Chesapeake Bay Introduced Species Database

Corbicula fluminea

Common name(s):
Asian Freshwater Clam
The Asian Freshwater Clam Corbicula fluminea is native to Asia, Indonesia, Philippines and probably Africa and Australia. It was introduced in western North America by Chinese immigrants as food before 1924. It is now found throughout the Pacific, Mississippi, Gulf, Great Lakes, and Atlantic drainages. Its rapid spread suggests that there were multiple introduction pathways and entry points including ballast water, canals, fisheries, and the aquarium fish-bait trades. It arrived in the Chesapeake Bay watershed in the 1970s and is now very common in most freshwater tributaries. The introduction of such a rapidly reproducing filter-feeder has increased water clarity and provided a new food resource, but may also have far-reaching effects on food webs, nutrient and organic material transport to lower parts of the Bay, and on migratory birds and fish. In areas with high population densities they compete for food and space with native freshwater mussels.
Image courtesy of Image courtesy of United States Geological Survey, via Wikimedia Commons public domain license. .

Chesapeake Bay Status:

First Record
Regular Resident

Source Region
Native Region
North America East Asia

Vector(s) of Introduction
Shipping(Barge,Ballast Water),Fisheries(Discarded Bait

History of Spread:

Corbicula fluminea (Asian Freshwater Clam) is native to Asia, including Indonesia and the Phillipines and probably also to Africa and Australia (Counts 1986; McMahon 1983). It is believed to have been introduced to western North America from Asia before 1924. The likeliest vector was the transport of clams as a potential food item by Chinese immigrants (Counts 1986; McMahon 1983). Its spread across North America was rapid, and perhaps indicates multiple introductions (McMahon 1983). North American records are summarized below:

Pacific Drainages - Corbicula fluminea was first collected on the Pacific Coast in the Nanaimo River, on Vancouver Island (British Columbia). In 1938, it was collected in the Columbia River at Knappton, WA (1938) and spread across southern WA eastward into the Snake River, and was widespread in the Columbia Basin by 1969-71. It was first collected in the Sacramento River CA in 1945 and soon spread through Delta region and fresher parts of estuary via canals. C. fluminea reached lower Colorado-Imperial Valley canals by 1953, Phoenix AZ by 1956, and by 1970's had fouled irrigation systems and reservoirs in most of lower Colorado Basin (Counts 1986).

Mississippi and Gulf Drainages - In the Eastern U.S., C. fluminea was first found in the Ohio River at Paducah KY in 1957, and rapidly spread through the Mississippi system, and adjacent rivers. To the east, it was dominant in the Tennesee River by 1969, and moved upstream to Cincinatti (1964). To the west, the Arkansas River; Black & White Rivers in AR were colonized by 1970, Lake Overholser OK by 1969, and Cherry Creek Reservoir, Arapahoe County CO by the 1990s (Nelson and McNabb 1994). Corbicula rapidly moved downstream, reaching LA in the Mississippi by 1962, the Calcasieu River, LA in 1961, and the Escambia River in Century; FL by 1960 (Counts 1986).

Great Lakes -St. Lawrence Drainages - Corbicula fluminea reached Lake Erie in 1978 and Lake Michigan by 1984 (Mills et al. 1993). In 2009, populations of C. fluminea were found in the freshwater portion of tue St. Lawrence River estuary, downstream of the ports of Bécancour and Trois-Rivières, in the thermal plume of a nuclear powerplant (Simard et al. 2012).

Atlantic Drainages- Corbicula fluminea spread rapidly up the Atlantic Coast in the 1970s. It was first collected in Altamaha River, GA (1971), and was abundant by 1974. Many collections to the north were nearly simultaneous: Pee Dee River, Savannah River, and Intracoastal Waterway (1972-76) SC; Catawba River NC (1971); James River, Richmond; VA (1971, probably before 1968); Potomac River, Washington D.C. (1976); Susquehanna Flats, Upper Chesapeake Bay (1975); Delaware River, NJ-PA (1971). Further north, this clam reached the Raritan River NJ in 1982, (Counts 1986); but has not yet not been yet reported from the Hudson River (Mills et al. 1997). However, in 1990, it colonized the tidal Connecticut River at East Haddam CT (Balcom 1994), and in 2001 was found in the Charles River near Boston (USGS Nonindigenous Species Program 2008).

Chesapeake history is summarized in more detail below:

James River - Corbicula fluminea was first recorded in 1971, in tidal fresh river near Richmond; size distribution indicated some shells at least 3 years old (1968). By 1972, it was found over River Miles 45-80 (measured from river mouth) , and the lower Appomattox River (Diaz 1974). By 1976, it comprised ~ 95% of all bivalves in tidal fresh river (Diaz 1994). Further downstream, at Hog Island Point, Surry VA; (0-5 ppt), it was less abundant, except during periods of low salinities (Jordan and Sutton 1984). By 1984, C. fluminea had spread through almost the entire non-tidal James River system, except for a few highly polluted areas (Clarke 1986).

Potomac River - The first record of C. fluminea was in 1977 in the tidal fresh river, but the size distribution suggests that it arrived before 1975. By 1978, it was present from center of Washington; River Mile 95 to River Mile 84.5 at mouth of Piscataway Creek, and by 1979, it was causing problems in Potomac Electric Company plants, Alexandria (Dresler and Cory 1980). C. fluminea reached a biomass peak in 1984 and declined to about one-eigth of its peak biomass by 1992, but still comprises a substantial biomass and is the dominant mollusc in the tidal fresh Potomac (Phelps 1994). A 'large population' occurs at Whites Ferry MD in nontidal river (~40 km upstream of Washington D.C., 1981) (Kennedy and Huekelem 1985) and the clam now occurs throughout the entire drainage (Taylor 1985).

Upper Bay and Drainages - The first record of C. fluminea was in 1977 at Susquehanna Flats, but it probably arrived by 1975, and is now present from Havre de Grace to Turkey Point (Counts 1986).

Susquehanna River - C. fluminea was first collected in the Susquehanna River at Conowingo Dam, in 1980, but was not found above the dam (Counts 1986; Nichols and Dommermuth 1981). By 1984, it was found above the dam, and by 2001 C. fluminea had colonized the North Branch of the Susquehanna in PA and was now present along at least 135 river miles (217 km) of the Susquehanna in PA (Mangan 2002).

Eastern Shore Drainages - C. fluminea was collected in the Wicomico River at Salisbury by 1981 (Counts 1986), and by 1985 was present in Nanticoke and Pocomoke River systems (Counts 1986; Kennedy and Huekelem 1985).

Delaware River - The first records of C. fluminea were in 1972; between Philadelphia PA and Trenton NJ; the largest individuals were ~2 years old (Fuller and Powell 1973).

Corbicula fluminea is now widespread in Europe (Den Hartog et al. 1992), and in South America, reaching Patagonia in the south (Cazzaniga 1997).

History References - Balcom 1994; Cazzaniga 1997; Clarke 1986; Counts 1986; Den Hartog et al. 1992; Diaz 1974; Diaz 1994; Dresler and Cory 1980; Fuller and Powell 1973; Jordan and Sutton 1984; Kennedy and Hukelem 1985; Mangan 2002; McMahon 1983; Mills et al. 1993; Mills et al. 1997; Nelson and McNabb 1994; Nichols and Donnermuth 1981; Phelps 1994; Taylor 1985

Invasion Comments:

Vector(s) of Introduction- Transport with barge, yacht, or dredge traffic through the Intracoastal Waterway is a plausible mechanism of transport for the rapid spread of C. fluminea up the East Coast to the Chespeake Bay (Counts 1986).

This data was last modified on Monday, January 27th, 2014.
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