Montana Field Guide

The Chinese Mysterysnail is a large (2-3 inches, 65mm tall) introduced snail in the genus Cipangopaludina which can be identified by their relatively large globose shells and concentrically marked opercula (Burch 1980). Cipangopaludina chinensis has a width to height ratio of 0.74–0.82, the shell has 6.0–7.0 whorls, and the inner coloration is white to pale blue (Clarke 1981, Jokinen 1992). This species has a small and round umbilicus and the spire is produced at an angle of 65–80º (Jokinen 1992). Cipangopaludina chinensis exhibits light coloration as a juvenile and olive green, greenish brown, brown or reddish brown pigmentation as an adult (Clarke 1981, Jokinen 1992). In juveniles, the last shell whorl displays a distinct carina, and the shell contains grooves with 20 striae/mm between each groove (Clarke 1981, Smith 2000).

The large size and width of the adult shell makes it unlikely to be confused with any native snails in Montana. Cipangopaludina chinensis exhibits light coloration as a juvenile and olive green, greenish brown, brown or reddish brown pigmentation as an adult (Clarke 1981, Jokinen 1992). In juveniles, the last shell whorl displays a distinct carina, and the shell contains grooves with 20 striae/mm between each groove (Clarke 1981, Smith 2000).

Prefers slow-moving freshwater rivers, streams, and lakes with soft, muddy or silty bottoms (Kipp et al 2017).

Cipangopaludina chinensis feeds on organic and inorganic bottom material as well as benthic and epiphytic algae, mostly by scraping, but diatoms are probably the most nutritious food it ingests at pond sites in eastern North America (Jokinen 1982).

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). This species has not caused serious 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).

This species is ovoviviparous (Jokinen 1992). Females live up to 5 years, while males live up to 3-4 years (Jokinen 1982, Jokinen 1992). Female fecundity is usually greater than 169 young in a life time, and may reach up to 102 for any given brood (Jokinen 1982). 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).

The easiest way to prevent introduction of the mysterysnail in Montana is to remove all vegetation or standing water from boats before launching into a body of water.

Contact information for Aquatic Invasive Species personnel:
Montana Fish, Wildlife, and Parks Aquatic Invasive Species staff
Montana Department of Natural Resources and Conservation's Aquatic Invasive Species Grant Program
Montana Invasive Species Council (MISC)
Upper Columbia Conservation Commission (UC3)

Because the mysterysnail prefers slow-moving rivers, streams, and lakes with soft, muddy or silty bottoms, this species would not survive introduction into most of Montana's cold-water trout rivers and would likely only become established in ponds or lakes.