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Common Aquatic Invasive Species of NY

The following table contains some of the more common aquatic invasive species found in New York, the areas of the state they currently inhabit, and the control strategy recommended to ensure that they are not spread to new waters via boating and fishing equipment.

Aquatic invasive plants and animals NY boaters need to be concerned about
Name Description Distribution Cleaning Strategy
Brazilian Elodea
Brazilian Elodea
B. Rice, sarracenia.com, Bugwood.org
Stems have numerous branches and can grow over 20 ft. in length. Is often confused with hydrilla and native elodea. Lance-shaped leaves are about 1/8 inches wide and 1.5 inches long and often have very minute teeth along the edges that may require magnification to see. Leaves are arranged in whorls around the stem with each whorl composed of 4 to 6 leaves. The number of leaves per whorls doubles or triples every 8 to 12 nodes. These "double nodes" are the only place where branches occur along the stem. Found primarily on Long Island, but recently discovered in Westchester County. Visual Inspection/Hand Removal
Brittle Naiad
Brittle Naiad
G. Lowell, ADCNR, Bugwood.org
Leaves are opposite (in pairs along the stem), but sometimes appear to be in a whorl at the tip. Leaves are 1-2 inches long, toothed, stiff and pointed. Plant is very brittle and easily breaks into pieces. Most abundant in the Hudson Valley and Central New York. It has also found its way into some Adirondack waters.
Visual Inspection/Hand Removal
Curly-leaf Pondweed
Curly-leaf Pondweed
L.J. Mehroff, Univ. of Ct., Bugwood.org
Stems are branched and somewhat flattened. Leaves are reddish-brown in color, oblong and about 3 inches long. Leaves are usually stiff and crinkled and unlike other pondweeds have finely toothed edges. Found throughout New York State Visual Inspection/Hand Removal
European Frogbit
European Frogbit
L.J. Mehroff, Univ. of Ct., Bugwood.org
Floating leaves are heart-shaped and 1-2 inches wide. They resemble the leaves of a miniature waterlily, veined on top and dark purplish red with a spongy coating on the underside. The plant has numerous roots up to 12 inches in length that float freely under the plant. First documented in Lake Ontario, the St. Lawrence River and adjacent waters, but has since expanded to Oneida Lake and other inland waters. Has recently been detected in some waters within the Adirondack Park.
Visual Inspection/Hand Removal
Eurasian Watermilfoil
Eurasian Watermilfoil
L.J. Mehroff, Univ. of Ct., Bugwood.org
Stems are usually 3 to 10 feet in length and can range from pale pink to reddish brown in color. Bright green feathery leaves are finely divided and occur in whorls (circles) around the stem. Each leaf has 12-21 leaflet pairs. Native northern watermilfoil which it can commonly be confused with has 5-10 leaflet pairs.
The most common and widely distributed aquatic invasive plant in New York State. It can be found in all watersheds, although still relatively rare on Long Island. Visual Inspection/Hand Removal
Fanwort
Fanwort
L.J. Mehroff, Univ. of Ct., Bugwood.org
Stems are long and appear tubular. Leaves are fan-like with a short stem and are arranged opposite each other on the stem. Plants have white to light pink flowers that float on the surface. Most common in southeastern NY, but also found in some southern Adirondack waters. Visual Inspection/Hand Removal
Hydrilla
Hydrilla
L.J. Mehroff, Univ. of Ct., Bugwood.org
Plants looks very similar to Brazilian elodea and other native Elodeas. Northern plants often lack the spiny underleaf and finely toothed leaves may be difficult to see. Best distinguishing characteristic is the turion or bulb connected to its roots that the other plants lack. Most widespread on Long Island, but also recently identified in the inlet to Caygua Lake and the Upper Niagara River. Visual Inspection/Hand Removal
Variable Leaf Milfoil
Variable Leaf Milfoil
L.J. Mehroff, Univ. of Ct., Bugwood.org
Leaves are similar to Eurasian watermilfoil except each leaf has 5-14 leaflets. As the stem reaches the surface it changes its growth pattern to become a stout emergent flower-spike carrying an entirely different type of leaf. These emergent leaves are stalkless, wedge-shaped, stiff, and pointed, with variably-toothed margins. Found primarily in Lake Champlain and other Adirondack waters. Visual Inspection/Hand Removal
Water Chestnut
Water Chestnut
L.J. Mehroff, Univ. of Ct., Bugwood.org
Stems are very flexible and can reach 12 to 15 ft. in length. On the waters surface the plant contains a circular cluster of saw-toothed edged, triangular floating leaves that are connected to an inflated petiole (bladder) that provides added floatation. Feather-like leaves can be found along the submerged stem. Fruit is a nut with four 1/2 inch barbed spines. Found primarily in the Hudson Valley, southern Lake Champlain and Mohawk River. Recently found in some western New York waters. Visual Inspection/Hand Removal
Parrot Feather
Parrot Feather
L.J. Mehroff, Univ. of Ct., Bugwood.org
Woody stems can grow over 5 feet in length, often extending outward onto the bank or shore. Emergent leaves are bright blue-green, rigid and deeply serrated. Leaves are arranged in whorls of 4-6 around the stem, with each leaf containing 10-18 segments. The leaves can extend 12" out of the water and look like miniature fir trees. The underwater leaves are red-brown in color and have 20-30 segments per leaf. They appear to be decaying and are often confused with Eurasian watermilfoil leaves. Found in the Peconic River on Long Island. Visual Inspection/Hand Removal
Creeping Water Primrose
Creeping Water Primrose
Leaves are willow-like and are alternately arranged on hollow red stems. Young leaves may be rounded. Has bright yellow flowers from spring - fall. Sprawling growth habit that forms dense mats. Currently found in the Peconic River and Prospect Park Lake on Long Island. Visual Inspection/Hand Removal
Asian Clam
Asian Clam
USGS Archive, USGS, Bugwood.org
Triangular or rounded triangular shell. Light brown in color with numerous rings on outside of shell. Inside of shell light blue or light purple in color. Scattered distribution across state including many Long Island waters, Finger Lakes, Chautauqua Lake, Lake Erie and Lake George. Dry or disinfect
Zebra Mussel
Zebra Mussel
USGS Archive, USGS, Bugwood.org
Shell "D" shaped usually with dark and light colored stripes. Widely distributed in New York State with the exception of Long Island, Lower Hudson Valley and the Adirondack region. Particularly abundant in the Great Lakes, Lake Champlain, Chautaqua Lake and many central NY waters. Dry or disinfect
Quagga Mussel
Quagga Mussel
A. Benson, USGS, Bugwood.org
Similar to the zebra mussel, but rounder in shape and has a paler color near the hinge. Found mostly in western and central New York waters. Not as widely distributed as zebra mussels. Dry or disinfect
Fishhook Waterflea
Fishhook Waterflea
I. Grigorovich, Bugwood.org
Body size 1-3 mm without tail, 6-13 mm with tail. Tail has 3 pairs of barbs and a characteristic loop (fish hook) near the end. Lake Ontario, Lake Erie, Finger Lakes and some adjoining waters. Dry or disinfect
Spiny waterflea
Spiny waterflea
Minnesota DNR
Can reach 15mm in length, with the tail making up 70% of more of total length. Tail has numerous spines along its length.
When they collect on fishing line, they look like bristly gobs of jelly with black spots.
Primarily found in the Great Lakes and adjacent waters, including the Finger Lakes. Recently discovered in Sacandaga Lake, Lake George and the Champlain Canal. Dry or disinfect
Bloody Red Shrimp
Bloody Red Shrimp
OMNR Archive, Bugwood.org
A relative of the Great Lakes opossum shrimp. bloody red shrimp are generally less than 1/2 inches in length. They can be distinguished from the native opossum shrimp by the flat end to its tail. Great Lakes, Oneida Lake and some Finger Lakes. Dry or disinfect
Starry Stonewort
Starry Stonewort
Looks like a rooted plant, but is actually an algae related to the native Chara. Can form dense mats on the lake bottom. Has long uneven-length gelatinous branches that look angular at each joint. May have one cream colored bulb at the base of each branch cluster. Great Lakes, St. Lawrence River, Oneida Lake Visual Inspection/Hand Removal
Didymo
Didymo
An invasive algae species that can form thick mats on the bottom of streams. Typically tan, brown or white in color (not green). Does not fall apart when rubbed between fingers and feels like wet wool (not slimy). Esopus Creek, Schoharie Creek, Delaware River, East Branch Delaware River, West Branch Delaware River, Battenkill Dry or disinfect
Alewife
Alewife
The alewife is native to the coastal waters of New York. Unfortunately, due to migrations from these waters and bait bucket introductions, this species has also become established in nuisance proportions in the Great Lakes and many inland waters in New York State, most recently in Lake Champlain. Alewives are silver in color with a blue-green metallic luster along the back, usually with a black spot behind the gill cover and a serrated belly. In freshwater, they usually grow to 3 to 6 inches in length; however, in saltwater they can attain lengths of a foot or more. Coastal waters, tidal Hudson River and lower Mohawk River, Great Lakes, Finger Lakes and a few other scattered lakes across New York. Do not release any fish or dump baitfish into a body of water that they did not come from.
Round Goby
Round Goby
Round gobies are bottom-dwelling fish that were introduced to the Great Lakes from central Eurasia. Round gobies are usually 3 to 6 inches in length, but can reach 10 inches. Key identifying characteristics include a black spot on the rear of the upper dorsal fin, a raised frog-like eye, thick lips and a body mostly slate gray or black, mottled with black or brown spots. Lake Erie, Upper and Lower Niagara River, Lake Ontario and the St. Lawrence River and their tributaries upstream to the first barrier impassible to fish. Do not release any fish or dump baitfish into a body of water that they did not come from.
White Perch
White Perch
White perch are an anadromous species that live most of their life in marine waters, but spawn in freshwater. Although a valued sportfish in some coastal waters, this species can become a nuisance when accidentally or purposefully introduced into landlocked waters. White perch are silvery-gray in color, with a light belly. Unlike the white bass and striped bass, they lack striping. They can attain lengths of 12 inches or more in freshwater and even larger in marine waters, but in overabundant populations rarely exceed 6 inches in length. Coastal waters, tidal Hudson River, Mohawk River, Oneida Lake, Onondaga Lake, Otisco Lake, Chautauqua Lake, Cassadaga Lakes, Erie Canal, Lake Ontario and scattered ponds and Reservoirs in the Hudson Valley and Long Island. Do not release any fish or dump baitfish into a body of water that they did not come from.