Texas Invasive Species InstituteCipangopaludina chinensis malleata
Chinese Mystery Snail
Synonym: Bellamya chinensis, Viviparus chinensis, Viviparous stelmaphora, Paludina malleata
Class: Gastropoda
Order: Architaenioglossa
Family: Viviparidae
Photographer: Oregon Department of Fish and Wildlife
Source: http://www.dfw.state.or.us/conservationstrategy/
Description
These snails are distinguished by their large size, reaching lengths of 1.5 inches from the tip of the whorl to the lip of the shell. The shell has 6-7 whorls and is an uniform olive green to greenish-brown or reddish-brown without banding on the outside and white to pale blue on the inside. The outer lip is round to oval and black.
Ecological Threat: The Chinese mystery snail competes with native snails for food and habitat; while also carrying parasites that can be transmitted to humans, like the intestinal fluke Echinostoma cinetorchis. This species also clogs screens water-intake pipes, making them an economical nuisance in addition to posing an ecological threat.
Biology: These snails are live-bearing meaning they do not lay eggs, instead they release living juveniles. In the eastern United States, embryos develop inside the female between May and August, and the young are born in shallow water from June through October. Each female may produce up to 100 juveniles in each brood. Females live up to five years and tend to have their largest broods in their later years. Males live an average of three years.
History: The earliest record of this snail dates back to 1982 in San Francisco, where they were imported for the live-food market. By 1911, a free-living population was thriving in San Francisco Bay. The Chinese mystery snail may have been accidentally introduced into Massachusetts in the early 1900s when goldfish were released as a biocontrol for mosquitoes. A population was established in Boston by 1915, again perhaps as a by-product of the local Asian food market. Snails entered Lake Ontario from the Niagara River between 1931 and 1942. They were then reported in Florida in 1950 and were established in Texas and Lake Erie, Michigan by 1965. Snail introductions initially seem to have been intentional releases either to develop local food supply of from the freshwater aquarium trade. It only takes one pregnant female to start a new population.
U.S. Habitat: These freshwater snails prefer quiet waters with soft substrates of silt, sand or mud. They can be found in lakes, ditches, rice paddies and slow-moving streams of water with depths up to 15 feet. They can tolerate pollution and may thrive on stagnant water, but they cannot survive very low oxygen levels and experience major die-offs under a combination of warm water and algal blows that reduce oxygen content.
Distribution
Native Origin: Southeast Asia
U.S. Present: AZ, CA, CO, CT, DC, KA, FL, IA, ID, IL, IN, MA, ME, MN, MO, NC, NE, NH, NJ, NY, OR, PA, RI, TX, UT, VA, VT, WA and WI.
Current Distribution as mapped by USGS.
Management
Prevention of new populations is the best control measure available. Eradication of existing populations is likely impossible. People should refrain from dumping bait and aquarium contents and should sanitize fishing and boating equipment before entering another body of water. Live animals of any sort should never be released into the wild.
Text References
Keeler, S. P., & Huffman, J. E. 2009. Echinostomes in the second intermediate host. In The Biology of Echinostomes (pp. 61-87). Springer New York.
Woodward, Susan L., and Joyce Ann. Quinn. 2011. Chinese Mystery Snail. Encyclopedia of Invasive Species: From Africanized Honey Bees to Zebra Mussels. Santa Barbara, CA: Greenwood. 58-60. Print.
Internet Sources
http://mdc.mo.gov/discover-nature/field-guide/chinese-mystery-snail
http://www.dnr.state.md.us/fisheries/regulations/pdfs/082310/chinesemysterysnailfactsheet.pdf
http://msue.anr.msu.edu/news/chinese_mystery_snail_recorded_in_michigan_lakes
