Chinese Pond Mussel
Photo credit: Ivan Kwan, https://flic.kr/p/MgyCR6
Report this Species!
If you believe you have found this species anywhere in Pennsylvania, please report your findings to iMapInvasives by submitting an observation record.
Species at a Glance
The Chinese pond mussel, also called the Eastern Asiatic clam, or swan-mussel, is a large, invasive, freshwater mussel that has rapidly spread to colonize Europe, Central America, the Indonesian Islands, and most recently, North America. Its life cycle involves a larval parasitic stage on freshwater fish, which helps contribute to its spread.
The large, wide shell reaches a maximum size of 30 cm (12 in). It has a deeply rounded ventral margin and the surface is irregularly rippled. The thin coating on the outside of the shell (periostracum) is brown, showing distinct shell rays that run perpendicular to growth lines. The nacre (inner shell surface) has a wide, pink band along the outer edge.
The native alewife floater (Anodonta implicata) is often confused with the Chinese pond mussel; however, in the alewife floater the periostracum color is variable, shell rays often are not visible in older individuals, and the nacre doesn’t have a pink band. In addition, alewife floaters only reach a maximum shell size of 18 cm (7 in). Identification of these mussels is difficult and often requires expert verification.
A habitat generalist, the Chinese pond mussel is able to tolerate environmental conditions considered unsuitable for native mussels, such as degraded and polluted habitats, heavily modified and artificial habitats, low oxygen conditions, and areas with high siltation rates. It prefers silt and clay substrates and turbid conditions with relatively high water temperatures in either standing or slow-flowing water.
The life cycle of the Chinese pond mussel includes a parasitic larval stage, where it lives for a short time attached to the fins or gills of freshwater fish species. Natural movement of the host fish, or the export of this mussel between regions for aquaculture and the live food trade has allowed it to spread to new locations and establish. It is prolific and begins reproducing within its first year of life.
Native to Eastern Asia, primarily from the Amur and Yangtze rivers, the Chinese pond mussel’s first and only documented occurrence in the United States has been in the ponds of a former fish farm in Franklin Township, New Jersey. It is considered locally established in these ponds, and was most likely introduced in the larval stage attached to the gills of imported Asian carp.
Note: Distribution data for this species may have changed since the publication of the Mid-Atlantic Field Guide to Aquatic Invasive Species (2016), the source of information for this description.
While its impact in the United States is currently unknown, the Chinese pond mussel could negatively impact native mussel populations as it outcompetes them for host fish during the larval stage. In addition, it may have a negative impact on macroinvertebrates communities and the overall structure of aquatic ecosystems.
Information for this species profile comes from the Mid-Atlantic Field Guide to Aquatic Invasive Species (2016).