Invasion History

First Non-native North American Tidal Record: 1895
First Non-native West Coast Tidal Record:
First Non-native East/Gulf Coast Tidal Record: 1895

General Invasion History:

Viviparus georgianus, together with other members of the 'V. georgianus' species complex, are native to the Mississippi drainage and Southeast Atlantic drainages from Illinois to Louisiana and Georgia to Florida (Clench 1962; Burch 1982; Katoh and Foltz 1994). Viviparus georgianus is an attractive snail, which has been widely distributed in Northeastern North America by collectors, the aquarium trade, and canals (Clench 1962; Clench and Fuller 1965; Mills et al. 1993; Mills et al. 1997).

North American Invasion History:

Invasion History on the East Coast:

The first introduction of Viviparus georgianus to Atlantic Coast drainages was to the Mohawk River, New York (NY) by James Lewis, an amateur naturalist, in 1867. Multiple introductions from aquarium releases, barge traffic, etc. are likely (Clench 1962; Mills et al. 1993; Mills et al. 1997). It was first found in Lake Michigan in 1906, in Lake Erie in 1914, and in the St. Lawrence estuary, Quebec in 1953 (Bousfield 1955). It probably reached the Hudson and Lake Erie by Lewis's introduction in the Mohawk River, but spotty distribution in the Hudson basin indicates multiple introductions. This snail reached the Hudson estuary at Albany by 1895 (Marshall 1895, cited by Strayer 1987). By 1922, it was found in Annandale, NY, in the Sawkill River about 75 km downstream. It was locally abundant in two 1980’s surveys (Strayer 1987; Jokinen 1992). However, no specimens were collected in a 2008 survey (Coote and Strayer 2008).

Introductions outside the Great Lakes and Hudson River probably came from the use of this attractive snail in aquariums and fish ponds. Viviparus georgianus was first reported from ponds in the Boston Public Gardens in 1916, and soon became widespread in the Charles River in the vicinity of Boston (Clench 1962; Clench and Fuller 1965). Along the Delaware River, it was first reported in Fairmont Park, Philadelphia in 1909 (Clench 1962; ANSP 98696, A9232, Academy of Natural Sciences of Philadelphia 2014). In the Chesapeake Bay region, V. georgianus has only been found in the Potomac River. The oldest United States National Museum of Natural History specimens are dated 1901, from Hunters Point, Alexandria, Virginia (VA). This snail was reported from Seneca, Maryland and Great Falls to Alexandria and Mount Vernon, VA (Clench 1962; United States National Museum of Natural History collections). Diilon (2013) noted a map record from Swan Creek Maryland, on upper Chespeake Bay (Dillon 2013).The present abundance and distribution are not known. Paul Fofonoff (Smithsonian Environmental Research Center) has not found shells of this snail in occasional searches along the tidal and lower nontidal Potomac (1996-2000), so it may be less abundant than Bellamya chinensis (Chinese Mystery Snail) and B. japonica (Japanese Mystery Snail) (Fofonoff, personal observation).


The shell of Viviparus georgianus is dextrally coiled, somewhat globular, and rather thin, with 4-5 rounded strongly convex whorls with a strong shoulder. The columella is narrow and arched. The umbilicus is either absent, or narrow and slit-like. The aperture is oval to subcircular. The outer lip is thin. The shell sculpture consists of fine growth lines. The operculum is horny with concentric growth lines. Large specimens can reach 44 mm. The shell is yellowish to dark-brownish green, with uniform color, or dark bands (Clench 1962).

Viviparus georgianus in the Southeastern United States appears to be a part of a species complex. Genetic and morphometric studies have established at least two new species, Viviparus limi (Ochlockonee Mystery Snail) and Viviparus goodrichi (Globose Mystery Snail), in Florida and Georgia Atlantic drainages. Additional species are likely within this complex (Katoh and Foltz 1994). Two other native species, V. subpurpureus and V. intertextus, native to Mississippi-Gulf drainages are more distinct, but still quite similar (Clench 1962). Some records and museum specimens in Atlantic Coast watersheds (St. Lawrence, Potomac) have been identified as the European V. viviparus or V. contectus (Bousfield 1955; Dundee 1974; Academy of Natural Sciences of Philadelphia 2014; Museum of Comparative Zoology 2014; US National Museum of Natural History collections), or as the North American V. subpurpureus (ANSP 27709, from Washington DC, Academy of Natural Sciences of Philadelphia 2014). We will follow Clench (1962) in referring to introduced populations in the Great Lakes, St. Lawrence River, and Atlantic drainages from Massachusetts to Virginia as V. goergianus, but clearly, the identity of these snails requires more examination.


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Mollusca
Class:   Gastropoda
Subclass:   Prosobranchia
Order:   Architaenioglossa
Family:   Viviparidae
Genus:   Viviparus
Species:   georgianus


Lymnea vivipara (Say, 1817)
Paludina georgiana (Lea, 1834)
Paludina linearis (Kuster, in Valenciennes, 1852)
Vivipara georgiana fasciata (Tryon, 1870)
Vivipara haldemanniana (Shuttleworth, in Fraunfeld, 1862)
Viviparus contectoides compactus (Pilsbry, 1916)
Vivpara contectoides (Binney, 1865)
Vivipara georgiana altior (Pilsbry, 1862)

Potentially Misidentified Species

Cipangoplaudina chinensis

Cipangoplaudina chinensis is native to China and widely introduced in North America (Clench 1962; Smith 2000). Its current occurrence and abundance in the Potomac River is uncertain.

Hexagen japonica

Hexagen japonica (formerly Cipangopaludina japonica) is naitve to Japan, and widely introduced in Noirth America.It is currently abundant in the Potomac estuary.

Viviparus goodrichi
Viviparus goodrichi is native to Gulf of Mexico drainages from the western portion of the Florida panhandle and Alabama (Katoh and Foltz 1994).

Viviparus intertextus
Viviparus intertextus is widespread in the Mississippi and Gulf drainages (Clench 1962).

Viviparus limi
Viviparus limi is native to the Gulf of Mexico drainages of the central portion of the Florida panhandle (Ocklochonee River drainage) (Katoh and Foltz 1994).

Viviparus subpurpureus
Viviparus subpurpureus is found in the Mississippi and some Gulf drainages (Clench 1962), and is introduced to Lake Marion, South Carolina, on the Santee River, an Atlantic tributary (Dillon et al. 2014).

Viviparus viviparus
This is a European species. Records of this snail in North American waters have been reported but not confirmed. Most records have been re-identifed as V. georgianus (Clench 1962).



Viviparus georgianus is a large freshwater snail. Sexes are separate and males have an enlarged right tentacle, which is used in copulation (Fretter and Graham 1962). Females are larger than males, overall mean size at maturation was 13 mm for males and 14 mm for females, and maturation occurred about 1 year after birth. Eggs are fertilized internally and develop in a brood chamber. Eggs take about 60 days to develop and the young are born at about 6 mm shell length. Estimated annual fecundity is 39 embryos per year (Keller et al. 2007). Male snails can live about 18 months and reach a maximum of 22 mm length, while females can live for 3 years and may measure 44 mm (Browne 1978).

Viviparus georgianus tolerates a wide range of temperature, ranging from the Gulf Coast to northern lakes that regularly have ice-cover. It inhabits slowly flowing and stagnant rivers, streams, canals, and lakes (Clench 1962; Strayer 1987; Jokinen 1992). Salinity tolerance of V. georgianus is not known, but is probably similar to that of European V. viviparus (Fretter and Graham 1962). In New York State it tolerated a wide range of soft/hard water conditions, and a pH range of 6.3-8.5 (Jokinen 1992). Typical habitats are muddy or silty and vegetated, but may include some rocks, coarse woody debris, or man-made structures (Duch 1976; Jokinen 1992).

Viviparus georgianus feeds like many other snails, scraping diatoms and other algae off the sediment surface and hard substrates with its radula (Duch 1976). However, it has another feeding mode, in which it lies half-buried in sediment and filters water through its elaborate gill filaments, capturing suspended particles of phytoplankton and sediment (Fretter and Graham 1963). Predators probably include crayfishes, fishes, waterfowl, and mammals.


phytoplanakton, periphyton

Trophic Status:




General HabitatFresh (nontidal) MarshNone
General HabitatGrass BedNone
General HabitatCoarse Woody DebrisNone
General HabitatNontidal FreshwaterNone
General HabitatTidal Fresh MarshNone
General HabitatUnstructured BottomNone
General HabitatRockyNone
Salinity RangeLimnetic0-0.5 PSU
Salinity RangeOligohaline0.5-5 PSU
Tidal RangeSubtidalNone
Vertical HabitatEpibenthicNone

Life History

Tolerances and Life History Parameters

Minimum Salinity (‰)0None
Maximum Salinity (‰)3Based on tolerance of European V. viviparus (Fretter and Graham 1963)
Minimum pH6.3Field Jokinen 1992
Maximum pH8.5Field Jokinen 1992
Minimum Length (mm)13Minimum length at maturity for males, 14 mm for females (Browne 1978)
Maximum Length (mm)44Clench 1963
Broad Temperature RangeNoneWarm temperate-Cold temperate
Broad Salinity RangeNoneNontidal Limnetic-Oligohaline

General Impacts

In some Minnesota lakes, Viviparus georgianus has developed very high biomasses, followed by die-offs, forming windrows of shells on the shore and unpleasant odors (Bury et al. 2007). However, we are not aware of impacts in invaded estuaries.

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
GL-III Lake Ontario 1912 Def Estab
GL-II Lake Erie 1914 Def Estab
GL-I Lakes Huron, Superior and Michigan 1906 Def Estab
M060 Hudson River/Raritan Bay 1895 Def Estab
M130 Chesapeake Bay 1901 Def Unk
M090 Delaware Bay 1909 Def Estab
S180 St. Johns River 0 Native Estab
NA-S3 None 1953 Def Estab
G080 Suwannee River 0 Native Estab
L127 _CDA_L127 (English-Salmon) 1988 Def Estab
S160 St. Andrew/St. Simons Sounds 0 Native Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Academy of Natural Sciences of Philadelphia 2002-2024a Malacology Collection Search. <missing URL>

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Bilger, Michael D.; Riva-Murray, Karen;Wall, Gretchen L. (2005) <missing title>, U. S. Geological Survey, Reston, VA. Pp. <missing location>

Bousfield, E. L. (1955) Viviparus viviparus in eastern Canada, Canadian Field-Naturalist 69: 27-28

Browne, Robert A. (1978) Growth, mortality, fecundity, biomass, and productivity of four lake populations of the prosobranch snail Viviparus georgianus, Ecology 59(4): 742-750

Burch, J. B. (1982) <missing title>, U.S. Environmental Protection Agency; Office of Research and Development, Cincinnati. Pp. <missing location>

Bury, Jennifer A.; Sietman, Bernard E.; Karns, Byron N. (2007) Distribution of the non-native viviparid snails, Bellamya chinensis and Viviparus georgianus, in Minnesota and the first record of Bellamya japonica from Wisconsin, Journal of Freshwater Ecology 22(4): 697-703

Clarke, Arthur H. (1981) <missing title>, National Museum of Natural Sciences, Ottawa. Pp. <missing location>

Clench, William J. (1962) A catalogue of the Viviparidae of North America with notes on the distribution of Viviparus georgianus Lea, Occasional Papers on Mollusks, Museum of Comparative Zoolgy, Harvard University 2(27): 261-287

Clench, William J.; Fuller, Samuel L. H (1965) The genus Viviparus in North America, Occasional Papers on Mollusks, Museum of Comparative Zoology, Harvard University 2(32): 385-412

Coote, Thomas W.; Strayer, David W. (2009) Final Reports of the Tibor T. Polgar Fellowship Program, Section IV: Hudson River Foundation, <missing place>. Pp. 1-32

Dillon, R. T. Jr.; Watson, B.T.; Stewart, T. W.; Reeves, W. K. 2006-2024 The freshwater gastropods of North America.

Duch, Thomas M. (1976) Aspects of the feeding habits of Viviparus georgianus, Nautilus 90(1): 7-10

Dundee, Dee S. (1974) Catalog of introduced molluscs of eastern North America (North of Mexico), Sterkiana 55: 1-37

Fretter, Vera; Graham, Alastair (1962) British prosobranch molluscs: their functional anatomy and ecology, In: (Eds.) . , London. Pp. <missing location>

Fuller, Samuel (1978) The changing molluscan community, In: Flynn, Kevin C., and Mason, William T.(Eds.) The Freshwater Potomac: Aquatic Communities and Environmental Stresses. , Rockville, MD. Pp. 124-131

Harvard Museum of Comparative Zoology 2008-2021 Museum of Comparative Zoology Collections database- Malacology Collection. <missing URL>

Jacobson, Morris K.; Emerson, William K. (1971) <missing title>, Dover Publications, Inc., New York. Pp. <missing location>

Johnson, C. W. (1918) Viviparus malleatus and contectoides in Massachusetts, Nautilus 31(3): 107-108

Jokinen, Eileen H. (1992) The freshwater snails (Mollusca: Gastropoda) of New York State, New York State Museum Bulletin 482: 1-89

Katoh, Masaya; Foltz, David (1994) Genetic subdivision and morphological variation in a freshwater snail species complex formerly referred to as Viviparus georgianus Lea, Biological Journal of the Linnean Society 53: 73-90

Keller, Reuben P.; Drake, John M.; Lodge, David M. (2007) Fecundity as a basis for risk assessment of nonindigenous freshwater molluscs, Conservation Biology 21(1): 191-200

Marsden, J. Ellen; Hauser, Michael (2009) Exotic species in Lake Champlain, Journal of Great Lakes Research 35: 250-265

Mills, Edward L.; Leach, Joseph H.; Carlton, James T.; Secor, Carol L. (1993) Exotic species in the Great Lakes: a history of biotic crises and anthropogenic introductions., Journal of Great Lakes Research 19(1): 1-54

Mills, Edward L.; Scheuerell, Mark D.; Carlton, James T.; Strayer, David (1997) Biological invasions in the Hudson River: an inventory and historical analysis., New York State Museum Circular 57: 1-51

Richards, Horace G. (1934) A list of mollusks of the District of Columbia and vicinity, American Midland Naturalist 15: 85-88

Stewart, Timothy; Dillon, Robert T. (2004) Species composition and geographic distribution of Virginia's freshwater gastropod fauna: A review using historical records., American Malacological Bulletin 10(1/2): 79-91

Strayer, David (1987) Ecology and zoogeography of the freshwater mollusks of the Hudson River Basin, Malacological Review 20: 1-68

Strayer, David L. (1987) Macrohabitats of freshwater mussels (Bivalvia: Unioniacea) in streams of the northern Atlantic Slope, Journal of the North American Benthological Society 12(3): 236-246

USGS Nonindigenous Aquatic Species Program 2003-2024 Nonindigenous Aquatic Species Database.

Vincent, B. (1979) Etude du benthos d'eau douce dans le haut-estuaire du Saint-Laurent (Quebec), Canadian Journal of Zoology 57: 2171-2182