Invasive Species

Large bodies of water, Chautauqua Lake in this case, possess a delicate ecosystem full of plants, animals, microorganisms and important water chemistry balances.  These ecosystems can easily be disrupted by plants and organisms that are not native or colonized and thus should not be introduced into the ecosystem.

Invasive water species are defined by the National Invasive Species Council as “an alien species whose introduction does or is likely to cause economic harm, environmental harm or harm to human health.  In the technical sense, the term ‘invasion’ simply denotes the uncontrolled or unintended spread of an organism outside its native range.” 

Chautauqua Lake supports two non-native plant species, Eurasian watermilfoil and curly leaf pondweed. They were termed invasive when they arrived. Their long-term presence in Chautauqua Lake has been such that they are now considered by NYS and biologists to be a colonized/naturalized component of the lake’s aquatic plant community. They remain to be termed invasive at other lakes where they are newly present.  Curly leaf pondweed has become an important component of fishery habitat in addition serving as a cover plant that slows the growth of Eurasian watermilfoil thereby permitting competing slower growing native plants to develop.  Curly leaf pondweed naturally dies off during late June and early July.  Eurasian watermilfoil remains present for the entire season while also serving an important role for the fishery.  Although formerly reaching the surface in dense quantities, nuisance milfoil conditions seldom occur today due to the impact that natural herbivores (moths, weevils, caddis flies) have had upon limiting the plant’s growth.

Zebra mussels are an invasive species that have become resident in Chautauqua Lake.  They have been present for several years and have cycled in quantity and size.  The cycling that has occurred has yet to be fully understood. Although the zebra mussels are not present along the entirety of the lake’s bottom, their locational presence is not predictable.  Recreationalists who routinely encounter the lake’s bottom therefore are encouraged to wear protective foot gear. Stepping on a zebra mussel’s sharp edge can cause a skin cut.  Although similar in appearance, zebra mussels should not be equated with the invasive quagga mussel.  Quagga mussels can have a greater detrimental impact upon the lake.  To date no quagga mussels have been found in Chautauqua Lake.

The photos below are intended to help you to identify the most likely invasive species of concern for Chautauqua Lake.  These species are already present within easy vehicular travel distance.  If discovered growing in the lake, the plants need to be immediately eradicated. Chautauqua Lake Watercraft Stewards are present at most boat launches on weekends throughout the summer.  They serve as voluntary invasive species spread prevention inspectors of incoming watercraft.  They also educate boaters about the need to be proactive in preventing the spread of invasive species.  Please view the Lake George Video on this tab to learn more about the Watercraft Steward Program.  There are other invasive species that exist that are not pictured below.  Please see the links to general invasive species information that we are providing.

Photo 1: Water Chestnut

Photo 2: Hydrilla

Photo 3: Zebra Mussel

Photo 4: Quagga Mussel

Should you discover what you believe to be an above pictured invasive species, please take close-up pictures of the plant and email them to the Chautauqua Lake Association ( along with an exact-as-is-possible identification of the location at which the plant was found. Please include the date and time of your finding.  CLA staff will follow-up.  The CLA is a WNY PRISM (Program For Regional Invasive Species Management) partner.  We collaborate with the PRISM on invasive species matters, including a statewide database and action network.  

Eurasian watermilfoil and Curly leaf pondweed continue to be plants of discussion in the community.  Pictured below are the two plants along with a picture of Coontail which is often mistaken for milfoil.  Coontail also provides an important role in the fishery along with providing a nutrient intake function.  It can grow to nuisance levels and is best controlled by harvesting in order that a sub-surface presence can remain.

Photo 1: Curly leaf pondweed

Photo 2: Eurasian watermilfoil

Photo 3: Coontail

Overabundant nutrient conditions enhance nuisance and invasive plant and algae growth.  Planting native species in the watershed and at the lake’s edge helps in reducing nutrient input into the lake.  Below please find Ten Reasons To Go Native on your property.  Working together we can keep Chautauqua Lake beautiful and healthy.


NYS Invasive Species Program

Aquatic Invasive Species Listing

Most Un-Wanted List:

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    1. Prevent erosion
      Soil in meant to remain on the land and not in our water bodies. The area soils are rich in nutrients, especially phosphorus which clings to soil particles. Soil deposition is a very efficient tool for delivering additional phosphorus to water bodies. The deep roots of trees and shrubs are excellent at preventing soil erosion and at a very low cost.


    1. Reduce phosphorus content in local watersheds
      Chautauqua Lake is shallow and has a very large watershed. The lake has been declared impaired due to its phosphorus content, which has been “slightly increasing” over the past 25 years. Human activities associated with development, such removal of natural areas, increased impervious surface, and increased sewer outputs, have been directly linked to increases in phosphorus. Since, phosphorus content is directly correlated to algal blooms, increasing natural areas to prevent nutrient-rich water from reaching any body of water is important.


    1. Keep runoff from the land on the land
      Areas with natural vegetation, trees, shrubs and plants, provide places where runoff can be slowed down and spread out. When it slows down, the water can be absorbed into the ground. It is then, that the nutrients and pollutants carried in the water can be absorbed by the root systems of that natural vegetation. The larger the natural area, the greater the benefits provided including flood control. Impervious surfaces provide faster paths for nutrient-rich runoff to reach the lake and streams. Disconnect downspouts and plant rain gardens.


    1. Protect your drinking water
      Runoff that can slow down and spread out in a natural area, will be filtered when it soaks into the ground. This process recharges the groundwater, the source of our drinking water. Natural buffer areas protect nearby wetlands, lakes or streams that also recharge the groundwater. Avoid use of petroleum products and lawn chemicals near wells. Test private water wells for coliform bacteria and nitrates. Native plants have developed natural defenses against predators preventing the need to buy or use pesticides.


    1. Create wildlife corridors
      Your property and the surrounding land are pieces of the regional environmental puzzle. Cornell University landscape department emphasizes the importance of restoring natural corridors to provide pathways for many species. See


    1. Increase your property value
      Areas with natural, park-like settings have higher property values. Natural preserves and landscaped areas have proven to help make homes and communities more saleable. Accessibility to natural areas is also more desirable. Why not in your own backyard?


    1. Encourage biodiversity
      The variety and interdependence of living things allows all of them to be healthy. The delicate balance and complexity of living relationships requires natural systems. The basis for healthy diversity is the natural plant communities at the edge of the water and in our yards. Water bodies and their shoreline areas support some of the richest biodiversity in the northern latitudes.


    1. Create wildlife habitats
      Twice the number of species of wildlife can be found at the shore as in the upland areas. These include insects, amphibians, fish, birds, waterfowl and more. All wildlife needs food, water, shelter and living space. Therefore, providing more native plants provides more food and shelter thus making a healthy foundation for all living things.


    1. Purchase natives
      The roots of a plant are key to its ability to absorb nutrients and hold soil. Generally, native plant roots are as deep in the ground as their above ground height. Trees and shrubs have the deepest roots, lawn grass has the shortest. Native plants have adapted to the area and are generally hardier and more disease resistant. They are the correct food supply for the native insects and other wildlife.


  1. Mow less and enjoy the butterflies
    Lawn has no nutritional value for wildlife. In the dry summer months, it is nearly as impervious as paved surfaces. Plus, it does require hours of maintenance. After planting a native garden, sit back and enjoy the beautiful creatures that will visit it. By adding native plants to your yard, pride yourself on doing something good for wildlife, your drinking water and a nearby body of water.