Invasion History

First Non-native North American Tidal Record: 1869
First Non-native West Coast Tidal Record:
First Non-native East/Gulf Coast Tidal Record: 1869

General Invasion History:

The freshwater snail Pleurocera canaliculata, including its acuta and pyrenellum morphs, has a broad native range in the Great Lakes-St. Lawrence and Mississippi Basins of North America from Minnesota and Quebec to Alabama and Louisiana (Dazo 1965; Dillon et al. 2013). The P. acuta morph was collected in the Erie Canal, the Mohawk River, and the tidal fresh Hudson River in Troy, New York as early as 1863. It is believed to have been transported through the canal, probably on barges (Strayer 1987; Mills et al. 1997).

North American Invasion History:

Invasion History on the East Coast:

Pleurocera canaliculata (as P. acuta) was collected in the Mohawk River, New York (NY) as early as 1863 (Museum of Comparative Zoology 2013) and the tidal Hudson River at Troy, NY in 1869 (Aldridge 1869, cited by Strayer 1987; ANSP 27361, Academy of Natural Sciences of Philadelphia 2013). It was abundant in the Erie Canal and Mohawk River (Dazo 1965; Lewis 1872, cited by Strayer 1987). In the Hudson River, aside from the records at Troy, dead shells were collected at the town of Hudson, 50km downstream (Townes 1937, cited by Strayer 1987). We do not have recent records from the Hudson River, but Strayer (1987) examined ~800 shells, so we presume that this snail is still established in the upper tidal reaches. However, in a 2008 survey, only one recently dead shell was found (Coote and Strayer 2009). This snail has not been reported from other East Coast tributaries, aside from the St. Lawrence River, where it is native (Dazo 1965).


Pleurocera canaliculata has an elongated, dextrally coiled shell with a conical spire. An adult shell typically has 9-11 whorls. The body whorl is angular, with oblique growth lines and scars. Carinae (keels) may be present (especially in younger snails) or absent. The aperture is roughly rhomboidal, and may form a canal on the inner surface. The color ranges from pale yellow-brown to chestnut brown, and sometimes pale yellow or black. The shell is often coated with mud or algal growth. The acuta morph of P. caniculata reaches maturity at an average of 16.7 mm (Dazo 1965).

Genetic (enzyme) and morphological data indicate that the snails described as P. acuta (Sharp Hornsnail) and P. pyrenellum (Skirted Hornsnail) are phenotypic variants of P. canaliculata, in which shell width and robustness tends to increase continuously with stream width, in a downstream direction, while upstream and downstream populations remain genetically similar. However, sharp breaks in shell size can occur when a small tributary enters a large river, creating the superficial appearance of distinct species, without genetic differentiation (Dillon et al. 2013).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Mollusca
Class:   Gastropoda
Order:   Neotaenioglossa
Family:   Pleuroceridae
Genus:   Pleurocera
Species:   canaliculata


Pleurocera acuta (Rafinesque, 1831)
Pleurocera pyrenellum (Conrad, 1834)

Potentially Misidentified Species

Elimia livescens
This snail, commonly known as the Liver Elimia, is native to the Interior Basin of North America and has been introduced to the Hudson River, via the Erie Canal (Strayer 1987; Mills et al. 1997). Dillon et al. (2013) place this snail in the genus Pleurocera, which has not yet been widely adopted in the literature.

Elimia virginica
This snail, commonly known as the Piedmont Elimia or the Virginia Hornsnail, is native to Atlantic drainages from Massachusetts to North Carolina, including the Hudson River, where it is joined by E. livescens and P. acuta (Strayer 1987; Mills et al. 1997). Dillon et al. (2013) place this snail in the genus Pleurocera, which has not yet been widely adopted in the literature.



Pleurocera canaliculata (= P. acuta) is a small freshwater snail. Sexes are separate and lab-reared snails at 22-23C mature at ~16.7 mm and ~18 months. Eggs are laid singly, or in groups of up to 19, on stones, leaves, bottles, or shells of dead and live mollusks, in spring. Development is direct and eggs hatch into miniature snails in about 15 days at 22°C (Dazo 1965).

In its native Midwestern range, P. canaliculata is known from a variety of habitats, including lakes, ponds and rivers, and substrates ranging from mud and sand to rock, with and without aquatic vegetation and woody debris (Dazo 1965; Pyron et al. 2008). In the Hudson basin, P. canaliculata was collected only in the Hudson and Mohawk Rivers (Strayer 1987). This snail is not known from brackish water and appears to be intolerant of pH levels below 7.8 (Dazo 1965). As a group, Pleurocerid snails are associated with clean, well-oxygenated water (Dazo 1965; Harman 1968a). Its food consists of green algae and diatoms scraped off substrates by the radula (Dazo 1965).

The shell morphology of P. canaliculata appears to be strongly influenced by environmental conditions, associated with stream size and gradients, which has led to naming of many synonymous species (Dazo 1965; Dillon et al. 2013).


diatoms, green algae


fishes, crayfish, ducks


other snails, Bithynia tentaculata

Trophic Status:




General HabitatNontidal FreshwaterNone
General HabitatFresh (nontidal) MarshNone
General HabitatGrass BedNone
General HabitatCoarse Woody DebrisNone
General HabitatUnstructured BottomNone
Salinity RangeLimnetic0-0.5 PSU
Vertical HabitatEpibenthicNone

Tolerances and Life History Parameters

Minimum Temperature (ºC)0Survival in freshwater under ice, (Dazo 1965)
Maximum Temperature (ºC)24Field, Michigan (Dazo 1965)
Minimum Salinity (‰)0This is a freshwater snail.
Minimum Length (mm)16.7Average size of smallest mature snails (Dazo 1965)
Maximum Length (mm)31.5Average size of largest mature snails (Dazo 1965)
Broad Temperature RangeNoneCold -warm temperate
Broad Salinity RangeNoneNontidal Limnetic-Tidal Limnetic

General Impacts

The freshwater snail Pleurocera canaliculata has a limited introduced range on the East Coast, in the Mohawk and upper tidal freshwater Hudson River (Strayer 1987). No ecological impacts have been reported.

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
M060 Hudson River/Raritan Bay 1869 Def Estab
GL-II Lake Erie 0 Native Estab
GL-I Lakes Huron, Superior and Michigan 0 Native Estab
GL-III Lake Ontario 0 Native Estab
L111 _CDA_L111 (Oak Orchard-Twelvemile) 0 Native Estab
L118 _CDA_L118 (Chaumont-Perch) 0 Native Estab
L114 _CDA_L114 (Oswego River) 0 Native Estab
L123 _CDA_L123 (St. Lawrence River) 0 Native Estab
L096 _CDA_L096 (Sandusky) 0 Native Estab
L106 _CDA_L106 (Niagara) 0 Native Estab
L094 _CDA_L094 (Maumee River) 0 Native Estab
L085 _CDA_L085 (Detroit) 0 Native Estab
L082 _CDA_L082 (Lake St. Clair) 0 Native Estab
L073 _CDA_L073 (Birch-Willow) 0 Native Estab
L072 _CDA_L072 (Pigeon-Wiscoggin) 0 Native Estab
L070 _CDA_L070 (Kawkawlin-Pine) 0 Native Estab
L058 _CDA_L058 (Boardman-Charlevoix) 0 Native Estab
L052 _CDA_L052 (Grand River) 0 Native Estab
L047 _CDA_L047 (Little Calumet-Galien) 0 Native Estab
L042 _CDA_L042 (Fox River) 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>

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

Dazo, Bonifacio Capili (1965) The morphology and natural history of Pleurocera acuta and Goniobasis livescens (Gastropoda: Cerithacea: Pleuroceridae), Malacologia 3(1): 1-80

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

Dillon, Robert T.; Jacquemin, Stephen J.; Pyron, Mark (2013) Cryptic phenotypic plasticity in populations of the freshwater prosobranch snail, Pleurocera canaliculata, Hydrobiologia 709: 117-127

Harman, Willard N. (1968a) Replacement of pleurocerids by Bithynia in polluted waters of Central New York, Nautilus 81(3): 77-83

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

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

Pyron, Mark; Beugly, Jayson; Martin, Erika; Spielman, Matthew S (2008) Conservation of the freshwater gastropods of Indiana: Historic and current distributions., American Malacological Bulletin 28: 137-151

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