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Invasive Species Profiles

Asian Clam

Corbicula fluminea

 

History

  • First confirmed report in North America was in 1938 in the Columbia River drainage
  • Since then Asian clams have become widely distributed especially in the southern United States

Characteristics

  • Shells greenish-yellow to brown with thick concentric rings
  • Thick symmetrical shell
  • Up to 2 inches (5 cm) long
  • Inside of shell is smooth and polished with a light purple tinge
  • Three cardinal teeth in each valve

Habitat

  • Large rivers and lakes
  • Clams burrow prefer sandy or silty sediments into which they burrow up to 6-8 inches

Known Distribution in the Northeast

  • Widely distributed in southern and western United States, in the Great Lakes and in southern New England
  • Discovered in 2010 in Lake George, NY in the Champlain basin

Known Distribution in New Hampshire

  • Cobbett’s Pond, Windham
  • Long Pond, Pelham
  • Sunset Lake (Wash Pond), Hampstead
  • Merrimack River south of Bow

Impacts

  • Clogging of power plant and industrial water systems, irrigation canals and pipes and drinking water supplies
  • May compete with native species for limited resources
  • May promote algae blooms due to localized nutrient loading from dense clam beds (observed in Lake Tahoe, CA)

Additional Information

Source: NEANS Panel On-line Guide to ANS

Asian Shore Crab

Hemigrapsus sanguineus

 

History

  • First recorded in the United States at Townsend Inlet, Cape May County, New Jersey in 1988
  • May have been introduced via discharge of ship ballast water transported from the western North Pacific Ocean

Characteristics

  • Commonly orange-brown, also green and maroon
  • Light and dark bands on legs with red spots on the claws
  • Square-shaped carapace (shell) with 3 spines on each side
  • Can grow up to 2-3 in (5-7.6 cm) wide

Habitat

  • Prefers rocks and cobble, but may be found in soft sediments and other habitats
  • Primarily in mid to low intertidal zones; sometimes below the low-tide line
  • Tolerant of a wide range of salinity and temperature
  • Tends to aggregate in large numbers under rocks

Known Distribution in the Northeast

  • Maine to North Carolina
  • Native to Russia, Korea, China, and Japan

Known Distribution in New Hampshire

  • Coastal areas

Impacts

  • Eats young clams, mussels, oysters, larval and juvenile fish, algae, salt marsh grass, and many other species
  • May threaten aquaculture
Green Crab

Carcinus maenas

 

History

  • Believed to have first arrived in eastern North America around 1817, most likely in the dry ballast of cargo ships
  • Negative impacts on soft-shell clams and other bivalves have been documented since 1950s

Characteristics

  • Green to dark brown, sometimes with yellow, orange, or red, with darker mottling
  • Walking legs green, speckled with black
  • Carapace (shell) has 5 spines on each side
  • Can grow up to 3.9 in (10 cm) wide

Habitat

  • Salt marshes, sandy beaches, and rocky shores
  • Usually on mud, sand, or pebbles
  • Prefers sheltered areas
  • Usually near the low-tide line
  • Tolerates wide range of salinities (as low as 6 ppt)

Known Distribution in the Northeast

  • Newfoundland to Delaware; has become the most common crab in many locations throughout this range
  • Native to North Atlantic coast of Europe and the North African coast

Known Distribution in New Hampshire

  • Coastal areas

Impacts

  • Has become a dominant predator, feeding on clams, oysters, crabs, and mollusks
  • Often blamed for collapse of soft-shell clam industry and reduction of other commercially important bivalves, including scallop and northern quahog
Fishhook Water Flea

Cercopagis pengoi

 

History

  • Fishhook water flea was first found in North America in 1998 in Lake Ontario

Characteristics

  • Aggressive, predatory zooplankton that preys on smaller zooplankton
  • Long tail spine with up to three pairs of barbs near its end
  • Head is essentially composed of a single, large eye

Habitat

  • Estuarine habitats, lakes, marine habitats, wetlands
  • Tolerates wide range of salinity and temperature

Known Distribution in the Northeast

  • New York and Great Lakes region
  • Native to Europe and Asia

Known Distribution in New Hampshire

  • Unknown

Impacts

  • A voracious predator that eats smaller zooplankton; competes with native fish and invertebrates that eat zooplankton
  • Interferes with fisheries by clogging nets and fishing gear
Mitten Crab

Eriocheir sinensis

 

History

  • Between 2005-2008, 19 individuals were confirmed along the U.S. Atlantic coast in the Chesapeake Bay (2005-2007), Delaware Bay (2007), Hudson River (2007-2008), and Raritan Bay and Toms River, New Jersey (2008)
  • In Quebec, specimens have been collected from St. Lawrence River at Notre-Dame-de-Pierreville in 2004 and Quebec City in 2005
  • Both females and males have been found, but an established reproductive population in eastern U.S. has not been confirmed as of the summer of 2008

Characteristics

  • Light brown to olive green
  • Carapace (shell) up to 4 in (10 cm) wide
  • 4 lateral spines on each side of carapace
  • Notch between the eyes
  • Claws hairy with white tips
  • Claws normally equal in size
  • Legs longer than twice the carapace width

Habitat

  • Estuaries, lakes, riparian zones, water courses, wetlands
  • Burrows in the bottom and banks of freshwater rivers and estuaries
  • Tolerates wide range of temperatures
  • Catadromous life cycle: begins as estuarine larva, migrates into freshwater streams for 1-4 years, then returns to coast to reproduce
  • Able to survive in highly polluted aquatic habitats
  • Adept at walking on land and around barriers

Known Distribution in the Northeast

  • Native to east Asia
  • Chesapeake Bay, Delaware Bay, Hudson River, New Jersey, Quebec

Known Distribution in New Hampshire

  • Unknown

Impacts

  • Efficient predator and competitor for food; may have a profound effect on native biological communities
  • Damage to fishing gear
  • Clogged pumps, screens, and intake pipes
  • Burrowing activity may accelerate erosion of banks and levees
Quagga mussel

Dreissena rostriformis bugensis


Similar Species

  • Zebra mussel Dreissena polymorpha

History

  • Native to Ukraine
  • Initial introduction believed to be the result of ballast water discharge from transoceanic ships
  • Since being first discovered in Great Lakes in 1988-89, the species has spread widely into freshwater habitats across North America
  • Slowly dominating over zebra mussel in US and Europe

Characteristics

  • Bi-valve up to 1.5 inches (4 cm)
  • Shell usually has dark concentric rings; color is paler near the hinge
  • When laid on edge, quagga shell topples over whereas the zebra shell is stable
  • Valves (shell halves) are asymmetrical forming a curved line when valves are closed

Habitat

  • Lakes, estuaries, streams
  • Can colonize both hard and soft substrata
  • Tolerate salinity to 6 ppt, temperatures to approximately 29 degrees C
  • Quagga mussel can live at greater depths than zebra mussel

Known Distribution in the Northeast

  • New York, Massachusetts, and the St. Lawrence River as far north as Quebec City

Known Distribution in New Hampshire

  • Unknown

Impacts

  • Voracious filter feeders, removing microscopic plants and animals from the water, reducing food available to other aquatic animals
  • May cause declines in fish populations
  • Clog intakes for power plants, industrial facilities, and public drinking water supplies
  • Heavily colonize both hard and soft surfaces including beaches, boat hulls, docks, etc.
  • High potential for rapid adaptation to extreme environmental conditions
  • Economic impacts in the billions of dollars
Rusty Crayfish

Orconectes rusticus


Similar Species

  • Native crayfish

Characteristics

  • Brown body up to 4 in (10.2 cm) long
  • Dark, rusty spots on each side of carapace
  • Large, black-tipped claws

Habitat

  • Lakes, ponds, streams
  • Clay, silt, sand, gravel, or rock bottom areas
  • Prefer areas with rocks, logs, or other debris as cover
  • Can live in both fast- and slow-moving areas of streams

Known Distribution in the Northeast

  • Maine, Massachusetts, New York, Vermont
  • Native range: Indiana, Ohio, Kentucky, Michigan

Known Distribution in New Hampshire

  • One record of specimen found near Lake Waukewan in 1989 (USGS database)

Impacts

  • Severely reduce cover of aquatic plants, eliminating habitat for invertebrates, food for fish and ducks, shelter for young fish, nesting substrate for fish, and erosion control
  • Reduce native crayfish populations by competing for food and daytime hiding locations
Spiny Water Flea

Bythotrephes longimanus


History

  • Spiny water flea was first found in North America in 1984 in Lake Huron

Characteristics

  • Small predatory crustacean
  • Grows up to 0.6 in (15 mm) long
  • Long, straight tail spine is twice as long as body

Habitat

  • Estuaries, lakes, wetlands
  • Upper water column of large and small temperate lakes
  • Can tolerate brackish water
  • Limited to regions where water temperature is 4-30 degrees C and salinity is 0.04-8.0%

Known Distribution in the Northeast

  • New York and Great Lakes region
  • Native to Europe and Asia

Known Distribution in New Hampshire

  • Unknown

Impacts

  • Competes directly for prey with juvenile and small fish; implicated as a factor in decline of alewife
  • Substantial impact on zooplankton community structure
  • Can foul fishing lines and downrigger cables
Zebra Mussel

Dreissena polymorpha


Similar Species

  • Quagga mussel Dreissena bugensis

History

  • Believed to be introduced to the Great Lakes during ballast water exchange from a cargo ship from the Black Sea
  • Since being discovered in Great Lakes in 1988, the species has spread widely into freshwater habitats across North America
  • Native to Black, Caspian, and Azov Seas

Characteristics

  • Named for the striped pattern on its shell - Black or brownish shell with cream or white stripes
  • Shells colors vary widely; some pale or completely white
  • Maximum size less than 2 in (5 cm) long; often less than 1 in
  • Zebra shell is stable when placed on it's flattened hinge side while quagga mussels, lacking a flat side, fall over
  • Valves (shell halves) are symmetrical, forming a straight line when closed whereas the quagga mussel valves are asymmetrical, forming a curved line when the valves are closed

Habitat

  • Lakes, estuaries, streams
  • Attached to hard surfaces such as rocks, wood, and plants and to manmade structures of concrete, metal, and fiberglass
  • Tolerate salinity to 6 ppt, temperatures to approximately 29 degrees C

Known Distribution in the Northeast

  • 21 states and 2 provinces including Quebec, New York, Vermont, Massachusetts, and Connecticut

Known Distribution in New Hampshire

  • Unknown

Impacts

  • Voracious filter feeders, removing microscopic plants and animals from the water, reducing food available to other aquatic animals
  • May cause declines in fish populations
  • Clog intakes for power plants, industrial facilities, and public drinking water supplies
  • Foul boat and ship hulls
  • Economic impacts in the billions of dollars

Additional Information