Invasion History

First Non-native North American Tidal Record: 2008
First Non-native West Coast Tidal Record: 2008
First Non-native East/Gulf Coast Tidal Record:

General Invasion History:

Spurwinkia salsa is native to estuaries of eastern North America from New Brunswick to northern Florida. It inhabits marshes, mudflats, and submerged vegetation from the upper intertidal to shallow subtidal, at salinities of 0 to 35 PSU (Davis et al. 2002; McAlpine et al. 2005; Pung et al. 2008; Academy of Natural Sciences of Philadelphia 2015; Rosenberg 2015). In 2008, populations were discovered in marshes at two locations in South San Francisco Bay (Hershler et al. 2015).

North American Invasion History:

Invasion History on the West Coast:

Spurwinkia salsa was found in 2008 at two locations in South San Francisco Bay, California: Eden Landing Ecological Reserve and the Alviso Salt Ponds, in saline intertidal marshes (Hershler et al. 2015). Possible vectors include seaweed used to pack baitworms, solid ballast of sailing ships, and less likely, oysters or ballast water. Given the inconspicuous size and appearance of the snails, they could have been introduced as early as the 19th century (Hershler et al. 2015).


The shell of Spurwinkia salsa is conical and dextrally coiled, with a sharp, pointed apex, consisting of 5-6 whorls. The whorls are very convex with moderately deep sutures. The aperture is 1/3 to1/2 of shell height, ovate to sub-circular, and sharply angled. The body whorl is relatively large, about 5/6 to 2/3 of shell height, compared to other hydrobiids (Pilsby 1905; Hershler and Davis 1980; Davis et al. 1982; Hershler et al. 2015). The apical whorl is rarely eroded. The shell has faint spiral grooves, and is greenish, 'with the luster of a dull silk' (Pilsbry 1905). Sometimes, when shells are heavily fouled with algae and detritus, the peristome (the region of the body whorl near the aperture) becomes detached and partly uncoiled, due to detritus and limonite deposits accumulating in the apertures. Adult female snails ranged from 3.3 mm to 10.5 mm, while males were 7 mm (Davis et al. 1982). A shell of a planktonic veliger is illustrated by Davis et al. (1982). 'Hydrobiid' snails, as a group, require identification by specialists, and are not adequately covered in general guidebooks (e.g. Abbott 1974; Morris 1975; Gosner 1978; McLean 2007).

Snails in the genus Spurwinkia were once included in the family Hydrobiidae, but that family has been broken up, with many New World species now placed in the family Cochliopidae, including the genera Littoridinops, , and Pyrgophorus, among others (Hershler et al. 2013; Appletans et al. 2018).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Mollusca
Class:   Gastropoda
Order:   Neotaenioglossa
Family:   Cochliopidae
Species:   salsa


Paludestrina salsa (Pilsbry, 1905)
Hydrobia salsa (Pilsbry, 1905)
Spurwinkia salsa (Davis, Mazurkiewicz & Mandracchia, 1982)

Potentially Misidentified Species

Amnicola cincinnatiensis
auct. non Anthony, 1840 (Rosenberg 2015)

Littoridinops monroensis
Northwest Atlantic native, introduced to San Francisco Bay (Hershler et al. 2007)

Potamopyrgus antipodarum
New Zealand Mud Snail, widely introduced in West Coast estuaries

Tryonia imitator
Native to California estuaries (Hershler et al. 2007)

Tryonia porrecta
Southwest North American freshwater snail, cryptogenic in San Francisco Bay (Hershler et al. 2007)



Spurwinkia salsa is a small estuarine snail, occurring in brackish tidal marshes and shallow estuarine waters (Davis et al. 1982). Sexes are separate and eggs are fertilized by copulation. Development is planktotrophic, with veligers remaining 45-60 days in the water column (Davis et al. 1982).

Spurwinkia salsa ranges from cold-temperate climates (Maine, New Brunswick) to subtropical regions (Georgia, northern Florida). It occurs in estuaries at salinities from 0-35 PSU, but is not known to maintain populations in non-tidal fresh water (Bryant 1908; Davis et al. 1982; McAlpine et al. 2005; Pung et al. 2008). Veliger larvae of S. salsa were found in Maine estuaries at 10-28 PSU. Hydrobiid snails, such as L. monroensis, feed on organic deposits, benthic diatoms, and can also scrape microbes off sand particles (Lopez and Kofoed 1980). Spurwinkia salsa is host to at least six species of trematodes (Stunkard 1967), and is likely prey, for crabs, fishes, and shorebirds.


Algae, detritus


Fishes, crabs, shorebirds

Trophic Status:




General HabitatGrass BedNone
General HabitatCoarse Woody DebrisNone
General HabitatSalt-brackish marshNone
General HabitatUnstructured BottomNone
Salinity RangeOligohaline0.5-5 PSU
Salinity RangeMesohaline5-18 PSU
Salinity RangePolyhaline18-30 PSU
Tidal RangeSubtidalNone
Tidal RangeLow IntertidalNone
Tidal RangeMid IntertidalNone
Tidal RangeHigh IntertidalNone
Vertical HabitatEpibenthicNone

Tolerances and Life History Parameters

Minimum Temperature (ºC)0Davis et al. 1982, Massachustts-Maine estuaries
Maximum Temperature (ºC)29Davis et al. 1982, Massachustts-Maine estuaries, probably higher in eouthern range
Minimum Salinity (‰)0None
Maximum Salinity (‰)35Pung et al. 2008, Georgia, but found in former San Francisco Bay salt ponds (Hershler et al. 205)
Minimum Reproductive Temperature14.5Davis et al. 1982, Massachustts-Maine estuaries
Maximum Reproductive Temperature25Davis et al. 1982, Massachustts-Maine estuaries, probably higher in southern range
Minimum Reproductive Salinity10.5Davis et al. 1982, Massachustts-Maine estuaries
Maximum Reproductive Salinity28Davis et al. 1982, Massachustts-Maine estuaries
Minimum Duration45Mazurkiewicz 1972, cited by Hershler et al. 2015
Maximum Duration60Mazurkiewicz 1972, cited by Hershler et al. 2015
Minimum Length (mm)6.5Mature males. Females, 8.5 mm (Davis et al. 1982)
Maximum Length (mm)10.5Mature females. Males, 7.7 (Davis et al. 1982)
Broad Temperature RangeNoneCold temperate-Warm Temperate
Broad Salinity RangeNoneOligohaline-Euhaline

General Impacts

No ecological impacts have been reported for introduced populations in San Francisco Bay.

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
P090 San Francisco Bay 2008 Def Estab
NEP-V Northern California to Mid Channel Islands 2008 Def Estab
NA-ET2 Bay of Fundy to Cape Cod 0 Native Estab
CAR-VII Cape Hatteras to Mid-East Florida 0 Native Estab
NA-ET3 Cape Cod to Cape Hatteras 0 Native Estab
NA-ET1 Gulf of St. Lawrence to Bay of Fundy 0 Native Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Abbott, R. Tucker (1974) American Seashells, Van Nostrand Reinhold, New York. Pp. <missing location>

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

Bryant, Owen (1908) A note on the type locality of Paludestrina salsa at Cohassett, Mass, Nautilus 22: 82

Davis, George M.; Mazurkiewicz, Michael; Mandracchia, Michael (1982) Spurwinkia, systematics and ecology of a new genus of North American marshland hydrobiidae (Mollusca: Gastropoda), Proceedings of the Academy of Natural Sciences of Philadelphia 138: 143-177

Gore, James F. (1967) A northernmost record and ecological data on Hydrobia salsa in Maine, Nautilus 80(4): 112-113

Gosner, Kenneth L. (1978) A field guide to the Atlantic seashore., In: (Eds.) . , Boston. Pp. <missing location>

Hershler, Robert and 6 authors (2015) New discoveries of introduced and cryptogenic fresh and brackish water gastropods (Caenogastropoda: Cochliopidae) in the western United States, Aquatic Invasions 10: In press

Hershler, Robert; Davis, Cheryl L.; Kitting, Christopher L.; Liu, Hsiu-ping (2007) Discovery of introduced and cryptogenic cochliopid gastropods in the San Francisco estuary, California., Journal of Molluscan Studies 73: 323-332

Hershler, Robert; Davis, George M. (1980) The morphology of Hydrobia truncata (Gastropoda: Hydrobiidae): Relevance to systematics of Hydrobia, Biological Bulletin 158: 195-219

Lopez, G. R.; Kofoed, L. H. (1980) Epipsammic browsing and deposit feeding in mud snails Hydrobiidae., Journal of Marine Research 38(4): 585-600

Mandracchia, Michael A.; Ruber, Ernest (1990) Production and life cycle of the gastropod Hydrobia truncata, with notes of Spurwinkia salsa in Massachusetts salt marsh pools, Estuaries 13(4): 479-485

McAlpine, Donald F.; Bateman, Deanna; Davis, Christina A. (2005) Spurwinkia salsa (Pilsbry 1905) (Gastropoda: Hydrobiid) in the Kennebecasis estuary, New Brunswick: A brackish-water snail new to Canada, Journal of Conchology 38: 317-321

McLean, James A. (2007) The Light and Smith Manual: Intertidal Invertebrates from Central California to Oregon, University of California Press, Berkeley CA. Pp. 713-1766

Morris, Percy A. (1975) A field guide to shells of the Atlantic, Houghton-Mifflin, Boston. Pp. <missing location>

Pilsbry, Henry A. (1905) A new brackish-water snail form New England, Nautilus 19: 90-91

Pung, Oscar J.; Grinstead, C. Brad; Kerstin, Kraig; Edenfield, Catherine L. (2008) Spatial distribution of hydrobiid snails in salt marsh along the Skidaway river in southeastern Georgia with notes on their larval trematodes, Southeastern Naturalist 7(4): 717-728

Rosenberg, Gary 1995-2023 Malacolog 4.1.

Ruiz, Gregory M.; Geller, Jonathan (2018) Spatial and temporal analysis of marine invasions in California, Part II: Humboldt Bay, Marina del Re, Port Hueneme, and San Francisco Bay, Smithsonian Environmental Research Center & Moss Landing Laboratories, Edgewater MD, Moss Landing CA. Pp. <missing location>

Stunkard, Horace W. (1967) Studies on the trematode genus Paramonostomum luhe, 1909 (Digenea: Notocotylidae), Biological Bulletin 132(1): 133-145

U.S. National Museum of Natural History 2002-2021 Invertebrate Zoology Collections Database.