Chinese mysterysnail, Oriental mysterysnail, Asian applesnail, Chinese applesnail, C. chinensis malleatus, Viviparus malleatus, V. chinensis malleatus, Bellamya chinensis, B. chinensis malleatus

The shell of C. chinensis grows allometrically (the height increasing faster than the width) and does so at a decreased rate in comparison with C. japonica, such that the adult shell is less elongate than that of its congener (Jokinen 1982). The radula (feeding structure) also may differ between C. japonica and C. chinensis, but there is so much variation even within one species that it is not a good diagnostic characteristic (Smith 2000). However, as a general guide, in one North American population, the radula of C. chinensis had seven small cusps on the marginal tooth and a large central cusp with four small cusps on either side (Jokinen 1982).

Mid-Atlantic Region: various ponds in Connecticut and Massachusetts; Potomac River, Maryland; Cocheco River, New Hampshire; Delaware River, New Jersey; Hudson River and Niagara River (1931), New York; the Catawba, Deep, Haw, Neuse, Roanoke, Yadkin, and lower Pee Dee rivers in North Carolina (B. Jones, pers. comm); Schuykill River and Susquehanna River, Pennsylvania; Annaquatucket River, Rhode Island; and a few isolated locations in Maine and Virginia.

Great Lakes Region: The first record of C. chinensis in the Great Lakes dates from some time between 1931 and 1942 from the Niagara River, which flows into Lake Ontario (Mills et al. 1993). Cipangopaludina chinensis occurs in Lake Erie, where it was introduced some time prior to 1968 (Wolfert and Hiltunen 1968). Cipangopaludina chinensis was found for the first time in Oneida Lake, which flows to Lake Ontario, in 1977-1978 (Clarke 1978, Jokinen 1992). Jokinen (1982) records occurrences of populations of C. chinensis in the drainages of Lake Erie, Lake Ontario and Lake Michigan, from the states of Michigan, Indiana, Ohio, Wisconsin, and New York.

It prefers lentic water bodies with silt, sand, and mud substrate in eastern North America, although it can survive in slower regions of streams as well (Jokinen 1982, Stanczykowska et al. 1971). This species has been found in waters in eastern North America with pH 6.5–8.4, calcium concentration of 5–97 ppm, magnesium concentration of 13–31 ppm, oxygen concentration of 7–11 ppm, depths of 0.2–3 m, conductivity of 63–400 μmhos/cm, and sodium concentration of 2–49 ppm (Jokinen 1982, Jokinen 1992, Stanczykowska et al. 1971).  It can tolerate conditions in stagnant waters near septic tanks (Perron and Probert 1973). Prefers slow-moving freshwater rivers, streams, and lakes with soft, muddy or silty bottoms.

This species is ovoviviparous (Jokinen 1992). Females live up to 5 years, while males live up to 3, occasionally 4 years (Jokinen 1982; Jokinen 1992). Female fecundity is very high, with brood pouches found to contain up to 133 embroys at once; larger females have larger broods, rather than larger embryos, increasing cluch sizes overall (Stephen et al. 2013). All females generally contain embryos from May to August and young are born from June through October in eastern North America in shallow water, then females begin migrating to deeper water for the winter in the fall (Jokinen 1982; Jokinen 1992; Stanczykowska et al. 1971). Females bear more young in their 4th and 5th years than in other years (Jokinen 1992).           

Johnson et al. (2009) showed that C. chinensis often co-occurs with the rusty crayfish (Faxonius rusticus), another species that has invaded the midwest; this co-occurrence is likey due to the resistance of C. chinensis to crayfish predation, which is attributed to their thick shell.

This species is a host to many parasites (see 'Impacts' section below; Chang et al 1968; Michelson 1970; Otsuru 1979; Chao et al. 1993; Chung and Jung, 1999; Sohn et al. 2013).

Summary of species impacts derived from literature review. Click on an icon to find out more...

Environmental	Socioeconomic	Beneficial

Realized:
To date, this species has exerted no recorded impacts in the Great Lakes and is considered relatively benign with respect to its potential to greatly change or influence ecosystems and native species (Mackie 1996).

Potential:
Like other mollusks, this introduced species may be a vector for the transmission of parasites and diseases. In the Boston area, C. chinensis is a regular host to the common native parasite Aspidogaster conchicola, which is a first time record in North America for a gastropod acting as host to this species (Michelson 1970).

Negative interactions with native gastropods are also possible. In a mesocosm experiment, the presence of C. chinensis was correlated with substantial decreases in abundance and/or biomass of native snails Physa gyrina, Lymnaea stagnalis, and Helisoma trivolvis, which the authors primarily attributed to competition for resources (Johnson et al. 2009). Where C. chinensis overlaps with the introduced rusty crayfish, Orconectes rusticus, impacts on native populations may be particularly severe. The relatively large and thick shell of C. chinensis reportedly enables this species to evade predation by O. rusticus more easily than native snails; thus, the risk of predation by O. rusticus remains relatively high while competition with C. chinensis add further pressure on native snail survival (Johnson et al. 2009). Johnson et al. (2009) also reported potential ecosystem impacts of C. chinensis introduction. At the community level, C. chinensis presence was correlated with a decline in periphyton levels, particularly on the sediment, and an increased N:P ratio in the water column. Further analysis suggested that higher levels of phosphorus uptake in C. chinensis tissue and reduced phosphorus levels in C. chinensis excrement relative to native snails is a plausible explanation for the latter observation, which suggests that this species may provide a phosphorus sink in invaded ecosystems (Johnson et al. 2009).

In a survey of Wisconsin lakes, Solomon et al. (2009) found the abundance of native Lymnaea stagnalis to be negatively correlated with the abundance of C. chinensis, suggesting that C. chinensis may be an important driver of competition and native snail displacement on the community-scale. However, this observation did not occur with other native snail species or at larger scales, indicating that the impacts of C. chinensis on native species or on the ecosystem may be restricted to local levels (Solomon et al. 2009).

Current research on the socio-economic impact of Cipangopaludina chinensis in the Great Lakes is inadequate to support proper assessment.

Potential:
As a grazer, the Chinese mystery snail may be attracted to algae coating the screens of water intake pipes, resulting in dense aggregations sufficient to clog affected pipes. Cipangopaludina chinensis is also a known host of parasites in its native range, at least one of which (Echinostoma cinetorchis, an intestinal trematode that causes echinostomiasis) is capable of infecting humans through ingestion of uncooked snails (Chung and Jung 1999, Graczyk and Fried 1998). However, no related cases of infection are currently known from the Great Lakes region.

There is little or no evidence to support that Cipangopaludina chinensis has significant beneficial effects in the Great Lakes.

Potential:
Mystery snails (Cipangopaludina spp.) have been popular aquarium species in the U.S., and their role in the aquarium/ornamental market is often invoked as the primary explanation of these species’ widespread dispersal (Cordiero 2002, Havel 2011, Karatayev et al. 2009, Mackie 2000, Mills et al. 1993). Cipangopaludina spp. has also had a presence in live food markets, particularly in Asian markets of the Western U.S. (Mackie 2000).

Note: Check federal, state/provincial, and local regulations for the most up-to-date information.

Control
Specific control methods for the Chinese mysterysnail have yet to be developed.

Biological
Manipulation of predator fishes and turtles that eat snails may be useful in the control of snail populations.  However, as a relatively large snail species, Cipangopaludina chinensis may escape predation by smaller fishes.

Physical
Preliminary research demonstrates that Cipangopaludina chinensis will not migrate upstream against a small current (Rivera 2008).  Authors suggest that acceleration of current may be an important management tool for preventing upstream spread.

Dessication (drying) is not an effective control method for Cipangopaludina chinensis.  Field experiments under mesic conditions indicated that this snail can survive exposure to air for at least 4 weeks (Havel 2011).

Chemical
There are copper compounds that are sold as snailicides but they are usually not selective in the snails they kill. With Chinese mysterysnails possessing the ability to “close up”, more damage would probably occur to native snails in the treatment area than to the target pest.

Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.

Taxonomy of the introduced populations of mysterysnails from Asia is confusing and there are many scientific names in use. There has also been debate regarding whether or not C. chinensis and C. japonica in North America are synonymous and simply different phenotypes of the same species. This database considers the two as separate species.  Smith (2000) argues that Cipangopaludina is a subgenus of Bellamya; however, because most North American literature does not use the genus Bellamya to refer to these introduced snails, the mysterysnails discussed here are referred to by the name Cipangopaludina. David and Cote (2019) did a genetic and morphological analysis on North American populations of both C. japonica and C. chinensis, finding them genetically distinct, morphologically indistinguishable, and co-occuring in multiple lakes of New York; the authors go on to discuss literature which also supports the idea that these two species have no shell characters that can be used to distinguish them morphologically.

Literature cited in this database regarding the Chinese mysterysnail may employ the following names: C. chinensis, C. chinensis malleatus, C. chinensis malleata, Viviparus malleatus, V. chinensis malleatus, B. chinensis and B. chinensis malleatus.