(Pallas, 1771) (zebra mussel)

Habitat: Temperate freshwater lakes and rivers; brackish water up to 12 ppt in Europe, 5 ppt in North America and have been found at >100 m in depth.
Life History: Can reach 50 mm, life span 4-5 years.  Optimal water temperature for spawning is 14-16^oC; 17-25^oC for growth, >32^oC is lethal. Over 40,000 eggs can be laid in a reproductive cycle.
Native Range: Eastern Europe and western Asia.
Nonindigenous Range: First identified in 1988 in Lake St. Clair; also Lake Erie, Lake Ontario, Hudson River, Erie Canal, Finger Lakes in New York, Lake Champlain, Ohio River, Allegheny River, Monongahela River, Kanawha River (West Virginia), and in quarries in Pennsylvania and Virginia.
Impacts: Biofouler for industrial and recreational water users (can be spread by boating activity); competition with native mussels and zooplankton; increased water clarity.
Comments: In closed environments control is possible using various chemicals, manual removal, desiccation, filters, screens, copper or silicone coatings, UV light, ozone, flushing, or anoxia/hypoxia. Control is limited in open environments to predators, parasites, diseases, or desiccation.

  (Andrusov, 1897) (quagga mussel)

Habitat: Temperate freshwater lakes and rivers; salinities up to 1 ppt in Europe, 5 ppt in North America; have been found at depths of 130 m in Lake Ontario.
Life History: Can reach 38 mm; water temperature >30^oC is lethal.
Native Range: Dneiper River drainage of Ukraine.
Nonindigenous Range: Lake Erie, Lake Ontario, Erie Canal, Lake George (New York), and a small reservoir in eastern Pennsylvania.
Impacts: Biofouler for water users; competition with native mussels and zooplankton; increased water clarity.
Comments: Shell is more rounded than the zebra mussel and valves are asymmetrical.  In closed environments control is possible using various chemicals, manual removal, desiccation, filters, screens, copper or silicone coatings, UV light, ozone, flushing, or anoxia/hypoxia. Control is limited in open environments to predators, parasites, diseases, or desiccation.

  (Müller, 1774) (Asian clam)

Habitat: Temperate to tropical freshwater lakes and rivers in sand, silt, or mud bottom; can tolerate brackish water.
Life History: Can reach 50 mm; breed from spring to fall; can self-fertilize; larval density can be as high as 1,000/ml; sexual maturity reached after several months.
Native Range: Eastern Asia including China, Korea, and Russia.
Nonindigenous Range: Much of Virginia, West Virginia, Maryland, Pennsylvania; more recently detected in the Charles River, Massachusetts and Lake Tiogue, Rhode Island; Lake Erie.
Impacts: A macrofouler in power plants like the zebra mussel; in high densities probably adversely affects native mussels; can reach adult densities of 10,000/m².
Comments: Introduced into the Pacific Northwest in the 1920s as possible food for the Asian population; has steadily been moving northward from southern states into New England.

  (G. B. Sowerby I, 1831) (Atlantic rangia)

Habitat: Estuarine, brackish waters (0-18 ppt salinity) with soft sand bottoms, can tolerate mud and mixtures of sand and clay bottoms.
Life History: Can reach over 90 mm in warm climates, 40-60 mm more common; spawning season in Virginia is from May to November when water temperatures reach 15^oC.
Native Range: Gulf of Mexico.
Nonindigenous Range: East coast of Florida to the Chesapeake Bay; James River and Potomac River in Virginia, lower portion of the Hudson River in New York.
Impacts: Unknown.
Comments: Not seen on the Atlantic coast before 1956. Could have been an accidental release with oyster mariculture or perhaps with intracoastal ballast water.  Harvested shells are used in roadway construction and cement production.

  Linneaus, 1758 (edible oyster)

Habitat: Estuarine waters with firm bottoms of rock, gravel, sand, silt or mud.  Found to a depth of about 10 m.
Life History: Can reach 110 mm; females mature at 50 mm; spawns in the summer, can produce over one million eggs, larvae settle within 30 days; suspension feeders; densities can reach 300 per square yard.
Native Range: Northeastern Atlantic Ocean from Norway to the Mediterranean and Black Sea.
Nonindigenous Range: Reported off coastal areas of Maine, Massachusetts, and Rhode Island.
Impacts: Unknown.
Comments: Established on the Atlantic Coast. This species has been cultured on both coasts of North America.

  (Müller, 1774) (greater European peaclam)

Habitat: Freshwater lakes and slow-moving rivers with soft bottoms; water temperatures of 1-21^oC.
Life History: Can reach 9 mm and live up to 3 years, mature at 4 mm (sexually mature as early as 3 months old in Europe); hermaphroditic; eggs incubated in a brood-sac in the parent; embryos develop and are released as miniature adults; suspension feeders on algae and bacteria.
Native Range: Europe.
Nonindigenous Range: Lake Ontario, Lake Champlain, and Hudson River in New York.
Impacts: Unknown.
Comments: Discovered in the late 1800s. High hypoxia tolerance.  Common in ten of thousands per square meter in Europe.

  (Linneaus, 1758) European fingernailclam)

Habitat: Freshwater lakes and slow-moving rivers; prefers eutrophic, shallow waters, vegetation; lives in the sediment.
Life History: Can reach 9 mm and live up to 3 years, mature at 4 mm (sexually mature as early as 3 months old in Europe); hermaphroditic; eggs incubated in a brood-sac in the parent; embryos develop and are released as miniature adults; suspension feeders on algae and bacteria.
Native Range: Europe and Asia.
Nonindigenous Range: Lake Erie, Lake Ontario, Lake Champlain, and Hudson River in New York.
Impacts: Unknown.
Comments: Pathway of introduction is unknown. High hypoxia tolerance.

  Clapp, 1923 (Bartsch shipworm)

Habitat: Marine coastal areas, living in wood; tolerates wide range of salinities.
Life History: Can reach 10 mm; shell valve located at front end of worm-like body; entire animal can be several inches long; pelagic larvae; veliger stage reached in 24 hours and lasts 3-4 weeks.
Native Range: South Carolina to Texas and Bermuda.
Nonindigenous Range: Long Island Sound off Connecticut and Barnegat Bay in New Jersey (prior to 1993).
Impacts: Can cause destroy untreated wooden structures (docks, boats).
Comments: Adapted for boring into wood; established in warmwater effluents of power plants; collected in Hawaii and Gulf of California; cannot distinguish the 66 species of shipworms worldwide by the shells, other structures must be used for identification; size usually indicates age. (Image is Teredo sp.).

  von Martens, 1894 (deep-cleft shipworm)

Habitat: Marine coastal areas, living in wood; tolerates wide range of salinities.
Life History: Shell height about 4 mm, shell valve located at front end of worm-like body; entire animal can be several inches long; fertilization may be internal and larvae may be retained in a brood pouch; veliger stage reached in 24 hours and last 3-4 weeks.
Native Range: Southwestern Pacific Ocean.
Nonindigenous Range: Barnegat Bay, New Jersey in 1974.
Impacts: Can cause destroy untreated wooden structures (docks, boats).
Comments: Adapted for boring into wood; established in warmwater effluents of power plants; collected in Hawaii.  (Image is Teredo sp.).

  Say, 1818 (elktoe)

Habitat: Small, shallow rivers and mid-sized streams with fast current and gravel and sand bottom.
Life History: Reaches 90 mm long; breeds from June to July; host fishes for glochidia (larvae) can be white sucker, northern hog sucker, shorthead redhorse, rock bass, and warmouth.
Native Range: Ohio, Tennessee, Cumberland, Susquehanna, and St. Lawrence drainages; Lake Huron.
Nonindigenous Range: Hudson River.
Impacts: Unknown.
Comments: Probably a natural migration via the Erie Canal.

  (Say, 1829) (paper pondshell)

Habitat: Shallow banks of rivers in fine sand or mud.
Life History: Can reach 100 mm; may be hermaphroditic, breeds in the fall; many species of native and exotic fish and several species of amphibians serve as the host for the glochidia.
Native Range: Mississippi River drainage as far west as Oklahoma; Great Lakes drainage.
Nonindigenous Range: Hudson River.
Impacts: Unknown.
Comments: Probably a natural migration via the Erie Canal.

  (Say, 1829) (giant floater)

Habitat: Most abundant in lakes and ponds with mud bottoms and little current.
Life History: Can reach 110 mm; spawns in August and releases glochidia in May; host fish include longnose gar and blacknose dace.
Native Range: The entire Mississippi River drainage including the Missouri; St. Lawrence River drainage and Lake Champlain.
Nonindigenous Range: Hudson River.
Impacts: Unknown.
Comments: May have been intentionally introduced.

  (Rafinesque, 1820) (Wabash pigtoe)

Habitat: Small streams to medium-sized and large rivers in coarse sand and gravel as deep as 15 feet.
Life History: Reaches up to 100 mm long; breeds from May to August; host fishes for glochidia can be white crappie, black crappie, and bluegill.
Native Range: The entire Mississippi drainage from western New York to South Dakota to Louisiana; also Lake Huron and Lake Erie.
Nonindigenous Range: Hudson River.
Impacts: Unknown.
Comments: Probably migrated naturally via the Erie Canal.

  Rafinesque, 1820 (plain pocketbook)

Habitat: Rivers and creeks with sand, gravel, or mud bottoms.
Life History: Can reach 160 mm; spawns in late July; glochidia are released the following early July.
Native Range: Upper Mississippi and Ohio drainages; from Lake Superior to the Ottawa River and Lake Champlain; fish species serve as a host for glochidia are white crappie, bluegill, largemouth bass, smallmouth bass, yellow perch and others.
Nonindigenous Range: Hudson River.
Impacts: Unknown.
Comments: May have been intentionally introduced.

  (Conrad, 1835) (green floater)

Habitat: Small to medium-sized streams with sand and gravel bottoms and low current.
Life History: Can reach 65 mm; spawns in August and releases glochidia the following June.
Native Range: Atlantic drainage of North Carolina, Virginia; Susquehanna River drainage; Kanawha and New rivers, West Virginia and Virginia.
Nonindigenous Range: Finger Lakes drainage in New York.
Impacts: Unknown.
Comments: May have been intentionally introduced into the Great Lakes drainage or migrated via the Erie Canal.

  (Rafinesque, 1820) (fragile papershell)

Habitat: Large to moderate rivers with sand, sand and gravel, silty sand, and silty mud bottoms
Life History: Can reach 150 mm long; spawns in late summer and releases glochidia the following July; host fish is the freshwater drum.
Native Range: Ohio and Mississippi drainages; St. Lawrence drainage
Nonindigenous Range: Oneida Lake and the Hudson River in New York
Impacts: Unknown.
Comments: May have been introduced via the Erie Canal.

  (Lamarck, 1819) (black sandshell)

Habitat: Varying sizes of creeks, rivers, and lakes with sand and gravel bottoms and moderate current.
Life History: Can reach 175 mm; spawns in August, glochidia are released the following July; host fishes are American eel, bluegill, and white crappie.
Native Range: Ohio and Mississippi drainages; St. Lawrence drainage to Lake Champlain.
Nonindigenous Range: Oneida Lake, New York.
Impacts: Unknown.
Comments: May have been introduced via the Erie Canal.

  (Say, 1817) (pink heelsplitter)

Habitat: Varying sizes and current speeds of rivers and lakes with sand to coarse gravel bottoms.
Life History: Can reach 160 mm; spawns in August and releases glochidia the following July; possible host fish is the freshwater drum.
Native Range: Mississippi River drainage north of Arkansas; St. Lawrence drainage to Lake Champlain.
Nonindigenous Range: Lake and the Hudson River in New York.
Impacts: Unknown.
Comments: May have been introduced via the Erie Canal.