Disclaimer & Copyright Notices; Optimized for the MS Internet Explorer

Alien Species

Soil & Water Conservation Society of Metro Halifax (SWCSMH)

July 26, 2006      Freshwater Benthic Ecology and Aquatic Entomology Homepage

Table 1: Alien species that probably have strong effects on native freshwater mollusks in North America (Strayer, 1999)
Dreissena polymorpha (zebra mussel)eastern USA, southeastern Canada; expandinghardwater lakes and riversstrong declines in bivalves; large increases in gastropods
Corbicula fluminea (Asian clam)continental USA, except for some northern states; Hawaiilakes, rivers, and creeksstrong declines in bivalves in at least some ecosystems
Potamopyrgus antipodarum (New Zealand mud-snail)Snake River, Madison River, Lake Ontario; expandinglakes, rivers, creeks, estuariespossibly competitive effects on gastropods
Orconectes rusticus (rusty crayfish)native to midwest, but introduced to north and east; expandinglakes, streamsstrong declines in gastropods
Neogobius melanostomus (round goby)Great Lakes; expandinglarge lakes, rivers, estuariesprobably causes declines in nearshore mollusks
Lepomis microlophus (red-ear sunfishnative to southeast, but introduced to north and westlakes, pondsstrong declines in gastropods
Lepomis gibbosus (pumpkinseed sunfish)native to northeast, but widely introduced elsewherelakes, pondsstrong declines in gastropods
various aquatic plants (cf. Table 2)most bodies of water in USA and southern Canada contain at least 1 alien plant speciesmost well lit, quiet watersprobably strong effects on gastropod abundance and species composition

Table 2: Examples of alien freshwater plants that probably affect local molluscan communities in North America (Strayer, 1999)
TaxonCommon name
Ceratopteris thalictroideswater sprite
Salvinia spp. 
Marsilea quadrifoliaEuropean water-clover
Hydrilla verticillatahydrilla
Eichornia crassipeswater hyacinth
Egeria densaBrazilian waterweed
Lythrum salicariapurple loosestrife
Trapa natanswater chestnut
Potamogeton crispuscurly pondweed
Nasturtium officinalewatercress
Myriophyllum spicatumEurasian water-milfoil

Table 3: Alien species of freshwater mollusks that have become established in North America. The list excludes species whose range within North America has been expanded by humans (Strayer, 1999)
TaxonProbable originNorth American range
  Sphaerium corneumEuropeOntario and New York to Ohio; large lakes and rivers
  Pisidium amnicumEuropeGreat Lakes to New Jersey and Ottawa, Canada; large lakes and rivers
  Pisidium henslowanumEuropescattered in Canada and northern USA
  Pisidium punctiferumCentral AmericaFlorida, Texas
  Dreissena polymorphaEuropeeastern North America, expanding; lakes and medium to large streams and rivers
  Dreissena bugensisEuropeeastern Great Lakes and St. Lawrence River, expanding; rivers and lakes
  Corbicula flumineasoutheast Asiamost of USA, but scattered or absent from the coldest states; lakes, rivers, and smaller streams
  Corbicula sp. 2AsiaTexas to Arizona; spring-fed streams
  Valvata piscinalisEuropeLakes Erie, Ontario, and Cayuga; Hudson and St. Lawrence Rivers
  Cipangopaludina chinensis
Japanwidely scattered in quiet waters throughout USA and southern Canada
  Cipangopaludina japonicaJapanwidely scattered in quiet waters throughout USA and southern Canada
  Marisa cornuarietisSouth or Central AmericaFlorida, Texas
  Pomacea bridgesiSouth AmericaFlorida
  Bithynia tentaculataEuropenortheastern North America; lakes and rivers
  Potamopyrgus antipodarumNew ZealandSnake River, Madison River (Montana), Lake Ontario; probably will spread widely
  Melanoides tuberculatusunknownFlorida, Texas, Arizona
  Melanoides turriculusPhilippinesFlorida
  Tarebia graniferaAsia, OceaniaFlorida, Texas
  Radix auriculariaEuropscattered through North America
  Physella acutaEuropeunknown
  Stenophysa marmorataSouth and Central AmericaTexas
  Stenophysa maugeriaeMexicoTexas
  Biomphalaria glabrataSouth AmericaFlorida


Freshwater Benthic Ecology and Aquatic Entomology Homepage                     Soil & Water Conservation Society of Metro Halifax (SWCSMH) Master Homepage

We salute the Chebucto Community Net (CCN) of Halifax, Nova Scotia, Canada for hosting our web site, and we applaud its volunteers for their devotion in making `CCN' the best community net in the world