Parks has organized invasive species pulls to help lower the effects of invasive species in our park lands. Pictured above are State Parks Boat Stewards pulling Water Chestnut from Selkirk Shores State Park. Photo by Meg Phillips OPRHP

How you can help!

Boaters/Anglers Wash and dry your boat properly. Be sure to remove all plant matter from boat, ballast, prop, trailer and all equipment. Dispose debris correctly. Use aquatic invasive species disposal station if available.

Campers/Hikers/Bikers Check clothing, boots, pets, and camping gear for seeds, plant matter and insects. Clean gear and dispose of debris properly. Use local firewood.

Gardeners Plant only native plants. Educate yourself and others about the importance of using native species. There are many native look-alikes that are just as beautiful.

Whether you are a boater, fisherman, hiker, gardener or simply a concerned citizen, it is important to educate yourself and others on the different species found in your home state. You can make a difference in stopping the spread of invasives! Here you can find information on invasive species found in the State of New York.

Many State Parks have events during New York Invasive Species Awareness Week to involve the public in preventing the spread of invasive species.

Learn more by contacting your local PRISM! Partnership for Regional Invasive Species Management for more information on Invasive Species.

Help Stop the Spread!