Invasion History

First Non-native North American Tidal Record: 1985
First Non-native West Coast Tidal Record:
First Non-native East/Gulf Coast Tidal Record: 1985

General Invasion History:

Valvata piscinalis is native to lakes, rivers, and slow-running streams in Europe, western Siberia, and the Caucasus. It is present in Britain and Ireland, but absent from Iceland (Grigorovich et al. 2005). In European estuaries and the Baltic, its salinity limit is between 2 and 3 PSU (Remane and Schleiper 1971; Wolff 1973; Zettler and Daunys 2007). It was first introduced into North America in the late 19th century, but estuarine populations were not noted until 1985 in the tidal Hudson River, New York.

North American Invasion History:

Invasion History on the East Coast:

In 1897, Valvata piscinalis was collected in Charlotte, New York in Lake Ontario (Baker 1898, cited by Mills et al. 1993) and subsequently found in several locations around this lake. In 1936, it was found in Lake Erie, at Presque Isle, Pennsylvania (Grigorovich et al. 2005). However, it was not until 1995 that I was found in the upper Great Lakes, in Superior Bay, Lake Superior (Grigorovich et al. 2005) and 2002 in Lake Michigan (Grigorovich et al. 2005). It is abundant in Oneida Lake, New York (Grigorovich et al. 2005) and also found in Lake Champlain (USGS Nonindigenous Aquatic Species Program 2014). Its range extends into the St. Lawrence River (Grigorovich et al. 2005), but occurrences in the estuary have not been reported. A likely early vector was marsh grasses, used as packing material, or stones and sand used as ballast (Mills et al. 1993). Its spread into Lake Erie may have been aided by the Welland Canal or the discharge of ballast water sediment.

In the tidal Hudson River, V. piscinalis was collected at several locations near Poughkeepsie, New York in 1985. This snail appears to be rare in the Hudson (Strayer 1987; Mills et al. 1997). It was not found in a 2008 survey of the river between Poughkeepsie and Albany (Coote and Strayer 2009), but such a small snail is easily overlooked. The Erie Canal or ballast sediments of ocean-going ships are possible vectors.


The shell of Valvata piscinalis is dextrally coiled with a blunt, but slightly raised, spire with 4-5 rounded whorls. The umbilicus is narrow and the inner lip or the aperture is slightly turned inward, and the aperture is slightly tear-drop shaped. Growth lines on the shell are fine and dense. The length of the shell is roughly equal to its width. The height of the spire increases with eutrophication, while the umbilicus becomes narrower. Shells of Great Lakes specimens reach 5 mm, but European shells may be 7 mm in length and 6.5 mm wide. There are branched gills (ctenidium) which sometimes protrude from the shell. The shell is yellowish, spotted with gray and white, with dark pigmentation on the snout and blue eyes. Description from: Fretter and Graham 1978 and Grigorovich et al. 2005.


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Mollusca
Class:   Gastropoda
Order:   Heterostropha
Family:   Valvatidae
Genus:   Valvata
Species:   piscinalis


Potentially Misidentified Species

Valvata lewisi
Native to northern North America (Grigorovich et al. 2005; Zoological Record Search)

Valvata sincera
Native to eastern North America (Grigorovich et al. 2005)



Valvata piscinalis is a freshwater snail found in standing and slowly flowing fresh waters. It is hermaphroditic, with one individual acting as a male and the other as a female, with internal fertilization. Breeding takes place at about 1 year of age, and the life span is about 13 to 21 months. Spawning occurs 2 or 3 times a year, with up to 150 eggs in each spawning. Eggs are laid on vegetation and hatch as miniature snails (Fretter and Graham 1962; Grigorovich et al. 2005).

The European Valve Snail apparently has a wide temperature tolerance, considering its wide range in Europe (Grigorovich et al. 2005). It has a very limited salinity tolerance though, not occurring above 2.5 PSU in the Baltic (Remane and Schleiper 1971). Its preferred habitats are silty, vegetated substrates, but it can survive where vegetation is sparse, and in highly disturbed habitats, such as canals (Fretter and Graham 1962; Grigorovich et al. 2005). It feeds on benthic macroalgae, epiphytic algae on plants, detritus, and the tissues of aquatic plants. It can also feed by filtering phytoplankton in eutrophic waters (Fretter and Graham 1962; Grigorovich et al. 2005).

This small snail is vulnerable to a wide variety of predators, including crayfish, fishes, and birds. It hosts a variety of trematode parasites. In Oneida Lake, these snails contained cercaria of Echinostoma sp., and in Europe they are known to carry Cyathocotyle bushiensis and Echinostoma recurvatum (Karatayev et al. 2012). Parasitism by C. bushiensis has been associated with mortality of waterfowl in the Great Lakes and upper Mississippi Valley (Hoeve and Scott 1988).


Algae, detritus, submerged vegetation, plankton


fish, crayfish

Trophic Status:




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

Tolerances and Life History Parameters

Minimum Salinity (‰)0This is a freshwater species.
Maximum Salinity (‰)2.5Field, Baltic, Remane and Schleiper 1971
Maximum Length (mm)7Fretter and Graham 1978; Grigorovich et al. 2005
Broad Temperature RangeNoneCold temperate-Warm Temperate
Broad Salinity RangeNoneNontidal Limnetic-Oligohaline

General Impacts

Valvata piscinalis is known in North America only from the Great Lakes, St. Lawrence River, and Hudson River estuary. It is rare but increasing in abundance in the Great Lakes (Grigorovich et al. 2005), and rare in the tidal Hudson River (Strayer 1987; Coote and Strayer 2009). Grigorovich et al. (2005) considered it a potential competitor for native snails, if its abundance increases. However, no detectable impacts have been reported from North America.

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
GL-III Lake Ontario 1897 Def Estab
GL-II Lake Erie 1936 Def Estab
M060 Hudson River/Raritan Bay 1985 Def Estab
GL-I Lakes Huron, Superior and Michigan 1995 Def Estab
L115 _CDA_L115 (Salmon-Sandy) 2002 Def Estab
B-XIII None 0 Native Estab
B-IX None 0 Native Estab
B-VII None 0 Native Estab
B-X None 0 Native Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Carlsson, Ralf (2006) Freshwater snail assemblages of semi-isolated brackish-water bays on the Aland Islands, SW Finland, Boreal Environment Research 11: 371-382

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

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>

Grigorovich, Igor A.; Mills, Edward L.; Richards, Carl B.; Breneman, Dan; Ciborowski, Jan J.H. (2005) European valve snail Valvata piscinalis (Müller) in the Laurentian Great Lakes Basin., Journal of Great Lakes Research 11: 135-143

Hoeve, John; Scott, Marilyn E. (1988) Ecological studies on Cyathocotyle bushiensis (Digenea) and Sphaeridiotrema globulus (Digenea), possible pathogens of dabbling ducks in southern Quebec, Journal of Wildlife Diseases 24(3): 407-421

Karatayev, Alexander Y. and 5 authors (2012) Exotic molluscs in the Great Lakes host epizootically important trematodes, Journal of Shellfish Research 31: 885-894

Kotta, Jonne and 6 authors (2013) Is a rapid expansion of the invasive amphipod Gammarus tigrinus Sexton, 1939 associated with its niche selection: a case study in the Gulf of Finland, the Baltic Sea, Aquatic Invasions 8: in press

Merilainen, Jamo (1988) Meiobenthos in relation to macrobenthic communities in a low-saline, partly-acidified estuary, Bothnian Bay, Finland, Annales Zoologici Fennici 25: 277-292

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

Remane, Adolf; Schleiper, Carl C. (1971) Biology of Brackish Water, In: (Eds.) . , New York. Pp. 1-210

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

Trebitz, Anett S. and 5 authors (2010) Status of non-indigenous benthic invertebrates in the Duluth-Superior Harbor and the role of sampling methods in their detection, Journal of Great Lakes Research 36: 747-756

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

Wolff, W. J. (1973) The estuary as a habitat: An analysis of data on the soft-bottom macrofauna of the estuarine area of the rivers Rhine, Meuse, and Scheldt, Zoologische Verhandelingen 126: 4-242

Zettler, Michael L.; Daunys, Darius (2007) Long-term macrozoobenthos changes in a shallow boreal lagoon: Comparison of a recent biodiversity inventory with historical data., Limnologica 37: 170-185