Invasion HistoryFirst Non-native North American Tidal Record: 2007
First Non-native West Coast Tidal Record: 2007
First Non-native East/Gulf Coast Tidal Record:
General Invasion History:
Assiminea parasitologica is a small snail, native to southern Japan and the southern coast of Korea (Kuroda et al. 2003; James T. Carlton, personal communication 2007). It is introduced in Oregon, where it was first found in 2007 in Coos Bay. It was subsequently found in other Oregon estuaries, including the Yaquina, Alsea, Umpqua and Coquille (Laferriere et al. 2010; Davidson 2013). This snail has a planktonic larva, and has the potential to be dispersed in ballast water. Since this snail can tolerate some air exposure, transport on the deck or the above-water hulls of ships is possible.
North American Invasion History:
Invasion History on the West Coast:
A small, unidentified snail was discovered July 5, 2007 in an upper estuary slough (10 PSU) of Coos Bay, Oregon at densities of thousands meter-2 (Carlton personal communication 2007; Laferriere et al. 2010). It was identified by Robert Hershler of the US National Museum of Natural History. It was subsequently found in the Umpqua and Yaquina Rivers in 2008 and the Alsea and Coquille Estuaries in 2009 (Laferriere et al. 2010; South Slough National Estuarine Research Reserve 2013).
Assiminea parasitologica is a small snail, about 5 mm in height. It is dextrally coiled, with 4-5 bulbous whorls in its rounded, bluntly conical shell. The youngest whorl is about 2/3 of the shell length. Its aperture has a broad inner lip. The overall color is brown, with some reddish tints. Younger shells have light yellow bands at the top and bottom of the body whorl, which become eroded as the animal matures. It inhabits the upper intertidal regions of salt and brackish marshes. The larvae of this snail are planktonic, but have not yet been described. Description from: Kuroda 1958; James T. Carlton, personal communication 2007; Laferriere et al. 2010; Davidson 2013.
Potentially Misidentified Species
Native species with five whorls, more conical and 2-3.5 mm in size. Ranges from British Columbia-Mexico and is found in upper intertidal marshes.
Native with four well-rounded whorls, a thin outer lip, and 5-7 mm in size. Ranges from British Columbia to Northern California and is found in salt marsh edges.
Introduced New Zealand Mudsnail, has 7-8 whorls and is 5-12 mm in size. It is found on mud in fresh and brackish water from California to British Columbia.
Assiminea parasitologica is a small snail inhabiting upper regions of tidal marshes (Kuroda et al. 2003; Laferriere et al. 2010). Snails of the genus have separate sexes and vary in their modes of reproduction. Some, such as A. californica, and the East Coast A. succinea, lay egg capsules and have direct development (J. P E. Morrison, cited by Wass 1972; Fowler 1980). This snail has planktonic development, but descriptions of larvae have not been published. In the Coos River estuary, Oregon, mating occurred in June-July, with young-of-the year appearing in August (Laferriere et al. 2010).
Assiminea parasitologica inhabits the middle-to-upper reaches of estuarine tidal marshes in its native Japan (Kuroda et al. 2003) and introduced range in Oregon (Laferriere et al. 2010). It tolerates a wide range of temperatures and salinities, although specific data on its tolerances are not available. In the Coos River estuary, it ranges from oligohaline (0-5 PSU) to euhaline (30-35 PSU) zones, but is most abundant in the mesohaline regions (5-18 PSU) (Laferriere et al. 2010). Snails of these genus tolerate considerable air exposure, but occur on moist, vegetated substrates (Fowler 1980; Kuroda et al. 2003). They probaly feed on plant detritus and benthic microalgae. This snail is vulnerable to predators such as crabs and shorebirds. It is of particular interest as the first host of a lung fluke, Paragonimus ohirae, whose second hosts are grapsid crabs, and ultimately infect rats and weasels (Agatsuma and Habe 1986).
Detritus, benthic microalgae
|General Habitat||Salt-brackish marsh||None|
|General Habitat||Unstructured Bottom||None|
|Salinity Range||Oligohaline||0.5-5 PSU|
|Salinity Range||Mesohaline||5-18 PSU|
|Salinity Range||Polyhaline||18-30 PSU|
|Salinity Range||Euhaline||30-40 PSU|
|Tidal Range||High Intertidal||None|
|Tidal Range||Mid Intertidal||None|
Tolerances and Life History Parameters
|Broad Temperature Range||None||Warm temperate|
|Broad Salinity Range||None||Oligohaline-Euhaline|
General ImpactsEcological impacts of Assiminea parasitologica have not yet been observed in Oregon. Potential concerns are the possibility of competition with native marsh fauna and the possible introduction of parasites that could affect native wildlife.
Regional Distribution Map
|Bioregion||Region Name||Year||Invasion Status||Population Status|
|NEP-IV||Puget Sound to Northern California||2007||Def||Estab|
ReferencesAgatsuma, Takeshi; Habe, Shigehisa (1986) Genetic variability and differentiation of natural populations in three Japanese lung flukes, Paragonimus ohirai, Paragonimus iloktsuenensis and Paragonimus sadoensis (Digenea:Troglotrematidae), Journal of Parasitology 72(3): 417-433
2013 <i>Assiminea parasitologica</i> - Asian marsh snail. http://www.clr.pdx.edu/abrpi/naso/Assiminea.php
Fowler, Bruce H. (1980) Reproductive biology of Assiminea californica (Tryon , 1865), The Veliger 23(9): 2
Fretter, Vera; Graham, Alastair (1962) British prosobranch molluscs: their functional anatomy and ecology, In: (Eds.) . , London. Pp. <missing location>
Kuroda, Miki ; Wada, Keiji; Kamada, Mahito; et al. (2003) [Distribution patterns of assimineid species (Gastropoda: Rissooidea) in the salt marshes of the Yoshino River, Tokushima Prefecture, Japan], Yuriyagai 9(1): 21-31
Kuroda, Tokube (1958) On the more species of Assiminea from Japan, Venus 33: 16-22
Laferriere, Alix M.; Harris, Heidi; Schaefer, John (2010) <missing title>, South Slough National Estuarine Research Reserve and Confederated Tribes, Coos Bay OR. Pp. 1-163
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>
2013 <i>Spartina alterniflora</i> (smooth cordgrass) in the Coos Estuary. http://www.oregon.gov/dsl/SSNERR/docs/invasiveSpecies.pdf
2003-2015 Nonindigenous Aquatic Species Database. Gainesville, FL. http://nas.er.usgs.gov
Wass, Melvin L. (1972) A Checklist of the Biota of Lower Chesapeake Bay, None <missing volume>: <missing location>